JP4962443B2 - Manufacturing method of semiconductor device - Google Patents

Description

  The present invention relates to a method for manufacturing a semiconductor device in which a base plate having a mounting hole and a case are bonded together with an adhesive.

  In an assembly process of a semiconductor device including a power semiconductor device, an insulating substrate on which a power semiconductor element or the like is mounted is disposed on a metal plate called a base plate. A case formed in a shape surrounding the insulating substrate is further bonded to the base plate. This adhesion is often performed as follows.

  First, a base plate is mounted on a cure base plate which is a jig for performing the above-described bonding. Next, the case is mounted on the base plate such that the adhesive surfaces, which are the surfaces to which the base plate and the case are to be bonded, sandwich the adhesive. In this state, heat is supplied from the bottom surface of the base plate by the cured base plate in contact with the bottom surface (the surface opposite to the bonding surface) of the base plate. By this heat supply, the above-mentioned adhesive is thermally cured and the base plate and the case are bonded.

  Generally, the base plate and the case described above are provided with mounting holes for mounting the power semiconductor device to which the above-described bonding has been performed at a predetermined position. At the stage where the bonding is finished, the mounting holes formed in the base plate and the mounting holes formed in the case need to be aligned without any deviation. Patent Documents 1-6 describe a method for positioning the base plate and the case with the mounting holes aligned.

Japanese Patent Laid-Open No. 03-032046 Japanese Patent Application Laid-Open No. 08-031967 Japanese Patent Laid-Open No. 2004-253589 JP-A-2005-237140 JP 2004-296645 A Japanese Patent Application Laid-Open No. 08-220186

  As described above, the mounting hole formed in the base plate and the mounting hole formed in the case need to coincide with each other without misalignment after bonding the base plate and the case to form one hole. is there. For this reason, for example, the above-described bonding may be performed in a state where a mounting hole formed in the base plate and a mounting hole formed in the case are penetrated by a bolt. In this case, the bolt often passes through a mounting hole formed in the base plate and a mounting hole formed in the case and is fixed to a screw groove provided in the cured base plate.

  If it does in this way, the hole for attachment formed in the base plate and the hole for attachment formed in the case will not shift through before and after adhesion of the base plate and the case. Here, when the base plate and the case are bonded by supplying heat to the adhesive, the base plate and the case are generally heated and thermally expanded. Therefore, as described above, in a state where the base plate and the case are fixed with bolts, there is a problem that thermal expansion is hindered and the base plate and the case are damaged.

  As described above, in order to finish the bonding of the base plate and the case with the mounting holes formed in the base plate and the mounting holes formed in the case being aligned, Fixing is necessary. However, there is a problem that the problem of damage caused by thermal expansion of the base plate and the case cannot be avoided if such fixing is performed.

  The present invention has been made in order to solve the above-described problems. After the base plate and the case are bonded, the mounting hole formed in the base plate and the mounting hole formed in the case are provided. It is an object of the present invention to provide a method of manufacturing a semiconductor device that can be aligned without deviation and that can avoid damage due to thermal expansion between a base plate and a case.

  The method of manufacturing a semiconductor device according to the invention of the present application includes mounting a base plate on a cured base plate, and mounting the case on the base plate so that an adhesive is sandwiched between bonding surfaces of the base plate and the case, The base plate and the case are bonded together by supplying heat from the cured base plate to the adhesive to thermally cure the adhesive. Formed on the base plate on a positioning pin that is attached to the cure base plate so as to be movable in a direction parallel to the upper surface of the cure base plate and has a protruding portion that is a portion protruding from the upper surface of the cure base plate The bonding is performed in a state where the first mounting hole formed and the second mounting hole formed in the case are fitted.

  According to the present invention, the base plate and the case accompanied by heating of the adhesive can be bonded without any harmful effect.

Embodiment 1
The present embodiment relates to a method of manufacturing a semiconductor device in which a base plate having a mounting hole and a case are bonded using a jig having a positioning pin. Hereinafter, with reference to FIGS. 1 to 8, jigs and the like used in the semiconductor device manufacturing method of the present embodiment will be described. First, FIG. 1 is a sectional view showing a state in which a semiconductor device is mounted on a jig, and FIG. 2 is a plan view. FIG. 1 corresponds to a section 1-1 in FIG. The jig is used in the bonding process between the base plate 12 and the case 14. The jig includes a cure base plate 10. The cure base plate 10 is a material having good thermal conductivity such as aluminum, and the base plate 12 is mounted as will be described later.

  Positioning pins 16 are attached to the cure base plate 10 at locations corresponding to the mounting holes of the device provided in the semiconductor device. FIG. 3 is a plan view of the cured base plate 10 to which the positioning pins 16 are attached. In FIG. 3, the locations where the base plate and the case are to be arranged are indicated by broken lines. FIG. 4 is an enlarged view of the periphery of one positioning pin 16 in FIG. FIG. 5 is a sectional view taken along line 5-5 of FIG. The positioning pin 16 is formed using, for example, SUS (stainless steel), and includes a portion included in the cure base plate 10 and a protruding portion protruding from the upper surface of the cure base plate 10. Here, the upper surface of the cure base plate 10 is a surface on which the semiconductor device, more specifically the base plate 12 of the semiconductor device, is mounted among the surfaces of the cure base plate 10. The positioning pins 16 are attached to the cure base plate 10 so as to be movable (float state) in a direction parallel to the above-described “upper surface of the cure base plate 10”. That is, the space for the cure base plate 10 to enclose the positioning pins 16 is intentionally formed wider than the outer shape of the positioning pins 16 in the direction parallel to the upper surface of the cure base plate 10 (see FIG. 5). The moving range is set in consideration of the amount of thermal expansion (coefficient) in the base plate 12 and the case 14.

  Further, the positioning pin 16 is restricted from moving in the direction in which the above-described protruding portion protrudes, that is, the direction upward from the upper surface of the cure base plate 10. This limitation is caused by the stopper 15 provided in the cure base plate 10. That is, the portion included in the cure base plate 10 of the positioning pin 16 cannot move upward from the upper surface of the cure base plate 10 by the stopper 15.

  Further, the positioning pin 16 includes a through hole penetrating the positioning pin 16 in the vertical direction on the upper surface of the cure base plate 10. The through hole is formed with a diameter into which a bolt 18 described later can be inserted.

  One cure base plate 10 further includes an opening so that the positioning pin 16 can be removed from the bottom surface for replacement or the like. Here, the bottom surface of the cure base plate 10 is a surface of the cure base plate 10 opposite to a surface on which a later-described base plate 12 is mounted. In addition, the cure base plate 10 supports the positioning pins to prevent the positioning pins 16 from dropping from the bottom surface of the cure base plate 10 except when the positioning pins 16 need to be replaced from the bottom surface of the cure base plate 10. A plate 24 is attached. Incidentally, the support plate 24 is formed of, for example, SUS, like the positioning pins 16.

  The jig further includes a bolt 18, a washer 20, and a nut 22. The bolt 18, washer 20, and nut 22 will be described later because the relationship between the base plate 12 and the case 14 is important. The jig of the present embodiment has the above-described configuration.

  Hereinafter, a method for bonding the base plate 12 and the case 14 using the above-described jig will be described.

  First, a jig in which the positioning 16 is mounted on the cure base plate 10 shown in FIG. 3 (with the bolts 18 and the washers 20 removed from the jig) is prepared, and the base plate 12 of the semiconductor device is used as the cure base plate 10. Mounted on top. This mounting is performed so that the mounting holes of the base plate 12 are fitted with the protruding portions of the positioning pins 16. Next, a thermosetting adhesive 26 is applied to the base plate bonding surface which is the surface to be bonded to the case 14 of the base plate 12. Next, the case 14 is mounted on the base plate 12 such that a case bonding surface, which is a surface to be bonded to the base plate 12 of the case 14, is placed on the surface to which the adhesive 26 is applied. That is, the adhesive 26 is sandwiched between the base plate bonding surface and the case bonding surface. This mounting is performed so that the mounting hole of the case 14 fits the protruding portion of the positioning pin 16 (see FIG. 8). Since the base plate bonding surface and the case bonding surface form parallel surfaces at the stage where the mounting of the case 14 is completed, these may be collectively referred to simply as bonding surfaces. In the present embodiment, the adhesive surface and the upper surface of the cure base plate 10 are parallel.

  When the mounting of the case 14 to the base plate 12 is finished, the bolt 18 is inserted into the through hole of the positioning pin 16 from the upper surface direction of the case 14. Then, the bolt 18 is bolted with a nut 22 arranged to support the positioning pin 16.

  Here, the washer 20 is used in the above-described bolt tightening. The washer 20 is disposed so as to be placed on the upper surface of the case 14. That is, when bolting is performed, the washer 20 presses the upper surface of the case 14 downward. At the same time, the nut 22 pushes the positioning pin 16 upward (in the protruding direction of the protruding portion). As described above, the positioning pin 16 is moved upward from the upper surface of the cure base plate 10 by the stopper 15. Is limited. Therefore, when the bolt is tightened, the case 14 and the base plate 12 are pressed against the cure base plate 10.

  In the state in which the above bolting is performed, heat is supplied from the cured base plate 10 to the adhesive 26 via the base plate 12. This heat supply generates a force that expands the base plate 12 and the case 14, but the positioning pin 16 can move in a parallel direction with respect to the upper surface of the cure base plate 10 (float state). It moves following the aforementioned expansion. When the adhesive 26 has been cured and the adhesion between the base plate bonding surface and the case bonding surface is completed, the heat supply is terminated. Thereafter, the integrated base plate 12 and case 14 are removed from the jig, and the processing is completed. The heat supply is not limited to heating from the base plate 12 (bottom surface side) as described above, and heat may be supplied from the entire surface by heating in a high-temperature atmosphere. And about specific heating temperature, in order to harden an adhesive agent, it is necessary to set it as about 150 degreeC.

  The manufacturing method of the semiconductor device of this embodiment is as described above. Here, a comparative example will be briefly described in order to help understanding of the features of the present invention. A comparative example will be described with reference to FIGS. The semiconductor device manufacturing method in the comparative example also includes mounting a base plate on a cured base plate and a case on the base plate, and bonding the base plate and the case with an adhesive. Further, mounting holes are formed in the base plate and the case, respectively.

  FIG. 12 is a plan view of a comparative example, and a positioning block 102 is fixed to the cure base plate 100 so as to be attached. Then, the base plate 105 is arranged in an area defined by the positioning block 102. Next, the case 104 is mounted on the base plate 105 such that the base plate bonding surface and the case bonding surface sandwich the adhesive. The case 104 is also arranged in an area defined by the positioning block 102 as with the base plate 105. As a result, the base plate 105 and the case 104 are arranged in an area defined by the positioning block 102.

  Next, the bolt 108 is inserted from the upper surface of the case 104 with the washer 106 therebetween so that the mounting hole formed in the case 104 and the mounting hole formed in the base plate 105 overlap. Bolts 108 are inserted into the mounting holes formed in the base plate so as to overlap the mounting holes formed in the case 104. FIG. 13 which is a cross-sectional view taken along line 13-13 in FIG. 12 shows a state in which the bolt 108 is inserted. The bolt 108 passes through a mounting hole provided in the base plate 105 and the case 104 and is bolted to a screw groove 110 provided in the cure base plate 100. Then, the adhesive 112 is heated from the cured base plate 100 through the base plate 105 in a state where the base plate 105 and the case 104 are fixed by the bolts 108. Here, when the case 104 and the base plate 105 are bonded, they are fixed in a direction parallel to or perpendicular to the bonding surface.

  The semiconductor device manufacturing method according to the comparative example has the following two problems. First, since the positioning of the base plate 105 and the case 104 is performed using the positioning block 102, the positioning is based on the outer shape of the base plate 105 (and the case 104), and the positioning accuracy is poor. is there. In other words, depending on the degree of manufacturing variation in the outer dimensions of the base plate 105 and the case 104 and the direction (the alignment direction) in which the base plate 105 and the case 104 are mounted, the outer dimensions are not specified or the mounting holes formed in the base plate 105 There arises a problem that the position does not match the position of the mounting hole formed in the case 104.

  The second problem is that the base plate 105 and the case 104 expand as the adhesive 112 is heated, and the base plate 105 and the case 104 are damaged. That is, as shown in FIG. 13, when heating the adhesive 112, the base plate 105 and the case 104 are fixed in a horizontal direction with respect to the bonding surface by the bolts 108. Therefore, the base plate 105 and the case 104 may not expand, and the internal stress may increase and be damaged.

  According to the manufacturing method of the semiconductor device of this embodiment, the above-mentioned problem can be avoided. First, in the present embodiment, the mounting holes formed in the base plate 12 and the mounting holes formed in the case 14 are fitted into the protruding portions of the positioning pins 16 so that the positions of the base plate 12 and the case 14 are fitted. Align. Therefore, in the comparative example, the displacement of the outer dimension of the base plate (and the case) becomes the displacement of the mounting hole as it is, whereas in the present embodiment, the mounting hole itself is used as a reference for alignment. The problem can be avoided.

  Furthermore, the positioning pins 16 used in the present embodiment are movable (float state) in a direction parallel to the upper surface of the cure base plate 10, that is, the bonding surface. Therefore, the positioning pin 16 can move so as to follow the expansion of the base plate 12 and the case 14 while the adhesive 26 is heated. Therefore, internal stress is not accumulated in the base plate 12 and the case 14, and the second problem described above can be avoided.

  The bolt tightening performed in this embodiment does not prevent the positioning pin 16 from moving in the direction parallel to the bonding surface, but fixes the movement of the positioning pin 16 in the direction perpendicular to the bonding surface. As described above, since the case 14 and the base plate 12 are pressed against the cure base plate 10 by this fixing, the base plate 12 and the case 14 can be firmly fixed by the adhesive 26.

  Further, in the comparative example, when the thread groove 110 shown in FIG. 13 is worn, the entire jig needs to be replaced. However, according to the jig used in the present embodiment, the nut 22 and the positioning pin 16 can be taken out from the bottom surface of the cure base plate 10. Therefore, when the nut 22 is worn, it is sufficient to replace only the nut 22, and when it is desired to replace the positioning pin 16, it is sufficient to replace the positioning pin 16 alone. As a result, the running cost of the jig can be reduced. Hereinafter, details will be described with reference to FIGS. 4 to 6.

  As described above, FIGS. 4 and 5 are an enlarged plan view of the periphery of the positioning pin 16 and a cross-sectional view thereof. The cured base plate 10 has an opening for replacing the positioning pin 16 or the nut 22 on the bottom surface. Is provided. A support plate 24 is attached to the jig described in the present embodiment so that the positioning pin 16 or the nut 22 does not fall out of the opening when the bolt is not tightened.

  As can be seen from FIG. 5, the support plate 24 has a U-shape, and a part thereof is placed on the upper surface of the cure base plate 10 (see FIG. 4). The support plate 24 and the cure base plate 10 have holes 25 on the surface on which the support plate 24 is placed on the cure base plate 10. The hole 25 forms one hole in the support plate 24 and the cure base plate 10, and a plate fixing pin 30 is inserted into the hole 25 (see FIG. 5).

  When replacing the nut 22 and the positioning pin 16, the plate fixing pin 30 is removed, and the support plate 24 is slid in the left direction in FIG. 6 corresponds to a section 6-6 in FIG. 4, but FIG. 6 shows a state in which the support plate 24 is removed from the carrier base plate 10 as compared with FIG. 4, and the nut 22 is also drawn outside the positioning pin 16. Thus, it is clearly shown that the nut 22 and the positioning pin 16 are detachable from the opening. Further, as can be seen from FIG. 6, in this embodiment, a groove 32 is formed in the cure base plate 10. Since the support plate 24 is inserted into the groove 32 and attached to the cure base plate 10, the support plate 24 is slid along the groove 32 and removed.

  In this embodiment, the nut 22 is located below the positioning pin 16 and is covered (positioned) by the structure so as not to rotate. 7A and 7B are diagrams for explaining the positioning pin 16 of the present embodiment. FIG. 7A is a cross-sectional view, and FIG. 7B is a bottom view. As shown in FIG. 7, the positioning pin 16 itself is installed (attached) so as not to rotate with respect to the opening of the cure base plate 10 by making its lower shape, for example, a square. As a result, even if the bolt 18 is removed from the nut 22, as long as the support plate 24 is attached to the cure base plate 10, the position of the nut 22 is not fixed (fixed). Can be bolted easily.

  In the present embodiment, the positioning pin 16 has a through hole, but this is not an essential component of the present invention. When there is no through hole, the effect of pressing (adhering) the base plate and the case to the cured base plate 10 by the bolt tightening described above cannot be obtained. However, the mounting holes formed in the base plate 12 and the case 14 can be made to coincide with each other by the positioning pins 16, and the above-mentioned "follow the thermal expansion of the base plate 12 and the case 14" can be achieved. Since the accumulation of stress can be avoided, the effect of the present invention is not lost.

  In the present embodiment, the case 14 and the base plate 12 are individually mounted on the jig (the cure base plate 10), but the present invention is not limited to this. The case 14 and the base plate 12 may be temporarily fixed with an adhesive or the like and mounted on the jig (the cure base plate 10) in an integrated state.

  In the present embodiment, the washer 20 is disposed on the upper surface of the case 14, but the present invention is not limited to this. For example, even if the head of the bolt 18 is placed on the upper surface of the case 14, the effect of the present invention is not lost because the effect of pressing the base plate 12 and the case 14 against the cure base plate 10 by bolting can be obtained.

  The feature of the present invention is that the positioning pins are aligned with respect to the mounting holes of the base plate and the case as a reference, and the positioning pins are parallel to the adhesive surface so as to follow the thermal expansion of the base plate and the case. It is the feature that it can move to. Therefore, in addition to the above-described modifications, various modifications can be made without departing from the scope of the present invention.

Embodiment 2
The present embodiment relates to a jig provided with a mechanism for pressing an electrode at the same time when a base plate and a case are bonded, and a method of manufacturing a semiconductor device using the jig. Hereinafter, the present embodiment will be described with reference to FIGS. FIG. 9 is a cross-sectional view showing a state where the semiconductor device is mounted on the jig according to the present embodiment, and FIG. 11 is a plan view. Here, FIG. 9 is a view taken along the line 9-9 in FIG. 11, and is a view visualizing, for example, the positioning pins 16 for convenience of explanation. FIG. 10 is an enlarged view of a part of FIG. In addition, since the component to which the code | symbol same as the code | symbol used in Embodiment 1 in FIG.9, 10 and 11 was attached | subjected is the same as what was demonstrated in Embodiment 1, description is abbreviate | omitted.

  A collar 40 is attached to the bolt 50 used in the present embodiment. An electrode pressing block 44 is disposed at a position between the head of the bolt 50 and the collar 40. The electrode pressing block 44 presses an electrode, which will be described later, downward (direction in which the electrode 42 is pressed against the insulating substrate 46 via the solder 54). As described above, the electrode holding block 44 is partly disposed between the head of the bolt 50 and the collar 40, and thus interlocks with the bolt 50. The collar 40 and the electrode pressing block 44 are made of SUS, and the electrode pressing block 44 includes a resin portion 48 in a part of the electrode pressing block 44 that abuts the electrode.

  On the other hand, an insulating substrate 46 is mounted on the base plate 12, a wiring pattern (not shown) is formed on the insulating substrate 46, and a semiconductor element (not shown) such as a power device is mounted on the wiring pattern. Yes. The electrode 42 is connected to a predetermined position on the wiring pattern of the insulating substrate 46 by solder 54.

  In this embodiment, when bolt tightening is performed, the resin portion 48 that is a part of the electrode pressing block 44 that is interlocked with the bolt 50 contacts a part of the electrode 42 and presses the electrode 42 downward. Thereby, the float of the electrode 42 accompanying expansion | swelling of the base plate 12 and the case 14 which arises by the heating of an adhesive agent can be suppressed. Here, even if the expansion of the base plate 12 and the case 14 is slight, the problem of floating of the electrode due to softening of the solder 54 may occur, but the adhesive is heated with the electrode pressed down as in the present embodiment. Such a problem can be avoided.

  Further, as can be seen from FIG. 11, it is possible to secure the stability of the electrode 42 by connecting the electrode holding block 44 to the second bolt 50 and pressing the plurality of electrodes 42 downward by the one electrode holding block 44. Therefore, it is preferable.

It is a figure explaining the adhesion method of the base board and case of Embodiment 1. It is a top view of FIG. It is a top view explaining the structure of a cure base board. It is a figure explaining a support plate. It is a figure explaining the state in which the board stop pin was able to be attached with the front view of FIG. It is a figure explaining the state which removed the support plate with the side view of FIG. It is a figure explaining arrange | positioning inside the positioning pin of a nut. It is a top view explaining the structure by which the base board and the case were mounted in the cure base board. It is a figure explaining the adhesion method of the base board and case of Embodiment 2. FIG. 10 is an enlarged view around the electrode of FIG. 9. FIG. 10 is a plan view of FIG. 9. It is a top view of a comparative example. It is a front view of a comparative example.

Explanation of symbols

10 Cure base plate, 12 Base plate, 14 Case, 15 Stopper, 16 Positioning pin, 18 Bolt, 22 Nut, 24 Support plate, 26 Adhesive, 42 Electrode, 44 Electrode holding block, 46 Insulating substrate

Claims (4)

A base plate is mounted on the cure base plate, the case is mounted on the base plate with an adhesive sandwiched between the adhesive surfaces of the base plate and the case, and heat is supplied from the cure base plate to the adhesive. In the method of manufacturing a semiconductor device for bonding the base plate and the case by thermally curing the adhesive,
Formed on the base plate on a positioning pin that is attached to the cure base plate so as to be movable in a direction parallel to the upper surface of the cure base plate and has a protruding portion that is a portion protruding from the upper surface of the cure base plate A method of manufacturing a semiconductor device, wherein the bonding is performed in a state in which the first mounting hole formed and the second mounting hole formed in the case are fitted. The positioning pin includes a through hole penetrating the positioning pin in a direction perpendicular to the bonding surface;
The cure base plate includes a stopper that restricts the positioning pin from moving in the protruding direction of the protruding portion,
Before performing the bonding, a bolt is inserted into the through hole from above the case so that a washer or a bolt head is on the upper surface of the case, and further, a nut and a bolt for supporting the positioning pin Tighten the bolt
The method of manufacturing a semiconductor device according to claim 1, wherein the bonding is performed in a state where the case and the base plate are pressed against the cure base plate by the bolting.   3. The method of manufacturing a semiconductor device according to claim 2, wherein an opening for taking out the nut or the positioning pin from the bottom of the cure base plate is formed in the bottom of the cure base plate. An insulating substrate with electrodes connected to the upper surface by soldering is disposed on the base plate,
The method of manufacturing a semiconductor device according to claim 2, wherein the bonding is performed in a state where the electrode is pressed downward by an electrode pressing block interlocked with the bolt.

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