Abstract:
A method of arranging microspheres with liquid, a microsphere arranging device, and a semiconductor device are provided. The method comprising the steps of placing the semiconductor device with a large number of pads with holes, on a loading table with a variable tilt angle, and pouring microspheres together with conductive liquid held in a holding container onto the semiconductor device. The microspheres are storably placed in the holes on the pads of the semiconductor device. The non-stored microspheres and conductive liquid are accumulated in a receiving tank, and the conductive liquid including the accumulated microspheres are transferred to the holding container by a pump.

Description:
TECHNICAL FIELD 
   This invention relates to the arrangement of a microsphere such as a solder bump in a bump electrode forming process for BGA (ball grid array), CSP (chip size package) and flip-chip bonding etc., and relates particularly to a method of arranging microspheres with liquid, a microsphere arranging apparatus and a semiconductor device. 
   BACKGROUND ART 
   Japanese patent application laid-open No. 5-129374 discloses a method of making an electrode bump such that a microsphere is mounted on a bump forming member. After mounting the microsphere, the microsphere is fused. In this method, microspheres are adsorbed into holes that are provided in the same arrangement as that of the bump forming member, and then they are transferred onto the semiconductor chip or circuit board. Examples of bump forming members are semiconductor chips (semiconductor devices) and circuit boards and solder balls are examples of a microspheres. 
   An adsorption head is provided that has adsorption holes for microspheres in the same arrangement as that of the bump forming member. The adsorption head is moved to the bump forming member while holding the microspheres in the adsorption holes. Then, by releasing the microspheres, the microspheres are transferred to the bump forming member. 
   In this case, it is necessary to adsorb the microspheres onto the adsorption head in the correct proportion. However, since the microspheres are laid at random, it is difficult to adsorb them at predetermined positions when a vacuum is used to adsorb the microspheres. Therefore, a microsphere arrangement pallet is prepared such that microspheres are disposed in advance in the same arrangement as that of electrode bumps. By vacuuming the microspheres on the pallet, they can be adsorbed in correct proportion to the adsorption head. 
   However, it is difficult to stably arrange microspheres on the microsphere arrangement pallet in atmosphere. Due to static electricity or moisture, the microspheres may be adhered to each other or be adsorbed upon the surface of arrangement pallet. 
   Japanese patent application laid-open No. 11-8272 discloses a method that an arrangement pallet is soaked in conductive liquid and then microspheres are dropped on the arrangement pallet, secured in respective arrangement holes, thereby removing the influence of static electricity or moisture. 
   In the above in-solution arrangement method, where micro-metal balls (microspheres) are arranged in conductive liquid, a stable arrangement operation can be conducted because of removing the influence of static electricity or moisture. However, since it uses ethanol, which is highly volatile, it is necessary to supplement evaporated portion so as to stabilize the operation. Thus, a large amount of ethanol is needed. Further, in transferring the arrangement pallet to the next step, it is difficult to remove the pallet from the conductive liquid. Thus, it is difficult to automate the taking-out step. 
   Japanese patent application laid-open No. 2001-210942 discloses a method where another closed vessel is prepared, other than a closed vessel that used when the arrangement operation is conducted, while soaking the arrangement pallet. The vessels are then connected through a flexible tube. The conductive liquid and micro-metal balls are transferred between the vessels using the gravity difference of the vessels. 
   In this method, the evaporation of conductive liquid can be prevented by using the closed vessel, and the usability of employed material can be improved by using repeatedly the conductive liquid and micro-metal balls. Furthermore, the operation can be facilitated such that, after completing the arrangement operation on the arrangement pallet, the conductive liquid and micro-metal balls in the arrangement pallet soaking vessel are evacuated while being transferred to the other vessel, and then the arrangement pallet is taken out from the one closed vessel. 
   Subsequently, the microspheres are secured in the arrangement holes and then adsorbed by the adsorption head of a vacuum apparatus. The adsorption head has a plane with air holes provided therein corresponding to the arrangement holes. The adsorption is conducted such that the adsorption head is in contact with the arrangement-holes forming surface of arrangement pallet, and then the microspheres are adsorbed to the air holes under vacuum. After adsorption, the microspheres on the adsorption head are aligned with the pad position of semiconductor wafer, and then by cutting off the vacuum the microspheres are dropped on the pads to mount them there. 
   However, in the conventional method of mounting the microspheres on the bump forming member of semiconductor device by using the arrangement pallet, there are some problems described below. 
   Since the process needs to be conducted such that the microspheres are accommodated in the holes (arrangement holes) in the arrangement pallet and then transferred onto the pads of semiconductor device, the number of steps in the bump electrode forming process must be increased. The manufacturing cost will also be increased. Further, the entire composition of bump electrode forming process is quite complicated. 
   Further, in recovering the conductive liquid and excess microspheres to reuse them, the microsphere may be deformed, crushed or defaced due to hitting the corner of vessel or being trapped in the gaps of vessel. In this case, the microsphere may not be accommodated in the arrangement hole or may not be adsorbed by the adsorption head even when accommodated. Thus, the microsphere cannot be transferred to the semiconductor device. Furthermore, although the conductive liquid and microspheres can be recovered by tilting or reversing the vessel, a small amount of them may be left in the vessel. Thus, they are wasted to some degree. 
   Further, in adsorbing the microsphere into the adsorption head, the surface of adsorption head needs to be in close contact with the arrangement holes forming surface of the arrangement pallet. Therefore, high processing accuracy is needed to flatten both surfaces. Further, if the step of adsorbing the microsphere to the adsorption head is conducted in atmosphere, the neighboring microspheres attract each other, thereby failing to be adsorbed. As a result, the manufacturing cost in the bump electrode forming process is increased. 
   Still further, in order to enhance the operating efficiency, a process of accommodating microspheres in another arrangement pallet needs to be conducted during the adsorption. Therefore, multiple arrangement pallets are needed and the operating cost is increased. 
   The invention is devised in view of the above problems, and it is intended to provide a method of arranging a microsphere by means of liquid, microsphere arranging apparatus and semiconductor device such that the manufacturing cost in the bump electrode forming process can be reduced, the entire composition of the process can be simplified, and the conductive liquid and microspheres can be recycled without being wasted. 
   SUMMARY OF INVENTION 
   In order to solve the above problems, according to the invention, a method of arranging microspheres with liquid comprises the steps of: 
   providing a semiconductor device that includes a semiconductor wafer with a predetermined semiconductor element and an interconnection and with a number of pads connected the interconnection and attached on a surface of the semiconductor wafer, and a resist formed on the semiconductor wafer and having a penetrating hole formed at the respective pad positions to mount the microsphere; and 
   pouring the microsphere into the hole together with conductive liquid to mount the microsphere on the pad. 
   The process of pouring the microsphere into the hole of the semiconductor device together with conductive liquid may be conducted in the air. 
   The process of pouring the microsphere into the hole of the semiconductor device together with conductive liquid may be conducted in the liquid. 
   The semiconductor device may be kept horizontal when pouring the microsphere into the hole of the semiconductor device together with conductive liquid. 
   The semiconductor device may be kept inclined when pouring the microsphere into the hole of the semiconductor device together with conductive liquid. 
   The microsphere may be transported together with the conductive liquid. 
   Further, according to the invention, a method of arranging microspheres with liquid comprises the steps of: 
   providing a semiconductor device that includes a semiconductor wafer with a predetermined semiconductor element and an interconnection and with a number of pads connected the interconnection and attached on a surface of the semiconductor wafer, and a mask with a penetrating hole formed at the respective pad positions to mount the microsphere, the mask being held on the semiconductor device to allow the hole to be disposed on the pad; and 
   pouring the microsphere into the hole together with conductive liquid to mount the microsphere on the pad. 
   The process of pouring the microsphere into the hole of the mask together with conductive liquid may be conducted in the air. 
   The process of pouring the microsphere into the hole of the mask together with conductive liquid may be conducted in the liquid. 
   The semiconductor device may be kept horizontal when pouring the microsphere into the hole of the mask together with conductive liquid. 
   The semiconductor device may be kept inclined when pouring the microsphere into the hole of the mask together with conductive liquid. 
   The microsphere may be transported together with the conductive liquid. 
   Further, according to the invention, a microsphere arranging apparatus comprises: 
   a mounting means for mounting a semiconductor device that includes a semiconductor wafer with a predetermined semiconductor element and an interconnection and with a number of pads connected the interconnection and attached on a surface of the semiconductor wafer, and a resist formed on the semiconductor wafer and having a penetrating hole formed at the respective pad positions to mount the microsphere; 
   a storing means for storing conductive liquid containing a number of microspheres and for supplying the microsphere together with the stored conductive liquid to the semiconductor device mounted on the mounting means; and 
   a retaining means for retaining the conductive liquid containing the microsphere supplied from the storing means to the semiconductor device. 
   Further, according to the invention, a microsphere arranging apparatus comprises: 
   a mounting means for mounting a semiconductor device that includes a semiconductor wafer with a predetermined semiconductor element and an interconnection and with a number of pads connected the interconnection and attached on a surface of the semiconductor wafer, and a resist formed on the semiconductor wafer and having a penetrating hole formed at the respective pad positions to mount the microsphere; 
   a storing means for storing conductive liquid containing a number of microspheres and for supplying the microsphere together with the stored conductive liquid to the semiconductor device mounted on the mounting means; 
   a retaining means for retaining the conductive liquid containing the microsphere supplied from the storing means to the semiconductor device; 
   a tube that connects between the storing means and the retaining means; and 
   a pump means that is built in the tube to transport the conductive liquid containing the microsphere being retained in the retaining means to the storing means. 
   Further, according to the invention, a microsphere arranging apparatus comprises: 
   a mounting means for mounting a semiconductor device that includes a semiconductor wafer with a predetermined semiconductor element and an interconnection and with a number of pads connected the interconnection and attached on a surface of the semiconductor wafer, and for holding a mask with a penetrating hole formed at the respective pad positions to mount the microsphere so as to allow the hole to be disposed on the pad; 
   a storing means for storing conductive liquid containing a number of microspheres and for supplying the microsphere together with the stored conductive liquid through the mask to the semiconductor device mounted on the mounting means; and 
   a retaining means for retaining the conductive liquid containing the microsphere supplied from the storing means to the semiconductor device. 
   Further, according to the invention, a microsphere arranging apparatus comprises: 
   a mounting means for mounting a semiconductor device that includes a semiconductor wafer with a predetermined semiconductor element and an interconnection and with a number of pads connected the interconnection and attached on a surface of the semiconductor wafer, and for holding a mask with a penetrating hole formed at the respective pad positions to mount the microsphere so as to allow the hole to be disposed on the pad; 
   a storing means for storing conductive liquid containing a number of microspheres and for supplying the microsphere together with the stored conductive liquid through the mask to the semiconductor device mounted on the mounting means; 
   a retaining means for retaining the conductive liquid containing the microsphere supplied from the storing means to the semiconductor device; 
   a tube that connects between the storing means and the retaining means; and 
   a pump means that is built in the tube to transport the conductive liquid containing the microsphere being retained in the retaining means to the storing means. 
   The pump means may comprise a base, a rotating means to rotate, and a plurality of rollers that are rotatably attached to the circumference of the rotating means; the tube is a flexible tube disposed between the roller and the base; and a clearance between the roller and the tube disposed is provided so as to have a gap that allows the microsphere contained in the conductive liquid to pass through inside the tube while having its original shape when the tube is pressed by the rotation of the roller. 
   The storing means may have a first ejection tube that ejects, in an arbitrary direction, the microsphere together with the stored conductive liquid. 
   The storing means may have a second ejection tube that ejects, in an arbitrary direction, the microsphere together with the stored conductive liquid. 
   A moving means may be provided that allows the mounting means to move into the retaining means. 
   An oscillating means may be provided that applies oscillation to the mounting means. 
   The oscillating means may have a mechanism that applies horizontal oscillation to the semiconductor device. 
   The oscillating means may have a mechanism that applies unidirectional shock to the semiconductor device. 
   Further, according to the invention, a microsphere arranging apparatus comprises: 
   a mounting means for mounting a semiconductor device that includes a semiconductor wafer with a predetermined semiconductor element and an interconnection and with a number of pads connected the interconnection and attached on a surface of the semiconductor wafer, and a resist formed on the semiconductor wafer and having a penetrating hole formed at the respective pad positions to mount the microsphere; 
   a storing means for storing conductive liquid containing a number of microspheres and for supplying the microsphere together with the stored conductive liquid to the semiconductor device mounted on the mounting means; 
   a retaining means for retaining the conductive liquid containing the microsphere supplied from the storing means to the semiconductor device; 
   a tube that connects between the storing means and the retaining means; and 
   a vertical movement means that allows the storing means to move to a position above or below the retaining means. 
   Further, according to the invention, a microsphere arranging apparatus comprises: 
   a mounting means for mounting a semiconductor device that includes a semiconductor wafer with a predetermined semiconductor element and an interconnection and with a number of pads connected the interconnection and attached on a surface of the semiconductor wafer, and for holding a mask with a penetrating hole formed at the respective pad positions to mount the microsphere so as to allow the hole to be disposed on the pad; 
   a storing means for storing conductive liquid containing a number of microspheres and for supplying the microsphere together with the stored conductive liquid through the mask to the semiconductor device mounted on the mounting means; 
   a retaining means for retaining the conductive liquid containing the microsphere supplied from the storing means to the semiconductor device; 
   a tube that connects between the storing means and the retaining means; and 
   a vertical movement means that allows the storing means to move to a position above or below the retaining means. 
   A moving means may be provided that allows the mounting means to move into the retaining means. 
   An oscillating means may be provided that applies oscillation to the mounting means. 
   The oscillating means may have a mechanism that applies horizontal oscillation to the semiconductor device. 
   The oscillating means may have a mechanism that applies unidirectional shock to the semiconductor device. 
   The storing means may have a first ejection tube that ejects, in an arbitrary direction, the microsphere together with the stored conductive liquid. 
   The storing means may have a second ejection tube that ejects, in an arbitrary direction, the microsphere together with the stored conductive liquid. 
   An adjusting means may be provided that defines, between the semiconductor device and the mask, a gap that prevents the gas or conductive liquid from being retained in the hole when accommodating the microsphere into the mask hole together with the conductive liquid. 
   A relief groove may be provided, in connection with the hole, that releases the gas or conductive liquid so as not retain it in the hole when accommodating the microsphere into the mask hole together with the conductive liquid. 
   The groove may be, without penetrating through the mask, provided on at least one of the mask surface on the semiconductor wafer side or the mask surface on the opposite side to the semiconductor wafer side. 
   The mask may have a thickness that allows the microsphere to be retained in the hole and prevents the two or more microspheres from being entered therein. 
   A minimum diameter of the hole to be generated due to a manufacture accuracy of the mask hole may be made to be greater than a value obtained by adding a gap to a maximum diameter of the microsphere, and a maximum diameter of the hole may be made to prevent the two or more microspheres from being entered into the one hole and prevent the microsphere from being released from the pad. 
   The mask hole may be formed rectangular. 
   The mask hole may be formed tapered such that the semiconductor wafer side is wider than the resist surface side. 
   Further, according to the invention, a semiconductor device comprises: 
   a semiconductor wafer with a predetermined semiconductor element and an interconnection and with a number of pads connected the interconnection and attached on a surface of the semiconductor wafer; and 
   a resist formed on the semiconductor wafer and having a penetrating hole formed at the respective pad positions to mount the microsphere, 
   wherein the resist has a thickness that allows the microsphere to be retained in the hole and prevents the two or more microspheres from being entered therein. 
   Further, according to the invention, a semiconductor device comprises: 
   a semiconductor wafer with a predetermined semiconductor element and an interconnection and with a number of pads connected the interconnection and attached on a surface of the semiconductor wafer; and 
   a resist formed on the semiconductor wafer and having a penetrating hole formed at the respective pad positions to mount the microsphere, 
   wherein a minimum diameter of the hole to be generated due to a manufacture accuracy of the hole is made to be greater than a value obtained by adding a gap to a maximum diameter of the microsphere, and a maximum diameter of the hole is made to prevent the two or more microspheres from being entered into the one hole and prevent the microsphere from being released from the pad. 
   Further, according to the invention, a semiconductor device comprises: 
   a semiconductor wafer with a predetermined semiconductor element and an interconnection and with a number of pads connected the interconnection and attached on a surface of the semiconductor wafer; and 
   a resist formed on the semiconductor wafer and having a penetrating hole formed at the respective pad positions to mount the microsphere, 
   wherein the resist has a thickness that allows the microsphere to be retained in the hole and prevents the two or more microspheres from being entered therein, a minimum diameter of the hole to be generated due to a manufacture accuracy of the hole is made to be greater than a value obtained by adding a gap to a maximum diameter of the microsphere, and a maximum diameter of the hole is made to prevent the two or more microspheres from being entered into the one hole and prevent the microsphere from being released from the pad. 
   A relief groove may be provided, in connection with the hole, that releases the gas or conductive liquid so as not retain it in the hole when accommodating the microsphere into the mask hole together with the conductive liquid. 
   Further, according to the invention, a semiconductor device comprises: 
   a semiconductor wafer with a predetermined semiconductor element and an interconnection and with a number of pads connected the interconnection and attached on a surface of the semiconductor wafer; and 
   a resist formed on the semiconductor wafer and having a penetrating hole formed at the respective pad positions to mount the microsphere, 
   wherein the resist has a thickness that allows a plurality of the microspheres to be accommodated in the hole. 
   Further, according to the invention, a semiconductor device comprises: 
   a semiconductor wafer with a predetermined semiconductor element and an interconnection and with a number of pads connected the interconnection and attached on a surface of the semiconductor wafer; and 
   a resist formed on the semiconductor wafer and having a penetrating hole formed at the respective pad positions to mount the microsphere, 
   wherein the hole is formed tapered such that the semiconductor wafer side is wider than the resist surface side. 
   Further, according to the invention, a semiconductor device comprises: 
   a semiconductor wafer with a pad formed in a predetermined pattern on its surface; 
   a resist formed on the semiconductor wafer and having a hole formed in the predetermined pattern at a corresponding position to the pad; and 
   a microsphere accommodated in the hole, 
   wherein the hole is provided with a relief means to release a conductive liquid and a gas left in the hole outside the hole when the microsphere is supplied together with the conductive liquid. 
   The resist hole may be formed rectangular. 
   Further, according to the invention, a method of arranging microspheres with liquid comprises the steps of: 
   providing a semiconductor device that includes a semiconductor wafer with a predetermined semiconductor element and an interconnection and with a number of pads connected the interconnection and attached on a surface of the semiconductor wafer, and a resist formed on the semiconductor wafer and having a penetrating hole formed at the respective pad positions to mount the microsphere; and 
   pouring the microsphere into the hole together with conductive liquid while rotating the semiconductor device to mount the microsphere on the pad. 
   The semiconductor device may be kept inclined and the microsphere may be poured together with conductive liquid to the upper portion of the semiconductor wafer being kept inclined and rotated. 
   The semiconductor device may be kept horizontal and the microsphere may be poured together with conductive liquid to the center portion of the semiconductor wafer being kept horizontal and rotated. 
   The process of pouring the microsphere into the hole of the semiconductor device together with conductive liquid may be conducted in the air. 
   The process of pouring the microsphere into the hole of the semiconductor device together with conductive liquid may be conducted in the liquid. 
   The microsphere may be transported together with the conductive liquid. 
   Further, according to the invention, a method of arranging microspheres with liquid comprises the steps of: 
   providing a semiconductor device that includes a semiconductor wafer with a predetermined semiconductor element and an interconnection and with a number of pads connected the interconnection and attached on a surface of the semiconductor wafer, and a resist formed on the semiconductor wafer and having a penetrating hole formed at the respective pad positions to mount the microsphere; 
   disposing the semiconductor device to be inclined; and 
   pouring the microsphere into the hole together with conductive liquid while oscillating an ejection means for ejecting the microsphere together with the conductive liquid between one end to the other end of the semiconductor device over the inclined semiconductor device so as to mount the microsphere on the pad. 
   The process of pouring the microsphere into the hole of the semiconductor device together with conductive liquid may be conducted in the air. 
   The process of pouring the microsphere into the hole of the semiconductor device together with conductive liquid may be conducted in the liquid. 
   The microsphere may be transported together with the conductive liquid. 
   Further, according to the invention, a method of arranging microspheres with liquid comprises the steps of: 
   providing a semiconductor device that includes a semiconductor wafer with a predetermined semiconductor element and an interconnection and with a number of pads connected the interconnection and attached on a surface of the semiconductor wafer, and a mask with a penetrating hole formed at the respective pad positions to mount the microsphere, the mask being held on the semiconductor device to allow the hole to be disposed on the pad; and 
   pouring the microsphere into the hole together with conductive liquid while rotating the semiconductor device to mount the microsphere on the pad. 
   Further, according to the invention, a method of arranging microspheres with liquid comprises the steps of: 
   providing a semiconductor device that includes a semiconductor wafer with a predetermined semiconductor element and an interconnection and with a number of pads connected the interconnection and attached on a surface of the semiconductor wafer, and a mask with a penetrating hole formed at the respective pad positions to mount the microsphere, the mask being held on the semiconductor device to allow the hole to be disposed on the pad; 
   disposing the semiconductor device to be inclined; and 
   pouring the microsphere into the hole together with conductive liquid while oscillating an ejection means for ejecting the microsphere together with the conductive liquid between one end to the other end of the semiconductor device over the inclined semiconductor device so as to mount the microsphere on the pad. 
   Further, according to the invention, a microsphere arranging apparatus comprises: 
   a mounting-rotating means for mounting a semiconductor device and for rotating the semiconductor device mounted, the semiconductor device including a semiconductor wafer with a predetermined semiconductor element and an interconnection and with a number of pads connected the interconnection and attached on a surface of the semiconductor wafer, and a resist formed on the semiconductor wafer and having a penetrating hole formed at the respective pad positions to mount the microsphere; 
   a storing means for storing conductive liquid containing a number of microspheres and for supplying the microsphere together with the stored conductive liquid to the semiconductor device mounted on the mounting-rotating means; and 
   a retaining means for retaining the conductive liquid containing the microsphere supplied from the storing means to the semiconductor device. 
   The storing means may have a first ejection tube that ejects in an arbitrary direction the microsphere together with the stored conductive liquid, and the mounting-rotating means may have a first mount base that mounts the semiconductor device being kept inclined, the microsphere being poured together with the conductive liquid from the first ejection tube to the upper portion of the semiconductor device being kept inclined and rotated while being mounted on the first mount base. 
   The storing means may have a second ejection tube that ejects only the stored conductive liquid in an arbitrary, the microsphere being poured together with the conductive liquid from the second ejection tube to the upper portion of the semiconductor device being kept inclined and rotated while being mounted on the first mount base. 
   The storing means may have a first ejection tube that ejects in an arbitrary direction the microsphere together with the stored conductive liquid, and the mounting-rotating means may have a second mount base that mounts the semiconductor device being kept horizontal, the microsphere being poured together with the conductive liquid from the first ejection tube to the center portion of the semiconductor device being kept horizontal and rotated while being mounted on the second mount base. 
   The storing means may have a second ejection tube that ejects only the stored conductive liquid in an arbitrary, the microsphere being poured together with the conductive liquid from the second ejection tube to the center portion of the semiconductor device being kept horizontal and rotated while being mounted on the second mount base. 
   The mounting-rotating means may be disposed above or in the retaining means. 
   An oscillating means may be provided that applies oscillation to the mounting-rotating means. 
   A tube may be provided that connects between the storing means and the retaining means; and a pump means may be provided that is built in the tube to transport the conductive liquid containing the microsphere being retained in the retaining means to the storing means. 
   Further, according to the invention, a microsphere arranging apparatus comprises: 
   a mounting means for mounting a semiconductor device while disposing the semiconductor device to be inclined, the semiconductor device including a semiconductor wafer with a predetermined semiconductor element and an interconnection and with a number of pads connected the interconnection and attached on a surface of the semiconductor wafer, and a resist formed on the semiconductor wafer and having a penetrating hole formed at the respective pad positions to mount the microsphere; 
   a storing means for storing conductive liquid containing a number of microspheres; 
   a first ejection tube for ejecting the microsphere together with the conductive liquid; 
   an oscillating means for oscillating the first ejection tube between one end to the other end of the semiconductor device over the semiconductor device inclined; and 
   a retaining means for retaining the conductive liquid containing the microsphere ejected from the first ejection tube to the semiconductor device. 
   A second ejection tube may be provided that ejects only the conductive liquid in the storing means, and the oscillating means may oscillate the second ejection tube as well. 
   The mounting means may be disposed above or in the retaining means. 
   An oscillating means may be provided that applies oscillation to the mounting means. 
   A tube may be provided that connects between the storing means and the retaining means; and a pump means may be provided that is built in the tube to transport the conductive liquid containing the microsphere being retained in the retaining means to the storing means. 
   Further, according to the invention, a microsphere arranging apparatus comprises: 
   a mounting-rotating means for mounting a semiconductor device and for rotating the semiconductor device mounted, the semiconductor device including a semiconductor wafer with a predetermined semiconductor element and an interconnection and with a number of pads connected the interconnection and attached on a surface of the semiconductor wafer, and for holding a mask with a penetrating hole formed at the respective pad positions to mount the microsphere so as to allow the hole to be disposed on the pad; 
   a storing means for storing conductive liquid containing a number of microspheres and for supplying the microsphere together with the stored conductive liquid to the pad on the semiconductor device mounted on the mounting-rotating means; and 
   a retaining means for retaining the conductive liquid containing the microsphere supplied from the storing means to the pad. 
   Further, according to the invention, a microsphere arranging apparatus comprises: 
   a mounting means for mounting a semiconductor device while disposing the semiconductor device to be inclined, the semiconductor device including a semiconductor wafer with a predetermined semiconductor element and an interconnection and with a number of pads connected the interconnection and attached on a surface of the semiconductor wafer, and for holding a mask with a penetrating hole formed at the respective pad positions to mount the microsphere so as to allow the hole to be disposed on the pad; 
   a storing means for storing conductive liquid containing a number of microspheres; 
   a first ejection tube for ejecting the microsphere together with the conductive liquid; 
   an oscillating means for oscillating the first ejection tube between one end to the other end of the semiconductor device over the pad of the semiconductor device; and 
   a retaining means for retaining the conductive liquid containing the microsphere ejected from the first ejection tube to the pad. 
   Further, according to the invention, a microsphere arranging apparatus comprises: 
   a mounting-rotating means for mounting a semiconductor device and for rotating the semiconductor device mounted, the semiconductor device including a semiconductor wafer with a predetermined semiconductor element and an interconnection and with a number of pads connected the interconnection and attached on a surface of the semiconductor wafer, and for holding a mask with a penetrating hole formed at the respective pad positions to mount the microsphere so as to allow the hole to be disposed on the pad; 
   a storing means for storing conductive liquid containing a number of microspheres and for supplying the microsphere together with the stored conductive liquid to the pad on the semiconductor device mounted on the mounting-rotating means; 
   a retaining means for retaining the conductive liquid containing the microsphere supplied from the storing means to the pad; 
   a tube that connects between the storing means and the retaining means; and 
   a vertical movement means that allows the storing means to move to a position above or below the retaining means. 

   
     BRIEF DESCRIPTION OF DRAWINGS 
       FIG. 1  shows the composition of a microsphere arranging apparatus in a first preferred embodiment of the invention. 
       FIGS. 2(   a ) and ( b ) illustrate a relationship between a tip portion of ejection tube in the microsphere arranging apparatus and a semiconductor device mounted on a mount base. 
       FIGS. 3(   a ) and ( b ) show the composition of a pump of the microsphere arranging apparatus. 
       FIG. 4  is a cross sectional view showing the composition of a semiconductor device mounted on the mount base of microsphere arranging apparatus. 
       FIG. 5  is a plan view showing a gap required in accommodating a microsphere with a maximum diameter in a resist hole. 
       FIG. 6  illustrates a situation that a microsphere deviates from an underlying pad diameter because of a resist hole providing an excessively large gap. 
       FIGS. 7(   a ), ( b ) and ( c ) are plan views showing a relief groove formed in connection with the resist hole. 
       FIG. 8  shows the composition of a microsphere arranging apparatus in a second preferred embodiment of the invention. 
       FIG. 9  shows the composition of a microsphere arranging apparatus in a third preferred embodiment of the invention. 
       FIGS. 10(   a ) and ( b ) illustrate a situation that a semiconductor device is mounted on a rotary mounting unit of the microsphere arranging apparatus. 
       FIG. 11  illustrates a situation that a semiconductor device is mounted on a rotary mounting unit being soaked in conductive liquid in the microsphere arranging apparatus in the third embodiment of the invention. 
       FIG. 12  shows the composition of a microsphere arranging apparatus in a fourth preferred embodiment of the invention. 
       FIG. 13  illustrates a situation that a semiconductor device is mounted on a rotary mounting unit being soaked in conductive liquid in the microsphere arranging apparatus in the fourth embodiment of the invention. 
       FIG. 14  shows the composition of a microsphere arranging apparatus in a fifth preferred embodiment of the invention. 
       FIG. 15  illustrates the operation of the microsphere arranging apparatus in the fifth embodiment of the invention. 
       FIG. 16  shows the composition of a microsphere arranging apparatus in a sixth preferred embodiment of the invention. 
       FIG. 17  illustrates the positions of a transfer bath of the microsphere arranging apparatus and of a semiconductor device mounted on the mount base. 
       FIGS. 18(   a ) and  18 ( b ) are plan views showing a relief groove formed in connection with a resist hole. 
       FIGS. 19(   a ), ( b ) and ( c ) are plan views showing the shape of resist holes and a relief groove formed in connection with a resist hole. 
       FIG. 20  is a plan view showing a relief groove formed in connection with a resist hole. 
       FIG. 21  is a plan view showing a relief groove formed in connection with a resist hole. 
       FIG. 22  shows the composition of a microsphere arranging apparatus in an eighth preferred embodiment of the invention. 
       FIG. 23  is a cross sectional view showing a positional relationship among a semiconductor wafer mounted on a mount base of the microsphere arranging apparatus, a pad on the wafer, and a hole formed in a mask to mount a microsphere. 
       FIGS. 24(   a ), ( b ) and ( c ) are cross sectional views showing a relief groove formed in the mask. 
       FIG. 25  shows the composition of a microsphere arranging apparatus in a ninth preferred embodiment of the invention. 
       FIG. 26  is a vibrating means (piezoelectric element) attached to a mount base to mount a semiconductor device. 
   

   DETAILED DESCRIPTION OF THE INVENTION 
   The embodiments of the invention will be explained below with reference to the drawings. 
     FIG. 1  shows the composition of a microsphere arranging apparatus in the first preferred embodiment of the invention. 
   The microsphere arranging apparatus as shown in  FIG. 1  is, for example, applied to a bump electrode forming process of semiconductor device. Namely, the bump electrode forming process is completed such that, after forming a resist on a semiconductor wafer, exposure, development, transferring solder balls to holes on the semiconductor wafer, reflowing of solder balls and removing of resist is conducted. The microsphere arranging apparatus of the invention is applied to a step of transferring solder balls to holes on the semiconductor wafer. 
   The microsphere arranging apparatus in  FIG. 1  is provided with a transfer bath  1 , that is, a container containing an accommodating conductive liquid. A mount base  3  to mount a semiconductor device  2  as detailed later in  FIG. 4  is disposed nearly at the center thereof. 
   The mount base  3  is composed such that its height in the vertical direction can be changed by a mount base shifter  12 . Further, its angle can be freely varied horizontally or vertically by a supporting portion  4 . The mount base  3  is attached to the mount base shifter  12 . 
   The transfer bath  1  has a bottom face to which one opening of a flexible circulation pipe  5  is connected. The other opening of the circulation pipe  5  is connected to the side face of a storage container  6 . It is desirable that the bottom face of transfer bath  1  has a structure to facilitate the flowing of microspheres  47  as shown in  FIG. 4  and conductive liquid into the circulation pipe  5 . For example, as shown in  FIG. 1 , the bottom of transfer bath  1  is shaped like a funnel to facilitate the flowing of microspheres  47  and conductive liquid into the circulation pipe  5 . 
   The storage container  6  is connected through the circulation pipe  5  with the transfer bath  1 , and it is connected with a washing pipe  8  at its side face and with an ejection pipe  7  at its bottom. Further, the storage container  6  is structured such that the system except for the pipe-connected portion is closed to prevent the evaporation of volatile conductive liquid as much as possible. 
   It is desirable that the bottom face of storage container  6  has a structure to facilitate the flowing of microspheres  47  and conductive liquid into the ejection pipe  7  so as to prevent the deformation of microspheres  47 . For example, the ejection pipe is shaped like a funnel to facilitate the flowing of microspheres  47  and conductive liquid into the ejection pipe  7 . 
     FIG. 2(   a ), ( b ) illustrates the relationship between the tip portion of ejection pipe  7  and the semiconductor device  2 . 
   A flow plate  9  is disposed at the top end of the semiconductor device  2 , and conductive liquid containing a number of microspheres  47  falls from the tip of ejection pipe  7  to the flow plate  9 . 
   The conductive liquid is, for example, of ethanol. Other than ethanol, alcohols such as methanol, isopropyl alcohol, butanol, cyclohexanol, glycenol and ethyleneglycol are available. Further, it may be water etc. or a mixture of these. Further, it may contain a small amount of additive agents such as dispersing agents and surfactants. For example, the additives are disodium phosphate hydrate, sodium hexametaphosphate, sodium pyrophosphate, sodium linoleate, or cation activator. Liquids with high conductivity are preferable because they provide highly effective static protection. 
   The microspheres  47  have a diameter of, e.g., 100 μm or less, i.e., 0.1 mm or less. The thickness of conductive liquid flowing through the inclined surface of semiconductor device  2  is about 1 to 2 mm. As compared to the size of microspheres  47 , the thickness (depth) is ten to twenty times. Thus, it is equivalent to the case that microspheres  47  are arranged in a bath with conductive liquid, and the same effect of static protection etc. can be obtained thereby. The outlet of ejection pipe  7  is, as shown an arrow Y 1  in  FIG. 2(   a ), shifted from side to side by a pipe shift mechanism  10  so as to supply the conductive liquid onto the entire surface of semiconductor device  2 . 
   Further, the circulation pipe  5  is provided with a pump  11  that serves to send the conductive liquid and microspheres  47  accumulated in the transfer bath  1  to the storage container  6 . The pump  11  is, as shown in  FIG. 3(   a ), composed of: a roller rotating body  31  that its rotation shaft  32  is fixed to a motor (not shown) and that rotates together with the rotation shaft  32  according to the rotation of motor so as to send the conductive liquid and microspheres  47  from the transfer bath  1  to the storage container  6 ; a plurality of rollers  33  that are attached evenly and rotatably on the circumference of roller rotating body  31 ; and a circulation tube pressing base  34  that is disposed to sandwich the circulation pipe  5  between the roller  33  and the base  34 . 
   The distance between the roller  33  and the circulation tube pressing base  34  is set such that, as shown in  FIG. 3(   b ), therebetween and at part of circulation pipe  5  (tube with elasticity) pressed by the rotation of roller  33 , a gap Y 2  is provided that allows a microspheres  47  to pass through while having their original shape. 
   Next, the composition of semiconductor device  2  will be explained with reference to  FIG. 4 . 
     FIG. 4  is a cross sectional view showing the composition of a semiconductor device. 
   The semiconductor device  2  as shown in  FIG. 4  is composed of: a semiconductor wafer (hereinafter simply referred to as semiconductor wafer)  43  that predetermined semiconductor elements and interconnections are formed and a number of pads  42  connected to the predetermined interconnection are arranged on the surface; and a resist  45  is provided with holes  44  to mount one of the microspheres  47  at each of the pads  42 . 
   Provided that the thickness of resist  45  is h, the diameter (hereinafter referred to as microsphere diameter) of one of microspheres  47  used is d, and the accuracy of microsphere diameter d is ±α microns (μm), 
   microsphere diameter minimum diameter dmin=d−α, and 
   microsphere diameter maximum diameter dmax=d+α. 
   Further, it is preferable to satisfy the condition that the thickness h of resist  45  to accommodate the microspheres  47  in the hole  44  is: 
   ½dmax&lt;h≦dmin 
   Further, provided that the diameter (hereinafter referred to as resist hole diameter) of hole  44  in the resist  45  is D, a dispersion in processing of hole  44  in the resist  45  is ±β microns, and a clearance needed to accommodate microspheres  47  with the maximum diameter dmax is γ microns, the minimum resist hole diameter Dmin=D−β has to be equal to or greater than a value obtained by adding a clearance 2γ to the maximum microsphere diameter dmax. Accordingly, it is preferable to satisfy the conditions: 
   D+β=Dmax (maximum resist hole diameter) 
   D−β=Dmin (minimum resist hole diameter) 
   D−β=Dmin≧dmax+2γ 
   Dmin−dmax≧2γ 
   For example, if microspheres  47  with a diameter of 100 microns are used, the clearance 2γ is suitably 5 to 30 microns. However, according as [Dmin-dmax] to give 2γ increases, two of the microspheres  47  may be entered in one hole  44  and it becomes difficult to dispose just one therein. On the other hand, it should be unlikely that the microspheres  47  slip out of a pad with diameter L as shown in  FIG. 6 . Accordingly, in consideration of the thickness h of resist  45 , it is necessary to select the clearance: 
   2γ=Dmin−dmax 
   Furthermore, in accommodating one of the microspheres  47  into the resist hole  44  in the liquid, a gas such as air may prevent the microspheres  47  from entering thereinto since the resist hole  44  is very small. Therefore, it is necessary to provide a relief passage (hereinafter referred to as relief groove) for gas or liquid in connection with the resist hole  44 . 
   The relief groove can be formed, e.g., by etching the resist  45 . As shown in  FIG. 7(   a ), a relief groove  49   a  to connect holes  44  may be provided. Also, as shown in  FIG. 7(   b ), a relief groove  49   b  formed at both sides (or one side) of the hole  44  may be provided. 
   The relief grooves  49   a ,  49   b  need to have such a width l such that a gas or liquid can flow through without being retained since the gas or liquid is difficult to relieve or flow if the width l is too narrow. For example, the width may be 5 microns or more. 
   The accuracy of width l of relief groove is given such that the position of one of the microspheres  47  located therein does not get out of a minimum pad diameter Lmin=L−σ, where a dispersion in processing is β and a dispersion in processing of pad diameter L is σ. It is preferable that: Dmax−dmin+{dmin−√{square root over ( )}(dmin 2 −lmax 2 )}≦Lmin, and lmax&lt;√{square root over ( )}{dmin 2 −(Dmax−Lmin) 2 } 
   Furthermore, it should be considered that there is a deviation in position between the pad  42  and the hole  44 . Although  FIG. 5  shows the case that the centers are aligned with each other, their positions in most cases deviated from perfect alignment. 
   Next, the process of arranging microspheres  47  into the arrangement holes  44  of semiconductor device  2  will be explained, where the method of arranging microspheres  47  with liquid using the microsphere arranging apparatus abovementioned is applied. 
   In this embodiment, the method of arranging microspheres  47  onto the semiconductor device  2  is conducted such that the arrangement pallet is not used, the semiconductor device  2  is placed in the air while being mounted on the mount base  3 , and, in the air, the microspheres  47  are directly mounted on the pad  42  by mixing them with conductive liquid. 
   At first, the semiconductor device  2  with no microspheres  47  is mounted on the mount base  3  that is angle-adjusted to be horizontal. Then, by inclining the mount base  3  at a predetermined angle suitable for the arrangement of microspheres  47 , the semiconductor device  2  is located inside (at the in-air position of) the transfer bath  1 . At that time, the outlets of washing pipe  8  and ejection pipe  7  are retracted at a position that does not prevent the mounting of semiconductor device  2  onto the mount base  3 . 
   Then, the washing pipe  8  is moved such that the outlet of washing pipe  8  is located over the semiconductor device  2  mounted on the mount base  3 . At that time, since the pump  11  is stopped, the storage container  6  is vacant and therefore the conductive liquid does not flow out of the outlet of washing pipe  8  and ejection pipe  7 . 
   When the pump  11  starts operating at a low speed, the conductive liquid retained in the transfer bath  1  and the flexible circulation pipe  5  is supplied to the storage container  6 . Then, the conductive liquid is ejected through the washing pipe  8  and falls on the semiconductor device  2 . The conductive liquid fallen on the semiconductor device  2  is flown from the hole  44  through relief groove down to the transfer bath  1 . Thereby, gas in the hole  44  can be removed. When a certain time elapses, the outlet of washing pipe  8  is retracted. 
   Subsequently, when the pump  11  starts operating at a high speed, the microspheres  47  retained in the transfer bath  1  and the flexible circulation pipe  5  are, with conductive liquid, supplied to the storage container  6 . Specifically, the elastic circulation pipe  5  (tube) is sequentially pressed by rotating the roller  33 , and the conductive liquid including the microspheres  47  are sent forward while being choked through circulation pipe  5 . Further, suction is generated by the passing of roller  33 , and the conductive liquid is sequentially sucked and continuously supplied (transported). 
   When the outlet of ejection pipe  7  is shifted as shown by the arrow Y 1  in  FIG. 2(   a ), the microspheres  47  and conductive liquid are ejected through the ejection pipe  7  and uniformly falls on the semiconductor device  2 . A portion of microspheres  47 , which have fallen on the semiconductor device  2 , enter in the hole  44 ; and the other part of the microspheres  47  with conductive liquid, are dropped on the bottom of transfer bath  1 . If the conductive liquid is not accumulated in the transfer bath  1  and the semiconductor device  2  is in the air, the microspheres  47  ejected from the ejection pipe  7  together with the conductive liquid are accommodated in hole  44  and the rest of microspheres  47  are dropped in the transfer bath  1 . 
   Since the hole  44  of semiconductor device  2  is provided with the relief groove being connected, the conductive liquid, which has entered in the hole  44 , is flown down through the relief groove, and then dropped from the mount base  3  onto the bottom of transfer bath  1 . Therefore, once the microspheres  47  have entered in the hole  44 , they are not pushed out by the conductive liquid. 
   The microspheres  47  and the conductive liquid flown down in the transfer bath  1  are sent through the circulation pipe  5  connected to the bottom of transfer bath  1  to the storage container  6  by the operation of pump  11 . 
   After ejectioning for a certain period of time, the pump  11  is switched into low speed operation, and the microspheres  47  which have flown down to the bottom of the transfer bath are retained at part of circulation pipe  5  and at the bottom of transfer bath  1  and, only conductive liquid is transported to the storage container  6 . 
   The mount base  3  is inclined at such an angle that the microspheres  47  already accommodated in the hole  44  do not escape therefrom due to the pressure of liquid, and then the outlet of washing pipe  8  is shifted as shown by the arrows Y 1  in  FIG. 2(   a ). 
   This washing process corresponds to the shaking or oscillation of liquid in the in-liquid arrangement method that the semiconductor device  2  is placed. Thereby, excessive microspheres  47  being stacked in the hole  44  with one of the microspheres  47  already accommodated therein or being left on the surface of semiconductor device  2  can be removed, and the excessive microspheres  47  can be accommodated in another hole  44  where no microsphere is accommodated. 
   After washing for a certain period of time, the pump  11  stops operating, and thereby the microspheres  47  and the conductive liquid, flow down on the bottom of transfer bath  1 , and are retained at part of circulation pipe  5  connected to the bottom of the transfer bath  1  and at the bottom of transfer bath  1 , and the transportation of conductive liquid to the storage container  6  stops. As a result, the storage container  6  becomes vacant after the conductive liquid left therein completes the flowing down through the washing pipe  8  and the ejection pipe  7 . 
   At the end, the mount base  3  is angle-adjusted to be horizontal, and the semiconductor device  2  with microspheres  47  arranged thereon is taken out. 
   By repeating the above process, the arrangement of microspheres  47  can be stably conducted while using the microspheres  47  and the conductive liquid repeatedly. 
   As described above, the microsphere arranging apparatus and the method of arranging microspheres with liquid in the first embodiment is composed such that the semiconductor device  2  is provided that includes: the semiconductor wafer  43  with the predetermined semiconductor element and interconnection and with a number of pads  42  connected the interconnection and attached on the surface thereof; and the resist  45  formed on the semiconductor wafer  43  while having the penetrating holes  44  formed at the respective pads  42  position to mount the microspheres  47 , and the microspheres  47  are poured into the hole  44  while being transported thereto together with conductive liquid, thereby being mounted on the pad  42 . 
   Thus, without using the conventional arrangement pallet, the microspheres  47  can be directly mounted on the pad  42  by pouring the microspheres  47  into the resist hole  44  of semiconductor wafer  43  while transporting it together with the conductive liquid. Accordingly, the conventional processes of accommodating the microspheres in the arrangement pallet and then transferring them to the resist hole  44  of semiconductor device  2  are not needed. Therefore, the manufacturing cost can be reduced and the step of transferring the microspheres  47  to the hole  44  of semiconductor device  2  in the bump electrode forming process can be simplified. In the above embodiment, the microspheres  47  are solder balls. The solder ball may be a ball consisting of solder, a plastic core covered with solder, a gold ball or a copper ball with silver plating, or various conductive micro-balls. 
   Further, since the above semiconductor device  2  has the resist  45  with a thickness of greater than ½ the maximum diameter of one of the microspheres  47  and less than the minimum diameter, one of the microspheres  47  can be surely accommodated in the hole  44  and can be mounted on the pad  42 . 
   Further, the minimum diameter of hole  44  to be generated in the manufacture accuracy is made to be greater than a value obtained by adding the clearance to the maximum diameter of one of the microspheres  47 , and the maximum diameter of hole  44  is set such that more than one of the microspheres  47  cannot enter into one hole  44  and none of the microspheres  47  can escape from the pad diameter L. Because of this, one of the microspheres  47  can be surely mounted on the pad  42 . 
   Further, since the relief groove used to flow the gas or conductive liquid from the hole  44  is formed to connect with the hole  44 , the microspheres  47  can be accommodated smoothly and securely. Therefore, one of the microspheres  47  can be surely mounted on the pad  42 . 
   Although in the above embodiment the thickness of resist  45  and the diameter of hole  44  are determined such that only one of the microspheres  47  enters into the hole  44  of semiconductor device  2 , two microspheres  47  may be vertically accommodated in the hole  44 , e.g., if the microspheres  47  are solder balls with plastic core contained therein. 
   The circulation pipe  5  has a clearance that allows the microspheres  47  to pass through while keeping their original shape, at the pressing part when the microspheres  47  are transported by means of the pump  11 . Because of this, the microspheres  47  can be securely accommodated in the hole  44  of semiconductor device  2  without being deformed, crushed or defaced. 
     FIG. 8  shows the composition of a microsphere arranging apparatus in the second preferred embodiment of the invention. 
   The liquid flow-down type arrangement method of moving microspheres  47  to the semiconductor device  2  in this embodiment is conducted such that, without using the arrangement pallet, the semiconductor device  2  mounted on the mount base  3  is disposed in the conductive liquid, and the microspheres  47  are directly mounted on the pad  42  by pouring the microspheres  47  into the pad  42  together with the conductive liquid. 
   The microsphere arranging apparatus in  FIG. 8  is different from that in the first embodiment in that the storage container  6  can be upward and downward moved by a storage container vertical movement means  25 . At first, the storage container  6  waits at a position lower than the transfer bath  1  while containing the microspheres  47  and conductive liquid. When, the semiconductor device  2  is mounted on the mount base  3 , the storage container  6  is elevated by operating the storage container vertical movement means  25 . Accordingly, as the storage container  6  is moved higher than the transfer bath  1 , the microspheres  47  and conductive liquid contained in the storage container  6  are ejected through the ejection pipe  7  and falls on the semiconductor device  2  in the conductive liquid. A portion of the microspheres  47  falling on the semiconductor device  2  settles into the hole  44  and the remaining microspheres  47  and conductive liquid flow into the transfer bath  1 . 
   The microspheres  47  and conductive liquid which have flown into the bottom of transfer bath  1  are retained at part of the circulation pipe  5  connected with the bottom of transfer bath  1  and at the bottom of transfer bath  1 . 
   When the microspheres  47  and conductive liquid contained in the storage container  6  are completely ejected, the storage container  6  is moved down to the lower position, and the microspheres  47  and conductive liquid retained at part of the circulation pipe  5  connected with the bottom of transfer bath  1  and at the bottom of transfer bath  1  flow into the storage container  6  through the circulation pipe  5 . 
   The microsphere arranging apparatus and the method of arranging microsphere with liquid in the second embodiment have the same effects as that in the first embodiment. 
   Further, since the microspheres  47  and conductive liquid are circulated by moving up and down the storage container  6 , instead of using the pump  11 , the microspheres  47  can be securely accommodated in the hole  44  of semiconductor device  2  without being deformed, crushed or defaced. 
   Although in the first and second embodiments, the microspheres  47  are supplied to the resist  45  on the semiconductor wafer  43 , the semiconductor wafer  43  may be replaced by a wiring board, a semiconductor chip etc. Such an embodiment is included in the technical scope of the invention. 
   In the first and second embodiments, if an oscillating means to oscillate the mount base  3  is incorporated, the microspheres  47  can be faster accommodated in the hole  44  of semiconductor device  2 . Thereby, the working efficiency can be enhanced and the manufacturing cost can be reduced. 
     FIG. 9  shows the composition of a microsphere arranging apparatus in the third preferred embodiment of the invention. 
   The microsphere arranging apparatus as shown in  FIG. 9  is composed of: a transfer bath  1 ; a rotary mounting unit  53  that the semiconductor device  2  is mounted thereon and rotated thereby; a pump  11 ; a circulation pipe  5 ; a storage container  6 ; an ejection pipe  7 ; a washing pipe  8 , a microsphere supplying nozzle  7   a ; and a washing nozzle  8   a.    
   The transfer bath  1  is a funnel-shaped container formed by combining a cylinder and a cone, and it accommodates a conductive liquid containing a number of microspheres  47 . The transfer bath  1  has an opening formed at the lowest portion and the storage container  6  has an opening formed at the side face. The flexible circulation pipe  5 , is connected between the openings through the pump  11 . 
   The storage container  6  is a funnel-shaped container formed by combining a cylinder and a cone, and it is placed and fixed over the transfer bath  1  by a supporting member (not shown), and it accommodates a conductive liquid containing a number of microspheres  47 . The storage container  6  has an opening formed at the lowest portion, and one end of the ejection pipe  7  with the microsphere supplying nozzle  7   a  attached thereto is connected to this opening. The storage container  6  also has an opening formed at an arbitrary position on the upper portion of its inclined surface, and one end of the washing pipe  8  with the washing nozzle  8   a  attached thereto is connected to this opening. The storage container  6  is sealed up except at the pipe-connected portions so as to prevent the volatilization of volatile conductive liquid as much as possible. 
   The rotary mounting unit  53  is built near the lowest portion of transfer bath  1 , and it is composed of: a motor  53   a ; a rotating shaft  53   b  of the motor  53   a ; a bearing  53   c  shaped like an elongated cylinder; and a mount base  53   d . The motor  53   a  is disposed outside the transfer bath  1 , and the rotating shaft  53   b  of motor  53   a  is rotatably inserted into a penetration hole of the bearing  53   c  that is fixed at the lower portion of the inclined surface of transfer bath  1 . The tip of rotating shaft  53   b  is secured to the center of mount base  53   d . Namely, the mount base  53   d  is disposed such that, it is inclined inside the transfer bath  1 . The mount base  53   d  is rotated with the rotating shaft  53   b  of motor  53   a , and thereby the semiconductor device  2  mounted on the mount base  53   d  is rotated. 
   The inclination angle of mount base  53   d  is set such that, after microspheres  47  are accommodated in the hole  44  of mounted semiconductor device  2  thereof, the microspheres  47  are not spun out from the hole  44  by centrifugal force, and they are not released therefrom due to the pressure of conductive liquid flowing from the washing nozzle  8   a . A shield for waterproofing is disposed between the bearing  53   c  and the rotating shaft  53   b.    
   The relationship between the microsphere supplying nozzle  7   a  and the semiconductor device  2  mounted on the mount base  53   d  will be explained below with reference to  FIGS. 10(   a ) and  10 ( b ). 
   Conductive liquid containing a number of microspheres  47  flows down from the tip of microsphere supplying nozzle  7   a  disposed over the top face of semiconductor device  2 . The microspheres  47  have a diameter of 100 μm or less, i.e. 0.1 mm or less, and the conductive liquid flowing down on the inclined surface of semiconductor device  2  has a thickness of about 1 to 2 mm. Thus, as compared to the size of microspheres  47 , the thickness (depth) is 10 to 20 times, and this is nearly equivalent to the case that the microspheres  47  are arranged in the bath with conductive liquid. Also, this method provides the same static protection, etc. In order to pervade the conductive liquid onto the entire surface of semiconductor device  2 , the semiconductor device  2  is rotated and the microsphere supplying nozzle  7   a  is placed at the highest point of semiconductor device  2 . 
   The pump  11  interposed on the path of the circulation pipe  5  serves to transport the conductive liquid and microspheres  47  retained in the transfer bath  1  to the storage container  6 . 
   Next, the process of arranging, in the air, the microspheres  47  into the arrangement hole  44  of semiconductor device  2  by using the microsphere arranging apparatus thus composed will be explained. 
   The liquid flow-down type arrangement method in this embodiment to arrange the microspheres  47  onto the semiconductor device  2  is conducted such that, without using the arrangement pallet, the microspheres  47  are directly arranged on the pad  42  on the semiconductor device  2  mounted on the mount base  53   d  being inclined by the motor  53   a  by pouring and rotating the microspheres  47  together with the conductive liquid, in the air. 
   At first, the semiconductor device  2  with no microspheres  47  arranged thereon is mounted on the inclined mount base  53   a  disposed inside (at the in-air position of) the transfer bath  1 . At that time, the microsphere supplying nozzle  7   a  and washing nozzle  8   a  are retracted at a position that allows the mounting of semiconductor device  2  onto the mount base  53   d.    
   The washing nozzle  8   a  is shifted such that it is located over the semiconductor device  2  mounted on the mount base  53   d . At that time, the storage container  6  is vacant because the pump  11  is stopped, and no conductive liquid is ejected from the nozzles  7   a  and  8   a.    
   Then, the semiconductor device  2  mounted on the mount base  53   d  is rotated by driving the motor  53   a . Further, by operating the pump  11  at a low speed, conductive liquid retained in the transfer bath  1  and the flexible circulation pipe  5  is supplied to the storage container  6 . Then, conductive liquid is ejected from the washing nozzle  8   a  through the washing pipe  8  and falls on the semiconductor device  2  being rotated. The conductive liquid fallen on the semiconductor device  2  enters the respective holes  44  while moving downward and in the rotation direction of the semiconductor device  2 , further passing through a relief groove (not shown) and then falling into the transfer bath  1 . Thereby, gas in the hole  44  is removed. When a certain time elapses, the washing nozzle  8   a  is retracted. 
   Then, by operating the pump  11  at a high speed, the microspheres  47  retained in the transfer bath  1  and circulation pipe  5  are supplied to the storage container  6  together with conductive liquid. Thereby, the microspheres  47  and conductive liquid are ejected through the ejection pipe  7  from the microsphere supplying nozzle  7   a , and uniformly fall on the semiconductor device  2  being rotated. The microspheres  47  on the semiconductor device  2  enter the hole  44  while being moved in the circumferential direction of semiconductor device  2 , and the rest of microspheres  47  and conductive liquid fall into the transfer bath  1 . 
   The microspheres  47  and conductive liquid fallen into the transfer bath  1  are transported, through the circulation pipe  5  connected to the lowest portion of the transfer bath  1 , to the storage container  6  by the operation of pump  11 . After a period of ejection, the pump  11  is switched into the low speed operation. Thereby, only the microspheres  47  are retained in part of the circulation pipe  5  being connected to the lowest portion of the transfer bath  1  and at the bottom of transfer bath  1 , and only the conductive liquid is transported to the storage container  6 . 
   At that time, the washing nozzle  8   a  is shifted again over the semiconductor device  2  mounted on the mount base  53   d.    
   This washing process corresponds to the shaking or oscillation of liquid in the in-liquid arrangement method that the semiconductor device  2  is soaked. Thereby, excessive microspheres  47  being stacked in the hole  44  with one of the microspheres  47  already accommodated therein or being left on the surface of semiconductor device  2  can be removed, and the excessive microspheres  47  can be accommodated in another hole  44  with no microsphere accommodated therein. 
   After a period of washing, the pump  11  is stopped. Thereby, the microspheres  47  and conductive liquid fallen into the transfer bath  1  are retained at part of the circulation pipe  5  being connected to the lowest portion of the transfer bath  1  and at the bottom of transfer bath  1 , and the transportation of conductive liquid to the storage container  6  is stopped. At the time of stopping, conductive liquid left in the storage container  6  falls through the nozzles  7   a  and  8   a  and thereby the storage container  6  becomes vacant. Finally, the semiconductor device  2  with the microspheres  47  arranged thereon is released from the mount base  53   d.    
   By repeating such operations, the microspheres  47  can be stably arranged while using the microspheres  47  and conductive liquid repeatedly. 
   Alternatively, by using a microsphere arranging apparatus with a similar construction, as shown in  FIG. 11 , the microspheres  47  may be, in the conductive liquid, arranged onto the arrangement hole  44  of semiconductor device  2 . Namely, this liquid flow-down type arrangement method to arrange the microspheres  47  onto the semiconductor device  2  is conducted such that, without using the arrangement pallet. While rotating with the motor  53   a , the microspheres  47  are directly arranged on the pad  42  by pouring the microspheres  47  together with the conductive liquid of the transfer bath  1 , and the inclined semiconductor device  2  mounted on the mount base  53   d.    
   In this case, the microspheres  47  ejected together with the conductive liquid from the microsphere supplying nozzle  7   a , and fall on the semiconductor device  2  being rotated. The microspheres are then accommodated in the hole  44  of the semiconductor device  2  while being moved downward and rotated. 
   However, by using, e.g., a mechanism to make the rotating shaft  53   b  extend and contract, the semiconductor device  2  mounted on the mount base  53   d  can be controllably located in the conductive liquid or in the air, whereby the setting and releasing of semiconductor device  2  can be facilitated. Further, the storage container  6  with a capacity greater than that of transfer bath  1  may be used. In this case, while closing the ejection port of nozzles  7   a ,  8   a  temporarily, by using the pump  11 , conductive liquid in the transfer bath  1  may be completely transported to the storage container  6  or may be transported thereto until the mount base  53   d  is exposed to the air, in order to allow the setting and releasing of semiconductor device  2 . 
   As described above, the microsphere arranging apparatus and the method of arranging microspheres with liquid in the third embodiment is composed such that the semiconductor device  2  consists of: the semiconductor wafer  43  with the predetermined semiconductor element and interconnection and with a number of pads  42  connected to the interconnection and attached on the surface thereof; and the resist  45  formed on the semiconductor wafer  43  while having the penetrating holes  44  formed at the respective pads  42  position to mount the microspheres  47  on the inclined mount base  53   d . The microspheres  47  are, together with conductive liquid, ejected from the microsphere supplying nozzle  7   a  to the upper portion of semiconductor device  2  while rotating the mount base  53   d  by the rotating shaft  53   b  of motor  53   a , thereby pouring the microspheres  47  into the hole  44  of semiconductor device  2  to mount it on the pad  42 . 
   Thus, without using the conventional arrangement pallet, the microspheres  47  can be directly mounted on the pad  42  by pouring the microspheres  47  into the resist hole  44  of semiconductor wafer  43  while transporting it together with the conductive liquid. In this case, the microspheres  47  are accommodated in the hole  44  while being moved by the centrifugal force of the semiconductor wafer  43  being rotated. Thus, the microspheres can be efficiently accommodated in the hole  44 . Further, the conventional processes of accommodating the microspheres in the arrangement pallet and then transferring them to the resist hole  44  of semiconductor device  2  are not needed. Accordingly, the microspheres  47  can be efficiently mounted on the pad  42 . Further, the semiconductor device  2  is rotated even when it is washed and, therefore, the washing effect can be enhanced since the conductive liquid falling from the washing nozzle  8   a  is moved by the centrifugal force of semiconductor device  2 . 
     FIG. 12  shows the composition of a microsphere arranging apparatus in the fourth preferred embodiment of the invention. 
   The microsphere arranging apparatus as shown in  FIG. 12  is composed of: a transfer bath  1 ; a rotary mounting unit  51  that the semiconductor device  2  is mounted thereon and rotated thereby; a pump  11 ; a circulation pipe  5 ; a storage container  6 ; an ejection pipe  7 ; a washing pipe  8 , a microsphere supplying nozzle  7   a ; and a washing nozzle  8   a.    
   In this embodiment, the rotary mounting unit  51  is composed of: a motor  51   a ; a rotating shaft  51   b  of the motor  51   a ; a bearing  51   c  shaped like an elongated cylinder; and a mount base  51   d . It is built in near the lowest portion of transfer bath  1  such that the mount base  51   d  is laid horizontally. 
   Namely, the mount base  51   d  is disposed horizontally inside the transfer bath  1 . The mount base  51   d  is rotated with the rotating shaft  51   b  of motor  51   a , and thereby the semiconductor device  2  mounted on the mount base  51   d  is rotated. The microsphere supplying nozzle  7   a  is disposed at the center or center portion of semiconductor device  2  mounted on the mount base  51   d . The washing nozzle  8   a  is disposed adjacent to the microsphere supplying nozzle  7   a.    
   Next, the process of arranging, in the air, microspheres  47  into the arrangement holes  44  of semiconductor device  2  will be explained, where the method of arranging microspheres  47  with liquid using the microsphere arranging apparatus abovementioned is applied. 
   The liquid flow-down type arrangement method is conducted such that the arrangement pallet is not used, and the semiconductor device  2  is placed in the air while being mounted on the horizontally disposed mount base  51   d . The microspheres  47  are directly mounted on the pad  42  by pouring it together with conductive liquid. 
   At first, the semiconductor device  2  with no microspheres  47  is mounted on the mount base  51   d  that is disposed horizontally inside (at the in-air position of) the transfer bath  1 . At that time, the washing pipe  8  and ejection pipe  7  are retracted to a position that does not prevent the mounting of semiconductor device  2  onto the mount base  51   d.    
   Then, the washing nozzle  8   a  is shifted such that it is located over the semiconductor device  2  mounted on the mount base  51   d . At that time, since the pump  11  stops, the storage container  6  is vacant and therefore the conductive liquid does not flow out of the nozzles  7   a  and  8   a.    
   Then, the semiconductor device  2  mounted on the mount base  51   d  is rotated by driving the motor  51   a . Further, by operating the pump  11  at a low speed, conductive liquid retained in the transfer bath  1  and the flexible circulation pipe  5  is supplied to the storage container  6 . Then, conductive liquid is ejected from the washing nozzle  8   a  through the washing pipe  8  and falls on the center portion of the semiconductor device  2  being rotated. The conductive liquid fallen on the semiconductor device  2  enters the respective holes  44  while moving in the circumference direction by the centrifugal force of the semiconductor device  2 , further passing through a relief groove (not shown) and then falling into the transfer bath  1 . Thereby, gas in the hole  44  is removed. When a certain time (a time needed to wash the semiconductor device  2 ) elapses, the washing nozzle  8   a  is retracted. 
   Then, by operating the pump  11  at a high speed, the microspheres  47  retained in the transfer bath  1  and circulation pipe  5  are supplied to the storage container  6  together with conductive liquid. Thereby, the microspheres  47  and conductive liquid are ejected through the ejection pipe  7  from the microsphere supplying nozzle  7   a , and falls on the center portion of the semiconductor device  2  being rotated. One of the microspheres  47  fallen thereon enters the hole  44  while being moved in the circumference direction by the centrifugal force of the semiconductor device  2 , and the rest of microspheres  47  and conductive liquid falls into the transfer bath  1 . 
   The microspheres  47  and conductive liquid, which have fallen into the transfer bath  1 , are transported, through the circulation pipe  5  connected to the lowest portion of the transfer bath  1 , to the storage container  6  by the operation of pump  11 . After a period of time where ejection occurs, the pump  11  is switched into the low speed operation. Thereby, the microspheres  47  are retained at part of the circulation pipe  5  being connected to the lowest portion of the transfer bath  1  and at the bottom of transfer bath  1 , and only the conductive liquid is transported to the storage container  6 . 
   At that time, the washing nozzle  8   a  is shifted again such that it is located over the center portion of the semiconductor device  2  mounted on the mount base  51   d , and then the washing process is conducted. Because of the washing process, excessive microspheres  47  being stacked in the hole  44  with one of the microspheres  47  already accommodated therein or being left on the surface of semiconductor device  2  can be removed, and the excessive microspheres  47  can be accommodated in another hole  44  with no microsphere accommodated therein. 
   After a period of washing, the pump  11  is stopped. Thereby, the microspheres  47  and conductive liquid, which have fallen into the transfer bath  1  are retained at part of the circulation pipe  5  being connected to the transfer bath  1  and at the bottom of transfer bath  1 , and the transportation of conductive liquid to the storage container  6  is stopped. At the time of stopping, conductive liquid left in the storage container  6  falls through the nozzles  7   a  and  8   a  and thereby the storage container  6  becomes vacant. At the end, the semiconductor device  2  with the microspheres  47  arranged thereon is released from the mount base  51   d.    
   By repeating such operations, the microspheres  47  can be stably arranged while using, the microspheres  47  and conductive liquid repeatedly. 
   Alternatively, by using a microsphere arranging apparatus with a similar construction, as shown in  FIG. 13 , the microspheres  47  may be, in the conductive liquid, arranged onto the arrangement hole  44  of semiconductor device  2 . Namely, this liquid flow-down type arrangement method to arrange the microspheres  47  onto the semiconductor device  2  is conducted such that, without using the arrangement pallet, while rotating by the motor  51   a , the microspheres  47  are directly arranged on the pad  42  by pouring the microspheres  47  together with the conductive liquid of transfer bath  1 , when the semiconductor device  2  mounted on the mount base  51   d  is horizontally disposed. 
   In this case, the microspheres  47  in the conductive liquid are ejected from the microsphere supplying nozzle  7   a , and fall on the center portion of the semiconductor device  2  being rotated. One of the microspheres  47  may be accommodated in the hole  44  while being moved in the circumferential direction by the centrifugal force of semiconductor device  2 . 
   However, by using, e.g., a mechanism to make the rotating shaft  51   b  extend and contract, the semiconductor device  2  mounted on the mount base  51   d  can be controllably located in the conductive liquid or in the air, whereby the setting and releasing of semiconductor device  2  can be facilitated. Further, the storage container  6  with a capacity greater than that of transfer bath  1  may be used. In this case, while temporarily closing the ejection port of nozzles  7   a ,  8   a , by using the pump  11 , the conductive liquid in the transfer bath  1  may be transported to the storage container  6  permanently or until the mount base  51   d  is exposed to the air, in order to allow the setting and releasing of semiconductor device  2 . 
   As described above, the microsphere arranging apparatus and the method of arranging microspheres with liquid in the fourth embodiment is composed such that the semiconductor device  2  consists of: the semiconductor wafer  43  with the predetermined semiconductor element and interconnection and with a number of pads  42  connected to the interconnection and attached on the surface thereof. Additionally, the resist  45  is formed on the semiconductor wafer  43  with penetrating holes  44  formed on the respective pads  42  in a position to mount the microspheres  47 . The semiconductor wafer  43  is mounted on the mount base  53   d  that is disposed horizontally, and the microspheres  47 , together with conductive liquid, are ejected from the microsphere supplying nozzle  7   a  to the center portion of semiconductor device  2  while the mount base  51   d  is rotated by the rotating shaft  51   b  of motor  51   a  Thereby, the microspheres  47  are poured into the hole  44  of semiconductor device  2 . 
   Thus, without using the conventional arrangement pallet, one of the microspheres  47  can be directly mounted on the pad  42  by pouring the microspheres  47  and conductive liquid into the resist hole  44  of semiconductor wafer  43 . In this case, one of the microspheres  47  is accommodated in the hole  44  while being moved from the center or center portion to the circumference by the centrifugal force caused by the rotation of the semiconductor wafer  43 . Thus, it can be efficiently accommodated in the hole  44 . Further, the conventional processes of accommodating the microspheres in the arrangement pallet and then transferring them to the resist hole  44  of semiconductor device  2  are not needed. Accordingly, one of the microspheres  47  can be efficiently mounted on the pad  42 . Further, the semiconductor device  2  is rotated even during washing and, therefore, the washing effect can be enhanced since the conductive liquid falling from the washing nozzle  8   a  is moved by the centrifugal force of semiconductor device  2 . 
     FIG. 14  shows the composition of a microsphere arranging apparatus in the fifth preferred embodiment of the invention. 
   The microsphere arranging apparatus as shown in  FIG. 14  is different from the microsphere arranging apparatus in  FIG. 9  in that, instead of the rotary mounting unit  53 , a mount base  70  for the semiconductor device  2  and an oscillating unit  71  to oscillate the microsphere supplying nozzle  7   a  are built in the transfer bath  1 . In  FIG. 14 , the pump  11 , storage container  6 , washing pipe  8  and washing nozzle  8   a  are omitted. Hereinafter, the omitted components are explained with reference to  FIG. 9 . 
   The mount base  70  is attached, in parallel, to the inclined face of transfer bath  1 . When the semiconductor device  2  is mounted thereon, the semiconductor device  2  is inclined securely. 
   The oscillating unit  71  is composed of: a motor  71   a  that is attached to a support member  73  fixed to a support portion  1   a  of transfer bath  1  through screws  72 ; a rotating shaft  71   b  of the motor  71   a ; a first timing pulley  71   c ; a nozzle oscillating lever  71   e  with one end L-shaped; a second timing pulley  71   f ; a nozzle attaching shaft  71   g ; and a timing belt  71   h.    
   The first timing pulley  71   c  is attached through a screw  72   d  to the support member  73  while having the rotating shaft  71   b  inserted through its penetrating hole. Thus, the first timing pulley  71   c  is attached to the support member  73  so as not to prevent the rotation of the rotating shaft  71   b.    
   The end of the rotating shaft  71   b  is securely fixed to the end of the nozzle oscillating lever  71   e . The lever  71   e  has a penetrating hole formed at its L-shaped edge, and the nozzle attaching shaft  71   g  is rotatably inserted through the penetrating hole. The nozzle attaching shaft  71   g  has a microsphere supplying nozzle  7   a  attached at its top end. The second timing pulley  71   f  is attached to the lower end of the nozzle attaching shaft  71   g  projecting a predetermined length from the L-shaped edge, and secured thereto by a nut  71   i . Namely, the microsphere supplying nozzle  7   a  and the second timing pulley  71   f  are fixed to the nozzle attaching shaft  71   g , but the nozzle attaching shaft  71   g  is rotatably attached to the L-shaped edge of nozzle oscillating lever  71   e.    
   The first timing pulley  71   c  and the second timing pulley  71   f  are connected through the timing belt  71   h.    
   The rotating shaft  71   b  of motor  71   a  oscillates at predetermined rotation angles. As shown in  FIG. 15 , the microsphere supplying nozzle  7   a , in an arc, oscillates, from one end to the other end of semiconductor device  2  in the direction illustrated by arrows Y 4 , Y 5 . 
   In this case, when the nozzle oscillating lever  71   e  is rotated in a direction shown by the arrow Y 4  together with the rotating shaft  71   b , the second timing pulley  71   f , that is connected through the timing belt  71   h  to the first timing pulley  71   c  fixed to the support member  73 , is rotated in the reverse direction to the rotating shaft  71   b  but with the same angle. Thereby, the microsphere supplying nozzle  7   a  attached to the second timing pulley  71   f  through the nozzle attaching shaft and  71   g  is shifted but always still faces downward without having its direction changed. Although the microsphere supplying nozzle  7   a  is shifted as described above, the washing nozzle  8   a  is shifted likewise because the washing nozzle  8   a  is also attached to the nozzle attaching shaft  71   g . Meanwhile, the washing nozzle  8   a  is omitted from the figures. 
   Next, the process of arranging microspheres  47  into the arrangement holes  44  of semiconductor device  2  will be explained, where the method of arranging microspheres  47  with liquid using the microsphere arranging apparatus previously described is applied. 
   At first, the semiconductor device  2  is mounted on the mount base  70  that is included and disposed inside (at the in-air position of) the transfer bath  1 . 
   The washing nozzle  8   a  is shifted such that it is located over the semiconductor device  2  mounted on the mount base  70 . At that time, since the pump  11  stops, the storage container  6  is vacant and therefore the conductive liquid does not flow out of the nozzles  7   a  and  8   a.    
   Then, the nozzles  7   a  and  8   a  are oscillated by driving the motor  71   a . Further, by operating the pump  11  at a low speed, conductive liquid retained in the transfer bath  1  and the flexible circulation pipe  5  is supplied to the storage container  6 . Then, conductive liquid is ejected from the oscillated washing nozzle  8   a  through the washing pipe  8 , and is flown down from one end to the other end of the semiconductor device  2 . Thereby, conductive liquid enters the respective holes  44  while moving from one end to the other end of the semiconductor device  2 , further passing through a relief groove (not shown) and then falling into the transfer bath  1 . Thereby, gas in the hole  44  is removed. When the time needed to wash the semiconductor device  2  elapses, the washing nozzle  8   a  is retracted or closed at its ejection port. 
   Then, by operating the pump  11  at a high speed, the microspheres  47  retained in the transfer bath  1  and circulation pipe  5  are supplied to the storage container  6  together with conductive liquid. Thereby, the microspheres  47  and conductive liquid are ejected through the ejection pipe  7  from the oscillated microsphere supplying nozzle  7   a , and flow down from one end to the other end of the semiconductor device  2 . Thereby, one of the microspheres  47  enters the hole  44  while being moved from one end to the other end of the semiconductor device  2 , and the rest of microspheres  47  and conductive liquid drains into the transfer bath  1 . 
   The microspheres  47  and conductive liquid which have fallen into the transfer bath  1 , are transported, through the circulation pipe  5  connected to the lowest portion of the transfer bath  1 , to the storage container  6  by the operation of pump  11 . After a period of ejection, the pump  11  is switched into the low speed operation. Thereby, the microspheres  47  are retained at part of the circulation pipe  5  being connected to the lowest portion of the transfer bath  1  and at the bottom of transfer bath  1 , and only the conductive liquid is transported to the storage container  6 . 
   Then, the washing process is conducted by using the washing nozzle  8   a . By the washing process, excessive microspheres  47  being stacked in the hole  44  with one of the microspheres  47  already accommodated therein or being left on the surface of semiconductor device  2  can be removed, and the excessive microspheres  47  can be accommodated in another hole  44  with no microsphere accommodated therein. 
   After a certain time of washing, the pump  11  stops operating. Thereby, the microspheres  47  and conductive liquid, which have fallen into the transfer bath  1  are retained at part of the circulation pipe  5  being connected to the transfer bath  1  and at the bottom of transfer bath  1 , and the transportation of conductive liquid to the storage container  6  is stopped. At the time of stopping, conductive liquid left in the storage container  6  falls through the nozzles  7   a  and  8   a  and thereby the storage container  6  becomes vacant. Finally, the semiconductor device  2  with the microspheres  47  arranged thereon is released from the mount base  70 . 
   By repeating such operations, the microspheres  47  can be stably arranged while recycling the microspheres  47  and conductive liquid repeatedly. 
   Alternatively, by using a microsphere arranging apparatus (not shown) with a similar construction, the microspheres  47  may be, in the conductive liquid, arranged onto the arrangement hole  44  of semiconductor device  2 . 
   In this case, the microspheres  47  and the conductive liquid are ejected from the microsphere supplying nozzle  7   a , and flow down from one end to the other end of the semiconductor device  2 . One of the microspheres  47  may be accommodated in the hole  44 . 
   As described above, the microsphere arranging apparatus and the method of arranging microspheres with liquid in the fifth embodiment is composed such that the semiconductor device  2  consists of: the semiconductor wafer  43  with the predetermined semiconductor element and interconnection and with a number of pads  42  connected to the interconnection and attached on the surface thereof. Additionally, the resist  45  is formed on the semiconductor wafer  43  while having the penetrating holes  44  formed on the respective pads  42  and positioned to mount the microspheres  47 . The semiconductor wafer  43  is mounted on the inclined mount base  70 , and the microspheres  47  and the conductive liquid are ejected from the microsphere supplying nozzle  7   a  while oscillating the microsphere supplying nozzle  7   a  from one end to the other end of semiconductor device  2 . Thereby, the microspheres  47  are poured into the hole  44  of semiconductor device  2 . 
   Thus, without using the conventional arrangement pallet, the microspheres  47  can be directly mounted on the pad  42  by pouring the microspheres  47  and conductive liquid into the resist hole  44  of semiconductor wafer  43 . In this case, one of the microspheres  47  is accommodated in the hole  44  while being moved from one end to the other end of semiconductor device  2  together with conductive liquid. Thus, the microspheres can be efficiently accommodated in the hole  44 . Further, the conventional processes of accommodating the microspheres in the arrangement pallet and then transferring them to the resist hole  44  of semiconductor device  2  are not needed. Accordingly, one of the microspheres  47  can be efficiently mounted on the pad  42 . Further, even when the semiconductor device  2  is washed, the washing effect can be enhanced since the conductive liquid flows down the semiconductor device  2  while being oscillated from one end to the other end of semiconductor device  2 . 
     FIG. 16  shows the composition of a microsphere arranging apparatus in the sixth preferred embodiment of the invention. 
   A liquid flow-down type arrangement method to arrange the microspheres  47  onto the semiconductor device  2  by using the microsphere arranging apparatus in the sixth embodiment as shown in  FIG. 16  will be explained below. The storage container  6  can be moved upward and downward by a storage container vertical movement means  81 . The storage container  6  is lifted by operating the storage container vertical movement means  81  such that the storage container  6  becomes higher than the transfer bath  1 . At that time, the microspheres  47  and conductive liquid accommodated in the storage container  6  are ejected from the microsphere supplying nozzle  9  through the ejection pipe  7 , and falling on the semiconductor device  2  in the conductive liquid. One of the microspheres  47 , which has fallen on the semiconductor device  2  is accommodated in the hole  44  and the rest of microspheres  47  and conductive liquid falls into the semiconductor device  2 . 
   The transfer bath  1  is supported by a support portion  82 . The transfer bath  1  and mount base  53   d  can be angle-controlled by the support portion  82 . When the microspheres  47  are transferred into the hole  44  while the microspheres  47  and conductive liquid flow down onto the semiconductor device  2  mounted on the mount base  53   d , the transfer bath  1  is preferably controlled to have a suitable angle. 
   Further, the mount base  53   d  can be rotated by a rotating means  83 . The semiconductor device  2  can be rotated at a suitable speed when one of the microspheres  47  is transferred into the hole  44  while the microspheres  47  and conductive liquid flow down onto the semiconductor device  2  mounted on the mount base  53   d . Thereby, the microspheres  47  can be efficiently transferred into the hole  44  and excessive microspheres  47  can fall onto the bottom of transfer bath  1 . 
   In the case when ethanol is used as the conductive liquid and SnPb eutectic solder balls with a diameter of 100 μm are used as the microspheres, the arrangement can be made more efficient by using a combination of an inclination angle and a rotation speed as shown in  FIG. 9 . If a suitable angle and rotation speed is used, liquid flow is generated in the conductive liquid retained in the transfer bath  1  due to the rotation of the semiconductor device  2  and mount base  53   d . Due to this liquid flow, the microspheres  47  are efficiently moved on the semiconductor device  2 . In this case, it is more effective that an agitator  84  be used with the mount base  53   d  to generate the liquid flow. The agitator may be shaped like a protrusion or a netted plate structure, to surround the semiconductor device  2 . The netted structure is preferred since the semiconductor device  2  can be easily taken out. 
   The microspheres  47  falling on the bottom of transfer bath  1  are retained at part of the circulation pipe  5  connected to the bottom of the transfer bath  1  and at the bottom of the transfer bath  1 . 
   When the storage container  6  descends to a predetermined lower position after the microspheres  47  and conductive liquid accommodated in the storage container  6  are completely ejected into the transfer bath  1 , the microspheres  47  and conductive liquid are retained at part of the circulation pipe  5  and at the bottom of the transfer bath  1  and flow through the circulation pipe  5  into the storage container  6 . 
   As shown in  FIG. 17 , mount base  53   d  and semiconductor device  2  may be placed such that they are not soaked in conductive liquid retained in the transfer bath  1 . One of the microspheres  47  then may be transferred into the hole  44  while the microspheres  47  and conductive liquid fall thereon. Further, the mount base  53   d  and semiconductor device  2  may not be inclined during the transferring. 
   The microsphere arranging apparatus and the method of arranging microspheres with liquid in the sixth embodiment thus composed can have the same effects as the first embodiment. 
   Referring to  FIGS. 18(   a ),  18 ( b ) and  18 ( c ),  19 ( a ),  19 ( b ) and  19 ( c ),  20  and  21 , various shapes of resist hole will be detailed. 
     FIGS. 18(   a ),  18 ( b ) and  18 ( c ) and  19 ( a ),  19 ( b ) and  19 ( c ) are plan views showing the shapes of a penetrating hole to mount the microsphere formed in the resist of semiconductor device in the seventh embodiment of the invention.  FIG. 21  is a cross sectional view showing a penetrating hole to mount the microsphere formed in the resist of semiconductor device in the seventh embodiment of the invention. 
   Accommodating the microspheres  47 , bathed in the liquid, into the resist hole  44  is difficult because obstructions such as air or gas are present in the microscopic hole  44 . Further, the conductive liquid used in the transferring of microspheres  47  becomes unnecessary after one of the microspheres  47  is transferred into the resist hole  44 . Therefore, after the transferring is completed, it is preferred that as much as possible of the conductive liquid left on the resist hole  44  and semiconductor device  2  is removed. Thus, a relief groove for gas or liquid needs to be formed connected to the hole  44  as described earlier. 
   The relief groove can be formed by, for example, etching the resist  45 . Further, it can be formed by using the photolithography technique such as exposure and development while using a photosensitive resist. Further, the hole can be formed by using a laser processing machine or a mechanical processing machine. The laser processing machine is preferred because, when an absorption agent, which reacts at the wavelength of laser, is added to the resist material, the processing accuracy can be enhanced and the processing can be conducted without any thermal damage on the surface of semiconductor wafer  43  or pad  42 . 
   When the relief groove  49 , as shown in  FIG. 18(   a ), is formed in the direction Y 6  of liquid flow, gas such as air can easily be removed in flowing conductive liquid. If the relief groove  49  has a greater than width l, the gas or liquid will be easy to remove, but it should not be large enough that microspheres  47  once accommodated in the hole  44  are released. Multiple relief grooves may be provided. If they are, as shown in  FIG. 18(   b ), disposed at an angle θ in relation to the direction Y 6  of liquid flow, the releasing of microspheres  47  can be prevented. The angle θ may be 0 to 90 degrees and preferably 30 to 60 degrees. Although the above example is illustrated with the relief grooves formed in two directions, they may be formed in three or more directions. The multiple relief grooves  49  may be also formed in one direction. 
   Further, the resist hole  44  may be rectangular as shown in  FIG. 19(   a ). As compared to the circular hole, the efficiency of accommodating microspheres  47  in the hole  44  can be enhanced by flowing the liquid in a certain direction. Also, the gas or liquid can be removed easier since its corner  48  functions as a groove  49 . As shown in  FIG. 19(   b ), the relief groove  49  may be formed such that neighboring holes  44  are connected. Further, as shown in  FIG. 19(   c ), the relief groove  49  may be formed at an angle θ in relation to the direction Y 6  of liquid flow. The angle θ may be 0 to 90 degrees and preferably 30 to 60 degrees. 
   If one of the microspheres  47  is accommodated into the resist hole  44  while rotating the mount base  53   d  by the rotating means  83 , as described in the sixth embodiment, the direction of liquid flow varies on the semiconductor device  2 . Thus, when the liquid flow-down type arrangement method is conducted using the rotating means, the relief groove  49  is desirably formed such that, as shown in  FIG. 20 , it defines radial directions Y 7  to the hole  44 . 
   Although the resist hole  44  may have a wall perpendicular to the surface of semiconductor wafer  43  as shown in  FIG. 4 , it may be, as shown in  FIG. 21 , formed tapered such that the semiconductor wafer  43  side is wider than the surface side of resist  45 . Thereby, once one of the microspheres  47  accommodated therein can be prevented from being released. Such a form can be made by adjusting the exposure conditions or development or adjusting the exposure focusing when forming the resist hole  44  by using the photolithography technique on the resist. Further, it may be made by laser processing while controlling the angle to irradiate laser light. 
   The above resist hole and relief groove can be applied to the microsphere arranging apparatus and the method of arranging microspheres with liquid in the first to sixth embodiments. Thereby, the microsphere can be arranged while facilitating the removing of gas or liquid and preventing the microsphere accommodated therein from being released. 
     FIG. 22  shows the composition of a microsphere arranging apparatus in the eighth preferred embodiment of the invention. 
   The microsphere arranging apparatus as shown in  FIG. 22  has the same mechanism as the microsphere arranging apparatus in the first embodiment as shown in  FIG. 1 . However, the semiconductor device  2  mounted on the mount base  3  does not have the resist  45  with the hole  44  for accommodating the microspheres  47 . Instead, a mask  46  is provided. Namely, the semiconductor wafer  43  is mounted on the mount base  3 , and the mask  46  with penetrating holes  44  for disposing the microspheres  47  at the position of pad  42  is formed on the semiconductor wafer  43 . 
     FIG. 23  is a cross sectional view showing a positional relationship among the semiconductor wafer  43  mounted on the mount base, the pad  42  on the semiconductor wafer  43 , and the hole  44  formed in the mask  46  to mount the microspheres  47 . The mask  46  has a hole  44  to accommodate one of the microspheres  47  just like the resist explained in the first embodiment or the seventh embodiment. The hole  44  is disposed at such a position that one of the microspheres  47  can be mounted on the pad  42 . Also, a holding member is provided that defines a relief gap Y 9  between the semiconductor wafer  43  and the mask  46 . When the conductive liquid flows, gas such as air or liquid can be removed through the relief gap Y 9 , and therefore the microspheres  47  can be easily accommodated. 
   The length t of relief gap Y 9  preferably satisfies the condition: 
   t≦½dmin 
   where the diameter of microsphere used is d, the accuracy of microsphere diameter d is α microns, therefore the minimum diameter of microsphere dmin=d−α and the maximum diameter of microsphere dmax=d+α. 
   It is further preferable to satisfy: 
   ¼dmin≦t≦1/2dmin 
   Also, the thickness T of mask  46  preferably satisfies the condition: 
   ½dmax&lt;T+t≦dmin 
   The mask  46  may be made by etching, laser-processing or mechanically processing a metal plate such as a stainless plate, copper plate and or aluminum plate. It may be made by the electroforming of nickel or copper. Further, a silicon mask is available. For example, the mask  46  may be made of silicon. The mask  46  of silicon is advantageous because a displacement from the pad  42  can be prevented later when forming a bump during the fusing of the microsphere. This is due to the coincidence in thermal expansion coefficient between the semiconductor device  2  and the mask. The mask  46  can be made by a mechanical processing such as laser processing or drilling or by etching. The anisotropic etching is preferred because of its advanced processing. For example, when a square pyramid with ( 111 ) orientation is made by conducting the anisotropic etching on a silicon wafer with ( 100 ) face on its surface, fine processing can be performed. A penetrating hole can be formed by conducting the anisotropic etching on one side of silicon wafer or by etching both sides thereof. It is preferable to etch both sides in order to control the sectional form of the penetrating hole to prevent the microsphere from being released. 
   In the case of using a metallic mask  46 , a resin material etc. may be coated thereon since the metallic mask may contact the microspheres  47  and thereby cause damage thereto. Also, it may be formed by photolithography using a photosensitive resin. A resin material with photosensitive group such as photosensitive polyimide, photosensitive fluorene resin and photosensitive acrylic resin may be used. A resin with rigidity such as photosensitive acrylic resin is desirable. 
     FIGS. 24(   a ),  24 ( b ) and  24 ( c ) are cross sectional views showing a relief groove formed in the mask. As shown, the relief groove  49  is formed on only the semiconductor wafer  43  side and without penetrating the mask  46 . Thereby, the gas or liquid can be removed easily. The mask  46  may be formed by conducting the electroforming in two or more stages. Further, it may be formed by half-etching, laser processing or mechanical processing after a mask is made by the abovementioned method. 
   Further, as shown in  FIG. 24(   c ), a bank  50  may be provided upstream of the pad  42  in a direction Y 8  of liquid flow. Thereby, the microspheres  47  once accommodated can be prevented from being released. 
   Further, as shown in  FIG. 24(   c ), a relief groove  49  may be formed upstream of the hole  44  in the direction Y 8  of liquid flow and on the surface side of mask  46 . Thereby, the microspheres  47  and conductive liquid can be drained smoothly. The hole  44  of mask  46  may be rectangular or tapered like the hole  44  of resist  45  as described earlier. 
   The microsphere arranging apparatus and the method of arranging microspheres with liquid in the eighth embodiment can have the same effects as the first embodiment. 
     FIG. 25  shows the composition of a microsphere arranging apparatus in the ninth preferred embodiment of the invention. 
   The microsphere arranging apparatus as shown in  FIG. 25  has the same mechanism as the microsphere arranging apparatus in the third embodiment as shown in  FIG. 9 . However, the semiconductor device  2  mounted on the mount base  53   d  does not have the resist  45  with the hole  44  for accommodating the microspheres  47  and, instead, a mask  46  is provided. The composition on the mount base  53   d  is the same as that in the eighth embodiment as explained with reference to  FIGS. 23 and 24 . 
   Therefore, the microsphere arranging apparatus and the method of arranging microspheres with liquid in the ninth embodiment can have the same effects as the above eighth embodiment. 
   Furthermore, when the mask  46  of the microsphere arranging apparatus in the ninth embodiment is provided on the semiconductor wafer  43  of the microsphere arranging apparatus in the fourth to sixth embodiments, the same effects can be obtained. 
   In the first to sixth and eighth and ninth embodiments, an oscillating means to oscillate the mount base may be incorporated. Thereby, the microspheres  47  can be more quickly accommodated into the hole  44  of semiconductor device  2 , and the operating efficiency can be enhanced and the manufacturing cost can be reduced. 
   The oscillating means may be, for example, a piezoelectric element provided on the back face as shown in  FIG. 26  or side face of the mount base  53   d . The oscillation is applied desirably in a horizontal direction Y 10  in relation to the semiconductor device  2  because the accommodated microspheres  47  may be released if the oscillation is applied in a vertical direction to the semiconductor device  2 . Further, when a traveling wave is generated to which is headed in one direction or multiple directions from the center to the circumference of semiconductor device  2 , the microspheres  47  can be more quickly accommodated in the hole  44  of semiconductor device  2 . Thereby, the operating efficiency can be enhanced. 
   In the first to tenth embodiments, the microspheres  47  are solder balls. The solder ball may be a ball consisting of solder, a plastic core covered with solder, a gold ball or a copper ball with silver plating, or various conductive micro-balls. 
   Although in all of the above embodiments the semiconductor wafer  43  is circular, it may be rectangular etc. Even in such a case, the same effects can be obtained. 
   Although the microspheres  47  are supplied into the resist  45  or mask  46  on the semiconductor wafer  43  therein, the semiconductor wafer  43  may be replaced by a wiring board, a semiconductor chip etc. Such a modified embodiment is also included in the technical scope of the invention. 
   As described above, according to the invention, a method of arranging microspheres with liquid comprises the steps of: 
   providing a semiconductor device that includes a semiconductor wafer with a predetermined semiconductor element and an interconnection and with a number of pads connected to the interconnection and attached on a surface of the semiconductor wafer, and a resist formed on the semiconductor wafer and having a penetrating hole formed at the respective pad positions to mount the microsphere; and 
   pouring the microsphere into the hole together with conductive liquid to mount the microsphere on the pad. 
   Further, according to the invention, a method of arranging microspheres with liquid comprises the steps of: 
   providing a semiconductor device that includes a semiconductor wafer with a predetermined semiconductor element and an interconnection and with a number of pads connected to the interconnection and attached on a surface of the semiconductor wafer, and a mask with a penetrating hole formed at the respective pad positions to mount the microsphere, the mask being held on the semiconductor device to allow the hole to be disposed on the pad; and 
   pouring the microsphere into the hole together with conductive liquid to mount the microsphere on the pad. 
   Thereby, without using the conventional arrangement pallet, the microsphere can be directly mounted on the pad by pouring the microsphere into the resist hole of semiconductor wafer while transporting it together with the conductive liquid. Accordingly, the conventional processes of accommodating the microspheres in the arrangement pallet and then transferring them to the resist hole of semiconductor device are not needed. Therefore, the manufacturing cost can be reduced and the step of transferring the microsphere to the hole of semiconductor device in the bump electrode forming process can be simplified. 
   Further, by mounting the semiconductor device on the mounting means whose inclination angle can be varied and by supplying the microsphere together with the conductive liquid stored in the storing means to the semiconductor device, the microsphere can be accommodated in the hole arranged in the semiconductor device or in the hole arranged in the mask mounted on the semiconductor device. The conductive liquid containing the microsphere not accommodated is retained by the retaining means and the conductive liquid containing the microsphere retained is transported to the storing means by the pump means. Therefore, the conductive liquid and microsphere can be recycled without being wasted. 
   Further, in the above semiconductor device, the resist or the combination of mask and relief gap has a thickness that allows the microsphere to be retained in the hole and prevents the two or more microspheres from being entered therein, and a minimum diameter of the hole to be generated due to a manufacture accuracy of the hole is made to be greater than a value obtained by adding a gap to a maximum diameter of the microsphere, and a maximum diameter of the hole is made to prevent the two or more microspheres from being entered into the one hole and prevent the microsphere from being released from the pad. Therefore, the microsphere can be properly mounted on the pad. 
   Further, the groove that allows the gas or conductive liquid to be removed without being retained in the hole when accommodating the microsphere in the hole is connected to the hole. Therefore, the microsphere can be smoothly and properly accommodated, and the microsphere can be properly mounted on the pad. 
   Further, with the semiconductor device that includes a semiconductor wafer with a predetermined semiconductor element and an interconnection and with a number of pads connected to the interconnection and attached on a surface of the semiconductor wafer, and a resist formed on the semiconductor wafer and having a penetrating hole formed at the respective pad positions to mount the microsphere, the microsphere is poured into the hole together with conductive liquid while rotating the semiconductor device to mount the microsphere on the pad. Therefore, the microsphere can be efficiently mounted on the pad of the semiconductor device.