Abstract:
Semiconductor devices are manufactured, using film substrates, as follows. Individual film substrates are separated from a film substrate tape having a plurality of film substrates continuously and integrally connected to each other, each the film substrate comprising a base film having first and second surfaces, a circuit pattern being formed on the first surface and a mounting section being formed on the second surface. The base film has an opening to which electrode terminals of a semiconductor element are exposed when the semiconductor element is mounted. The individual film substrates are adhered to respective reinforcement members of a reinforcement frame, which has a plurality of the reinforcement members continuously and integrally connected to each other. Each reinforcement member has an accommodation hole for accommodating the semiconductor element, so that the semiconductor element mount section is exposed in the accommodation hole. A semiconductor element is mounted on the film substrate by adhering an electrode terminal-forming surface of the semiconductor element to said mounting section so that electrode terminals of the semiconductor element are exposed in the accommodation hole. The electrode terminals exposed in the opening are electrically connected to the circuit patterns. The opening is sealed with resin and then the individual reinforcement members are separated from the reinforcement frame.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a process for manufacturing a semiconductor device and, particularly to a process for manufacturing a semiconductor device wherein a film substrate is adhered to an electrode-forming surface of a semiconductor chip. 
     2. Description of the Related Art 
     FIG. 11 illustrates one example of a so-called chip-size package formed by adhering a film substrate  12  onto an electrode terminal-forming surface of a semiconductor surface of a semiconductor chip  10 . The film substrate  12  has a circuit pattern  16  with lands on one side surface of an electrically-insulating base film  14  of polyimide or others, and carries an adhesive layer  18  on the other surface to be adhered onto the electrode terminal-forming surface of the semiconductor chip  10 . The semiconductor device illustrated in FIG. 11 carries the semiconductor chip  10  provided with two rows of electrodes  20  arranged in the lengthwise direction in a generally central region of the electrode terminal-forming surface thereof. An opening for a wire-bonding operation is formed at a center of the film substrate  12 , through which the electrode terminals  20  are connected to bonding parts  22  of the circuit pattern  16  via bonding wires  24 . Reference numeral  26  denotes an external connection terminal bonded to the land of the circuit pattern  16 , and  28  denotes a shield resin for shielding the bonded portion. 
     Reduction in size of the semiconductor chip  10  is a recent trend for the purpose of increasing the number thereof obtainable from one wafer, which in turn results in the difficulty in arranging external connection terminals within a space corresponding to the electrode terminal-forming surface of the minimized semiconductor chip  10 , because a circuit board on which the semiconductor device is mounted or an external connection terminal, such as a solder ball, still adopts the conventional mounting method. 
     Therefore, as shown in FIG. 12, there might be a case wherein the film substrate  12  on which the external connection terminals are arranged becomes larger than the minimized semiconductor chip  10 . If the semiconductor chip  10  is smaller than the film substrate  12  as described above, the peripheral region (designated as “A” in the drawing) of an area defined on a surface of the film substrate  12  could not be supported by the semiconductor chip  10 , which requires taking some measures for the reinforcement of the peripheral region of the film substrate  12 . 
     FIGS.  13 ( a ) to  13 ( c ) show the prior art steps for manufacturing the semiconductor device in which the semiconductor chip  10  is smaller in size than the film substrate  12 . 
     FIG.  13 ( a ) illustrates a rectangular film substrate tape  120  cut off from a long-sized film substrate tape in which a plurality of film substrates are consecutively arranged. The film substrate tape  120  is divided into sections having the same circuit pattern  16 , for mounting the semiconductor chips  10 , respectively. Each of the sections has a bonding opening  15  extending in the longitudinal direction in the middle portion thereof. 
     FIG.  13 ( b ) illustrates the film substrate tape  120  secured onto a carrier frame  30  for assuredly carrying out various steps for the manufacturing, such as mounting of semiconductor chip, wire-bonding or shielding. The carrier frame  30  is made of a metallic sheet or the like into a frame shape, and serves to support the periphery of the film substrate tape. 
     Then, a reinforcement member  32  is bonded to the peripheral region of the respective section on a side of the film substrate  12  to which the semiconductor chip  10  is to be adhered (a side opposite to that carrying the circuit pattern) (see FIG.  13 ( c )). The reinforcement member  32  is of a frame shape formed in conformity with the contour of the film substrate  12  and a size of the semiconductor chip  10 . The reinforcement member  32  is made of a resinous material having a high shape-retaining ability such as a polyimide tape or a thin metallic plate. The reinforcement member  32  is formed separately from the film substrate tape  120  and the carrier frame  30 , and is individually adhered to the film substrate tape  12  by an adhesive layer  18  provided on the film substrate tape  120 . 
     After the reinforcement member  32  has been adhered to the respective film substrate  12  of the film substrate tape  120 , the semiconductor chip  10  is adhered. Thereafter, a bonding part  22  of the circuit pattern  16  is wire-bonded to an electrode terminal  20  of the semiconductor chip through the opening of the film substrate  12 . After exposed portions of the bonding parts  22  or others have been resin-shielded and the external connection terminals have been bonded to the lands of the circuit pattern, the respective film substrates  12  are cut into sections from the film substrate tape  120  to result in individual semiconductor devices. 
     FIGS.  14 ( a ) and  14 ( b ) are a side sectional view and a bottom view, respectively, of the semiconductor device thus obtained. As apparent therefrom, the outer peripheral region of the film substrate  12  is strengthened with the reinforcement member  32  adhered to the side of the former on which the semiconductor chip  10  is mounted. 
     The prior art process for manufacturing the semiconductor device described above includes the steps of supporting the film substrate tape  120  by the carrier frame  30 , and adhering the reinforcement member  32  to the film substrate tape  120 . Such a manufacturing process has drawbacks in that a material cost is expensive and the manufacturing steps are complicated because the semiconductor device is formed by combining the film substrate tape  120 , the carrier frame  30  and the reinforcement member with each other. 
     SUMMARY OF THE INVENTION 
     An object of the present invention is to provide a process for easily manufacturing a semiconductor device of a good quality by improving the prior art manufacturing process so that the manufacturing steps are simplified to reduce the manufacturing cost. 
     According to the present invention, there is provided with a process for manufacturing a semiconductor device, the process comprising the following steps of: separating individual film substrates from a film substrate tape having a plurality of film substrates continuously and integrally connected to each other, each film substrate comprising a base film having first and second surfaces, a circuit pattern being formed on the first surface and a semiconductor element mounting section being formed on the second surface, the base film having an opening to which electrode terminals of a semiconductor element are exposed when the semiconductor element is mounted; adhering the individual film substrates to respective reinforcement members of a reinforcement frame having a plurality of the reinforcement members continuously and integrally connected to each other, each reinforcement member having an accommodation hole for accommodating the semiconductor element, so that the semiconductor element mount section is exposed in the accommodation hole; mounting the semiconductor element on the film substrate by adhering an electrode terminal-forming surface of the semiconductor element to said mounting section so that electrode terminals of the semiconductor element are exposed in the accommodation hole; electrically connecting the electrode terminals exposed in the opening to the circuit patterns; sealing the opening with resin; and separating the individual reinforcement members from the reinforcement frame. 
     The electrode terminals of the semiconductor element can be electrically connected to the circuit patterns by wire-bonding. 
     The film substrate is such that tip ends of the circuit pattern extend into the opening as lead portions. 
     The reinforcement frame may comprise a frame base and the plurality of reinforcement members suspended by the frame base. The reinforcement frame may be a metallic reinforcement frame. 
     According to another aspect of the present invention, there is provided a process for manufacturing a semiconductor device, the process comprising the following steps of: separating individual film substrates from a film substrate tape having a plurality of the film substrates continuously and integrally connected to each other, each the film substrate comprising a base film having first and second surfaces, a circuit pattern being formed on the first surface and an mounting section being formed on the second surface, the mounting section provided with connecting terminals connected to the circuit patterns by means of vias; adhering the individual film substrates to respective reinforcement members of a reinforcement frame having a plurality of the reinforcement members continuously and integrally connected to each other, each the reinforcement member having an accommodation hole for accommodating a semiconductor element, so that the mount section is exposed in the accommodation hole; mounting the semiconductor element on the film substrate by flip-chip electrically connecting the electrode terminals of the semiconductor element to the connecting terminals; and separating the individual reinforcement members from the reinforcement frame. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a plan view of one embodiment of a film substrate used for the manufacturing of a semiconductor device; 
     FIG. 2 is a plan view of one embodiment of a reinforcement frame used for the manufacturing of a semiconductor device; 
     FIG. 3 is a plan view of individual film substrates adhered to the reinforcement frame; 
     FIG. 4 is a side sectional view of individual film substrates adhered to the reinforcement frame through P-P′ of FIG. 3; 
     FIG. 5 is a side sectional view of a semiconductor chip mounted onto the film substrate; 
     FIG. 6 is a side sectional view of the semiconductor chip mounted onto the film substrate and resin-shielded thereto; 
     FIG. 7 is a side sectional view of a semiconductor device formed by using a film substrate provided on opposite sides thereof with conductive layers; 
     FIGS.  8 ( a ) and  8 ( b ) are side sectional views, respectively, of semiconductor devices, each being formed by using a film substrate wherein a lead section is formed at a distal end of a circuit pattern; 
     FIG. 9 is a side sectional view of a semiconductor device wherein a semiconductor chip is mounted onto a film substrate by the wire-bonding carried out in the outer peripheral region of an electrode terminal-forming surface thereof; 
     FIG. 10 is a side sectional view of a semiconductor device wherein a semiconductor chip is mounted onto a film substrate by a flip-chip bonding; 
     FIG. 11 is a side sectional view of a prior art semiconductor device wherein a film substrate is adhered to an electrode terminal-forming surface; 
     FIG. 12 is a side sectional view of a semiconductor device mounting onto a film substrate a semiconductor chip having a smaller outer dimension than that of the film substrate; 
     FIGS.  13 ( a ) to  13 ( c ) illustrate the prior art steps for manufacturing a semiconductor device, respectively; and 
     FIGS.  14 ( a ) and  14 ( b ) are a side sectional view and a bottom view of a semiconductor device, respectively, wherein a film substrate is strengthened by a reinforcement member. 
    
    
     DETAILED DESCRIPTION OF THE EMBODIMENTS 
     The preferred embodiments of the present invention will now be described in detail below with reference to the attached drawings. 
     FIG. 1 illustrates a film substrate tape  122 , on which are consecutively and integrally arranged a number of film substrates  12 , each to be adhered to an electrode terminal-forming surface of a semiconductor chip  10 . The film substrate  12  formed on the film substrate tape  122  while dividing the latter into sections at a predetermined interval has the same structure as that of the prior art film substrate  12  described hereinabove; that is, a circuit pattern  16  is formed on one side of a base film  14 , while a mounting area is defined on the other side of the base film  14 , for mounting the semiconductor chip  10 . A slit-like opening  15  is provided for the wire-bonding, and lands  16   a  are provided to be connected to external connection terminals. The surface of the film substrate  12  is covered with a protective layer made, for example, of solder resist, except for the exposed part such as lands  16   a  or bonding parts  22 . 
     When the film tape  122  is produced, a long-sized tape consisting of the base film  14  clad on one side thereof with a copper foil is first punched to have sprocket holes  124 . Then, a photosensitive resist is coated on the surface of the copper foil to form a resist layer which is exposed and developed in conformity with the predetermined circuit patterns  16  including the bonding parts  22  and the lands  16   a  to form resist patterns which in turn are used as a mask for etching the copper foil to form the circuit patterns  16 . After the resist patterns have been removed, the surface of the base film  14  on which the circuit patterns  16  are formed is coated with a protective layer such as solder resist except for part to be exposed outside such as the bonding portions which are then applied with a protective plating of gold or the like. Finally, an adhesive layer is provided on the other surface of the base film  14 , and the openings  15  are formed by a perforation process to result in the film base tape  122 . 
     FIG. 2 illustrates a reinforcement frame  40  to be adhered to the film substrates  12 . The reinforcement frame  40  is used as a carrier frame for supporting the film substrates  12  and the semiconductor chips  10  mounted onto the film substrates  12 , and also provides the semiconductor device with a reinforcement member  32  (FIG. 7) for strengthening the film substrate  12 . 
     That is, the reinforcement frame  40  is formed of the same material as that of the reinforcement member  32  to have an elongated rectangular shape wherein reinforcement members  42 , each having a rectangular frame shape in conformity with the shape of the reinforcement member  32  for the semiconductor device, are consecutively aligned to each other. The respective reinforcement member  42  has an accommodation hole  44  for accommodating the semiconductor chip  10 . 
     The reinforcement frame  40  illustrated is formed of a thin sheet of stainless steel by a pressing work to impart the latter with a shape wherein the reinforcement members  42  are consecutively aligned. In the illustrated embodiment, the reinforcement member  42  is suspended from the frame solely by corners thereof for the purpose of enhancing the severance/separation of the reinforcement member  42  from the frame. Of course, instead of suspending the reinforcement member  42  by the corners thereof, it is possible to suspend the same by intermediate regions of the respective side. Also, it is possible to solely provide the accommodation holes  44  in the stainless sheet for accommodating the semiconductor chips  10 , which is then punched along the contour of the reinforcement members  32  to result in individual semiconductor devices. 
     FIG. 3 shows a the reinforcement frame  40 , to which the film substrates  12  individually separated from the film substrate tape  122  are adhered. B represents a region in which the film substrate  12  has been adhered, while C represents a region in which the film substrate  12  is not adhered. When the individual film substrate  12  is adhered to the reinforcement frame  40 , the film substrate  12  is first cut off from the film substrate tape  122  and then registered with the reinforcement member  42  of the reinforcement frame  40  while holding the former by suction or the like. Instead of providing an adhesive layer  18  (FIG. 4) in advance on the film substrate  12 , the adhesive layer  18  may be preliminarily formed on the reinforcement frame  40  to adhere the film substrate  12 . The adhesive layer  18  may be provided solely in a region of the reinforcement member  42  or all over the reinforcement frame  40 . 
     FIG. 4 is a side sectional view taken along line P-P′ in FIG.  3 . The reinforcement members  42 , each having the accommodation hole  44  for accommodating the semiconductor chip  10 , are consecutively aligned at a pitch. On one side of the reinforcement member  42  is adhered the individual film substrate  12 . The opening  15  is provided in a widthwise central region of the film substrate  12  adhered to the reinforcement member  42 . Bonding sections  22  of the circuit patterns are disposed along edges of the opening  15 , while lands  16   a  are formed outside of the bonding sections  22 , to be connected to external connection terminals. 
     After the film substrate  12  has been adhered to the respective reinforcement member  42 , the semiconductor chip  10  is bonded to the film substrate  12  while being accommodated within the accommodation hole  44 . 
     FIG. 5 is a side sectional view of the film substrate  12  carrying the semiconductor chip  10  thereon. The semiconductor chip  10  is supported by the film substrate  12  while being adhered thereto via the adhesive layer  18  provided on the bottom surface of the film substrate  12 . Although only one reinforcement member  42  in the reinforcement frame  40  is illustrated in this drawing to clarify the explanation, the semiconductor chips  10  are sequentially adhered to all the reinforcement members  42  of the reinforcement frame  40 . Reference numeral  23  denotes a protective film, for example, of solder resist. 
     After the semiconductor chip  10  has been mounted, the electrode terminals  20  of the semiconductor chip  10  are wire-bonded to the bonding parts  22  of the film substrate  12 , and the electrode terminals  20 , the bonding parts  22  and the bonding wires  24  are shielded with resin, as shown in FIG.  6 . 
     Finally, external connecting terminal, such as solder balls, are attached to the land portions  16   a , as shown in FIG.  7 . 
     Thus, the semiconductor devices are formed in every section of the reinforcement frame  40 , and are divided into single units by separating the respective reinforcement members  42  in the respective sections from each other. The resultant semiconductor device has the same structure as that shown in FIG.  14 . 
     Since the film substrate  12  in the outer peripheral region of the semiconductor chip  10  is supported by the reinforcement member  42  formed in the reinforcement frame  40  according to the process of this embodiment, the manufacturing of the semiconductor device is enhanced if reinforcement frame  40  is used, which has functions both for a carrier frame and a reinforcement member  32 . 
     The manufacturing process according to the present invention eliminates a carrier frame exclusively used for supporting and transporting the film substrate tape  122  along the manufacturing line, whereby the manufacturing process is simplified and waste is reduced to effectively lower the manufacturing cost. 
     The film substrate tape  122  may be designed solely to transfer the individual film substrates  12  to the reinforcement frame  40 . If the film substrate tape is designed to obtain as large a number as possible of the film substrates  12 , material for forming a base film such as polyimide could be effectively saved to efficiently produce the film substrate  12 . 
     Since a metallic material such as stainless steel, which is less expensive than resinous material, could be used for forming the reinforcement frame  40 , it is possible to lower the manufacturing cost while maintaining a sufficient strength for a carrier frame as well as enhancing the transportation workability. 
     In this regard, a resinous material may be used for forming the reinforcement frame  40 . If the same resinous material as that used for forming the film substrate  12  is employed, coefficients of thermal expansion of the film substrate  12  and the reinforcement member  32  are equal to each other to improve the reliability of the resultant semiconductor device. If heat-resistant resinous material is used, a thermally reliable semiconductor device is obtainable. 
     FIGS. 7 and 8 illustrate other embodiments of a semiconductor device produced by a process similar to the above-mentioned process for manufacturing a semiconductor device. 
     In a semiconductor device shown in FIG. 7, a film substrate  12  is used, which is provided on one side of a base film  14  with circuit patterns  16  and on the other side with a conductor layer  17  used as a ground layer or a power source layer. A reinforcement member  32  and a semiconductor chip  10  are bonded via an adhesive layer  18  to the film substrate  12 . Reference numeral  16   a  denotes a land, and  22  denotes a bonding part. The electrical connection between the circuit patterns  16  including the land  16   a  or the bonding part  22  and the conductor layer  17  is made by a via  17   a  pierced through the base film  14 . 
     The bonding part  22  and the land  16   a  may be independently formed and connected respectively to the conductor layer  17  by the respective vias  17   a . Or the circuit pattern  16  electrically connecting the bonding part  22  and the land  16   a  may be formed and then suitable positions of the circuit pattern  16  may be connected by the vias  17   a  to the conductor layer  17 . 
     After the film substrate  12  is bonded to a reinforcement frame  40  and the semiconductor chip  10  is adhered thereto, an electrode terminal  20  is wire-bonded to the bonding part  22 , and the electrode terminal  20  and the bonding part  22  are shielded with resin, after which external connection terminals  26  are bonded to the lands  16   a . Finally, the semiconductor device shown in FIG. 7 is individually separated from the reinforcement frame  40 . 
     In a semiconductor device shown in FIG. 8, a film substrate  12  is used, having a base film  14  with an opening at a position corresponding to an area in which electrode terminals  20  of a semiconductor chip  10  are provided. Leads  16   b  of circuit patterns  16  extend into the opening. A reinforcement member  32  and the semiconductor chip  10  are bonded to the film substrate  12  via an adhesive layer  18 . In FIG.  8 ( a ), the film substrate  12  is provided on the outer surface of the base film  14  with circuit patterns  16 . The semiconductor chip  10  is adhered to the base film  14  with the adhesive layer  18 . In FIG.  8 ( b ), the film substrate  12  is provided on the inner surface of the base film  14  with circuit patterns  16 . A semiconductor chip  10  and a reinforcement member  32  are adhered via an adhesive layer  18  to a shock-absorbing layer  19  covering the inner surface of the base film  14 . In this regard, the embodiment shown in FIG.  8 ( b ) may be modified so that the shock-absorbing layer  19  is eliminated and the semiconductor chip  10  and the reinforcement member  32  are adhered to the film substrate  12  via an electrically-insulating adhesive layer  18 . 
     The leads  16   b  are arranged to be aligned with the electrode terminals  20 , and each of the leads  16   b  may be wire-bonded and electrically connected to the respective electrode terminal  20  by bending a tip end thereof toward an electrode terminal-forming surface of the semiconductor chip  10  with a bonding tool. 
     After the film substrate  12  has been adhered to the reinforcement frame  40  and the semiconductor chip  10  has been bonded, the leads  16   b  are adhered to the electrode terminals  20  as described above, the electrode terminals  20  and the leads  16   b  are shielded with resin, and external connection terminals  26  are bonded to the lands  16   a . Finally, individual semiconductors are separated from the reinforcement frame  40  to result in the semiconductor devices shown in FIGS.  8 ( a ) and  8 ( b ). 
     While the semiconductor chip  10  used in the semiconductor device according to the above-mentioned embodiments has electrode terminals  20  arranged in a central region of the electrode terminal-forming surface, a semiconductor chip  10  used in an embodiment shown in FIG. 9 has electrode terminals  20  arranged in the peripheral region of the electrode terminal-forming surface. The electrode terminals  20  are electrically connected to circuit patterns of a film substrate  12  in the peripheral region of the semiconductor chip  10  by a wire bonding, and the electrode terminals  12 , bonding wires and bonding sections are shielded with shielding resin  28 . Such a semiconductor device may also be produced in a similar manner as described above wherein a film substrate tape  122  and a reinforcement frame  40  are prepared in shape in conformity with a semiconductor chip  10 , and the reinforcement frame  40  is used as a carrier frame. 
     FIG. 10 illustrates a further embodiment of a semiconductor device wherein a semiconductor chip  10  is mounted to a film substrate  12  by a flip-chip bonding. On one surface of a base film  14  of the film substrate  12  are provided circuit patterns  16 , while on the other surface thereof defining a mounting surface for the semiconductor chip  10  are provided connection terminals  50  to be bonded to connector bumps  20   a  formed on a electrode terminal-forming surface of the semiconductor chip  10 . The connection terminal  50  and the circuit pattern  16  are electrically connected to each other with conductive vias  52  provided by penetrating the base film  14  in the thickness direction. Reference numeral  32  denotes a reinforcement member for supporting the film substrate  12  in the outer peripheral region of the semiconductor chip  10 . 
     According to this embodiment, the film substrate  12  cut off from the film substrate tape  122  is adhered to a reinforcement frame  40 , and the semiconductor chip  10  is bonded to the film substrate  12  while aligning the connection terminals  50  of the film substrate  12  with the bumps  20   a . After the semiconductor chip  10  has been mounted, the electrode terminal-forming surface of the semiconductor chip  10  is shielded with shield resin  28  by a potting method. 
     Finally, external connection terminals  26  are bonded to lands provided in the circuit patterns  16 , and the reinforcement members  32  are cut off from the reinforcement frame  40  to result in individual semiconductor devices. 
     In this respect, according to these embodiments described above, external connection terminals such as solder balls may be bonded after the reinforcement members  32  have been cut off and the individual semiconductor devices have been obtained. Or, if the connection terminals are already provided on a circuit board on which the semiconductor device is to be mounted, the external connection terminals may be eliminated. 
     According to a process for manufacturing a semiconductor device of the present invention, as described above, a film substrate is adhered onto an electrode terminal-forming surface of a semiconductor chip and is reinforced with an reinforce member, whereby the process for manufacturing the semiconductor device can be simplified to effectively reduce the manufacturing cost. Also, by using a metallic frame as a reinforcement frame, the workability is improved to result in a reliable semiconductor device.