Mounting apparatus and method

A mounter apparatus includes a first block disposed so as to be able to be reciprocated by an actuator in a first direction, the first block has a conical hole having a conical internal wall and an axis parallel to the first direction, a second block disposed so as to face the first block and is held by the first block with an elastic body interposed between the first block and the second block, the second block moving by the actuator together with the first block in the first direction, the second block approaching the first block while compressing the elastic body, the second block moving away from the first block due to an elastic force of the elastic body, and a suction head portion rotatably held by the second block and has a suction nozzle on the opposite side from the side where the first block is disposed.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is based upon and claims the benefit of priority of the prior Japanese Patent Application No. 2010-10728, filed on Jan. 21, 2010, the entire contents of which are incorporated herein by reference.

FIELD

The embodiments discussed herein are related to a mounting apparatus and a mounting method.

BACKGROUND

Apparatuses described in Japanese Laid-open Patent Publication No. 8-17872 and Japanese Laid-open Patent Publication No. 2001-135649 suction the upper surface of a part with a suction nozzle to hold the part. For this purpose, the apparatuses are provided with a tube used for suction.

When a heat spreader is attached to the upper surface of a chip, sometimes the resulting upper surface is not parallel to the lower surface. In addition, depending on the adhesive used for attaching the heat spreader, the inclination of the upper surface to the lower surface differs from chip to chip.

The apparatuses described in the above patent documents can suction and move a part the upper and lower surfaces of which are not parallel.

However, the apparatuses described in the above patent documents are prevented from returning the suction nozzle to the reference state (return to horizontal position) by the influence of the tube eccentrically attached to the suction nozzle and the influence of the weight and tension of the tube itself. If the operation to suction a part is repeated without returning to the horizontal position, the inclination of the suction nozzle accumulates. If the inclination of the suction nozzle accumulates, the suction nozzle cannot follow the inclination of the upper surface of the part because of the position of the center of gravity. If the suction nozzle comes into contact with the part when the suction nozzle cannot follow the inclination of the upper surface of the part, the suction nozzle cannot produce a vacuum and fails to suction the part. In addition, a point load acts on the part and breaks the part.

The present invention returns a suction nozzle of a mounter apparatus to the reference state every time the operation to move a part is completed.

SUMMARY

According to an embodiment, a mounter apparatus includes a first block disposed so as to be able to be reciprocated by an actuator in a first direction, the first block has a conical hole having a conical internal wall and an axis parallel to the first direction, a second block disposed so as to face the first block and is held by the first block with an elastic body interposed between the first block and the second block, the second block moving by the actuator together with the first block in the first direction, the second block approaching the first block while compressing the elastic body, the second block moving away from the first block due to an elastic force of the elastic body, a suction head portion rotatably held by the second block and has a suction nozzle on an opposite side from a side where the first block is disposed, an immobilizing mechanism immobilizing the suction head portion and stops the rotational operation of the suction head portion, a taper block having an external wall having a conical shape corresponding to the shape of the internal wall of the conical hole, the taper block placed in the conical hole, and a flexible connecting member connecting the suction head portion and the taper block.

The object and advantages of the invention will be realized and attained by at least the features, elements, and combinations particularly pointed out in the claims.

DESCRIPTION OF EMBODIMENTS

Embodiments of the present invention will be described with reference to the accompanying drawings. Some of the Figures may not be completely drawn to scale. In some of the Figures, details may be omitted. In some sectional views, hatching may be omitted, or each part may not be hatched differently.

A mounter apparatus1shown inFIG. 1has a first block2that is disposed so as to be able to be reciprocated by an actuator5in a first direction indicated by an arrow3. The first block2has a conical hole4that has a conical internal wall as shown inFIGS. 2,3, and5. The axis AX of the conical hole4is parallel to the first direction indicated by the arrow3. The first direction is parallel to the vertical direction. The axis AX is also parallel to the vertical direction. The first block2has slide bearings10.

The mounter apparatus1has a second block6that is disposed so as to face the first block2and is held by the first block2with springs9interposed between the first block2and the second block6. A spring9is an example of an elastic body. The mounter apparatus1has a connecting block7attached to the second block6as shown inFIGS. 1 and 2. Two slide shafts8are erected on the connecting block7. That is to say, one ends of the slide shafts8are inserted into the connecting block7and fixed. The other ends of the slide shafts8are passed through the slide bearings10of the first block2. C-shaped washers11are attached to the ends of the slide shafts8exposed from the slide bearings10. The second block6is held by the first block2in this way. The slide shafts8are inserted into the springs9. The springs9are sandwiched between the connecting block7and the slide bearings10. The second block6and the connecting block7may be integrally formed.

The foregoing second block6can be moved by the actuator5together with the first block2in the first direction indicated by the arrow3. In addition, the second block6can approach the first block2while compressing the springs9. That is to say, when the first block2is moved by the actuator5with the movement of the second block6restricted, the first block2and the second block6approach each other. At this time, the springs9are compressed. The second block6can be moved away from the first block2by the elastic force of the springs9. That is to say, when the operation of the actuator5is stopped with the springs9compressed, the first block2tries to return to the original position due to the elastic force of the springs9, and the first block2and the second block6move away from each other. The springs9also function as buffers for overload prevention.

The mounter apparatus1has a suction head portion14. As shown inFIG. 2, the suction head portion14has a spherical member15and a suction nozzle18attached to the spherical member15. The second block6has a holding member16that holds the spherical member15. The spherical member15is rotatably held. In this way, the suction head portion14is rotatably held by the second block6. The spherical member15has a cavity inside, in which a cap member17is fitted. The cap member17has a cap portion17aand a cylindrical portion17bconnected to the cap portion17a. The cap member17is attached to the spherical member15by inserting the cylindrical portion17binto the spherical member15. The cap member17is attached to the spherical member15such that the cap portion17ais located on the side where the first block2is disposed. On the opposite side from the side where the first block2is disposed, the suction nozzle18is provided. The cap member17is provided with an air passage for suction. The top portion30of the cap portion17ais provided with a mouth member17a1for connecting a suction tube19. The suction tube19is an example of a connecting member that connects the suction head portion14and a taper block12to be described later, and it has flexibility. The suction tube19supplies suction force to the suction head portion14. The suction tube19is formed of a slightly elastic material, such as nylon or polyurethane. The length of the suction tube19is determined in accordance with a reference state where the distance between the first block2and the second block6is maximal. That is to say, the suction tube19has such a length that when the distance between the first block2and the second block6is maximal, the suction tube19connecting the suction head portion14and the taper block12is straight (not bent).

The mounter apparatus1has an immobilizing mechanism that immobilizes the suction head portion14and stops the rotational operation of the spherical member15. As shown inFIGS. 2,8, and9, the immobilizing mechanism has a brake block20and an annular brake pad21attached thereto. In addition, the immobilizing mechanism has an air cylinder22that drives the brake block20. The brake pad21is formed of an elastic body having a high coefficient of friction. In this embodiment, the brake pad21is formed of rubber. The air cylinder22is an example of an actuator that drives the brake block20. Another type of actuator, for example, an oil hydraulic cylinder may be used. Alternatively, an electric motor may be used to drive the brake block20. The air cylinder22moves the brake block20in the vertical direction. That is to say, the brake block20moves in a direction in which a part (chip51) is suctioned and locks the suction head portion14. Thus, the undersurface of the chip51can be kept horizontal. That is to say, for example, when lock operation is performed, the chip51is not raised slightly, and the undersurface of the chip51can be easily kept horizontal.

The mounter apparatus1has a taper block12.FIG. 7is a perspective view of the taper block12. The taper block12has a cylindrical portion12aand an external wall12bthat is connected to the cylindrical portion12aand has a conical shape corresponding to the shape of the internal wall of the conical hole4of the first block2. The external wall12bforms a truncated cone. Inside the taper block12, an air passage12cis formed. One mouth portion of the air passage is provided in the side wall of the cylindrical portion12a. The other mouth portion of the air passage is provided in the center of the truncated cone. As shown inFIG. 7, the mouth portions are provided with connecting members13aand13bfor connecting suction tubes. To the connecting member13bis connected the suction tube19. To the connecting member13ais connected a suction tube that is connected to a pump included in a suction mechanism.

The foregoing taper block12is placed in the conical hole4. The inclination angle of the external wall12bof the taper block12corresponds to the inclination angle of the internal wall of the conical hole4. Therefore, the taper block12can be brought into a seated state where the taper block12is in close contact with the internal wall of the conical hole4. The taper block12in the seated state is restricted from moving in the horizontal direction. When the first block2and the second block6approach each other and the suction tube19is bent, the taper block12is pushed up by the suction tube19and is unseated from the conical hole4for an instant. The taper block12in the unseated state can move in the horizontal direction.

The position of the center of rotation of the suction head portion14in the foregoing mounter apparatus1will be described with reference toFIG. 2. The suction head portion14has a spherical member15rotatably held by a holding member16as described above. Inside the foregoing spherical member15, a center M of rotation is set.

As described above, the first direction in this embodiment is the vertical direction. Assume a plane perpendicular to the vertical direction, that is to say, a horizontal plane F. The center M of rotation is set so as to coincide with the position of the axis AX in the horizontal plane F. The suction tube19connects the connecting member13bprovided in the center of the taper block12and the top portion30of the cap portion17aincluded in the suction head portion14. By setting as described above, the connecting member (suction tube)19extends in the vertical direction with the taper block12pulled up and the suction nozzle18not in contact with the part (chip)51. Thus, the suction head portion14can be returned to the reference state where the suction nozzle18faces downwardly.

The mounter apparatus1has a sensor that measures the distance between the first block2and the second block6. The sensor is used for acquiring data for calculating the timing to activate the air cylinder included in the immobilizing mechanism and to apply a brake on the suction head portion14. The foregoing sensor may be a sensor that measures the sliding of the first block2relative to the slide shafts8. The mounter apparatus1is connected to a control portion. The operation of the mounter apparatus1is controlled by the control portion.

Next, a part mounting method using the above-described mounter apparatus1will be described. Here, a description will be given of a method for picking up a part (chip)51from a table50and placing it on a substrate52. As shown, for example, inFIG. 11, the upper surface, that is to say, the surface51ato be suctioned of the chip51is inclined. This inclination is caused by bonding a heat spreader to the chip51.

First, the process of suctioning and picking up the chip51from the table50using the mounter apparatus1will be described with reference to a time chart shown inFIG. 10. For the purpose of describing the movements of the mounter apparatus1, figures schematically showing the mounter apparatus1, such asFIG. 8, will be used. InFIG. 8, the cap member17, the holding member16, and others are omitted.

The suctioning process is started from a standby state shown inFIG. 11. This state will be referred to as OPERATION1. In this state, the elastic force of the spring9acts so as to move the first block2and the second block6away from each other, and the distance between the first block2and the second block6is maximal. The tension of the suction tube19acts so as to pull the spherical member15and the taper block12. The spherical member15is not immobilized by the immobilizing mechanism. The taper block12, being pulled by the suction tube19, is seated in the conical hole4. The actuator5is not activated and does not perform the operation in the vertical direction (Z-axis direction). The state of each part in OPERATION1is as described above.

From the state of OPERATION1shown inFIG. 11, the mounter apparatus1activates the actuator5and lowers the first block2(OPERATION2). At this time, the second block6also lowers, while maintaining the distance to the first block2. Because the second block6lowers, the suction nozzle18attached to the spherical member15held by the second block6also lowers. Because the spherical member15is pulled by the suction tube19, the suction nozzle18keeps the center position and maintains the vertically downward position. In this way, the mounter apparatus1brings the suction nozzle18into contact with the surface51ato be suctioned of the chip51from the first direction (vertical direction) with the center position of the suction nozzle18kept as shown inFIG. 12. In this state, the elastic force of the spring9still balances with the tension of the suction tube19, and the spherical member15cannot rotate.

From the state shown inFIG. 12, the mounter apparatus1continues the operation of the actuator5as indicated by an arrow25inFIG. 13. Thus, the first block2is moved in the first direction (vertical direction) toward the chip51. As a result, the spring9is compressed and deformed. The spring9is compressed and deformed as the distance between the first block2and the second block6is reduced. When the distance between the first block2and the second block6becomes shorter than the length of the suction tube19, the taper block12is unseated from the conical hole4as shown inFIG. 13. Thus, the spherical member15becomes rotatable, and the suction head portion14rotates according to the inclination of the surface51ato be suctioned as shown inFIG. 14. When the inclination of the suction head portion14has become equal to the inclination of the surface51ato be suctioned, OPERATION3is completed.

When activating the actuator5, the mounter apparatus1measures the distance between the first block2and the second block6with a sensor. In this embodiment, when the distance between the first block2and the second block6is reduced by 2 millimeters (mm) from the reference state, it is determined that the suction nozzle18is in close contact with the surface51ato be suctioned. When it is detected that the distance between the first block2and the second block6reaches a specified distance (reduced by 2 mm), the state of the actuator5is maintained (OPERATION4). The distance between the first block2and the second block6is set to a distance long enough for the suction nozzle18to follow the surface51ato be suctioned. The inclination of the surface51ato be suctioned varies but is within a specified range. So, the above distance is set so that this variation can be covered.

The mounter apparatus1then activates the pump included in the suction mechanism and attaches the chip51to the suction nozzle18of the suction head portion14(OPERATION5).

After attaching the chip51, the mounter apparatus1activates the immobilizing mechanism, immobilizes the suction head portion14, and stops the rotational operation of the suction head portion14as shown inFIG. 15. More specifically, the air cylinder22is activated, the brake pad21is pressed against the spherical member15(actually the cap member17), and a brake is put on the spherical member15to lock the spherical member15. After the spherical member15is locked, the actuator5is raised. At this time, the distance between the first block2and the second block6is extended by the elastic force of the spring9(OPERATION6).

After locking the spherical member15, the mounter apparatus1pulls up the chip51being suctioned as shown inFIG. 16and moves over the substrate52on which the chip51is to be mounted. At this time, the undersurface of the chip51is maintained horizontal.

Next, the process of releasing the chip51from the suctioned state and mounting it on the substrate52will be described with reference to a time chart shown inFIG. 17. The release of the chip51is started from the state of OPERATION6. A brake is put on the spherical member15and the spherical member15is locked. The spring9is slightly compressed and is not fully restored. The taper block12can be unseated from the conical hole4. The actuator5still maintains the lowered state.

While maintaining such a state, the mounter apparatus1disposes the chip51at a mounting position on the substrate52as shown inFIG. 18(OPERATION7). The mounter apparatus1then stops suctioning the chip51with the suction mechanism and releases the chip51from the suction nozzle18(suction head portion14). Thus, the chip51is placed on the substrate52.

After that, the mounter apparatus1raises the first block2with the actuator5as indicated by an arrow27inFIG. 19(OPERATION8).FIG. 19shows a state where the spherical member15is still locked by the immobilizing mechanism and therefore the spherical member15is inclined. The mounter apparatus1then releases the immobilization of the suction head portion14by the immobilizing mechanism as shown inFIG. 20. When the actuator5raises the first block2, the distance between the first block2and the second block6is extended by the elastic force of the spring9acting as indicated by arrows28inFIG. 20. Finally, the distance between the first block2and the second block6returns to the reference state. As described above, when moving the first block2by the restoring force of the spring9, the mounter apparatus1moves the taper block12in the vertical direction at the same time (OPERATION9).

When raised together with the first block2, the taper block12is seated in the conical hole4, and the axis of the taper block12becomes coincident with the axis AX of the conical hole4. As the distance between the first block2and the second block6is extended, the spherical member15released from the locked state is pulled up by the suction tube19as indicated by an arrow29inFIG. 20. As a result, the spherical member15rotates, and the suction nozzle18attached to the spherical member15returns to the center position. The center position is the reference position of the suction nozzle18, where the suctioning surface of the suction nozzle18is kept horizontal and the axis of the suction nozzle18coincides with the axis AX of the conical hole4.

Thus, the mounter apparatus1of this embodiment can return the suction nozzle18to the reference state every time the operation to move a chip51is completed.

The mounter apparatus1of the above-described embodiment is configured to suction the chip51mainly by the operation in the vertical direction, and therefore the overall structure can be made compact. Because the operation in the vertical direction is mainly performed, even when other parts are mounted near the chip mounting position, interference with these parts can be avoided. In addition, the suction head portion14is returned to the horizontal position by the suction tube19that connects the taper block12held in the conical hole4provided in the first block2and the suction head portion14rotatably held by the second block6. Such a structure can be made at low cost. The suction tube19extends vertically from the center of the taper block12, and the suction head portion14is provided at the lower end thereof. Thus, the influence of the weight and tension of the suction tube19on the direction of the suction nozzle18can be reduced. Because the mounter apparatus1returns the suction nozzle18to the reference state when the operation to move a part is completed, the suction nozzle18can follow the inclination of the upper surface of the part when the suction nozzle18comes into contact with the part. Thus, the part can be reliably suctioned and breakage of the part is avoided.