JP7458966B2 - Semiconductor device manufacturing apparatus and semiconductor device manufacturing method - Google Patents

Description

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

Conventionally, wire bonding requires thermal energy as a bonding element. This requires the lead frame to be heated, but prolonged heating can cause the copper that makes up the lead frame to oxidize, resulting in product defects.

To solve this problem, for example, Patent Document 1 discloses a device that prevents oxidation of the lead frame when wire bonding is performed by exhausting an anti-oxidant gas from a die pad gas suction port located in the area where the tip of the inner lead is located.

Japanese Patent Application Laid-Open No. 9-246309

However, in the device described in Patent Document 1, since room temperature gas is blown onto the lead frame, there is a problem in that the temperature of the lead frame decreases and the bondability of the metal wires decreases.

Therefore, an object of the present disclosure is to provide a technique that can suppress oxidation of a lead frame and ensure bondability of metal wires when wire bonding is performed.

A semiconductor device manufacturing apparatus according to the present disclosure includes a heating jig that heats a lead frame on which a semiconductor element is mounted when performing wire bonding, and the heating jig includes a gas that suppresses oxidation of the lead frame. an inlet to be introduced, a heating area to heat the introduced gas, an outlet to discharge the heated gas , and a switch to control the introduction of the gas by opening and closing the inlet; The inlet is configured to detect the concentration of the gas discharged from the outlet and close the inlet when the concentration reaches a level sufficient to prevent the temperature of the lead frame from decreasing while the wire bonding is being performed. and a gas concentration meter for controlling a switch , and the outlet is formed at a position corresponding to a location on the lead frame where the semiconductor element is mounted.

According to the present disclosure, since the heated gas is blown onto the lower surface of the portion of the lead frame where the semiconductor element is mounted, it is possible to suppress a decrease in the temperature of the portion. Thereby, it is possible to suppress oxidation of the lead frame during wire bonding and to ensure the bondability of the metal wire.

2 is a plan view of a heating jig provided in the semiconductor device manufacturing apparatus according to the first embodiment; FIG. FIG. 2 is a plan view of a lead frame on which a plurality of semiconductor elements are mounted. FIG. 2 is a plan view showing a state in which a lead frame is set on a heating jig included in the semiconductor device manufacturing apparatus according to the first embodiment. 2 is a cross-sectional view showing a state in which a lead frame is set on a heating jig provided in the semiconductor device manufacturing apparatus according to the first embodiment; FIG. 3 is an explanatory diagram for explaining wire bonding using the semiconductor device manufacturing apparatus according to the first embodiment. FIG. 3 is an explanatory diagram for explaining a case where wire bonding is performed on a semiconductor element. 3 is a flowchart showing a method for manufacturing a semiconductor device according to Embodiment 1. FIG. 3 is a plan view of a heating jig included in the semiconductor device manufacturing apparatus according to Embodiment 2. FIG. 10 is a flowchart showing a method for manufacturing a semiconductor device according to a second embodiment. 13 is a plan view of a heating jig provided in a semiconductor device manufacturing apparatus according to a third embodiment. FIG. 7 is a flowchart showing a method for manufacturing a semiconductor device according to a third embodiment.

<Embodiment 1>
Embodiment 1 will be described below using the drawings. FIG. 1 is a plan view of a heating jig 1 included in the semiconductor device manufacturing apparatus according to the first embodiment. FIG. 2 is a plan view of the lead frame 2 on which a plurality of semiconductor elements 3 are mounted. FIG. 3 is a plan view showing a state in which the lead frame 2 is set on the heating jig 1. FIG. 4 is a cross-sectional view showing the lead frame 2 set on the heating jig 1, and is a cross-sectional view taken at the right end of the heating jig 1 in FIG.

As shown in FIGS. 1 to 4, a semiconductor device manufacturing apparatus is an apparatus used in a wire bonding process, and is equipped with a heating jig 1. As shown in FIGS. The heating jig 1 is a jig that heats a copper lead frame 2 on which a plurality of semiconductor elements 3 are mounted when performing wire bonding. The semiconductor device manufacturing apparatus further includes an ultrasonic horn 15 (see FIG. 5) and a capillary 14 (see FIG. 5) for wire bonding. Note that the semiconductor element 3 is a power chip or the like.

Before explaining each component of the heating jig 1, wire bonding will be briefly explained. FIG. 5 is an explanatory diagram for explaining wire bonding using a semiconductor device manufacturing apparatus. FIG. 6 is an explanatory diagram for explaining a case where wire bonding is performed on the semiconductor element 3.

As shown in FIGS. 3 and 4, with the lead frame 2 set in the heating jig 1, the heating jig 1 heats the lead frame 2 to a high temperature. As shown in FIG. 5, a capillary 14 is attached to the tip of an ultrasonic horn 15 attached to a bonding head (not shown), and a metal wire 12 extends from the tip of the capillary 14. Further, a spark rod 16 is provided so as to face the metal wire 12. During the sparking operation, the sparking operation is performed from the spark rod 16 toward the tip of the metal wire 12, thereby generating an electric discharge at the tip of the metal wire 12 and forming a FAB (Free Air Ball) 17.

Once the FAB 17 is formed, the ultrasonic horn 15 and capillary 14 move in the vertical direction to press the FAB 17 against the electrodes of the semiconductor element 3 and apply ultrasonic waves, thereby performing wire bonding as shown in FIG. 6, and joining the metal wire 12. Note that FIG. 6 shows the case where wire bonding is performed on the semiconductor element 3, but it is also possible to perform wire bonding on the lead frame 2.

Next, each structure of the heating jig 1 and the lead frame 2 set in the heating jig 1 will be explained using FIGS. 1 to 4. In addition, when looking at the page of FIG. 1, the left and right direction will be described as the left and right direction, the lower side as the front, the upper side as the rear, the front side as the upper side, and the back side as the lower side.

As shown in FIGS. 2 to 4, die pads 2a are formed on the front and rear upper surfaces of the lead frame 2, on which the semiconductor elements 3 are mounted. The die pad 2a formed at the rear of the lead frame 2 is formed in a stepped shape with a height higher than that of the die pad 2a formed at the front of the lead frame 2. The plurality of semiconductor elements 3 are mounted on die pads 2 a formed on the front and rear upper surfaces of the lead frame 2 . As shown in FIGS. 1, 3, and 4, the heating jig 1 has a step with a height position higher at the rear than at the front so that the lead frame 2 can be set on the top surface. It is formed in the shape of Although eight semiconductor elements 3 are mounted in FIGS. 2 and 3, the present invention is not limited to this, and any number of semiconductor elements 3 may be one or more.

As shown in FIGS. 1 and 4, the heating jig 1 includes an inlet 5, a heating area 10, and a plurality of outlets 11.

The heating jig 1 is provided with, for example, a heater (not shown) so as to heat the lead frame 2 set on the upper surface. The heating area 10 is a space formed inside the heating jig 1 over most of the rear part. The inlet 5 is provided at the right end of the rear part of the heating jig 1, and a gas that suppresses oxidation of the lead frame 2 is introduced into the heating jig 1. The inlet 5 is also connected to the heating area 10, so that the gas introduced from the inlet 5 flows into the heating area 10. Here, the gas that suppresses oxidation of the lead frame 2 is an inert gas such as nitrogen or argon.

The heating area 10 is provided with, for example, a heater (not shown). In the heating area 10, gas introduced into the heating area 10 from the inlet 5 is heated. By adjusting the temperature of the gas heating heater provided in the heating area 10, the temperature of the gas heated in the heating area 10 can be adjusted.

The plurality of outlet ports 11 are provided at positions corresponding to die pads 2a, which are locations on the lead frame 2 on which the semiconductor elements 3 are mounted. Specifically, the plurality of outlets 11 are provided at positions corresponding to the die pad 2a located at the front of the heating jig 1. The plurality of outlet ports 11 are provided in accordance with the number of semiconductor elements 3 mounted on the front part of the lead frame 2, and communicate with the heating area 10. Furthermore, the contours of the plurality of outflow ports 11 in plan view are smaller than the contours of die pad 2a at the front portion of lead frame 2 in plan view.

Note that the plurality of outlets 11 are provided not only at positions corresponding to the die pad 2a located at the front of the heating jig 1, but also at positions corresponding to the die pad 2a located at the rear of the heating jig 1. Good too.

Therefore, the gas introduced into the heating area 10 from the inlet 5 and heated in the heating area 10 is discharged from the plurality of outlets 11. By spraying the heated gas onto the lower surface of the die pad 2a at the front of the lead frame 2, it is possible to suppress the temperature at that location from decreasing. Thereby, when performing wire bonding, oxidation of the die pad 2a at the front part of the lead frame 2 can be suppressed, and the bondability of the metal wire 4 can be ensured.

Next, a wire bonding process as a method for manufacturing a semiconductor device will be explained. FIG. 7 is a flowchart showing a method for manufacturing a semiconductor device according to the first embodiment.

As shown in FIG. 7, in the heating jig 1, the introduction of gas is started from the inlet 5 (step S1), and the heater for heating the gas provided in the heating area 10 is activated. Then, heating of the gas is started (step S2). The gas heated in the heating area 10 flows toward the plurality of outlets 11, and discharge of the heated gas from the plurality of outlets 11 is started (step S3).

Next, the lead frame 2 on which the semiconductor element 3 is mounted is set on the top surface of the heating jig 1, and the heater for heating the lead frame provided on the heating jig 1 is activated, so that the lead frame 2 is heated. The process is started (step S4). Here, the lead frame 2 is heated to about 100° C. or higher and 250° C. or lower. Next, wire bonding is performed while heating the lead frame 2 and discharging the superheated gas from the plurality of outlets 11. After the wire bonding is completed (step S5), the process ends.

Next, in a transfer molding process which is a process after the wire bonding process, the lead frame 2 on which the semiconductor element 3 is mounted is transfer molded, and an insulating sheet (not shown) is bonded to the bottom surface of the lead frame 2. , the semiconductor device is assembled. Here, the insulating sheet is composed of metal foil and insulating resin such as epoxy resin, and is integrated into two layers that overlap. The thickness of the insulating sheet is 0.1 mm or more and 1 mm or less.

As described above, in Embodiment 1, the semiconductor device manufacturing apparatus includes the heating jig 1 that heats the lead frame 2 on which the semiconductor element 3 is mounted when performing wire bonding, and the heating jig 1 includes: It has an inlet 5 into which a gas that suppresses oxidation of the lead frame 2 is introduced, a heating area 10 which heats the introduced gas, and an outlet 11 which discharges the heated gas. It is formed at a position corresponding to the location on the lead frame 2 where the semiconductor element 3 is mounted.

Therefore, since the heated gas is blown onto the lower surface of the portion of the lead frame 2 where the semiconductor element 3 is mounted, it is possible to suppress a drop in the temperature of the portion. Thereby, when performing wire bonding, oxidation of the lead frame 2 can be suppressed, and the bondability of the metal wire 12 can be ensured.

Furthermore, by suppressing oxidation of the lead frame 2, it is possible to improve the adhesion between the lead frame 2 and the insulating sheet, thereby improving the reliability of the product.

<Embodiment 2>
Next, a semiconductor device manufacturing apparatus according to a second embodiment will be described. FIG. 8 is a plan view of a heating jig 1A included in the semiconductor device manufacturing apparatus according to the second embodiment. Note that, in the second embodiment, the same components as those described in the first embodiment are given the same reference numerals, and a description thereof will be omitted.

As shown in FIG. 8, in the second embodiment, the heating jig 1A further includes a switch 7 in contrast to the first embodiment. That is, the heating jig 1A includes an inlet 5, a switch 7, a heating area 10, and a plurality of outlets 11.

The switch 7 is an electromagnetic switch and is attached to the inlet 5. The switch 7 controls the introduction of gas into the heating area 10 by opening and closing the inlet 5 . Specifically, the switch 7 has a function of counting the time since the inlet 5 is opened, and is controlled to open the inlet 5 for a predetermined time while wire bonding is being performed. do. Thereby, it is possible to reduce the amount of gas used and to suppress the manufacturing cost of the semiconductor device.

Next, a wire bonding process as a method for manufacturing a semiconductor device will be explained. FIG. 9 is a flowchart showing a method for manufacturing a semiconductor device according to the second embodiment.

As shown in FIG. 9, in the heating jig 1, introduction of gas is started from the inlet 5 (step S11), the inlet 5 is opened by the switch 7, and the introduction of gas into the heating area 10 is started. (Step S12). By operating the gas heating heater provided in the heating area 10, heating of the gas is started in the heating area 10 (step S13). The gas heated in the heating area 10 flows toward the plurality of outlets 11, and discharge of the heated gas from the plurality of outlets 11 is started (step S14).

Next, the lead frame 2 on which the semiconductor element 3 is mounted is set on the top surface of the heating jig 1, and the heater for heating the lead frame provided on the heating jig 1 is activated, so that the lead frame 2 is heated. The process is started (step S15). Here, the lead frame 2 is heated to about 100° C. or higher and 250° C. or lower. Next, wire bonding is performed while heating the lead frame 2 and discharging the superheated gas from the plurality of outlets 11 (step S16).

Next, the switch 7 determines whether a predetermined time has elapsed since the inlet 5 was opened. If a predetermined time has elapsed since the inlet 5 opened (step S17: YES), the inlet 5 is closed by the switch 7, and the introduction of gas into the heating area 10 is stopped (step S18). , the process moves to step S19. At this time, gas is discharged from the plurality of outlet ports 11 until the gas existing in the heating area 10 is exhausted.

On the other hand, if the predetermined time has not elapsed since the inlet 5 was opened (step S17: NO), the inlet 5 remains open and the process proceeds to step S19.

Here, the predetermined time during which the inlet 5 is opened by the switch 7 is set as a time during which the temperature of the lead frame 2 does not decrease while wire bonding is being performed. This time is determined by the user through experimentation in advance.

Next, when wire bonding is completed (step S19: YES), the process ends. On the other hand, if wire bonding is not completed (step S19: NO), the process returns to step S17. Note that the transfer molding process, which is a post-wire bonding process, is the same as in Embodiment 1, so a description thereof will be omitted.

As described above, in the second embodiment, the heating jig 1A further includes the switch 7 that controls the introduction of gas by opening and closing the inlet 5. Therefore, since the switch 7 is controlled to open the inlet 5 only for a predetermined time while wire bonding is being performed, the amount of gas used can be reduced and the manufacturing cost of the semiconductor device can be suppressed.

<Third embodiment>
Next, a semiconductor device manufacturing apparatus according to a third embodiment will be described. Fig. 10 is a plan view of a heating jig 1B included in the semiconductor device manufacturing apparatus according to the third embodiment. Note that in the third embodiment, the same components as those described in the first and second embodiments are given the same reference numerals and the description thereof will be omitted.

As shown in FIG. 10, in the third embodiment, the heating jig 1B is different from the second embodiment in that it further includes a gas concentration meter 9. That is, the heating jig 1B includes an inlet 5, a switch 7, a gas concentration meter 9, a heating area 10, and a plurality of outlets 11.

The gas concentration meter 9 is provided at one of the plurality of outlets 11 . The gas concentration meter 9 detects the concentration of gas discharged from the outlet 11 and controls the switch 7 based on the detected gas concentration. Specifically, while wire bonding is being performed, the gas concentration meter 9 opens and closes to close the inlet 5 when the concentration of gas discharged from the outlet 11 reaches a predetermined concentration or higher. control device 7. As a result, the amount of gas used can be reduced and the manufacturing cost of the semiconductor device can be suppressed without conducting experiments in advance as in the case of the second embodiment.

Next, a wire bonding process as a method for manufacturing a semiconductor device will be explained. FIG. 11 is a flowchart showing a method for manufacturing a semiconductor device according to the third embodiment.

As shown in FIG. 11, in the heating jig 1, introduction of gas is started from the inlet 5 (step S21), the inlet 5 is opened by the switch 7, and the introduction of gas into the heating area 10 is started. (Step S22). By operating the gas heating heater provided in the heating area 10, heating of the gas is started in the heating area 10 (step S23). The gas heated in the heating area 10 flows toward the plurality of outlets 11, and discharge of the heated gas from the plurality of outlets 11 is started (step S24).

Next, the lead frame 2 on which the semiconductor element 3 is mounted is set on the top surface of the heating jig 1, and the heater for heating the lead frame provided on the heating jig 1 is activated, so that the lead frame 2 is heated. The process is started (step S25). Here, the lead frame 2 is heated to about 100° C. or more and 250° C. or less. Next, wire bonding is performed while heating the lead frame 2 and discharging the superheated gas from the plurality of outlets 11 (step S26).

Next, the gas concentration meter 9 determines whether the concentration of the gas discharged from the outlet 11 is equal to or higher than a predetermined concentration. If the concentration of the gas discharged from the outlet 11 is equal to or higher than a predetermined concentration (step S27: YES), in other words, the concentration is such that the temperature of the lead frame 2 does not drop while wire bonding is being performed. If the gas is being discharged, the inlet 5 is closed by the switch 7, the introduction of the gas into the heating area 10 is stopped (step S28), and the process moves to step S29. At this time, gas is discharged from the plurality of outlet ports 11 until the gas existing in the heating area 10 is exhausted.

On the other hand, if the concentration of the gas exhausted from the outlet 11 is lower than the predetermined concentration (step S27: NO), the process moves to step S29 while the inlet 5 remains open.

Next, if wire bonding is completed (step S29: YES), the process ends. On the other hand, if wire bonding is not completed (step S29: NO), the process returns to step S27. Note that the transfer molding process, which is a process subsequent to the wire bonding process, is the same as in the first embodiment, so a description thereof will be omitted.

As described above, in the third embodiment, the heating jig 1B further includes a gas concentration meter 9 that detects the concentration of the gas discharged from the outlet 11 and controls the switch 7 based on the detected gas concentration. Therefore, during wire bonding, when the gas concentration meter 9 detects that the gas concentration is equal to or greater than a predetermined concentration, the switch 7 is controlled to close the inlet 5. This reduces the amount of gas used and the manufacturing costs of the semiconductor device without the need to conduct prior experiments as in the second embodiment.

Note that it is possible to freely combine each embodiment, or to modify or omit each embodiment as appropriate.

1, 1A, 1B heating jig, 2 lead frame, 3 semiconductor element, 5 inlet, 7 switch, 9 gas concentration meter, 10 heating area, 11 outlet.

Claims (3)

Equipped with a heating jig that heats the lead frame on which semiconductor elements are mounted during wire bonding.
The heating jig is
an inlet into which a gas for suppressing oxidation of the lead frame is introduced;
a heating area for heating the introduced gas;
an outlet for discharging the heated gas ;
a switch that controls the introduction of the gas by opening and closing the inlet;
The inlet is configured to detect the concentration of the gas discharged from the outlet and close the inlet when the concentration reaches a level sufficient to prevent the temperature of the lead frame from decreasing while the wire bonding is being performed. It has a gas concentration meter that controls the switch ,
In the semiconductor device manufacturing apparatus, the outlet is formed at a position corresponding to a location on the lead frame where the semiconductor element is mounted. A method for manufacturing a semiconductor device using the semiconductor device manufacturing apparatus according to claim 1,
(a) starting the introduction of the gas from the inlet and starting heating of the introduced gas in the heating area;
(b) commencing exhaust of the heated gas from the outlet;
(c) setting the lead frame on which the semiconductor element is mounted on an upper surface of the heating jig and starting to heat the lead frame;
(d) performing wire bonding;
The manufacturing method of a semiconductor device comprising the steps of: Equipped with a heating jig that heats the lead frame on which semiconductor elements are mounted during wire bonding.
The heating jig is
an inlet into which a gas for suppressing oxidation of the lead frame is introduced;
a heating area for heating the introduced gas;
and an outlet for discharging the heated gas,
In the semiconductor device manufacturing method using a semiconductor device manufacturing apparatus, the outlet is formed at a position corresponding to a location on the lead frame where the semiconductor element is mounted,
The heating jig includes a switch that controls the introduction of the gas by opening and closing the inlet, and a switch that detects the concentration of the gas discharged from the outlet and based on the detected concentration of the gas. further comprising a gas concentration meter that controls the switch,
(a) starting the introduction of the gas from the inlet and starting heating the introduced gas in the heating area;
(b) starting to discharge the heated gas from the outlet;
(c) setting the lead frame on which the semiconductor element is mounted on the top surface of the heating jig and starting heating the lead frame;
(d) a step of performing wire bonding;
Equipped with
During the step (d), the switch is controlled to close the inlet when the concentration reaches a level that does not lower the temperature of the lead frame as determined by the gas concentration meter. Method.

Images