JP2013131662A - Insulating/heat dissipating substrate for power module and method for manufacturing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an insulating/heat dissipating substrate for a power module, which can suppress increase in contact thermal resistance between a metal layer, which is used as a circuit layer, a heat diffusion layer, and so on, and a high thermal conducting insulation particle.SOLUTION: An insulating/heat dissipating substrate P for a power module, which conducts heat from a semiconductor chip mounted on one surface side to a cooler installed on the other surface side, comprises at least: an insulating resin substrate 1 having a high thermal conducting insulation particle 4 at a part corresponding to a mounting area of the semiconductor chip; a thin conductor layer 7 stacked on front/back surfaces of the insulating resin substrate; and a thick conductor layer 8 stacked on the front/back surfaces via the thin conductor layer 7. The front surface of the insulating resin substrate positioned on the mounting area of the semiconductor chip and a surface of the high thermal conducting insulation particle exposed from the insulating resin substrate are formed flush with each other, and a thickness of the insulating resin substrate positioned on a non-mounting area of the semiconductor chip is formed so as to be thinner that of the insulating resin substrate positioned on the mounting area.

Description

  The present invention relates to an insulated heat dissipation substrate for power modules that generates a very large amount of heat from a semiconductor element, and more particularly to an insulated heat dissipation substrate for power modules that is improved in heat dissipation and reduced in thickness.

A power module including a semiconductor chip such as an IGBT or MOSFET that can operate at a high voltage and a large current has a very large amount of heat generated from the semiconductor chip. In order to quickly dissipate heat, a measure has been taken.
An example of such a power module (see, for example, Patent Document 1) will be described using the schematic cross-sectional view shown in FIG.

  The power module PM is mounted via an insulating heat dissipation board Pa provided with a circuit layer 11a on one surface of an insulating substrate 16 made of ceramics and a heat diffusion layer 12a on the other surface, and solder 14 on the circuit layer 11a. A structure having a semiconductor chip 15 formed, a heat radiator 18 joined to the lower surface of the heat diffusion layer 12a via a solder 14, and a cooler 20 attached to the lower surface of the heat radiator 18 by a mounting screw 19. The heat generated from the semiconductor chip 15 is transmitted to the cooler 20 through the insulating heat dissipation board Pa and the heat dissipating body 18, and finally dissipated to the outside by the cooling water 21 in the cooler 20. It has become.

Incidentally, specific examples of each member are as follows.
That is, “insulating substrate 16” is AlN, Al ₂ O ₃ , Si ₃ N ₄ , SiC, etc., “circuit layer 11a, thermal diffusion layer 12a, radiator 18” is Cu, Al, etc., and “low thermal expansion material 17” is Invar alloy or the like.

  In recent years, such power modules PM have come to be used in electric vehicles and hybrid vehicles that are attracting particular attention, and further higher output and smaller size are demanded.

  Therefore, as the simplest means for meeting the above requirements, it is conceivable to simply reduce the thickness of the insulating substrate 16 made of ceramics. This is because if the insulating substrate 16 is made thinner, the entire power module PM can be reduced in size, and the heat transfer resistance can be lowered by the thickness. That is, since the insulating substrate (ceramic substrate) 16 having a higher heat transfer resistance than the circuit layer 11a made of metal or the heat diffusion layer 12a becomes thin, heat generated from the semiconductor chip 15 can be quickly transmitted to the cooler 20 side.

  However, since ceramics are very fragile when they are thinned, there is a limit to thinning them. As a result, even if AlN (thermal conductivity 170 W / mK) having high thermal conductivity is used as the insulating substrate 16, the heat dissipation effect as expected is not obtained. It was a thing.

  Therefore, an insulating resin substrate that is hard to break even if the plate thickness is reduced is used as an insulating substrate, and the high heat conductivity and insulation between the circuit layer and the thermal diffusion layer formed on the front and back of the insulating resin substrate Thermal connection with particles made of ceramics with excellent "hardness" (hereinafter referred to as "high thermal conductivity insulating particles") is to make the power module thinner and lower heat transfer resistance. Such a configuration is already disclosed in Patent Document 2 (see FIG. 11).

FIG. 11 shows an enlarged cross-sectional view of a main part of an insulating heat dissipation board Pb (corresponding to “insulating heat dissipation board Pa” shown in FIG. 10) used in the power module. An insulating resin substrate 1c made of a thermosetting resin, and a circuit layer 11b and a heat diffusion layer 12b ("circuit layer 11b" and "thermal diffusion layer 12b") laminated on the front and back of the insulating resin substrate 1c Similarly, it is made of Cu, Al, or the like) and high thermal conductive insulating particles 4 [diamond, SiC, Si ₃ N ₄ , AlN which are thicker than the insulating resin substrate 1c and harder than the circuit layer 11b and the thermal diffusion layer 12b. , Particles having a thermal conductivity of 50 W / mK or higher (preferably particles having a power of 150 W / mK or higher) higher than that of Al ₂ O ₃ . The protruding portions 4d of the high thermal conductive insulating particles 4 protruding from the front surface A1 and the rear surface B1 of the insulating resin substrate 1c are penetrated into the circuit layer 11b and the thermal diffusion layer 12b, respectively, so that the contact thermal resistance between them is reduced. (That is, the contact thermal resistance can be made smaller than the structure in which both are simply brought into contact with each other) by the low thermal conductivity of the insulating resin substrate 1c (for example, containing a high thermal conductive filler such as Al ₂ O ₃ ) (Even in the case of epoxy resin, the thermal conductivity is about 3 W / mK), so that an expected heat dissipation effect is obtained.

  However, in the configuration of FIG. 11, although the thermal conductivity of the entire insulating layer (corresponding to the insulating resin substrate 1c including the high thermal conductive insulating particles 4) is high, the circuit layer 11b, the thermal diffusion layer 12b, and the high thermal conductive insulating particles Since there is a contact thermal resistance that cannot be ignored with respect to 4, the actual situation is that the expected heat dissipation effect cannot be obtained in the same manner as the insulating heat dissipation substrate Pa shown in FIG.

The reason was due to the connection structure between the circuit layer 11b and the thermal diffusion layer 12b and the high thermal conductive insulating particles 4.
The reason for this will be described with reference to FIG. 12 showing the contact interface between the circuit layer 11b and the high thermal conductive insulating particles 4 (the thermal diffusion layer 12b has a similar connection structure. And the connection structure between the high thermal conductive insulating particles 4 is omitted).

  As shown in FIG. 12A, the penetration connection between the circuit layer 11b and the high thermal conductive insulating particle 4 is performed on the metal foil 11ba (the portion shown in the figure) that will later become the circuit layer 11b with respect to the high thermal conductive insulating particle 4. Is performed by pressing the mat surface of the metal foil 11ba (that is, the anchor pattern 11bb) in the direction of the arrow, and the metal foil 11ba (circuit layer 11b) and the high thermal conductive insulation. As shown in FIG. 12 (b), the connection structure with the particles 4 is a high heat conductive insulating particle whose surface state is simply a concavo-convex shape 23 (a concavo-convex shape when a large high heat conductive material is pulverized into particles). 4 has a structure that only penetrates the metal foil 11ba (circuit layer 11b), and therefore, the connection strength between the two is almost the same. In such a connection state, the insulating resin substrate 1c expands due to heat generated from the semiconductor chip, that is, the contact interface 22 (see FIG. 12B) between the circuit layer 11b and the high thermal conductive insulating particles 4 is expanded. For this reason, the peeling portion 25 as shown in FIG. 12C is generated at the contact interface 22 between the circuit layer 11b and the high thermal conductive insulating particles 4 to increase the contact thermal resistance between them. FIG. 12C shows a state exaggerated from the actual one in order to make the peeling phenomenon easier to understand. Reference numeral 24 denotes a metal unfilled portion formed between the metal foil 11ba and the high thermal conductive insulating particles 4.

  Incidentally, in Patent Document 2, in order to improve the connectivity between the circuit layer 11b and the thermal diffusion layer 12b and the high thermal conductive insulating particles 4, the surface of the high thermal conductive insulating particles 4 is subjected to Cu plating or Ni plating. However, the surface state of the highly thermally conductive insulating particles 4 made of ceramics or the like, which is less adhesive than the insulating resin in the first place, is not obtained even if the metals are thermocompression bonded. As described above, since the concavo-convex shape 23 remains, the contact state between the high thermal conductive insulating particles 4 and the plating becomes extremely unstable, and eventually the circuit layer 11b and the thermal diffusion layer 12b, The connection strength with the high thermal conductive insulating particles 4 could not be made satisfactory.

JP 2004-153075 A JP 2005-236266 A

  Even when an insulating resin substrate is used as an insulating substrate of an insulating heat dissipation substrate for a power module, the present invention is provided between a metal layer (a metal layer used as a circuit layer, a heat diffusion layer, etc.) and a high thermal conductive insulating particle. It is an object to provide an insulating heat dissipation substrate for a power module that can suppress an increase in contact thermal resistance.

  The present invention is an insulating heat dissipation substrate for a power module that transfers heat generated from a semiconductor chip mounted on one surface side to a cooler installed on the other surface side, and at least mounting the semiconductor chip An insulating resin substrate having high thermal conductive insulating particles in a portion corresponding to the area; a thin film conductor layer laminated on the front and back surfaces of the insulating resin substrate; and a thick conductor layer laminated via the thin film conductor layer In addition, the surface of the insulating resin substrate located in the mounting area of the semiconductor chip and the surface of the high thermal conductive insulating particles exposed from the surface of the insulating resin substrate located in the mounting area of the semiconductor chip are formed flush with each other. In addition, the thickness of the insulating resin substrate located in the non-mounting area of the semiconductor chip is thinner than the thickness of the insulating resin substrate located in the mounting area of the semiconductor chip. The power module insulated radiating substrate, characterized in that there is obtained by solving the above problems.

  Further, the present invention is a method for manufacturing an insulated heat dissipation substrate for a power module that transfers heat generated from a semiconductor chip mounted on one surface side to a cooler installed on the other surface side, A first step of providing a cutout at a portion corresponding to the mounting area of the semiconductor chip in the semi-cured insulating adhesive layer, and a first metal foil on one surface of the insulating adhesive layer having the cutout A third step of filling the heat-insulating insulating particles having a thickness larger than that of the insulating adhesive layer into the extracted portion provided in the insulating adhesive layer, and the insulating adhesive layer. A fourth step of disposing the second metal foil on the other surface of the first metal foil, and a spacer jig provided with an opening in a portion corresponding to the punched portion provided in the insulating adhesive layer. And after placing on the second metal foil, Polishing the protruding part raised by the heating / pressurizing process to be flush with the exposed side surface of the metal foil located in the part removed from the opening of the spacer jig An insulated heat dissipation substrate for a power module, comprising a sixth step and a seventh step of sequentially laminating a thin film conductor layer and a thick conductor layer on the front and back surfaces of the intermediate laminate having the protrusions polished. The above-mentioned problem is solved by this manufacturing method.

  According to the present invention, even when heat generated from the semiconductor chip flows into the insulating heat dissipation substrate, the contact thermal resistance between the high thermal conductive insulating particles and the conductor layer can be maintained in substantially the same state as at normal temperature, Thus, the heat generated from the semiconductor chip can be quickly released to the cooler side.

The schematic sectional drawing for demonstrating the structure of the insulated heat dissipation board | substrate for this invention power module. The schematic cross-section manufacturing-process figure for obtaining the insulated heat dissipation board | substrate for this invention power module. The schematic sectional drawing for demonstrating the surface state of the high heat conductive insulating particle used for the insulated heat dissipation board | substrate for this invention power module. The schematic sectional drawing for demonstrating the connection state of the thin-film conductor layer formed at the process of FIG.2 (g), and the high heat conductive insulating particle with which the insulating resin board | substrate was filled. The schematic sectional drawing for demonstrating the other manufacturing process of the insulated heat dissipation board | substrate for this invention power module. The schematic sectional drawing for demonstrating another manufacturing process of the insulated heat dissipation board | substrate for this invention power module. The schematic cross-section manufacturing-process figure for obtaining the thing of the other structure of the insulated heat dissipation board for this invention power module. The principal part expanded sectional view at the time of forming the circuit layer and heat-diffusion layer of the insulation thermal radiation board | substrate for power modules of FIG. 1 with a subtractive method. The principal part expanded sectional view at the time of forming the circuit layer and heat-diffusion layer of the insulation thermal radiation board | substrate for power modules of FIG. 1 with a semi-additive method. The schematic sectional drawing for demonstrating the structure of the conventional power module. The schematic sectional drawing for demonstrating the structure of the conventional insulated heat dissipation board for power modules which solves the problem of the insulated heat dissipation board used for the conventional power module. The principal part expanded sectional view for demonstrating the problem of the insulation thermal radiation board | substrate for power modules of FIG. Occurs when a metal foil without an opening is placed and stacked without using a spacer jig when filling high thermal conductivity insulating particles having a thickness about twice the thickness of the insulating adhesive layer The schematic sectional drawing for demonstrating the problem to do.

  A first embodiment of the present invention will be described with reference to FIG. In addition, the same code | symbol was attached | subjected to the same site | part as the prior art.

  FIG. 1 is a schematic cross-sectional view of an insulating heat dissipation substrate for power module of the present invention (hereinafter simply referred to as “insulated heat dissipation substrate”) P. The insulating heat dissipation substrate P has a semiconductor chip mounting area ( 1 corresponds to “filling area 9 of high thermal conductive insulating particles 4.” Hereinafter, the “semiconductor chip mounting area” will be described as “filling area 9 of high thermal conductive insulating particles 4” for convenience of explanation.) And the semiconductor chip non-mounting area (ie, “non-filling area 10 of the high heat conductive insulating particle 4” in FIG. 1). For convenience of explanation, the “area” will be described as “the non-filled area 10 of the high thermal conductive insulating particles 4”.) And the insulating resin substrate 1 having the metal foil 3 on the front and back surfaces, and the front and back surfaces of the insulating resin substrate 1. Sequential product The circuit layer 11 and the heat diffusion layer 12 including the thin film conductor layer 7 and the thick conductor layer 8 are exposed, and are exposed from the surface 1d of the insulating resin substrate 1 and the surface 1d of the insulating resin substrate 1 The surface 3c of the metal foil 3 and the surface 4e of the high thermal conductive insulating particle 4 exposed from the surface 1d of the insulating resin substrate 1 are formed flush with each other (see FIG. 2 (f)), and the high thermal conductive insulation The thickness T2 of the insulating resin substrate 1 between the metal layers 3 and 3 located in the unfilled area 10 of the particles 4 is equal to the insulating resin between the thin film conductor layers 7 and 7 located in the filled area 9 of the high thermal conductive insulating particles 4. The substrate 1 is formed to be thinner than the thickness T1.

  Then, the manufacturing method of the insulation heat dissipation board P shown in FIG. 1 is demonstrated using FIG.

  First, as shown in FIG. 2A, a semi-cured insulating adhesive layer 1a (for example, “prepreg”) in which a reinforcing base material 2 such as glass fiber is impregnated with a thermosetting resin such as an epoxy resin is used. Next, the punched portion 2a is formed in a portion corresponding to the filling area 9 (see FIG. 1) of the high thermal conductive insulating particles 4 (that is, a portion corresponding to the semiconductor chip mounting area) by punching processing or router processing (see FIG. 1). (Refer FIG.2 (b)).

Here, the insulating adhesive layer 1a has been described using the one containing the reinforcing base material 2. However, when the power module is not large and there is no concern about warping, the insulating adhesive does not contain the reinforcing base material 2. It is also possible to use the agent layer 1a, and for example, it is also possible to use a film of resin such as epoxy, polyimide, polyamide, polyamideimide, polyethylene, liquid crystal polymer, acrylic, polycarbonate, silicone, etc. It is preferable to use a liquid crystal polymer having excellent properties and stress relaxation properties).
Although not shown in the figure, a filler that is the same material as the high thermal conductive insulating particles 4 and has a smaller diameter than the high thermal conductive insulating particles 4 is added to the insulating resin substrate 1 (the relevant one). Filling the insulating adhesive layer 1a in a range where the stress relaxation property of the insulating adhesive layer 1a is not affected decreases the total thermal resistance of the insulating resin substrate 1 including the high thermal conductive insulating particles 4 (that is, heat (In order to increase conductivity).

Next, as shown in FIG. 2C, after the metal foil 3 (for example, “copper foil”) is disposed on one side of the insulating adhesive layer 1a on which the punched portion 2a is formed, the punched portion 2a is formed. After filling the inside with the high thermal conductive insulating particles 4 and then disposing the metal foil 3 on the other side of the insulating adhesive layer 1a as shown in FIG. Resin that has flowed out of the insulating adhesive layer 1a by applying heat / pressure treatment (hereinafter referred to as "lamination press") through a spacer jig 5 having an opening 5a in a portion corresponding to 9 The high thermal conductive insulating particles 4 are embedded in 1b (see the arrow in the figure), and the insulating adhesive layer 1a containing the resin 1b is cured to form the insulating resin substrate 1 (see FIG. 2 (e)).
2C to 2E, as shown in FIGS. 5A and 5B, as the metal foil 3 to be laminated, the filling area 9 of the high thermal conductive insulating particles 4 is used. It is also possible to arrange a member having an opening 3a at a portion corresponding to the above and perform a lamination press on the metal foil 3 via a cushioning material 13 having releasability and a spacer jig 5. Incidentally, in the case of this configuration, since the metal foil located on the protrusion is removed in advance during the polishing step for removing the protrusion performed later, FIG. 2 (c) to FIG. 2 (e). The polishing process can be performed more easily than the manufacturing process in this step. Thus, in the case of this configuration, the metal foil 3 does not exist in the portion corresponding to the filling area 9 of the high thermal conductive insulating particles 4 (see FIG. 5B), but the metal foil 3 is laminated. In the first place, the insulating resin substrate 1 located in the non-filled area 10 of the high thermal conductive insulating particles 4 is laminated to reduce the thickness, or to be used as an index of a cutting stop line in a polishing process performed later, If it is formed in the non-filled area 10 of the high thermal conductive insulating particle 4, its functional role can be sufficiently fulfilled.

Here, as the material of the high thermal conductivity insulating particles 4, ceramics having both insulating properties and relatively high thermal conductivity, for example, Al ₂ O ₃ (thermal conductivity: 20 W / mk), SiC, SiN (thermal conductivity) Rate: 70 W / mk), AlN (thermal conductivity: 170 W / mk), and the like, and can be selected and used depending on the heat dissipation performance required as appropriate.

  Moreover, as the size of the high heat conductive insulating particles 4, a portion protruding from the surface of the metal foil 3 located in the non-filling area 10 (see FIG. 1) of the high heat conductive insulating particles 4 is shown in FIG. 2 (e). There is no particular limitation as long as the size is such that it is exposed when polished along the polishing line 6. However, a resin void (resin generated between the filled high thermal conductive insulating particles 4 during the lamination press) is not necessary. In this respect, the exposed area of the high thermal conductive insulating particles 4 after polishing can be earned (for example, an exposed area of 50% or more with respect to the filled area 9 of the high thermal conductive insulating particles 4) without generating It is preferable to fill the insulating adhesive layer 1a with a thickness of about twice the thickness.

  Next, by performing a polishing process (for example, buffing or the like) on the protruding portion located outside the polishing line 6 shown in FIG. 2 (e), the filling area 9 (see FIG. 1), the surface 1 d of the insulating resin substrate 1, the surface 4 e of the high thermal conductive insulating particles 4 exposed from the surface 1 d of the insulating resin substrate 1, and the metal foil 3 exposed from the surface 1 d of the insulating resin substrate 1. Next, the front and back surfaces of the intermediate laminate SP are cleaned by a desmear process, and then electroless plating treatment or sputtering is performed. A thick conductor layer 8 (for example, an electrolytic copper-plated film having a thickness of about 150 to 300 μm or the thickness is interposed through a thin film conductor layer 7 (for example, a copper thin film having a thickness of about 0.5 to 1.0 μm) deposited by Thick copper plate with metal And the like) are stacked (see FIG. 2G).

Here, in the above description, an example in which a “copper thin film” is deposited as the thin film conductor layer 7 is shown. However, if a “nickel thin film” having a crystal grain size smaller than that of the copper thin film is deposited, the copper foil film Since a dense film can be deposited, the initial contact thermal resistance can be further reduced (that is, heat generated from the semiconductor chip can be released to the cooler side more quickly).
When the nickel thin film is deposited by electroless plating, any nickel plating such as nickel-phosphorous plating or nickel-boron plating may be deposited. It is preferable that the initial contact thermal resistance can be further reduced.

In addition, as a connection structure between the high thermal conductive insulating particles 4 and the thin film conductor layer 7, a configuration in which electroless plating or the like is deposited on a polished surface such as buff polishing has been described (of course, even in this state, the connection strength between the two is Before the thin film conductor layer 7 is deposited (that is, after the desmear treatment is performed), the exposed surface 4e of the high thermal conductive insulating particles 4 has a soot as shown in FIG. It is preferable to provide a concave portion 4a in order to further strengthen the connection strength between the two (that is, to suppress an increase in contact thermal resistance between the two). That is, since the thin-film conductor layer 7 is connected to the bowl-shaped recess 4a so as to engage with each other, even when the insulating resin substrate 1 expands due to heat from the semiconductor chip, the connection state between the two is maintained. It can be maintained firmly (see the enlarged cross-sectional view of the main part in FIGS. 4A and 4B showing the state where the thin-film conductor layer 7 bites into the bowl-shaped recess 4a).
Incidentally, at the stage of the process of FIG. 2C, the surface of the high thermal conductivity insulating particle 4 (see the untreated “high thermal conductivity insulating particle 4” shown in FIG. 3A) in advance is placed on the surface of FIG. If the one having the recesses 4a formed as shown in FIG. 2 is filled, the adhesion to the insulating resin substrate 1 can be improved (see FIGS. 4A and 4B).
Note that the “ridge-shaped recess” 4a is formed by, for example, treating the surface of the high thermal conductive insulating particle 4 with sodium hydroxide, hydrofluoric acid, or the like, and inside the opening, the void is removed from the opening area of the opening 4b. It has a portion 4c (see FIG. 3C).

  Finally, the circuit layer 11 and the thermal diffusion layer 12 are formed by a general subtractive method to obtain the insulated heat dissipation substrate P shown in FIG.

  What should be noted in the present embodiment is that the high heat conductive insulating particles 4 are connected to the circuit layer 11 and the heat diffusion layer 12 through a thin film conductor layer 7 such as an electroless plating film or a sputtered film. In addition, the thickness T2 of the insulating resin substrate 1 located in the unfilled area 10 of the high thermal conductive insulating particles 4 is made thinner than the thickness T1 of the insulating resin substrate 1 located in the filled area 9 of the high thermal conductive insulating particles 4. In the point.

  As a result, it is possible to suppress an increase in contact thermal resistance between the two in comparison with the conventional connection structure in which the high thermal conductive insulating particles are penetrated into the circuit layer and the thermal diffusion layer and connected. Since the thickness T2 of the insulating resin substrate 1 located in the unfilled area 10 of the particles 4 is made thinner than the thickness T1 of the insulating resin substrate 1 located in the filled area 9 of the high thermal conductive insulating particles 4, the semiconductor chip emits The amount of thermal expansion of the insulating resin substrate generated when the generated heat flows into the insulating heat dissipation substrate can be suppressed (that is, the stress acting in the direction of peeling the high thermal conductive insulating particles 4, the circuit layer 11 and the heat diffusion layer 12) Therefore, it is possible to further suppress an increase in contact thermal resistance between the two.

  Furthermore, the distance between the metal foils 3 and 3 formed on the front and back surfaces of the insulating resin substrate 1 located in the unfilled area 10 of the high thermal conductive insulating particles 4 is shortened (that is, between the circuit layer 11 and the heat diffusion layer 12). Compared with the case where the thickness of the insulating resin substrate 1 in this portion is the same as that of the insulating resin substrate 1 located in the filling area 9 of the high thermal conductive insulating particles 4, the heat dissipation bottom is improved. (Since the heat generated from the semiconductor chip extends not only directly under the mounting of the semiconductor chip but also around it, a further heat dissipation effect can be expected).

  Moreover, in the lamination press process (process of FIG.2 (d)-(e)), it laminates | stacks via the spacer jig | tool 5 provided with the opening part 5a in the part corresponding to the filling area of the high heat conductive insulating particle 4. FIG. This is also a notable point.

  That is, as described above, when the size of the high thermal conductive insulating particles 4 to be filled is about 2 times the thickness of the insulating adhesive layer 1a, the size is shown in FIG. As described above, when the lamination is performed using only the cushion material 13 without using the spacer jig 5, the metal foil 3 follows the gap between the filled high thermal conductive insulating particles 4 as shown in FIG. As a result, the resin flowing out from the insulating adhesive layer 1a does not wrap around the high thermal conductive insulating particles 4 (that is, the metal foil 3 blocks the flowing resin), and as a result, a polishing process performed later. There are problems such as formation of groove portions 26 that cannot be removed, and voids 27 (herein, “voids” refer to unfilled portions of the resin) between the high thermal conductive insulating particles 4. However, By stacking through the support jig 5 is of such a problem can be easily solved.

In addition, if the metal foil 3 shown in FIG. 13 having the same opening 3a as shown in FIG. 5 is laminated, unevenness is formed on the surface, but the resin flowing out from the insulating adhesive layer 1a. Since 1b is not completely dammed, it is also possible to laminate without interposing the spacer jig 5 (see FIG. 6).
In this case, an unnecessary spacer jig 5 is not required for a normal laminating press process, so that the laminating press process can be simplified. However, as shown in FIG. 13B, since it cannot be said that a groove portion that cannot be completely removed by polishing is not completely generated, it is a quality to be laminated through the spacer jig 5 again. It can be said that it is preferable.

Next, a second embodiment of the present invention will be described with reference to FIG.
The insulated heat dissipation substrate PP shown in FIG. 7D is the same as the insulated heat dissipation substrate P shown in FIG. 1 except that the metal foil 3 is not formed in the unfilled area 10 of the high thermal conductive insulating particles 4. The manufacturing process is the same as that shown in FIG. 2 except that a step of etching and removing the metal foil 3 formed on the surface of the insulating resin substrate 1 (corresponding to FIG. 7A) in FIG. (See the schematic cross-sectional manufacturing process diagrams shown in FIGS. 7A to 7D).
Accordingly, the basic operational effects are the same as those of the first embodiment, and therefore only the features in comparison with the first embodiment will be described here.

  First, when the circuit layer 11 and the thermal diffusion layer 12 are formed by the subtractive method, the metal foil 3 previously formed in the unfilled area 10 of the high thermal conductive insulating particles 4 is removed, Although the recessed part 31 for the said metal foil 3 removal will generate | occur | produce on the surface of the circuit layer 11 and the thermal-diffusion layer 12 which are located (refer FIG.7 (c), (d)), the circuit after an etching process There is an advantage in that the crease formed at the etching interface between the layer 11 and the thermal diffusion layer 12 can be reduced, and the insulating heat dissipation board PP can be made smaller than the insulating heat dissipation board P of the first embodiment.

  That is, in the case of the first embodiment, as shown in FIG. 8A, when the portion exposed from the etching resist pattern 28 is removed by etching, the metal foil 3 remaining inside is also combined. Therefore, the etching process time must be lengthened accordingly. For this reason, as shown in FIG. 8B, since the bend portion 29 formed at the etching interface between the circuit layer 11 and the heat diffusion layer 12 becomes large, the circuit layer 11 and the heat diffusion layer 12 In order to secure the required area, it is necessary to set the size of the insulating heat dissipation substrate to a slightly larger size in consideration of the etching amount of the metal foil 3, but in the second embodiment, such consideration is taken into account. Since it is not necessary, it can be made smaller than that of the first embodiment.

  Second, since the circuit layer 11 and the heat diffusion layer 12 can be formed by a semi-additive method, the insulating heat dissipation substrate can be further downsized.

That is, when the insulating heat dissipation substrate P of the first embodiment is formed by the semi-additive method, as shown in FIG. 9A, the thick conductor which is the main part of the circuit layer 11 and the heat diffusion layer 12 is used. In the formation of the layer 8, since it is configured such that electrolytic plating (for example, “electrolytic copper plating”) is deposited on a portion where the plating resist pattern 30 is not formed, the layer 8 can be formed with a desired size.
However, as shown in FIG. 9B, after the plating resist pattern 30 is peeled off, the thin film conductor layer 7 exposed from the thick conductor layer 8 (for example, a copper thin film having a thickness of 0.5 to 1.0 μm) and metal When the foil 3 (for example, a copper foil having a thickness of 12 to 18 μm) is removed by etching, it is formed at the etching interface between the circuit layer 11 and the thermal diffusion layer 12 as described in the case of the subtractive method. In addition, since the wrinkled portion 29a becomes large, and the surface of the thick conductor layer 8 is also removed thickly by the etching and removal of the metal foil 3 (see FIG. 9C), the first In the configuration of the insulating heat dissipation substrate P of the second embodiment, the manufacturing method by the semi-additive method is impossible, but in the configuration of the insulating heat dissipation substrate PP of the second embodiment, the seed layer of electrolytic plating Except for thin film conductor layer 7 Since the manufacturing method by the usual semi-additive method to be left is possible, it can be made smaller than the insulating heat dissipation substrate P of the first embodiment.

  Although the features of the second embodiment have been described above, in the first embodiment, as shown in FIG. 4, the thin film conductor layer 7 is formed via the metal foil 3 having the anchor pattern 3b. Therefore, the adhesion strength of the circuit layer 11 and the thermal diffusion layer 12 to the insulating resin substrate 1 can be made higher than that of the second embodiment in which the thin film conductor layer 7 is directly deposited on the insulating resin substrate 1. In the case where the heat generation temperature of the semiconductor chip is high and importance is attached to the adhesion between the insulating resin substrate 1 and the circuit layer 11 and the heat diffusion layer 12, the one of the first embodiment is selected, or from the semiconductor chip The exothermic temperature is not so high, and we want to emphasize the dimensional accuracy of the circuit layer 11 and the thermal diffusion layer 12 and the miniaturization of the insulating heat dissipation substrate rather than improving the adhesion between the insulating resin substrate 1 and the circuit layer 11 and the thermal diffusion layer 12. in case of Including selecting the one of the two embodiments, may be selected depending on the application.

  In describing the present invention, as a means for suppressing an increase in contact thermal resistance between the high thermal conductive insulating particles and the circuit layer and the thermal diffusion layer, a thin film deposited on the high thermal conductive insulating particles by electroless plating or sputtering. A thick conductor layer is laminated via the conductor layer, and the thickness of the insulating resin substrate located in the non-filling area of the high thermal conductive insulating particles is made thinner than the thickness of the insulating resin substrate located in the filling area of the high thermal conductive insulating particles. Although the example has been explained, if an anisotropic linear expansion resin having a smaller linear expansion coefficient in the vertical direction than that in the horizontal direction is used as the insulating resin for the insulating resin substrate, the heat radiation reliability of the insulating heat dissipation board can be improved. It can be improved further.

  Further, as an example of embedding the high thermal conductive insulating particles, an example in which only the resin flowing out from the insulating adhesive layer is filled at the time of the lamination press has been described. In addition, if resin powder made of uncured thermosetting resin finely pulverized is added as an auxiliary, defects such as voids due to insufficient resin can be reliably eliminated.

  In addition, although the high heat conductive insulating particles have been described using polygonal particles that image a crushed product, the high heat conductive insulating particles may have any shape as long as they are in a certain lump shape, for example, Of course, it is possible to use a pre-molded material such as a spherical shape or a column shape.

1, 1c: Insulating resin substrate 1a: Insulating adhesive layer 1b: Resin 1d: Surface of insulating resin substrate 2: Reinforcing fiber 2a: Extracted portion 3: Metal foil 3a: Opening (opening of metal foil)
3b: Anchor pattern 3c: Surface of metal foil exposed from insulating resin substrate 4: High heat conductive insulating particles 4a: Wrinkled recess 4b: Opening (opening of wrinkled recess)
4c: Dripping portion 4d: Protruding portion 4e: Surface of the high thermal conductive insulating particle exposed from the insulating resin substrate 5: Spacer jig 5a: Opening portion (opening portion of the spacer jig)
6: Polishing line 7: Thin film conductor layer 8: Thick conductor layer 9: Filled area 10: Unfilled areas 11, 11a, 11b: Circuit layer 11ba: Metal foil 11bb: Anchor pattern 12, 12a, 12b: Thermal diffusion layer 13: Cushion material 14: Solder 15: Semiconductor chip 16: Insulating substrate 17: Low thermal expansion material 18: Heat radiator 19: Mounting screw 20: Cooler 21: Cooling water 22: Contact interface 23: Simple uneven shape 24: Metal unfilled portion 25 : Peeling part 26: Groove part 27: Void 28: Etching resist pattern 29, 29 a: Bending part 30: Plating resist pattern 31: Indented part P, PP, Pa, Pb,: Insulating heat dissipation board SP for power module: Intermediate laminate PM: Power module A, B: Exposed side surface of metal foil A1: Front surface of insulating resin substrate B1: Back surface of insulating resin substrate T1: Insulation of filling area Fat substrate thickness T2: insulating resin substrate thickness of unfilled areas

Claims (18)

  An insulating heat dissipation substrate for a power module that transfers heat generated from a semiconductor chip mounted on one surface side to a cooler installed on the other surface side, at least corresponding to the mounting area of the semiconductor chip An insulating resin substrate having high thermal conductive insulating particles at a site, a thin film conductor layer laminated on the front and back surfaces of the insulating resin substrate, a thick conductor layer laminated via the thin film conductor layer, and The surface of the insulating resin substrate located in the mounting area of the semiconductor chip and the surface of the high thermal conductive insulating particles exposed from the surface of the insulating resin substrate located in the mounting area of the semiconductor chip are formed flush with each other. The thickness of the insulating resin substrate located in the non-mounting area of the semiconductor chip is formed thinner than the thickness of the insulating resin substrate located in the mounting area of the semiconductor chip. It insulated radiating substrate for a power module characterized.   A metal foil having a surface flush with the surface of the insulating resin substrate located in the mounting area of the semiconductor chip is provided between the insulating resin substrate located in the non-mounting area of the semiconductor chip and the thin film conductor layer. The insulating heat dissipation substrate for a power module according to claim 1.   The high thermal conductive insulating particle has a bowl-shaped recess at least on an exposed surface from the insulating resin substrate, and a part of the thin film conductor layer bites into the bowl-shaped recess. The insulating heat dissipation substrate for a power module according to claim 1 or 2. The insulating resin substrate contains the same material as the high thermal conductive insulating particles and contains a filler having a diameter smaller than that of the high thermal conductive insulating particles. The insulated heat dissipation board for power modules as described.   The insulated heat dissipation substrate for a power module according to any one of claims 1 to 4, wherein the thin film conductor layer is made of electroless Ni plating.   The power module according to any one of claims 1 to 5, wherein the insulating resin substrate is made of an anisotropic linear expansion resin having a smaller linear expansion coefficient in the vertical direction than the linear expansion coefficient in the horizontal direction. Insulating heat dissipation board.   The insulating heat dissipation substrate for a power module according to any one of claims 1 to 6, wherein the insulating resin substrate includes reinforcing long fibers therein.   A method of manufacturing an insulating heat dissipation substrate for a power module that transfers heat generated from a semiconductor chip mounted on one surface side to a cooler installed on the other surface side, and at least a semi-cured insulation A first step of providing a cutout in a portion of the adhesive layer corresponding to the mounting area of the semiconductor chip, and a second of disposing a first metal foil on one surface of the insulating adhesive layer provided with the cutout A third step of filling the heat-insulating insulating particles having a thickness larger than that of the insulating adhesive layer into the extracted portion provided in the insulating adhesive layer, and the other surface of the insulating adhesive layer. A fourth step of disposing the second metal foil, and a spacer jig having an opening in a portion corresponding to the punched portion provided in the insulating adhesive layer, the first metal foil and the second metal After placing on the foil, the fifth is to heat and pressurize And a sixth step of polishing the protruding portion raised by the heating / pressurizing process so as to be flush with the exposed surface of the metal foil located in a portion off the opening of the spacer jig, And a seventh step of sequentially laminating a thin-film conductor layer and a thick conductor layer on the front and back surfaces of the intermediate laminate with the protrusions polished, and a method for producing an insulated heat dissipation substrate for a power module.   The metal foil arranged in the second and fourth steps has an opening at a portion corresponding to the mounting area of the semiconductor chip, and the heating / pressurizing treatment performed in the fifth step is performed. 9. The method for manufacturing an insulating heat dissipation substrate for a power module according to claim 8, wherein a cushioning material having releasability is provided between the first and second metal foils and the spacer jig.   10. The method for manufacturing an insulated heat dissipation substrate for power modules according to claim 9, wherein the heating / pressurizing process is performed without using a spacer jig.   The method for manufacturing an insulating heat dissipation substrate for a power module according to any one of claims 8 to 10, wherein a step of removing the metal foil is added between the sixth and seventh steps.   The process of forming a bowl-shaped recessed part in the exposed surface of the high heat conductive insulating particle exposed by the polishing of the sixth process is added between the sixth and seventh processes. 11. A method for manufacturing an insulating heat dissipation substrate for a power module according to any one of 11.   The method for producing an insulated heat dissipation substrate for a power module according to any one of claims 8 to 12, wherein the highly thermally conductive particles filled in the third step have a bowl-shaped recess on the surface. .   The insulating adhesive layer is made of the same material as the high thermal conductive insulating particles and contains a filler having a diameter smaller than that of the high thermal conductive insulating particles. The manufacturing method of the insulated heat dissipation board | substrate for power modules of Claim 1.   The insulated heat dissipation for a power module according to any one of claims 8 to 14, wherein the thin film conductor layer laminated in the seventh step is made of a nickel film deposited by electroless nickel plating. A method for manufacturing a substrate.   The power according to any one of claims 8 to 15, wherein the insulating adhesive layer is made of an anisotropic linear expansion resin having a linear expansion coefficient in the vertical direction smaller than that in the horizontal direction. A method of manufacturing an insulating heat dissipation board for modules.   The method for producing an insulating heat dissipation substrate for a power module according to any one of claims 8 to 16, wherein the insulating adhesive layer contains reinforcing long fibers therein.   Between the third and fourth steps, adding a step of putting resin powder made of finely pulverized uncured thermosetting resin into the extracted part of the insulating adhesive layer filled with high thermal conductive insulating particles The method for manufacturing an insulating heat dissipation substrate for a power module according to any one of claims 8 to 17.