JP7607541B2 - Semiconductor manufacturing apparatus and method for manufacturing semiconductor device - Google Patents

Description

This disclosure relates to a semiconductor manufacturing apparatus and a method for manufacturing a semiconductor device.

Conventionally, there is a semiconductor device in which a conductive lead frame carrying a semiconductor element is sealed in insulating resin.

For example, Patent Document 1 discloses a wire bonding device for the lead frame of a small-capacity (compact) semiconductor device. In the technology described in Patent Document 1, during wire bonding, the lead frame is fixed by a bonding table and a lead holder arranged to face the bonding table.

Japanese Unexamined Patent Publication No. 4-340238

However, when wire bonding is performed on a large-capacity (large) semiconductor device, the lead frame also becomes large, and the technology described in Patent Document 1 is unable to securely fix the lead frame because the size of the lead holder is small compared to the size of the lead frame.

Therefore, with the technology described in Patent Document 1, there is a concern that the ultrasonic vibrations during wire bonding may not be properly transmitted to the lead frame, resulting in unstable bond strength of the wire bonding.

Therefore, the present disclosure aims to provide a technology that can achieve stable wire bonding strength even in the case of large-capacity semiconductor devices.

The semiconductor manufacturing apparatus of the present disclosure comprises a receiving stand for placing a lead frame on its upper surface, a fixing jig arranged above the receiving stand and fixing the lead frame between the receiving stand, a first table for holding the outer periphery of the fixing jig, an image processing camera for detecting first position information indicating the position of the lead frame through an opening of the fixing jig, a first ball screw attached to the first table, a first motor for moving the fixing jig laterally together with the first table by rotating the first ball screw, and a control unit for controlling the drive of the first motor based on the first position information detected by the image processing camera, wherein the fixing jig has a main body for holding the upper surface of the lead frame, the opening for exposing a wire bonding area in which wire bonding is performed on the lead frame, and a lead frame presser for pressing the wire bonding area of the lead frame towards the receiving stand at the opening.

According to the present disclosure, even in the case of a large-capacity semiconductor device, the lead frame presser of the fixing jig can firmly fix the wire bonding area of the lead frame. This allows the ultrasonic vibrations during wire bonding to be properly transmitted to the lead frame, resulting in stable wire bonding strength.

1 is a schematic diagram showing an entire semiconductor manufacturing apparatus according to an embodiment; 1 is a top view showing a main part of a semiconductor manufacturing apparatus according to an embodiment; 1 is a side view showing a main part of a semiconductor manufacturing apparatus according to an embodiment; 1 is a top view showing a state in which a fixing jig and a first XY table are omitted from a main part of a semiconductor manufacturing apparatus according to an embodiment. FIG. 1 is a side view showing a state in which a fixing jig and a first XY table are omitted from a main part of a semiconductor manufacturing apparatus according to an embodiment. FIG. 13 is a top view showing another example of the receiving stand. 13 is a cross-sectional view showing a state in which a lead frame is placed on another example of the receiving stand. FIG. FIG. 13 is a top view showing still another example of the receiving stand. 13A and 13B are diagrams showing the display on the monitor screen when adjusting the position of a fixing jig. 4 is a flowchart showing a method for manufacturing a semiconductor device using the semiconductor manufacturing apparatus according to the embodiment.

<Embodiment>
<Configuration of semiconductor manufacturing equipment>
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the accompanying drawings. Fig. 1 is a schematic diagram showing an entire semiconductor manufacturing apparatus 1 according to an embodiment of the present invention.

As shown in FIG. 1, the semiconductor manufacturing device 1 includes a housing 1a, a receiving table 8, a fixing jig 7, a transport rail 6, a bonding head 4, a monitor 5, a loader 2, and an unloader 3. The semiconductor manufacturing device 1 is capable of performing wire bonding on small-capacity (compact) semiconductor devices and large-capacity (large) semiconductor devices.

The interior of the housing 1a contains a plate-shaped receiving stand 8, a plate-shaped fixing jig 7, a transport rail 6, and a bonding head 4. The loader 2, unloader 3, and monitor 5 are located outside the housing 1a.

The receiving table 8 is a member for placing the lead frame 9 on its upper surface. The transport rail 6 is placed between the loader 2 and the unloader 3 via the upper surface of the receiving table 8. The transport rail 6 transports the lead frame 9 placed on the loader 2 to below the bonding head 4 in order to perform wire bonding on the lead frame 9, and transports the lead frame 9 to the unloader 3 when wire bonding is completed.

The fixing jig 7 is placed above the receiving base 8 and fixes the lead frame 9 to the receiving base 8. Details of the fixing jig 7 will be described later.

The bonding head 4 is positioned above the fixture 7 and can be moved up and down and left and right to perform wire bonding on the lead frame 9. The monitor 5 is attached to the outer surface of the housing 1a and displays program information and progress status related to wire bonding. This allows the user to check the program information and progress status related to wire bonding from outside.

The lead frame 9 may be equipped with one or more power semiconductor elements (not shown) capable of carrying a current of several amperes or more and several hundred amperes or less. When performing wire bonding on a large-capacity semiconductor device, a gold, silver, copper or aluminum wire having a diameter of 100 μm or more may be set on the bonding head 4.

Figure 2 is a top view showing the main parts of the semiconductor manufacturing device 1. Specifically, it is a view looking from the bonding head 4 side toward the lead frame 9 side.

As shown in FIG. 2, the fixing jig 7 is placed on the upper surface of the lead frame 9, which is placed on the upper surface of the receiving base 8, and fixes the lead frame 9 together with the receiving base 8. The fixing jig 7 has a main body 7a that is rectangular when viewed from above, an opening 7b, and a lead frame holder 15.

In the center of the main body 7a, an opening 7b that is rectangular when viewed from above is formed. The opening 7b exposes the wire bonding area in the lead frame 9 where wire bonding is performed. This makes it possible to perform wire bonding with the fixing jig 7 attached.

The receiving base 8 is formed in a rectangular shape when viewed from above, and the contour of the receiving base 8 when viewed from above is larger than the contour of the opening 7b when viewed from above. Furthermore, the contour of the main body 7a when viewed from above is larger than the contour of the receiving base 8 when viewed from above. This makes it possible for the main body 7a and the receiving base 8 to fix the periphery of the wire bonding area in the lead frame 9.

Because the lead frame 9 is cut out by pressing or the like to form a circuit (not shown), the rigidity of the lead frame 9 is low. In other words, the ultrasonic vibrations output from the bonding head 4 during wire bonding are not easily transmitted to the lead frame 9 properly. When a semiconductor device has a large capacity, the size of the power semiconductor element is also large, and if multiple power semiconductor elements are mounted, the number of wires bonded also increases, which in turn increases the wire bonding area.

As such, in large-capacity semiconductor devices, the opening 7b becomes wider, and when wire bonding is performed near the center of the opening 7b, the ultrasonic vibrations output from the bonding head 4 during wire bonding are not transmitted correctly to a position on the lead frame 9 that corresponds to the center of the opening 7b, resulting in unstable bond strength of the wire bonding.

To solve this problem, in this embodiment, seven rod-shaped lead frame pressers 15 are provided that protrude from the opening end of the opening 7b toward the inner periphery. The seven lead frame pressers 15 are arranged so that they can press the periphery of the wire bonding location, which is the location of the wire bonding area where wire bonding is actually performed. The seven lead frame pressers 15 press the wire bonding area of the lead frame 9 with low rigidity in the opening 7b from the bonding head 4 side to the conveyor rail 6 side (i.e., the receiving table 8 side). As a result, even with a lead frame 9 with low rigidity, the ultrasonic vibration output from the bonding head 4 during bonding is correctly transmitted to the lead frame 9, making it possible to stabilize the bonding strength of the wire bonding.

Although seven lead frame holders 15 are shown in FIG. 2, the number of lead frame holders 15 may be one or more, and the bonding strength can be further stabilized by arranging the lead frame holders 15 around the wire bonding location. Also, the lead frame holder 15 may be in a shape other than a rod shape.

The lead frame retainer 15 may be detachable, or may be integral with the opening end of the opening 7b. If the lead frame retainer 15 is detachable, the lead frame retainer 15 may be attached to a desired position at the opening end of the opening 7b. Furthermore, various detachable structures, such as various fitting structures, can be used to make the lead frame retainer 15 detachable from the opening end of the opening 7b.

Next, the structure for adjusting the positions of the receiving platform 8 and the fixing jig 7 will be described. Figure 3 is a side view showing the main parts of the semiconductor manufacturing equipment 1. Figure 4 is a top view showing the main parts of the semiconductor manufacturing equipment 1 with the fixing jig 7 and the first X-Y table 13a omitted. Figure 5 is a side view showing the main parts of the semiconductor manufacturing equipment 1 with the fixing jig 7 and the first X-Y table 13a omitted.

As shown in Figures 2 and 3, the semiconductor manufacturing apparatus 1 further includes a first X-Y table 13a (corresponding to the first table), an image processing camera 14, a first X-Y ball screw 11a (corresponding to the first ball screw), a first X-Y motor 10a (corresponding to the first motor), a control unit 17, a second X-Y table 13b (corresponding to the second table), a second X-Y ball screw 11b (corresponding to the second ball screw), a second X-Y motor 10b (corresponding to the second motor), and a sensor 16.

The control unit 17 controls each part of the semiconductor manufacturing device 1 based on a control program related to wire bonding stored in its own memory. The control unit 17 is, for example, a processor.

The first X-Y table 13a is formed into a rectangular frame shape when viewed from above. The receiving platform 8, except for its lower end, is disposed in the opening 13a1 of the first X-Y table 13a, and the upper surfaces of the first X-Y table 13a and the upper surfaces of the receiving platform 8 are located at the same height. A fixing jig 7 is disposed on the rectangular frame-shaped upper surface of the first X-Y table 13a via a lead frame 9. Therefore, the outer periphery of the fixing jig 7 is held by the first X-Y table 13a.

A first X-Y ball screw 11a and a first X-Y motor 10a are attached to at least two adjacent sides of the first X-Y table 13a, and the first X-Y ball screw 11a rotates when driven by the first X-Y motor 10a. The drive of the first X-Y motor 10a is controlled by the control unit 17.

By rotating the first X-Y ball screw 11a, the first X-Y table 13a can be moved on the X-Y plane. By moving the first X-Y table 13a, the fixed jig 7 arranged above the first X-Y table 13a can also be moved on the X-Y plane. Here, the X-Y plane is a horizontal (lateral) surface. In other words, the first X-Y table 13a is a table for moving the fixed jig 7 on the X-Y plane.

The image processing camera 14 is positioned above the fixture 7 and detects first position information indicating the position of the lead frame 9 through the opening 7b of the fixture 7. The control unit 17 aligns the fixture 7 on the X-Y plane by controlling the drive of the first X-Y motor 10a based on the first position information detected by the image processing camera 14.

As shown in Figures 3 to 5, the second X-Y table 13b is formed in a rectangular shape when viewed from above, and is disposed below the first X-Y table 13a. A support 8 is disposed on the upper surface of the second X-Y table 13b. A set of a second X-Y ball screw 11b and a second X-Y motor 10b is attached to at least two adjacent sides of the second X-Y table 13b, and the second X-Y ball screw 11b rotates when driven by the second X-Y motor 10b. The drive of the second X-Y motor 10b is controlled by the control unit 17.

By rotating the second X-Y ball screw 11b, the second X-Y table 13b can be moved on the X-Y plane. By moving the second X-Y table 13b, the support table 8 placed on the upper surface of the second X-Y table 13b can also be moved on the X-Y plane. In other words, the second X-Y table 13b is a table for moving the support table 8 on the X-Y plane. Note that the support table 8 and the second X-Y table 13b may be provided integrally.

The sensor 16 is disposed around the second X-Y table 13b and detects second position information indicating the position of the second X-Y table 13b. The control unit 17 controls the driving of the second X-Y motor 10b based on the second position information detected by the sensor 16, thereby aligning the receiving table 8 on the X-Y plane.

As described above, the receiving platform 8 is placed in the opening 13a1 of the first X-Y table 13a, and a clearance is provided between the receiving platform 8 and the first X-Y table 13a so that the receiving platform 8 and the first X-Y table 13a do not come into contact when the receiving platform 8 moves on the X-Y plane.

Next, the shape of the upper surface of the receiving base 8 will be described. Fig. 6 is a top view showing another example of the receiving base 8. Fig. 7 is a cross-sectional view showing the state in which the lead frame 9 is placed on another example of the receiving base 8. Fig. 8 is a top view showing yet another example of the receiving base 8.

If the lead frame 9 is flat, the top surface of the receiving base 8 should also be flat so that the ultrasonic vibrations output from the bonding head 4 during bonding are properly transmitted to the lead frame 9, resulting in stable wire bonding strength.

When the lead frame 9 has a step, as shown in Figures 6 and 7, by providing a recess 8a capable of accommodating the step of the lead frame 9 in the area on the top surface of the support 8 where the lead frame 9 is placed, ultrasonic vibrations can be properly transmitted to the lead frame 9, and the bonding strength of the wire bonding can be stabilized. In addition, the support 8 may be moved on the X-Y plane to match the step of the lead frame 9.

Furthermore, as shown in FIG. 8, multiple receiving bases 8 may be connected to arrange multiple lead frames 9.

Next, we will explain how to adjust the initial position of the fixture 7. Figure 9 shows the display on the monitor screen when adjusting the position of the fixture 7.

The initial position of the fixture 7 is adjusted to ensure that the lead frame 9 is fixed in the same position every time, in order to obtain stable wire bonding strength.

The control unit 17 acquires and learns the first position information detected by the image processing camera 14 as past history, and controls the drive of the first X-Y motor 10a to adjust the initial position of the fixing jig 7 based on the learning results of the past history. In other words, the control unit 17 performs fine adjustments in advance for the initial position of the fixing jig 7 based on the past history. This reduces the frequency and amount of position adjustment of the fixing jig 7, improving the manufacturing efficiency of semiconductor devices.

Learning of past history can be achieved, for example, using AI (Artificial Intelligence) technologies such as machine learning and deep learning, which enables more advanced learning.

In FIG. 9, the horizontal axis indicates the X axis and the vertical axis indicates the Y axis. The intersection of the X axis and the Y axis is displayed in the upper left as the XY coordinates. Furthermore, the frame 20a on the left side indicates the correct position where the fixing jig 7 should be placed, and the frame 20b on the right side indicates the current position of the fixing jig 7. The current position of the fixing jig 7 is the position of the fixing jig 7 when it is placed on the lead frame 9 and before the fixing jig 7 holds down the lead frame 9.

The control unit 17 controls the drive of the first X-Y motor 10a so that the right frame 20b is aligned with the left frame 20a. In the next wire bonding, the control unit 17 controls the drive of the first X-Y motor 10a so that the fixing jig 7 is shifted by the amount of the current position adjustment.

<Method of Manufacturing Semiconductor Device>
Next, a description will be given of a method for manufacturing a semiconductor device using the semiconductor manufacturing apparatus 1. FIG 10 is a flow chart showing a method for manufacturing a semiconductor device using the semiconductor manufacturing apparatus 1.

As shown in FIG. 10, first, the control unit 17 transports the lead frame 9 from the loader 2 on the transport rail 6, and places the lead frame 9 on the top surface of the receiving table 8 (step S1). After that, the control unit 17 places the fixing jig 7 on the top surface of the lead frame 9.

Next, the control unit 17 checks the positional relationship between the lead frame 9 and the receiving table 8 using the sensor 16, and adjusts the position of the receiving table 8 together with the second X-Y table 13b by moving the second X-Y table 13b based on the second position information detected by the sensor 16 (step S2).

Next, the control unit 17 adjusts the position of the fixture 7 together with the first XY table 13a based on the first position information detected by the image processing camera 14 (step S3). At this time, the position of the lead frame holder 15 provided on the main body 7a of the fixture 7 is also adjusted.

Next, the control unit 17 presses the fixing jig 7 against the lead frame 9 to fix the lead frame 9 between the fixing jig 7 and the receiving stand 8 (step S4), and then checks the position and size information of the wire bonding area of the lead frame 9 with the image processing camera 14 and performs wire bonding (step S5).

Next, the control unit 17 moves the fixing jig 7 upward to release it from the lead frame 9 (step S6), then transports the lead frame 9 to the unloader 3 on the transport rail 6, and stores the lead frame 9 in the unloader 3 (step S7).

Finally, the lead frame 9 is covered with sealing resin (step S8) to complete the semiconductor device.

＜Effects＞
As described above, the semiconductor manufacturing apparatus 1 of the embodiment comprises a receiving table 8 for placing a lead frame 9 on its upper surface, and a fixing jig 7 that is positioned above the receiving table 8 and fixes the lead frame 9 together with the receiving table 8. The fixing jig 7 has a main body 7a that holds the upper surface of the lead frame 9, an opening 7b that exposes a wire bonding area in the lead frame 9 where wire bonding is performed, and a lead frame presser 15 that presses the wire bonding area of the lead frame 9 towards the receiving table 8 at the opening 7b.

Therefore, even in the case of a large-capacity semiconductor device, the lead frame holder 15 of the fixing jig 7 can firmly fix the wire bonding area of the lead frame 9. This allows the ultrasonic vibrations during wire bonding to be properly transmitted to the lead frame 9, resulting in stable wire bonding strength. As a result, the yield of semiconductor devices can be improved.

The semiconductor manufacturing device 1 also includes a first X-Y table 13a that holds the outer periphery of the fixture 7, an image processing camera 14 that detects first position information indicating the position of the lead frame 9 through the opening 7b of the fixture 7, a first X-Y ball screw 11a attached to the first X-Y table 13a, a first X-Y motor 10a that moves the fixture 7 laterally together with the first X-Y table 13a by rotating the first X-Y ball screw 11a, and a control unit 17 that controls the drive of the first X-Y motor 10a based on the first position information detected by the image processing camera 14.

This makes it possible to improve the accuracy of alignment between the lead frame 9 and the fixture 7. This allows for more stable wire bonding strength to be obtained.

The semiconductor manufacturing apparatus 1 also includes a second X-Y table 13b with a support 8 disposed on its upper surface, a second X-Y ball screw 11b attached to the second X-Y table 13b, a second X-Y motor 10b that moves the support 8 laterally together with the second X-Y table 13b by rotating the second X-Y ball screw 11b, and a sensor 16 that detects second position information indicating the position of the second X-Y table 13b, and the control unit 17 controls the driving of the second X-Y motor 10b based on the second position information detected by the sensor 16.

This makes it possible to improve the accuracy of alignment between the receiving base 8 and the lead frame 9. This is particularly effective when the lead frame 9 has a step and a recess 8a is formed in the receiving base 8, and it is possible to obtain a more stable bonding strength for wire bonding.

The control unit 17 also acquires and learns the first position information detected by the image processing camera 14 as past history, and controls the drive of the first X-Y motor 10a to adjust the initial position of the fixing jig 7 based on the learning results of the past history.

As a result, the frequency and amount of position adjustment of the fixing jig 7 is reduced, improving the manufacturing efficiency of semiconductor devices.

The embodiment can be modified as appropriate.

1 semiconductor manufacturing device, 7 fixing jig, 7a main body, 7b opening, 8 receiving stand, 9 lead frame, 10a first XY drive motor, 10b second XY drive motor, 11a first ball screw, 11b second ball screw, 13a first XY table, 13b second XY table, 14 image processing camera, 15 lead frame holder, 16 sensor, 17 control unit.

Claims (4)

a support for placing a lead frame on an upper surface thereof;
a fixing jig disposed above the support base and fixing the lead frame to the support base;
A first table that holds an outer periphery of the fixing jig;
an image processing camera that detects first position information indicating a position of the lead frame through an opening of the fixing jig;
a first ball screw attached to the first table;
a first motor that rotates the first ball screw to move the fixture together with the first table in a lateral direction;
a control unit that controls driving of the first motor based on the first position information detected by the image processing camera,
The fixing jig is a semiconductor manufacturing device having a main body that holds the upper surface of the lead frame, an opening that exposes a wire bonding area where wire bonding is performed on the lead frame, and a lead frame presser that presses the wire bonding area of the lead frame toward the receiving table at the opening. a second table on whose upper surface the pedestal is disposed;
a second ball screw attached to the second table;
a second motor that rotates the second ball screw to move the support together with the second table in the lateral direction;
a sensor for detecting second position information indicating a position of the second table;
The semiconductor manufacturing apparatus according to claim 1 , wherein the control unit controls driving of the second motor based on the second position information detected by the sensor. The semiconductor manufacturing device according to claim 2, wherein the control unit acquires and learns the first position information detected by the image processing camera as a past history, and controls the driving of the first motor so as to adjust the initial position of the fixture based on the learning result of the past history. A method for manufacturing a semiconductor device using the semiconductor manufacturing apparatus according to claim 2 or 3, comprising the steps of:
(a) placing the lead frame on an upper surface of the pedestal;
(b) placing the fixture on an upper surface of the lead frame;
(c) adjusting the position of the cradle together with the second table based on the second position information detected by the sensor;
(d) adjusting the position of the fixture together with the first table based on the first position information detected by the image processing camera;
(e) fixing the lead frame with the fixing jig and the support;
(f) performing wire bonding on the wire bonding area of the lead frame;
The manufacturing method of a semiconductor device comprising the steps of:

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