JP2003068800A - Jig holder - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a jig holder which can constantly hold a lead frame and is consisting of common components. SOLUTION: A jig 30 holding the lead frame at a prescribed position is composed of three components, a first portion 42, a second portion 43 and a third portion 44. The second portion 43 is provided with connecting convex portions 45 at both ends of it. The first portion 42 and the third portion 44 are provided with the connecting convex portions 45 and connecting concave portions 46 possible to be fitted at portions adjacent to the second portion 43. The first to third portions 42 to 44 can be slid relatively and mutually by fitting the connecting convex portion 45 and the connecting concave portions 46.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a holding jig for holding a lead frame.

[0002]

2. Description of the Related Art The most popular IC (integrated circuit) at present
As a package, there is a resin sealed package. The resin sealed package is manufactured using a lead frame made of a metal sheet. That is, the element chip is joined to a part of the lead frame, and the joint portion of the lead frame including the element chip is resin-sealed. Next, the IC package is manufactured by separating the sealing portion from the lead frame.

A lead frame used for manufacturing an IC package includes a long frame and a plurality of leads provided on the frame. The leads are provided at a plurality of equal intervals perpendicular to the longitudinal direction of the frame so as to project from the frame.

The element chip is joined to a part of the lead with solder or the like. The joining is performed by heating with a joining material such as solder provided between the element chip and one surface of the lead. After the joining, the leads are resin-sealed together with the element chip, and further separated from the frame in the vicinity of the connecting portion with the frame. As a result, an IC package is obtained.

Here, each of the above processes is performed in a state where the lead frame is held by a holding jig. Usually, the holding jig is provided with a groove having a width substantially equal to that of the lead frame, and fits in the groove to hold and fix the lead frame. In the bonding (heating) step, the holding jig is heated to the bonding temperature together with the lead frame.

Due to the heating, the lead frame and the holding jig are thermally expanded. Here, if the holding jig has a coefficient of thermal expansion that is excessively lower than that of the lead frame, the expansion of the holding jig does not catch up with that of the lead frame, and the lead frame is stably held and positioned in the jig. It will be difficult. As a result, the process of mounting the element chip on the lead frame becomes less reliable. Therefore, the holding jig needs to have a thermal expansion coefficient equivalent to that of the lead frame.

[0007]

Conventionally, in order to obtain a coefficient of thermal expansion equivalent to that of a lead frame, the holding jig is made of a special material such as a material obtained by plating copper with nickel. However, when the holding jig is made of a special material, the cost is higher than when a general material such as graphite is used. Also, since jigs made of special materials are rare, frequent jig updates cannot be performed. If there is no jig replacement inventory and the jig cannot be renewed, the yield deteriorates because the reliability of the process deteriorates due to the deterioration of the jig.

From the above, it is desirable that the holding jig is made of a general material and easily available. However, even if the general material has a high coefficient of thermal expansion, it is about 5 × 10 ^−6.
It is as low as / ° C, and it is not possible to construct a jig with the same structure as a special material. As described above, there has been no conventional holding jig that can hold the lead frame stably and can be accurately positioned, and that can be made of a general material.

In order to solve the above problems, it is an object of the present invention to provide a holding jig which can hold a lead frame in a stable manner and which can be constructed from a general material.

[0010]

In order to achieve the above object, a holding jig according to the present invention has a lead frame which is formed in an elongated shape and has a plurality of leads at predetermined intervals in a longitudinal direction thereof. A holding jig for holding at an arrangement position, wherein the holding jig is composed of a plurality of members sequentially arranged in the longitudinal direction of the lead frame, and the adjacent members of the plurality of members are And is configured to be movable in the longitudinal direction relative to each other.

In the above structure, the plurality of members move relative to each other in the longitudinal direction according to the thermal expansion of the lead frame when the lead frame is heated while being held by the holding jig. It is desirable to hold the lead frame at the predetermined position.

In the above structure, one of the members adjacent to each other among the plurality of members has a columnar convex portion extending in the longitudinal direction on the adjoining surface thereof, and the other has the convex portion on the adjoining surface thereof. It is preferable that the members adjacent to each other are provided with a concave portion that can be fitted with each other, and that the members adjacent to each other move relative to each other in a state where the convex portion and the concave portion are fitted with each other.

In the above structure, the lead frame is provided with a plurality of guide holes, and the holding jig is fitted in the guide holes to hold the lead frame at the predetermined arrangement position. Preferably, the member comprises at least one guide pin.

In the above structure, for example, the holding jig is composed of the three members. In the above structure, the holding jig is made of graphite, for example.

[0015]

DETAILED DESCRIPTION OF THE INVENTION A jig for holding a lead frame according to an embodiment of the present invention will be described below with reference to the drawings. The jig of the present embodiment is a jig for holding a lead frame, and the lead frame is held by the jig and is subjected to processing such as soldering with a semiconductor element chip (diode chip) and resin sealing. Is applied.

FIG. 1 is a plan view of the lead frame 11 according to this embodiment. As shown in FIG. 1, the lead frame 11 includes a pair of first frames 12 separated from each other.
And a second frame 13. The first frame 12 and the second frame 13 are composed of a long sheet made of copper. The lead frame 11 is formed by punching, etching or the like.

The first frame 12 includes a substantially rectangular first rail 14 and a plurality of first leads 15 provided on the first rail 14 so as to project in a direction perpendicular to the longitudinal direction thereof. Prepare The first rail 14 is provided with a plurality of positioning first guide holes 16 at predetermined intervals.

The first leads 15 are provided on the first rail 14 at equal intervals. The first lead 15 includes a first outer lead 17, a first dam bar 18, and a first connector portion 19
And The first outer lead 17 includes the first rail 14
Is formed so as to extend in a strip shape from. First dam bar 18
Are formed to extend in a strip shape from the first outer leads 17 and have a width narrower than that of the first outer leads 17. The first connector portion 19 extends in a strip shape from the first dam bar 18 and is formed narrower than the first external lead 17.

The second frame 13 includes a substantially rectangular second rail 20 and a plurality of second leads 21 provided on the second rail 20 so as to project in a direction perpendicular to the longitudinal direction thereof. Prepare The second rail 20 is provided with a plurality of second positioning guide holes 22 at predetermined intervals.

The second leads 21 are provided on the second rail 20 at equal intervals. The second lead 21 includes a second outer lead 23, a second dam bar 24, and a second connector portion 25.
And The second outer lead 23 is connected to the second rail 20.
Is formed so as to extend in a strip shape from. Second dam bar 24
Are formed to extend in a strip shape from the second external leads 23 and have a width narrower than that of the second external leads 23. The second connector portion 25 extends in a strip shape from the second dam bar 24 and is formed narrower than the second external lead 23. The second connector portion 25 includes a neck 26 extending from the second dam bar 24,
The island 27 extends from the neck 26 and is wider than the neck 26.

The first lead 15 and the second lead 21 are
The first frame 12 and the second frame 13 are provided at substantially the same intervals, respectively. Therefore, when the first frame 12 and the second frame 13 having substantially the same length are arranged in parallel to face each other, the first lead 15 and the second lead 21 are in a state of facing each other.

FIG. 2 shows a plan view of the jig 30 for holding the lead frame 11 according to the present embodiment.

As shown in FIG. 2, the jig 30 is formed in a long shape and has a length substantially equal to that of the lead frame 11. The jig 30 is made of graphite, which is a general material.

A pair of first grooves 31 is formed on the upper surface of the jig 30.
And the second groove 32 is formed in a substantially linear shape. First
The groove 31 and the second groove 32 are separated by a convex portion 33 extending along the longitudinal direction of the jig 30, and are provided in parallel with each other over the entire length of the jig 30.

The convex portion 33 has chip fixing portions 34 at predetermined intervals. The chip fixing portion 34 includes a first recess 35 connected to the first groove 31, a second recess 36 connected to the second groove 32, a first recess 35 and a second recess 36. The first concave portion 35 and the second concave portion 36 are connected at the central portion of the convex portion 33, and a through hole 37 is provided in the connecting portion.

The first concave portion 35 is the first concave portion of the first frame 12.
It is a recess that can accommodate the tip of the connector portion 19. The second recess 36 is a recess that can accommodate the island 27 of the second connector portion 25 of the second frame 13. The through hole 37 is a linear hole that communicates with the back surface side of the jig 30.

The first guide pin 38 and the second guide pin 3 are provided at the sides of the bottom surfaces of the first groove 31 and the second groove 32.
Three 9 are provided at predetermined intervals. The first guide pin 38 and the second guide pin 39 are respectively
It can be inserted into the first guide hole 16 of the first frame 12 and the second guide hole 22 of the second frame 13, respectively. A plurality of first guide pins 38 and second guide pins 3
9 and, in the first groove 31 and the second groove 32,
The first frame 12 and the second frame 13 are fixed at predetermined positions.

A plurality of heat dissipation holes 40 penetrating the jig 30 are provided at the centers of the bottom surfaces of the first groove 31 and the second groove 32. The heat dissipation holes 40 prevent overheating of the lead frame 11 and the jig 30 during the heat treatment.

FIG. 3 shows a cross section taken along the line AA 'of the jig 30 with the lead frame 11 held. Here, FIG. 3 shows a state in which the element chip 41 is mounted on the lead frame 11 before soldering. As shown in FIG. 3, the second groove 32 has a depth similar to the thickness of the second frame 13. Further, the first groove 31 is provided deeper than the second groove 32.

The first groove 31 has a width slightly shorter than the width of the first frame 12, and the end of the first frame 12 on the side where the first lead 15 is not formed has the first groove 31. 31
The tip of the first connector portion 19 overlaps the convex portion 33 in a state of being in contact with the outer end portion of the. Where the first
The frame 12 has the first guide hole 16 and the first guide pin 3
The tip of the first connector portion 19 is accommodated in the first concave portion 35 of the convex portion 33 and the upper portion of the through hole 37 in a state of being positioned and fixed by fitting with 8.

The second groove 32 has a width slightly shorter than the width of the second frame 13, and the end portion of the second frame 13 on the side where the second lead 21 is not formed has the second groove 32. 32
The island 27 of the second connector portion 25 overlaps the convex portion 33 in a state of being in contact with the outer end portion of the. Here, in a state where the second frame 13 is positioned and fixed by fitting the second guide hole 22 and the second guide pin 39, the island 27 is located above the second concave portion 36 of the convex portion 33 and the through hole 37. Be accommodated.

As described above, the first groove 31 is formed deeper than the second groove 32. As a result, the jig 3
0 to the lead frame 11 (first frame 12 and second frame
With the frame 13) held, the tip of the first connector portion 19 of the first frame 12 is covered with the island 27 of the second frame 13 through the through hole 37 of the convex portion 33.
The element chip (diode chip) 41 is sandwiched between the first connector portion 19 and the island 27 in the soldering process.

Returning to FIG. 2, the jig 30 having the above construction is
It is composed of a portion 42, a second portion 43, and a third portion 44. The first to third parts 42 to 44 are each formed by dividing the jig 30 into three parts (from three parts). 4A to 4C show respective configurations of the first to third portions 42 to 44.

As shown in FIG. 4B, the second portion 43
Is provided with connecting convex portions 45 on the side portions of the portions that contact the first portion 42 and the third portion 44, respectively. Connection convex part 4
5 is formed in a columnar shape with a rectangular cross section and has a predetermined length and extends in the longitudinal direction of the jig 30. On the other hand, FIG.
As shown in (a) and (c), the first portion 42 and the third portion 44 of the jig 30 are respectively provided with two connecting recesses 46 on the side portions of the portions which are in contact with the second portion 43. The connecting concave portions 46 of the first portion 42 and the third portion 44 are formed to have a depth equal to or greater than the length of the connecting convex portion 45 and to be fittable with the connecting convex portions 45.

The first to third parts 42 to 44 are the first
One guide pin 38 and one second guide pin 39
It is prepared one after another.

Since the connecting convex portion 45 and the connecting concave portion 46 can be fitted to each other as described above, as shown in FIG. 5, the first portion 42 and the third portion 44 have the second portion. It is slidable relative to the portion 43 in the longitudinal direction of the jig 30.

A process of forming a diode package from the lead frame 11 and the element chip 41 using the jig 30 having the above structure will be described below.

First, the first frame 12 and the second frame 1
A lead frame 11 composed of 3 and an element chip 41 whose both surfaces are coated with solder are prepared. Next, the first frame 12 is placed in the first groove 31 of the jig 30 so that the first guide hole 16 and the first guide pin 38 fit together. Here, the first connector portion 19 of the first frame 12
Are fixed to the chip fixing portion 34 of the convex portion 33.

Next, the element chip 41 is mounted on the first connector section 19. At this time, the element chip 41 is also fixed by the chip fixing portion 34. Then, the second frame 13 is arranged in the second groove 32 so that the second guide hole 22 and the second guide pin 39 are fitted to each other. here,
The island 27 of the second frame 13 is fixed to the chip fixing portion 34 of the convex portion 33. As a result, as shown in FIG. 3, the element chip 41 is sandwiched between the first connector portion 19 and the island 27.

Subsequently, in the heating furnace in which the lead frame 11 is held by the jig 30 as described above, in the heating furnace which is sent to the heating furnace, as shown in FIG. The tools 47a and 47b press the first connector portion 19 and the island 27. In this state, heating is performed at about 400 ° C., for example. This melts the solder 48 applied to both sides of the element chip 41,
The lead frame 11 and the element chip 41 are joined.

After joining, the first joined to the element chip 41
The lead 15 and the second lead 21 are the first external lead 1
7 and the second external lead 23 are resin-sealed in a protruding state. For example, an epoxy resin is used as the sealing resin. After the resin sealing, the sealing body is the first external lead 17
The second outer lead 23 is separated from the first rail 14 and the second rail 20. As a result, a diode package is obtained.

Here, in the joining step, the lead frame 11 is made of copper, while the jig 30 is made of graphite. However, while the thermal expansion coefficient of copper is about 17 × 10 ⁻⁶ / ° C., the thermal expansion coefficient of graphite is about 3 × 10 ⁻⁶ / ° C. to 5 × 10 ⁻⁶ / ° C. As described above, since the lead frame 11 (copper) and the jig 30 (graphite) have different thermal expansion coefficients, the size of the lead frame 11 at the time of heating, particularly, the length in the longitudinal direction is different from that of the jig 30. It will be very different from the size.

Due to the difference in the coefficient of thermal expansion as described above, when the lead frame 11 thermally expands during heating and its size, especially length, becomes long, the first guide hole 16 and the second guide hole of the lead frame 11 are formed. The first guide pin 38 and the second guide pin 39 fixing 22 are pulled by the lead frame 11 on the contrary.

Here, the first guide pin 38 and the second guide pin 39 are separated from each other by the first to third portions 42.
~ 44 are provided one by one. Therefore, the first guide pins 38 adjacent to each other due to the thermal expansion of the lead frame 11
The tension applied between the second guide pins 39 and between the first guide 42 and the second guide 43 is
And the third portion 44 and the third portion 44, respectively.

In this way, the first to third portions 42 to 44 of the jig 30 are separated from each other during the heat treatment.
Here, the first to third portions 42 to 44 are configured to slide in the longitudinal direction while maintaining the holding state of the lead frame 11 by fitting the connecting convex portion 45 and the connecting concave portion 46 to each other. Has become. With this slide configuration,
The lead frame 11 can be stably held and can cope with elongation in the longitudinal direction due to thermal expansion of the lead frame 11.

As described above, in the present invention,
The jig 30 for holding the lead frame 11 is divided into three parts, each of which is configured to be relatively slidable. With this division structure, the first to third portions 42 to 44 of the jig 30 are separated from each other by the difference in expansion due to the difference in the thermal expansion coefficient between the lead frame 11 made of copper and the jig 30 made of graphite. Is compensated by.

As described above, the jig 30 has a divided structure, so that the thermal expansion can be performed without using a special material such as nickel-plated copper, which has a high thermal expansion coefficient like the lead frame 11 made of copper. It is possible to form the jig 30 from a general material (graphite) having a low coefficient. The jig 30 that can be configured from a general material can be obtained at low cost, and the jig 30 can be easily updated. As described above, according to the present invention, it is possible to obtain the jig 30 which can hold the lead frame 11 stably and can be accurately positioned, and which can be formed of a general material.

The present invention is not limited to the above embodiment, but various modifications and applications are possible. Hereinafter, modifications of the above-described embodiment applicable to the present invention will be described.

In the above embodiment, the lead frame 11
Although it is made of copper, the material is not limited to this and may be any material such as iron-nickel alloy and phosphor bronze as long as it is a material generally used as the material of the lead frame 11. Further, the entire surface of the lead frame 11 and a part thereof may be subjected to surface treatment such as silver plating. Further, the shape of the lead frame 11 is not limited to the above-mentioned two-divided type, but may be a lead frame having a general integral type.

The jig 30 of this embodiment is made of graphite. However, the material is not limited to this, and any material such as ceramic may be used as long as it is a material that has heat resistance and is generally used for a jig for carrying and holding.

In the above embodiment, the jig 30 is divided into three parts. However, the present invention is not limited to this, and it may be divided into two or four or more. In this case, for each split member,
At least one each of the first guide pin 38 and the second guide pin 39 may be provided. Furthermore, the lead frame 1
The number of guide pins 38 and 39 for positioning 1 may be two or more instead of one at each divided portion.

The connecting projections 45 provided on the second portion 43 are provided in two columnar shapes having a rectangular cross section. However, the shape is not limited to this, and may be a columnar shape having a circular or polygonal cross section. Furthermore, a structure in which a groove is formed on the side surface of the columnar portion may be used. In addition, the second portion 43 may include two connecting concave portions 46, and the first portion 42 and the third portion 44 may include the connecting convex portion 45. Further, the number is not limited to two and may be three or more.
In either case, the connecting recess 46 may have a corresponding shape.

In the above-described embodiment, the solder 48 is applied to both surfaces of the element chip 41, and is applied to the first lead 15 and the second lead 15.
The heating was performed while sandwiched between the leads 21. However, not limited to this, the first lead 15 and / or the second lead 15
You may make it apply | coat solder to the contact surface by the side of the lead 21. Also, the joining material is not limited to solder, but resin paste,
Tape or the like may be used.

[0054]

As described above, according to the present invention,
Provided is a holding jig which can hold a lead frame stably and can be made of a general material.

[Brief description of drawings]

FIG. 1 is a diagram showing a configuration of a lead frame according to an exemplary embodiment of the present invention.

FIG. 2 is a diagram showing a configuration of a holding jig for the lead frame shown in FIG.

FIG. 3 is a view showing a cross section taken along line AA ′ of the jig shown in FIG.

FIG. 4 is a diagram showing a configuration of each divided portion of the jig shown in FIG.

FIG. 5 is a diagram showing a configuration of a lead frame according to the exemplary embodiment of the present invention.

FIG. 6 is a diagram showing a configuration of a lead frame according to the exemplary embodiment of the present invention.

[Explanation of symbols]

11 lead frame 12 First Frame 13 Second frame 14 First rail 15 First lead 16 First guide hole 17 First external lead 18 First Dam Bar 19 1st connector part 20 second rail 21 second lead 22 Second guide hole 23 Second external lead 24 Second Dam Bar 25 Second connector part 26 neck 27 islands 30 jigs 31 first groove 32 second groove 33 convex 34 Chip fixing part 35 First recess 36 Second recess 37 through hole 38 First guide pin 39 Second guide pin 40 heat dissipation hole 41 element chip 42 First Part 43 Second Part 44 Third Part 45 Convex portion for connection 46 Connection recess 47 Pressing tool 48 solder

Claims (6)

[Claims] 1. A holding jig for holding a lead frame formed in an elongated shape and provided with a plurality of leads at predetermined intervals in a longitudinal direction thereof at a predetermined arrangement position, wherein the holding jig comprises: It is composed of a plurality of members arranged in order in the longitudinal direction of the lead frame, and adjacent members of the plurality of members are configured to be movable relative to each other in the longitudinal direction. And holding jig. 2. The plurality of members, when the lead frame is heated while being held by the holding jig,
The holding jig according to claim 1, wherein the lead frame moves relative to each other in the longitudinal direction according to thermal expansion of the lead frame to hold the lead frame at the predetermined arrangement position. 3. One of the members adjacent to each other among the plurality of members has a columnar convex portion extending in the longitudinal direction on the adjacent surface thereof, and the other member fits the convex portion on the adjacent surface thereof. The holding jig according to claim 1 or 2, further comprising: a concave portion that can be fitted, and the members adjacent to each other move relative to each other in a state where the convex portion and the concave portion are fitted to each other. Ingredient 4. The lead frame is provided with a plurality of guide holes, and the holding jig is provided with a plurality of guide pins for holding the lead frame at the predetermined arrangement position by fitting with the guide holes. The holding jig according to any one of claims 1 to 3, wherein the member includes at least one of the guide pins. 5. The holding jig according to any one of claims 1 to 4, wherein the holding jig is composed of three members. 6. A holding jig according to claim 1, wherein the holding jig is made of graphite.