JP2002270744A - Lead frame, method for manufacturing the same, and method for manufacturing heat conductive substrate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a lead frame with a heat conductive resin sheet member for the purpose of suppressing the occurrence of resin burs on the lead frame in manufacturing of a highly heat-conductive substrate, and of shortening the tact of the manufacture of the heat conductive substrate. SOLUTION: The lead frame (102) has a heat conductive resin sheet member (101), which is positioned on it and integrated with it, the heat conductive resin sheet member is formed of a material containing 70 to 95 pts.wt. organic filler and 5 to 30 pts.wt. thermosetting resin composition containing at least thermosetting resin, and the thermosetting resin is in a half-cured state in the lead frame with the heat conductive resin sheet member.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a circuit board having improved heat dissipation by a mixture of a resin and an inorganic filler, and more particularly, to a high heat dissipation resin board for mounting power electronics (namely, a heat conductive board). ). More specifically, the present invention relates to a heat conductive substrate, a lead frame having a heat conductive resin sheet member used for manufacturing the same, and a method for manufacturing these.

[0002]

2. Description of the Related Art In recent years, with the demand for higher performance and smaller size of electronic equipment, there has been a demand for higher density and higher function of semiconductor devices. Accordingly, a small and high-density circuit board for mounting them is also desired. As a result, it is becoming important to design the circuit board in consideration of heat radiation.

As a technique for improving the heat radiation of a circuit board,
A metal base substrate is known in which a metal plate such as aluminum is used for a conventional printed substrate made of glass epoxy resin, and a circuit pattern is formed on one surface of the metal plate via an insulator. Further, when higher thermal conductivity is required, a substrate in which a copper plate is directly bonded to a ceramic substrate such as alumina or aluminum nitride is used.

[0004] For a relatively low power application, a metal base substrate is generally used. However, in order to improve heat conduction, the insulator must be thin, and the metal base substrate is affected by noise. In addition, there is a problem in withstand voltage. Further, the ceramic substrate has a problem that the cost is high.

[0005] As described above, it is difficult to achieve compatibility between the metal base substrate and the ceramic substrate in terms of performance and cost. (For example, Japanese Patent Application Laid-Open No. 9-2).
No. 98344, JP-A-9-321395).

[0006] This injection-molded heat conduction module is excellent in mechanical strength as compared with a ceramic substrate, but it is difficult to fill a high concentration of an inorganic filler for imparting heat radiation to a thermoplastic resin. Therefore, heat dissipation is poor.
This is because, when the thermoplastic resin is melted at a high temperature and kneaded with the filler, if the amount of the filler is large, the melt viscosity increases rapidly, so that not only kneading is impossible but also injection molding cannot be performed. In addition, the filler to be filled acts as an abrasive, causing the molding die to wear, making it difficult to perform molding many times. For this reason, there is a problem in that the amount of the filled filler is limited, and only low performance can be obtained as compared with the heat conduction of the ceramic substrate.

In order to solve these problems, Japanese Patent Laid-Open No.
In Japanese Patent Publication No. 0-173097, a mixture of a thermosetting resin having flexibility in a semi-cured state and an inorganic filler for improving heat conduction (also referred to as a “thermosetting resin mixture”).
To produce a thermally conductive resin sheet member filled with an inorganic filler at a high concentration, and a lead frame as an electrode and a metal radiating plate are laminated and heated and pressed so as to sandwich the sheet member. By filling the heat conductive resin sheet member up to the surface of the lead frame and curing the thermosetting resin, the lead frame, the heat conductive resin sheet member and the metal heat sink are integrated. A heat conductive substrate in which a lead frame and a metal heat radiating plate face each other and a method for manufacturing the same are disclosed. The contents of this published patent publication constitute a part of the present specification by this citation.

[0008]

In the case of manufacturing a heat conductive substrate by the above-described method, if appropriate manufacturing conditions are not selected, the periphery of the exposed surface of the metal radiator plate and the exposure of the lead frame during heating and pressing. The thermosetting resin mixture may spill around the surface, which may cure and cause resin burrs and surface fouling. The resin burrs and surface stains cause soldering problems when mounting components on the heat conductive substrate, and are also undesirable in appearance of the heat conductive substrate.
A step of removing these is additionally required.

In the case where the heat conductive resin sheet member is manufactured by the above-described method, there are variations in the thermosetting resin mixture itself and various fluctuations in the process, and a stable thickness (accordingly, volume) is obtained. It is not easy to manufacture the heat conductive resin sheet member.

[0010] In particular, if the heat conductive resin sheet member is too thick, and therefore too large, a large amount of the thermosetting resin mixture protrudes around the exposed surface of the lead frame, and as a result, the lead frame is exposed. Resin burrs and stains on the surface increase. Further, when the size of the heat conductive resin sheet member fluctuates, the thickness of the finally manufactured heat conductive substrate fluctuates, so that stable substrate supply may not be performed. That is, in order to stably manufacture the heat conductive substrate, it is necessary to stably manufacture an appropriate heat conductive resin sheet member.

On the other hand, when a heat conductive substrate is manufactured by the above-described method, a heat conductive resin sheet member formed of a thermosetting resin having flexibility in a semi-cured state has a mechanical strength. There is a problem that handling is not easy because it is not always sufficient. In addition, the heat conductive resin sheet member during storage before manufacturing the heat conductive substrate is managed so as to have a long gel time (for example, 4 minutes or more) in consideration of long-term storage stability. However, when such a thermally conductive resin sheet member is cured and integrated with a lead frame, not only the above-described resin burrs are generated but also the integration step is lengthened due to a long curing time. There is a problem of becoming tact.

[0012]

Means for Solving the Problems The present inventors have previously integrated a lead frame with a thermally conductive resin sheet member in which the contained thermosetting resin is in a semi-cured state, thereby obtaining a thermally conductive resin sheet. The member is reinforced by the lead frame, and as a result, the handleability of the thermally conductive resin sheet member can be improved, and the thermally conductive resin sheet member integrated with the lead frame is overlapped with the metal heat sink. It has been found that by performing heating and pressurization, a heat conductive substrate can be manufactured in a state improved with respect to at least one of the various problems described above.

Accordingly, in a first aspect, the present invention provides:
A lead frame having a heat conductive resin sheet member, and being located thereon and integrated therewith, wherein the heat conductive resin sheet member comprises 70 to 95 parts by weight of an inorganic filler and a thermosetting resin. Thermosetting resin composition 5 comprising
30% by weight of the thermosetting resin mixture, wherein the thermosetting resin is in a semi-cured state.

If the amount of the inorganic filler in the thermosetting resin mixture is less than this range, the heat dissipation of the substrate manufactured using the lead frame with the heat conductive resin sheet member may be insufficient, and conversely, If it is more than this range, the adhesiveness of the thermally conductive resin sheet member may be reduced, and a sufficient substrate cannot be manufactured. In addition, from the viewpoint of further improved thermal conductivity and adhesiveness of the obtained thermally conductive resin sheet member, the mixing ratio of the inorganic filler and the thermosetting resin composition is determined as follows: inorganic filler: thermosetting resin composition (weight Ratio) of 85 to 95:15 to 5 is particularly preferred.

In such a lead frame with a heat conductive resin sheet member, since the heat conductive resin sheet member is integrated with the lead frame, the heat conductive resin sheet member is reinforced, and as a result, cracks and Breakage such as chipping is less likely to occur, and handling is improved. In the present specification, the term “integrated” is easily understood by those skilled in the art of manufacturing a thermally conductive substrate using a thermosetting resin, but is unique to the thermally conductive resin sheet member. Properties (especially heating (including heating for promoting curing and heating in a state where curing is not proceeding) and / or properties when pressurized (or pressed) and, if necessary, when subsequently cooled The heat conductive resin sheet member adheres to other elements, for example, a lead frame, a metal radiator plate described later, etc., based on the properties of the heat conductive resin sheet member (particularly, a sufficient adhesive state for use of the manufactured heat conductive substrate). ).

In the lead frame with a thermally conductive resin sheet member of the present invention, the thermally conductive resin sheet member is formed from a thermosetting resin mixture, has electrical insulation properties, and can function as an insulating layer. This thermosetting resin mixture is composed of a thermosetting resin composition and an inorganic filler, and contains a solvent (or diluent or dispersant) for adjusting the viscosity of the mixture as necessary. The thermosetting resin composition contains a thermosetting resin as its main component.

As such a thermosetting resin, it is preferable that the thermosetting resin is usually used for an electronic substrate, particularly for its electric insulation purpose. More preferably, at least one of them is used, and any combination of these can be used. These resins have electrical properties (especially electrical insulation),
It is particularly preferable to use it because it has excellent mechanical properties (particularly mechanical strength).

Further, the thermosetting resin composition may further contain other components. As such other components, it is preferable to include a curing agent and / or a curing accelerator. As the curing agent, for example, a bisphenol A-type novolak resin can be used, and as the curing accelerator, for example, imidazole can be used. Further, the thermosetting resin composition,
If necessary, additives such as a coupling agent, a dispersant, a colorant, and a release agent may be further included. These additives are not particularly limited, and may be appropriately selected. As the coupling agent, for example, an epoxysilane-based coupling agent, an aminosilane-based coupling agent, a titanate-based coupling agent, or the like can be used. As the dispersant, for example, a phosphoric ester or the like can be used. As the colorant, for example, carbon black, chromium oxide or the like can be used, and as the release agent, for example, a silicone resin or the like can be used.

The inorganic filler contained in the thermosetting resin mixture (ie, thermosetting resin composition + inorganic filler + solvent (if necessary)) imparts thermal conductivity to the resulting thermally conductive resin sheet member. Al ₂ O ₃ , MgO, BN and AlN
The filler is preferably at least one kind of filler selected from the group consisting of: and any combination thereof can be used.
This is because these fillers are particularly excellent in thermal conductivity and can produce a substrate having high heat dissipation. In particular, when Al ₂ O ₃ is used, mixing with the thermosetting resin composition becomes easier, and when AlN is used, the heat dissipation of the finally obtained heat conductive substrate is particularly high. Is preferred. Although the form of the filler is not particularly limited, for example, a powdery, granular, and / or fibrous filler can be used. When the inorganic filler is in a powder or granular form, the particle size is preferably from 0.1 to 100 μm. If the particle size is too large or too small, the compoundability of the inorganic filler may not be sufficient.

In the lead frame with a thermally conductive resin sheet member of the present invention, the thermosetting resin contained in the thermally conductive resin sheet member is in a semi-cured state (or a partially cured state).
It is in. This state is a so-called B-stage. In the lead frame of the present invention, the semi-cured state is such that the heat conductive resin sheet member
Preferably, it has a gel time at 155 ° C. in the range of 0 seconds. This gel time is
More preferably in the range of 40 seconds to 100 seconds, especially 50 seconds to
The range is 90 seconds. If the gel time is too short, sufficient adhesiveness to the metal radiator plate may not be obtained in the heating and pressurizing step for integration with the metal radiator plate later. Also, if the gel time is too long, the tact of manufacturing the heat conductive substrate integrated with the metal heat sink becomes longer,
In some cases, the thermosetting resin mixture exudes to the periphery of the exposed surface of the heat conductive substrate and the periphery of the exposed surface of the lead frame and cures, causing resin burrs and surface contamination.

In the present specification, the gel time of a heat conductive resin sheet member is defined as a temperature at which a heat conductive resin sheet member containing a thermosetting resin in a semi-cured state rapidly flows at a predetermined temperature (usually by heating). It means the time to lose its properties and reach a solidified state, and is a certain temperature (here, 15
(Using 5 ° C.).

Specifically, the gel time used in the present specification means a value measured by the following method: A tablet (typically about 25 mm in diameter) is prepared from a thermally conductive resin sheet member in a semi-cured state. 8g).
In addition, this sample may be collected from the one integrated with the lead frame. This is because the hardening of the thermosetting resin does not proceed during integration with the lead frame. Next, Curast Meter (Model Vp, manufactured by JSR Corporation)
Using s), the upper and lower hot plates are heated to 155 ° C., the sample is interposed between them, sine wave vibration is applied to the sample, and the resulting torque is measured. As the curing of the thermosetting resin contained in the thermally conductive resin sheet member progresses, the measured torque increases.
The time to exceed kgf / cm ² (time after sandwiching) is obtained as the gel time at 155 ° C. The principle of such a gel time measuring method is generally known.

In the lead frame with a thermally conductive resin sheet member of the present invention, the viscosity of the thermally conductive resin sheet member is preferably in the range of 10 ² to 10 ⁵ Pa · s, more preferably 10 ^3. It is in the range of 〜１０10 ⁵ Pa · s. 10 deformation amount is too large at the time of the thermally conductive substrate prepared in 2 ^Pa · s or less viscosity, resin burrs on the exposed surface of the lead frame, the generation of surface dirt may not be sufficiently suppressed, conversely, 10 ⁵ When the viscosity is Pa · s or more, the flexibility of the heat conductive resin sheet member is not sufficient, and it may be difficult to manufacture the heat conductive substrate.

The viscosity of the heat conductive resin sheet member can be obtained by the following measuring method: The measurement is carried out using a viscoelasticity measuring device (cone and plate type).
e) A dynamic viscoelasticity measuring apparatus MR-500, manufactured by Rheology Co., Ltd.) is used. The sheet is processed into a predetermined size, sandwiched between a cone and a plate having a cone diameter of 17.97 mm and a cone angle of 1.15 deg. It is obtained by calculating the phase difference and calculating the viscosity. With respect to the heat conductive resin sheet member of the present invention, a value at 25 ° C. was obtained using a sine wave of 1 Hz, a strain of 0.1 deg, and a load of 500 g.

In the lead frame with a thermally conductive resin sheet member of the present invention, since the thermally conductive resin sheet member is integrated with the lead frame in a semi-cured state, a thermally conductive substrate is manufactured. In this case, the production tact time is shorter than when the lead frame and the metal radiating plate are integrated with the uncured thermosetting resin. Moreover,
As will be described later, since the integration of the heat conductive resin sheet member including the thermosetting resin in the semi-cured state and the lead frame is performed under the condition that the curing does not substantially proceed, the integrated lead frame No resin burrs, stains, etc. are generated on the exposed surface of.

In one embodiment of the lead frame with a thermally conductive resin sheet member of the present invention, a part of the lead frame is integrated with the thermally conductive resin sheet member. For example, the heat conductive resin sheet member does not exist below the outer peripheral portion of the lead frame, and therefore, the portion of the lead frame excluding the outer peripheral portion is integrated with the heat conductive resin sheet member.
In such an example, the lead frame is connected via a common terminal (preferably a common terminal extending outward from the heat conductive resin sheet member) to the outer frame portion.
It is desirable that all other terminals of the lead frame are electrically connected to the outer frame. Thereby, any terminal of the lead frame can be prevented from falling off from the lead frame with the heat conductive resin sheet member, and the handleability of the lead frame with the heat conductive resin sheet member is improved.

In one preferred embodiment, in the lead frame with a thermally conductive resin sheet member of the present invention, a part of the lead frame is integrated with the thermally conductive resin sheet member,
In addition, it is desirable that at least one wiring pattern or terminal electrically independent from the integrated lead frame is integrated with the thermally conductive resin sheet member (on the same side as the lead frame). As a result, the independent wiring patterns or terminals are electrically isolated from the lead frame, but are held as isolated islands on the thermally conductive resin sheet member. The lead frame with the thermally conductive resin sheet member does not fall off from the lead frame with the thermally conductive resin sheet member, and the handleability of the lead frame with the thermally conductive resin sheet member is improved.

As described in detail below, the above-described lead frame with a thermally conductive resin sheet member is formed by laminating a lead frame with a thermally conductive resin sheet member in which the thermosetting resin contained is in a semi-cured state. At the same time, by heating as necessary, the thermosetting resin of the heat conductive resin sheet member is pressurized (or pressed) at a temperature at which the thermosetting resin does not harden (therefore, hardening does not proceed), thereby integrating them. It is obtained by doing. In such a lead frame, the heat conductive resin sheet member and the lead frame are flush with each other.
Is preferably formed, that is, a wiring pattern is formed on the lead frame, and therefore, the lead frame has at least one through opening. It is preferable that the through opening is filled to the level of the exposed surface of the lead frame with a thermally conductive resin sheet member.

The lead frame to be used may be one generally used for an electronic circuit board, and is not particularly limited. The material of the lead frame may be any material as long as it has high conductivity and is easy to process. For example, copper, iron, nickel, aluminum, silver, or various alloys containing these as a main component may be used. A wiring pattern is formed on the lead frame, and as a wiring pattern processing method, for example, a known method by chemical etching, a punching method by a die, or a punching method by punching can be used. Further, the lead frame may be plated to prevent oxidation of the surface and improve solder wettability. As plating types, for example, tin, nickel,
Lead, silver, gold, palladium, chromium, or alloys containing these as main components can be used. Further, it is preferable to roughen the bonding surface of the lead frame in order to improve the bonding property with the heat conductive resin sheet member. The method for roughening is not particularly limited, and for example, sand blasting, polishing, chemical etching and the like can be used.

As described above, the step of integrating the heat conductive resin sheet member in which the thermosetting resin is in a semi-cured state and the lead frame is performed by curing the thermosetting resin contained in the heat conductive resin sheet member. Is carried out under the conditions (particularly temperature) in which the thermosetting resin does not substantially proceed, the overflow of the thermosetting resin mixture to the exposed surface of the lead frame is suppressed. The resulting lead frame with a thermally conductive resin sheet member may then be cooled as needed (eg, cooled to room temperature).
Well, you can save it in that state.

Further, when the thermosetting resin sheet member integrated with the lead frame is superimposed on a metal radiator plate and heated for curing, and then heated and pressed to produce a thermally conductive substrate, The wraparound of the thermosetting resin mixture on the exposed surfaces of the lead frame and the metal radiator plate is suppressed, and the occurrence of dirt on the exposed surface and generation of resin burrs can be prevented.

Accordingly, in a second aspect, the present invention provides:
Formed from a thermosetting resin mixture containing a thermosetting resin composition containing a thermosetting resin and an inorganic filler, and a thermoconductive resin sheet member in which the thermosetting resin is in a semi-cured state. A method for manufacturing a lead frame with a thermally conductive resin sheet member, comprising a lead frame located thereon and integrated therewith, wherein (a) a thermosetting resin comprising a thermosetting resin A step of obtaining a thermally conductive resin sheet member from a thermosetting resin mixture comprising the composition and an inorganic filler; (b) a step of heat-treating the thermally conductive resin sheet member so as to have a predetermined gel time; And (c) arranging a lead frame on the thermally conductive resin sheet member and pressing them toward each other at a temperature at which curing of the thermosetting resin does not proceed, thereby integrating them. To provide a method of manufacturing a lead frame.

In the various methods of the present invention, the above description of the lead frame with a thermally conductive resin sheet member of the present invention (for example, details of thermosetting resin, inorganic filler, gel time, lead frame, etc.) and the following description The description also applies to the various methods of the invention described below, unless otherwise indicated.

In the method for manufacturing a lead frame according to the present invention, the step (a) comprises blending a thermosetting resin, an inorganic filler, and, if necessary, one or more other components. For example, methyl ethyl ketone (MEK), toluene, isopropanol, etc.) to obtain a thermosetting resin mixture whose viscosity has been adjusted, apply the obtained thermosetting resin mixture on a substrate, and dry to remove the solvent. To obtain a sheet. The thermosetting resin mixture may be treated by another method, for example, an extrusion method, as long as a sheet can be obtained. This step is preferably performed under the condition that the curing of the thermosetting resin constituting the sheet member does not progress. In this case, since the heat conductive resin sheet member can maintain a long gel time, the heat conductive resin sheet member can be stably stored for a long time. However, in another aspect, the curing of the thermosetting resin may proceed in step (a) as long as the gel time adjusted in step (b) can be achieved. For example,
Even if the step (a) is performed at a temperature at which curing proceeds, the gel time adjusted in the step (b) can be achieved if the time required for the step is short. Since the control of the curing of the thermosetting resin is usually performed by temperature control, the step (a)
Whether or not the curing progresses in depends on the thermal condition, that is, the temperature condition, to which the thermosetting resin composition and the inorganic filler are exposed when obtaining the sheet-shaped member. The temperature conditions at which curing proceeds differ depending on the thermosetting resin used,
Generally, step (a) is performed at a temperature of 90 ° C or less, preferably 85 ° C or less, more preferably 80 ° C or less.

The method for preparing the thermosetting resin mixture is not particularly limited as long as the components to be mixed can be sufficiently mixed. For example, mixing using a ball mill, mixing using a stirrer, and mixing using a planetary mixer can be used. The method for applying the thermosetting resin mixture, that is, the film forming method is not particularly limited, and for example, a doctor blade method, a coater method, an extrusion method, or the like can be used. In particular, when preparing and applying a thermosetting resin mixture using a solvent, it is preferable to use the doctor blade method in that the film formation is easy.

This coating (or film formation) may be carried out on a release film, in which case the heat conductive resin sheet member can be easily handled during storage. The release film is not particularly limited, and for example, a PET (polyethylene terephthalate) film, a PPS (polyphenylene sulfide) film, or the like can be used. Further, it is preferable that the surface of the film is subjected to a release treatment using a release agent, for example, silicone.

For details of the step (a), reference can be made to Japanese Patent Application Laid-Open No. Hei 10-173097 and US Pat. No. 6,060,150 corresponding thereto. The matters described in these patent documents relating to a) constitute a part of the present specification.

In the method for manufacturing a lead frame according to the present invention, in the step (b), the heat conductive resin sheet member obtained in the step (a) is heat-treated. The thermally conductive resin sheet member to be heat-treated may be one that has been cooled and stored as necessary after step (a), or one that has just been obtained in step (a) (accordingly, (May be warm)
It may be. In the heat treatment in the step (b), the thermally conductive resin sheet member is subjected to a predetermined temperature condition for a predetermined time, for example, is placed in an atmosphere at a predetermined temperature, and its gel time is within a predetermined range. This is the processing to be performed. Generally, the higher the predetermined temperature, the shorter the predetermined time. In the step (b), the curing of the thermosetting resin partially progresses to reach a predetermined gel time. Usually, the heat treatment is 80 ~
It is carried out at 140C, preferably 85-130C, more preferably 90-125C. The predetermined temperature and the predetermined time of the heat treatment are determined by measuring the gel time of the heat conductive resin sheet member obtained by performing the heat treatment at various temperatures and times according to the thermosetting resin to be used. The skilled person can appropriately select a predetermined time and a predetermined temperature that result in
Can be selected by error method. It is generally preferred that the predetermined gel time be 20 to 120 seconds at 155C, as described above. After heating for a predetermined time in the step (b), the heat conductive resin sheet member is cooled to a temperature at which curing does not substantially proceed (for example, 80 ° C or less, preferably 50 ° C or less, for example, cooled to room temperature), and After storing as required, step (c) is performed.

In the method for manufacturing a lead frame of the present invention, in the step (c), the heat conductive resin sheet member having a predetermined gel time and the lead frame are cured by hardening the thermosetting resin of the heat conductive resin sheet member. Pressurized under conditions that do not proceed progressively (ie, press them towards each other),
The heat conductive resin sheet member and the lead frame are integrated. At the time of pressurization, the heat conductive resin sheet member is usually not so high in temperature (for example, at room temperature). Then, the lead frame is heated and heated in a state where the lead frame is arranged on the heat conductive sheet member to impart adhesiveness, and the lead frame is integrated. On the other hand, when the heat conductive resin sheet member already has sufficient adhesiveness (or tackiness) for integration when pressed, if the heat conductive resin sheet member has a relatively high temperature, for example, immediately after step (b). If, there is no need for heating. In the step (c), care must be taken so that the curing of the thermosetting resin does not proceed. Whether or not the curing is progressing can be easily determined by measuring the gel time of the thermosetting resin sheet member after the step (c) and comparing it with the gel time adjusted in the step (b). If it is determined that curing is in progress, the temperature at which step (c) is performed may be reduced. In the lead frame manufacturing method of the present invention, in this step (c), generally, 30 to 9
0 ° C., preferably 40-80 ° C., more preferably 50-80 ° C.
At a temperature of 70 ° C., for example 65 ° C., typically 1-20 MP
a, preferably 3 to 15 MPa, more preferably 6 to 1
At a pressure of 2 MPa, for example 10 MPa, generally 10 to 10 MPa
The pressing is performed for 200 seconds, preferably 30 to 100 seconds, more preferably 40 to 80 seconds, for example, 60 seconds.

As described above, the lead frame preferably has at least one through opening, and the step (c) is preferably performed so that the thermally conductive resin sheet member fills the exposed surface of the lead frame. Therefore, the exposed surface of the lead frame and the portion of the thermally conductive resin sheet member that fills the through opening form a substantially flush surface (ie, a single surface).

In one preferred embodiment, in the above-mentioned method for manufacturing a lead frame with a thermally conductive resin sheet member according to the present invention, the thermally conductive resin sheet member is provided between the step (b) and the step (c). It is desirable to include a step of forming into a shape. This predetermined shape can be appropriately selected by those skilled in the art according to the use of the finally obtained heat conductive substrate. Specifically, the obtained heat conductive resin sheet member can be cut into a predetermined shape. Alternatively, a mold having a predetermined shape may be punched out of the heat conductive resin sheet member using a mold having a shape corresponding to the predetermined shape. With the predetermined shape as described above, the weight of the formed thermally conductive resin sheet member can be controlled.

In the preferred embodiment described above, the step of forming the heat conductive resin sheet member into a predetermined shape includes sandwiching the heat conductive resin sheet member between a pair of plates, bringing these plates closer to each other, and Is pressurized so as to be a predetermined distance, a heat conductive resin sheet member having a predetermined thickness corresponding to the distance between the plates is obtained, and then processed into a predetermined shape. When processed in this way, the thickness of the thermally conductive resin sheet member becomes uniform,
The amount (volume or weight) per unit area of the heat conductive resin sheet member becomes constant. As a result, by processing such a heat conductive sheet member into a predetermined shape, for example, by cutting the heat conductive sheet member, it is possible to form a heat conductive resin sheet member per sheet. The amount of the curable resin mixture (that is, the mixture of the thermosetting resin composition and the inorganic filler) can be controlled. As a result, the volume of the heat conductive sheet member integrated with the lead frame in the next step can be made constant.

In another preferred embodiment, the above-described method for manufacturing a lead frame with a thermally conductive resin sheet member according to the present invention includes, after the step (c), removing a part of the lead frame integrated with the thermally conductive resin sheet member. Remove. The part of the lead frame to be removed is preferably a part integrated with the heat conductive resin sheet member after the step (c). By removing such a part,
A part of the lead frame integrated with the heat conductive resin sheet member can be a wiring pattern or a terminal that is electrically independent from other parts. In this case, since the electrically independent wiring patterns or terminals are held by the thermally conductive resin sheet member, the electrically independent wiring patterns or terminals do not fall off,
It is possible to form a lead frame with a thermally conductive resin sheet member having the other portion as a lead frame.

In one embodiment, the method for manufacturing a lead frame with a thermally conductive resin sheet member according to the second aspect of the present invention is characterized in that in the step (c), the thermally conductive resin sheet member is sandwiched between two plates. And the lead frame are sandwiched, and the heat conductive resin sheet member and the lead frame are pressed toward each other by bringing the plates closer to each other so as to have a predetermined plate-to-plate distance, and a predetermined thickness integrated with the lead frame. And (d) thereafter, processing the heat conductive resin sheet member integrated with the lead frame into a predetermined shape. This embodiment is efficient in that the adjustment of the thickness of the heat conductive resin sheet member and the integration with the lead frame can be performed simultaneously.

A lead frame manufactured by the above-described method for manufacturing a lead frame with a heat conductive resin sheet member can be used for manufacturing a heat conductive substrate in combination with a metal heat sink. Therefore, according to the third aspect, the present invention provides a method for manufacturing a heat conductive substrate having a heat conductive resin sheet member, a lead frame, and a metal radiator plate, wherein (1) the lead frame and the metal radiator plate Disposing a metal heat radiating plate on a lead frame with a heat conductive resin sheet member manufactured by the method for manufacturing a lead frame according to the second aspect of the present invention, such that the heat radiating plate is opposed to the heat conductive resin sheet member via the heat conductive resin sheet member. (2) a step of subjecting the lead frame with the thermally conductive resin sheet member and the metal radiator plate to a heat treatment at a temperature not lower than the temperature at which the curing of the thermosetting resin proceeds without being pressed toward each other for a predetermined time; (3)
Thereafter, while continuing the heat treatment, the lead frame and the metal radiator plate are pressed against each other at a predetermined pressure to further promote the curing of the thermosetting resin, and the metal radiator plate and the lead with the heat conductive resin sheet member are further advanced. Provided is a method for manufacturing a thermally conductive substrate including a step of integrating a frame.

In this method of manufacturing a heat conductive substrate, when manufacturing a lead frame with a heat conductive resin sheet member, a plurality of, preferably many heat conductive sheet members are manufactured in advance in the step (a). If the gel time is adjusted by heat-treating them together in (b), since the thermosetting resin contained in the heat-conductive resin sheet member of all the lead frames has already been cured, the heat conduction is increased. The time required for curing when manufacturing a conductive substrate, and thus the time required for steps (1) to (3), can be reduced. In addition, since the integration of the lead frame and the thermally conductive resin sheet member has already been performed while suppressing the generation of resin burrs and dirt as described above, the integration on the lead frame used in the production of the thermally conductive substrate is performed. The presence of resin burrs and dirt is suppressed. Since the lead frame integrated with such a heat conductive resin sheet member and the metal radiator plate are integrated, resin burrs and dirt present on the exposed surface of the lead frame of the finally obtained heat conductive substrate are obtained. Can be suppressed. In particular, in the initial stage of integration with the metal heat sink, after the metal plate is overlaid on the lead frame integrated with the heat conductive sheet member and only heating is performed to advance the curing of the thermosetting resin in advance When these are pressed against each other, that is, when step (2) is performed and then step (3) is performed, resin burrs and dirt on the exposed surfaces of the lead frame and the metal radiator plate are reduced. Presence can be further suppressed.

In the method of manufacturing a thermally conductive substrate according to the present invention, in the step (1), the heat conductive resin sheet member of the lead frame manufactured by the above-described method of manufacturing a lead frame with a thermally conductive resin sheet member is formed. A metal heat radiating plate is arranged at a position where the lead frame and the metal heat radiating plate face each other. The metal radiator plate used may be a flat plate having a high thermal conductivity. For example, an aluminum plate, a copper plate or the like can be used. Also, as in the case of the lead frame, it is preferable to roughen the bonding surface of the heat sink to the heat conductive resin sheet member, and the surface can be roughened in the same manner as the lead frame. Furthermore, a radiator plate that is not made of metal can be used as long as it has the same function. Further, as the lead frame, those having a form in which the main surface opposite to the bonding surface is not flat (for example, a surface having a wavy shape, a surface having fins) can be used, and these are members used as so-called heat sinks. There may be.

In the method of manufacturing a heat conductive substrate according to the present invention, in the step (2), the heat conductive sheet member is placed on the heat conductive resin sheet member or the heat conductive sheet member is placed on the metal heat sink plate. Are heat-treated at a temperature at which curing of the thermosetting resin proceeds for a predetermined time. In this specification,
"Heat treatment" refers to maintaining an object at a predetermined temperature for a predetermined time and, if necessary, heating to maintain such a temperature (in this sense, heat treatment is also referred to as heating (treatment)). means. Usually, the time during which the object is present in the atmosphere at the predetermined temperature and the temperature thereof correspond to the predetermined time and the predetermined temperature of the heat treatment. In this heat treatment, the metal radiator plate and the lead frame are not positively pressed toward each other. This does not mean that the pressure that inevitably acts is not excluded, but does not exclude the pressure caused by the weight of the metal radiator plate, the lead frame, the heat conductive resin sheet member, and the like. The temperature at which curing proceeds may be the same as or higher than the temperature at which the gel time is adjusted. In general, the thermosetting resin used may be at the temperature recommended by the manufacturer to effect curing, or higher. Generally, it is particularly preferred to be higher than the curing temperature of the thermosetting resin, and this curing temperature is understood to be the peak temperature usually obtained when the thermosetting resin is subjected to thermal analysis. It is generally preferred to carry out step (2) at a temperature of from 100 to 230C, preferably from 140 to 180C. The predetermined heat treatment time is generally within 1 minute,
Preferably, it is within 30 seconds, for example, about 15 seconds.

As is apparent, the predetermined heat treatment time and the temperature at which the curing proceeds (therefore, the heat treatment temperature) can be appropriately selected according to the thermosetting resin to be used. In order to prevent the adhesive strength of the conductive resin sheet member from dropping sharply and to make the integrity of the heat conductive base material obtained after performing the next step (3) insufficient, the curing proceeds so much. And the viscosity of the heat conductive resin sheet member is relatively small, and resin burrs, dirt, and the like are formed on the exposed surfaces of the metal heat sink and the lead frame of the heat conductive base material obtained after performing the following step (3). It must be chosen so that it does not occur excessively. Such a heat treatment temperature and a heat treatment time can be selected by, for example, a trial and error method in the same manner as when selecting a predetermined time and a predetermined temperature that provides a predetermined gel time.

In the method for producing a thermally conductive substrate of the present invention, in the step (3), after the step (2), the heat treatment is continued, and the temperature at which the curing is continued (this may be performed at the step (2) Press the metal heat sink and the lead frame toward each other at a higher or lower temperature).
That is, it is positively pressed. In this step, the curing of the thermosetting resin further proceeds, and the thermosetting resin is in a so-called rigid state. This state does not need to be completely cured as long as it can be used as a heat conductive substrate. Step (3)
Then, generally 100 to 230 ° C., preferably 120 to 230 ° C.
At a temperature of 200C, more preferably 130-180C, for example 140C, generally at a pressure of 1-20 MPa, preferably 4-19 MPa, more preferably 6-18 MPa, for example 14 MPa, generally 1-120 Min, preferably 5 to 60 min, more preferably 8 to 30 min, for example 10 min.

Therefore, in the method for manufacturing a thermally conductive substrate according to the present invention, if the curing is not completely completed after the step (3) is completed, the obtained thermally conductive substrate may be used, if necessary. Is additionally heat-treated (that is, placed under heating) to sufficiently cure the thermosetting resin. This additional heat treatment must, of course, be performed at a temperature at which curing proceeds further, and the treatment temperature and treatment time can be selected according to the desired degree of curing. Such additional heat treatment is generally at 100-230 ° C., preferably at 12 ° C.
At a temperature of 0 to 200 ° C, more preferably 150 to 180 ° C, for example 175 ° C, generally for 1 to 10 hours, preferably 2 to 9 hours, more preferably 3 to 7 hours, for example 6
Conduct for hours. If necessary, generally 1-20MPa,
Preferably 3 to 19 MPa, more preferably 4 to 18 M
It may be pressed at a pressure of Pa, for example, 6 MPa.

According to a fourth aspect of the present invention, there is provided a method of manufacturing a heat conductive substrate comprising a heat conductive resin composition, a lead frame and a metal heat sink, wherein (A) at least A step of obtaining a heat conductive resin sheet member from a material containing a thermosetting resin composition and an inorganic filler, and (B) heat treating the heat conductive resin sheet member so as to have a desired gel time. The process of
(C) a step of arranging a metal radiator plate on the thermally conductive resin sheet member and pressing them toward each other at a temperature at which curing of the thermosetting resin does not proceed, thereby integrating them;
A step of arranging the lead frame on the heat conductive resin sheet member integrated with the metal heat sink, such that the lead frame and the metal heat sink are opposed via the heat conductive resin sheet member;
(E) heat-treating the thermally conductive resin sheet member and the lead frame integrated with the metal radiator plate at a temperature higher than the temperature at which the curing of the thermosetting resin proceeds for a time; There is provided a method of manufacturing a heat conductive substrate, comprising a step of pressing them toward each other to integrate them, and advancing the curing of a thermosetting resin.

In this method of manufacturing a heat conductive substrate, the steps (A) and (B) include a step of obtaining a heat conductive resin sheet member (the above-described step (a)) and a step of adjusting the gel time (the above-described step). The description given above for step (b) applies. Further, as described above, the details described in relation to the first to third aspects of the present invention also apply to the fourth aspect unless a special inconvenience occurs.

In this another method of manufacturing a heat conductive substrate, in the step (C), a metal heat radiating plate is placed on the heat conductive resin sheet member, and heat-treated at a temperature at which hardening of the thermosetting resin does not proceed. Press to integrate them. In this step, a step of arranging the lead frame on the heat conductive resin sheet member and integrating them (the above step (c))
The preceding explanations apply. Here, the “temperature at which the curing of the thermosetting resin does not proceed” is the same as the temperature described above in the case where the lead frame and the thermally conductive resin sheet member are integrated.

In this another method for manufacturing a thermally conductive substrate, in the step (D), the lead frame and the metal heat sink are arranged so as to face each other, as in the step (1) described above. Step (E) is the same as step (3) described above.
(Therefore, the description thereof is applicable), and heat treatment is performed while pressing the lead frame and the metal radiator plate toward each other to cure the thermosetting resin.
In addition, in this another method for manufacturing a heat conductive substrate, a step of heating without pressing (corresponding to the above-mentioned step (2)) is not essential, but such a step may be performed. As before, if the thermosetting resin is not completely cured in the obtained conductive substrate and it is desired to further cure it, additional heat treatment can be performed to achieve a sufficient degree of curing.

According to the present invention, a thermosetting resin mixture containing an inorganic filler and a thermosetting resin composition containing at least a thermosetting resin that has not yet been cured is processed into a sheet, Thereafter, the thermally conductive resin sheet member obtained by adjusting the gel time is integrated with the lead frame in a semi-cured or partially cured state, and preferably, the thermally conductive resin sheet member is filled up to the surface of the lead frame. The lead frame with the thermally conductive resin sheet member obtained is basically used.

Such a lead frame with a heat conductive resin sheet member of the present invention is used when manufacturing a heat conductive substrate having excellent heat radiation properties, and is formed by applying heat and pressure together with a metal heat radiating plate. Is cured in a state containing a high concentration of inorganic filler, and lead frame,
The heat conductive resin sheet member and the metal radiator plate are integrated, and a heat conductive substrate can be easily obtained. Also,
By integrating the thermally conductive resin sheet member with the lead frame, the thermally conductive resin sheet member is reinforced as a result, and the handleability is improved.

[0058]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A lead frame with a thermally conductive resin sheet member according to the present invention, a method for manufacturing the same, and a method for manufacturing a thermally conductive substrate using the same will be described in more detail with reference to the accompanying drawings. I do.

(Embodiment 1) FIG. 1 is a sectional view schematically showing the structure of a lead frame with a thermally conductive resin sheet member of the present invention. In FIG. 1, a heat conductive resin sheet member 101 is integrated with a lead frame 102, fills a through opening 103 of the heat conductive resin sheet member 101, and exposes the exposed surface of the lead frame (the upper surface in the illustrated embodiment). ), The heat conductive resin sheet member 101 and the lead frame 102 together form a single surface (i.e., the upper flush surface). The heat conductive resin sheet 101 is formed from a mixture containing, for example, 70 to 95 parts by weight of an inorganic filler and 5 to 30 parts by weight of a resin composition containing at least a thermosetting resin, and is in a semi-cured or partially cured state. .

(Embodiment 2) FIGS. 2 (a) to 2 (c)
One embodiment of a method for manufacturing a lead frame with a thermally conductive resin sheet member according to the present invention is schematically shown in a sectional view for each step. The materials used are the same as those described in the above description (including the description of Embodiment 1) unless otherwise specified.

FIG. 2 (a) shows a thermally conductive resin sheet member 201 obtained from a thermosetting resin mixture.
It is adjusted to have a predetermined gel time as described below.

The heat conductive resin sheet member 201 is obtained by applying a thermosetting resin mixture in the form of a film or a sheet onto a base material (which may be a release film), and then removing the solvent by drying. It is formed by hardly remaining in the film. Thus, the heat conductive resin sheet member 2
It is preferable to prevent the thermosetting resin contained from proceeding to form when forming No. 01. As a result, at this point, the heat conductive resin sheet member 201 is in a state of maintaining a long gel time. Yes, and therefore, the heat conductive resin sheet member 201 can be stably stored for a long period of time.

Next, the heat conductive resin sheet member 201 obtained as described above is heat-treated to adjust the gel time to a predetermined value, and after the heat treatment, cooled to a temperature at which hardening does not substantially proceed. This heat treatment is performed by the heat conductive resin sheet member 201.
Can be carried out for a predetermined time at a predetermined temperature (if necessary, heating may be performed), and for this purpose, for example, a drying oven or the like may be used. In this heat treatment, a plurality of heat conductive resin sheet members to be integrated with the lead frame can be preliminarily processed, and thus the heat treatment is efficient, and the generation of resin burrs and dirt during integration with the lead frame is suppressed. It is possible to do. Also,
In this heat treatment, it is possible to remove the residual amount of the solvent added for adjusting the viscosity during the above-described formation or film formation of the heat conductive resin sheet member, and also to remove moisture due to moisture absorption during storage and handling, The tackiness of the thermally conductive resin sheet member is reduced, and the handleability is improved.
It is desirable that the heat treatment be performed at a temperature lower than the curing temperature of the thermosetting resin in the heat conductive resin sheet. Further, in order to reduce voids in the heat conductive resin sheet member, the heat treatment is performed under vacuum or reduced pressure. May be performed.

In FIG. 2B, the lead frame 202 is
Thermal conductive resin sheet member 20 having a predetermined gel time
1 above. They are pressurized at a temperature at which curing of the thermosetting resin contained in the thermally conductive resin sheet member does not proceed (may be heated if necessary), and FIG.
As shown in (c), the lead frame with the thermally conductive resin sheet member of the present invention is obtained by filling the surface of the lead frame 202 with the thermally conductive resin sheet member 201 so that they are integrated. . In this case, the heating may be performed in a state where the lead frame 202 and the thermally conductive resin sheet member 201 are not in contact with each other, or may be performed in a state where they are in contact with each other. The pressing may be performed simultaneously with the heating, may be performed after the heating, or may be performed after the pressing.

In this embodiment, it is desirable to process the heat conductive resin sheet member into a predetermined shape after the heat treatment step of adjusting the gel time of the heat conductive resin sheet member. Note that “formed into a predetermined shape” refers to a dimension (or dimension,
(Including the thickness of the sheet member) close to a predetermined one, preferably substantially the same. Thereby, the weight of the formed heat conductive resin sheet member can be controlled, that is, a heat conductive sheet member having a predetermined weight (or volume) can be obtained.

FIGS. 3A to 3D and FIGS.
(D) schematically shows a procedure for forming the heat conductive resin sheet member into a predetermined shape. In these drawings, the drawings on the left are sectional views, and the drawings on the right are top views.

FIG. 3A shows a thermally conductive resin sheet member 301 whose gel time has been adjusted by the heat treatment described with reference to FIG. As shown in FIG. 3B, a thermally conductive resin sheet member is provided between a pair of plates 302 having spacers 305 having a thickness L disposed therebetween so as to be able to approach each other up to a predetermined distance (L). Then, the plate 302 is brought close to a predetermined distance, and the heat conductive resin sheet member 301 is pressed. After pressing, the thermally conductive resin sheet member 303 taken out from between the plates is shown in FIG. The heat conductive resin sheet member 303 has a constant thickness corresponding to the thickness L of the spacer. After that, the heat conductive resin sheet member 303 is processed (for example, cut) according to a predetermined shape, and FIG.
A heat conductive resin sheet member 304 having a predetermined shape as shown in FIG. This heat conductive resin sheet member 30
4 has a constant thickness so that the amount per unit area of the heat conductive resin sheet member 304 is constant, that is, is controlled and has a predetermined shape. Is also constant, that is,
Is controlled.

A set of plates 30 that can be used in this case
2 is not particularly limited as long as the material and shape are selected so as not to be substantially deformed in the above-described operation. For example, a pair of flat plates provided with a gap having a constant thickness, or a mold combining an opening having a predetermined size and a punch can be used as the plate 302. In particular, punching using a mold is preferable. This is because it can be accurately processed in a predetermined shape in a short time. As a material used for these, for example, silicon steel, stainless steel, or the like can be used.

When forming into a predetermined shape as described above,
It is preferable to carry out under a temperature condition under which the curing of the thermosetting resin contained in the thermally conductive resin sheet member does not substantially proceed. Such conditions may be substantially the same as the conditions for integrating the thermally conductive resin sheet member and the lead frame.

More specifically, the temperature at which the heat conductive resin sheet member is pressed between a pair of plates, for example, the temperature of the plate and / or the heat conductive resin sheet member, or the atmosphere in which the pressing is performed. The temperature is preferably a temperature at which the curing of the thermosetting resin in the thermally conductive resin sheet member does not progress, and it is preferable to perform the pressing. May be implemented. This is because by performing the treatment at a higher temperature, the viscosity of the thermally conductive resin sheet member is reduced, and as a result, the amount can be easily controlled. As described above, the temperature for forming a predetermined shape may be determined according to the viscosity reached by the thermally conductive resin sheet member, but is preferably in the range of approximately 50 to 90 ° C. At a temperature higher than this range, the tackiness of the thermally conductive resin sheet member tends to appear, and the curing of the thermosetting resin tends to progress excessively.

The pressure at the time of pressing is not particularly limited as long as a heat conductive resin sheet member having a predetermined thickness can be obtained. Generally 2MPa-20MPa
If it is lower than this range, it may be difficult to control the thermally conductive resin sheet member to a constant thickness due to insufficient pressing force. Conversely, if it is higher than this range, the strength of the plate and the pressing device Must be kept high in durability, which is disadvantageous in practical use. Preferably 6 MPa to 15 MPa, for example, 1
The pressure may be generally 10 seconds to 100 seconds, preferably 20 seconds to 60 seconds, for example, 30 seconds, at a pressure of 0 MPa.

When a heat conductive resin sheet member having a predetermined shape is obtained, the viscosity of the heat conductive resin sheet member is set to 20,000P.
It is preferably not more than a · s, more preferably 1000 to 20000 Pa · s. If the viscosity exceeds 20000Pas,
In some cases, the heat conductive resin sheet member becomes stiff, making it difficult to control the sheet thickness during pressurization. That is, a change in the shape of the sheet member is unlikely to occur due to the high viscosity, and a predetermined sheet thickness cannot be obtained when the pressing pressure is low. This is because there is a risk that the device itself may be damaged. Further, when the viscosity of the heat conductive resin sheet member is too low at the time of pressing, it is not easy to maintain the shape of the sheet member itself.

Further, when the heat-conductive resin sheet member having a controlled thickness is processed into a predetermined shape, for example, when punching is performed as described above, the heat-curing It is preferable to heat the resin to a temperature lower than the curing temperature, for example, 40 to 90 ° C. This is because the heating reduces the viscosity of the heat conductive resin sheet member, thereby facilitating punching. As a result, cracking or chipping of the heat conductive resin sheet member at the time of punching can be prevented. If the temperature is higher than this range, the tackiness of the thermally conductive resin sheet member tends to appear, and the punching process is rather difficult.

FIGS. 4A to 4D show another method of forming a heat conductive resin sheet member having a predetermined shape used for manufacturing a lead frame with a heat conductive resin sheet member according to the present invention. Shown schematically. In FIG. 3, one heat conductive sheet member is formed in a predetermined shape. However, in FIG. Single heat conductive resin sheet member 4 having a thickness of
No. 03 is obtained, and thereafter, it is processed into a heat conductive resin sheet member 404 having a predetermined shape in the same manner as above.

In the embodiment shown in FIG. 4, even when the thickness of the thermally conductive resin sheet member 401 is relatively small, a thick thermally conductive resin sheet 403 can be obtained by stacking and integrating a plurality of thermal conductive resin sheet members. Can be. As a result, it is possible to control the thickness and the amount of the heat conductive resin sheet member by pressing once even with respect to the heat conductive resin sheet member having a large thickness that is difficult to obtain unless a plurality of sheets are laminated. This is convenient.

In the embodiment shown in FIG. 4, when a plurality of heat conductive resin sheet members 401 are overlapped, the direction of the front (front) surface and the back surface of each heat conductive resin sheet member 401 is unified. It is preferable to combine them (that is, to arrange each heat conductive resin sheet member so that the back surface is on the lower side or vice versa). In addition, the front (front) surface of each heat conductive resin sheet member is an exposed surface when a film is formed on a substrate using a thermosetting resin mixture, and the back surface is a surface in contact with the substrate. It is. By stacking in this manner, a delicate difference in composition that may occur between the front and back surfaces of the thermally conductive resin sheet member, a difference in residual solvent amount can be substantially averaged, It is possible to easily distinguish between the front surface and the back surface of each of the obtained heat conductive resin sheet members 403 integrated.

In each of the above-described embodiments, when the heat conductive resin sheet member is sandwiched between a pair of plates and pressed (or pressed), the upper and lower main surfaces of the heat conductive resin sheet member, or the heat conductive resin sheet member, When a plurality of conductive resin sheet members are stacked, a release film is preferably arranged on the uppermost surface and the lowermost surface. This is because the release film prevents the thermally conductive resin sheet member having the controlled thickness from adhering to the plate, and facilitates taking out the thermally conductive resin sheet member having the controlled thickness from between the plates. As the release film at this time, the same release film that can be used when forming the thermally conductive resin sheet member can be used.

(Embodiment 3) FIGS. 5A to 5D are cross-sectional views schematically showing another method of manufacturing a lead frame with a thermally conductive resin sheet member according to the present invention for each step. Regarding materials and conditions to be used, unless otherwise specified
The details described above can be applied.

A plurality of thermally conductive resin sheet members 501 whose gel time has been adjusted as shown in FIG. 5A are superimposed on a lead frame 502 as shown in FIG. 5B, and approached until a predetermined distance is reached. The heat conductive resin sheet member 501 is placed between a pair of plates 503, and then the plate is brought close to a predetermined distance at a temperature at which hardening of the thermosetting resin in the heat conductive resin sheet member 501 does not proceed. The resin sheet member 501 and the lead frame 502 are pressed.

Thus, a thermally conductive resin sheet member 501 integrated with the lead frame 502 as shown in FIG. 5C is obtained. As shown, a plurality of thermally conductive resin sheet members are also integrated, and FIG.
FIG. 5C and FIG. 5D show this state.
Since the thermosetting resin in the heat conductive resin sheet member has not substantially hardened, the adjusted gel time has not substantially changed.

In this embodiment, the heat conductive resin sheet member fills the through-opening of the lead frame and is adhered to the lead frame. At the same time, they are controlled to a substantially predetermined thickness. However, as shown in the figure, the outer peripheral portion of the lead frame and the edge portion of the heat conductive resin sheet member are not subject to the thickness control. Thereafter, as shown in FIG.
By processing only the heat conductive resin sheet member into a predetermined shape, a lead frame with a heat conductive resin sheet member in which the amount of the heat conductive resin sheet member is controlled can be obtained.

In the present embodiment, a plurality of heat conductive resin sheet members are superimposed and bonded to the lead frame, and the thickness is simultaneously controlled. In this case, a lead frame with a thermally conductive resin sheet member can be obtained in the same steps.

(Embodiment 4) FIGS. 6A to 6D are a top view and a cross-sectional view schematically showing another embodiment of a method for manufacturing a lead frame with a thermally conductive resin sheet member according to the present invention. It is. As for the materials and conditions to be used, the details described above can be applied unless otherwise specified. FIG.
The top views of (b) to (d) show one possible form of a region surrounded by a broken line of the lead frame with the thermally conductive resin sheet member shown in FIG.

FIG. 6A shows a lead frame with a thermally conductive resin sheet member manufactured by any of the methods described above, wherein the thermally curable resin is in a semi-cured state. 601 is filled up to the surface of the lead frame 602 and integrated therewith. In the illustrated lead frame 602, the outer frame portion 610 can function as an outermost common terminal, and each wiring pattern in the lead frame or a terminal attached thereto is ultimately connected via a common terminal 612 connected to the outer frame portion 610. Connected to external common terminal.

The outer frame portion 610 is formed by cutting the lead frame with the heat conductive resin sheet member and the metal heat radiating plate later, and then cutting off a part of the common terminal 612 on the outer peripheral portion of the lead frame connected to the outer frame portion 610. And the remaining common terminal 61 on the outer peripheral portion of the lead frame protruding outward.
2 becomes an external extraction electrode of the heat conductive substrate. As shown in the figure, in the lead frame, all the wiring patterns are electrically connected to the outer frame portion 610 via the common terminals 612 (therefore, they are mechanically connected).
Therefore, except for the outer frame portion 610 of the lead frame and a part of each common terminal, the remaining lead frame portion is integrated with the heat conductive resin sheet member, so that any terminal or wiring pattern of the lead frame can be obtained. Can also be prevented from falling off, and the handleability of the lead frame can be improved. In FIG. 6A, each common terminal 612 of the lead frame is connected to the outer frame portion 610, but this does not limit the present invention, and the lead frame may have another form. .

FIG. 6 shows a heat conductive resin sheet member 601.
Although the lead frame 602 adheres over substantially the entirety of one main surface of the heat conductive resin sheet member, it is not always necessary that the lead frame be present over the entirety of one main surface of the thermally conductive resin sheet member. Therefore, in another aspect, the lead frame may be present on a part of one surface of the thermally conductive resin sheet member.

In still another embodiment of the lead frame integrated with the heat conductive resin sheet member of the present invention, a wiring pattern or terminal electrically independent from the lead frame integrated with the heat conductive resin sheet member is provided. It may be integrated with the heat conductive sheet member on the same side as the side where the lead frame exists. 6B to 6D are enlarged views of a region surrounded by a broken line in FIG. The lead frame integrated with the thermally conductive resin sheet member of the present invention is shown in FIG.
As shown in (d), a wiring pattern or terminal 600 that is not electrically connected to any wiring pattern of the lead frame may be provided. The wiring pattern 600 that exists independently as described above is dropped off because it is held by the heat conductive resin sheet member 601 even though it is electrically isolated from other wiring patterns and has an island shape. No, handling is improved.

The above-mentioned island-shaped wiring pattern (or terminal) may be originally a part of a lead frame, and is formed by processing a lead frame integrated with a heat conductive resin sheet member. Can be. Specifically, a part of the lead frame integrated with the heat conductive resin sheet member is removed so that the target wiring pattern 600 remains in an isolated island shape. For this removal, for example, as shown in FIG. 6B, a pin 604 and a die 605 of a punching machine are used to remove a portion 606 of the lead frame adjacent to the target wiring pattern 600 to a portion under the thermal conductivity just below it. Punched together with a part of the resin sheet member,
This may be implemented by forming a through hole 603 as shown in FIG. Here, the punching was performed by a punching machine, but it is needless to say that the punching is not particularly limited, and other methods may be used as appropriate according to the thickness of the lead frame with the heat conductive resin sheet member and the desired hole diameter. Just choose. For example, a punching method using a die, a processing method using a drill, and the like can be used. These are preferred in that they can be easily drilled with high positional accuracy.

Incidentally, the process of processing the lead frame as described above can be carried out in other modes.
After the step shown in (c), the process may be performed by removing a part of the lead frame. In the case where a part of the lead frame is mechanically cut off or removed by etching, it is not necessary to remove a part of the thermally conductive resin sheet member.

In the embodiment shown in FIG. 6, after the holes 603 are formed as shown in FIG. 6C, the lead frame with the thermally conductive resin sheet member is placed in a semi-cured state in which the curing of the thermosetting resin does not proceed. By heating and pressurizing in FIG.
As shown in the figure, the through hole 603 can be filled with a heat conductive resin sheet member around the through hole 603. In this way, as shown in FIG. 6 (d), a thermally conductive resin sheet member which is integrated with the lead frame but further has a wiring pattern or terminal which is electrically independent therefrom is obtained. . In the above description, in order to fill the through hole with the semi-cured heat conductive resin sheet, the heat conductive resin sheet member around the through hole was filled by flowing under pressure. Of course, it is not particularly limited. For example, a filling method in which a desired amount of an uncured or semi-cured thermally conductive resin sheet member, preferably a small piece thereof, is separately supplied and heated and pressed under non-cured conditions can also be used.

(Embodiment 5) FIGS. 7 (a) to 7 (c)
It is sectional drawing which shows the manufacturing method of the heat conductive substrate of this invention typically by process. For the materials and conditions used,
Unless otherwise noted, the details described above can be applied.

FIG. 7A shows, for example, the second embodiment.
Alternatively, a lead frame 700 with a thermally conductive resin sheet member of the present invention obtained by the same steps as in Embodiment 3 is shown. A semi-cured thermally conductive resin sheet member 701 fills the opening of the lead frame 702 up to the surface thereof and is integrated therewith. However, as described with reference to FIGS. 3 and 4 and as described in relation to the third embodiment, the thickness of the heat conductive resin sheet member, and hence the amount per unit area, is controlled. (Therefore, it has a predetermined thickness). More preferably, the volume per heat conductive resin sheet member is a predetermined amount. Also, a lead frame 700 with a heat conductive resin sheet member
May have the configuration described with reference to FIGS. 6A to 6D in the fourth embodiment.

As shown in FIG. 7 (b), the lead frame 7 of the lead frame 700 with the heat conductive resin sheet member
The metal heat radiating plate 703 is positioned and overlapped on the surface opposite to the surface where 02 is located. As a result, the lead frame 702
And the metal radiating plate 703 are formed of a heat conductive resin sheet member 701.
Face each other. Next, these are heat-treated and pressurized to cure the thermosetting resin of the thermally conductive resin sheet member. Heat sink 7
Thus, a heat conductive substrate is obtained in which the heat conductive substrates 03 are integrated.

As described above, the heating and pressurizing is performed at a temperature at which the curing of the thermosetting resin proceeds for a predetermined time without pressing the lead frame 700 with the heat conductive resin sheet member on which the metal radiating plate 703 is stacked. Heat-treating to the above temperature, preferably to a temperature higher than the curing temperature, and then to a predetermined temperature at that temperature or at a different temperature (heating to a higher temperature or cooling to a lower temperature as necessary) It is preferable to separately perform the step of pressurizing with the pressure described above to further cure the thermosetting resin, that is, the step of continuing the heat treatment under pressure. In the present invention, prior to integration with the metal heat radiating plate, the heat conductive resin sheet member is integrated with the lead frame only, which means that the metal heat radiating plate is integrated with the lead frame with the heat conductive resin sheet member. In the method of manufacturing a heat conductive substrate by heating and pressurizing, a thermosetting resin mixture is prevented from wrapping around the lead frame surface, and as a result, resin burrs are generated and surface dirt is suppressed.

Also, in the step of heating at a temperature higher than the temperature range where the thermosetting resin starts to cure for a predetermined time without pressing the lead frame with the heat conductive resin sheet member on which the metal heat radiating plate is stacked, By appropriately adjusting the degree of progress of the curing reaction of the thermally conductive resin sheet member before pressing,
The effect of suppressing excessive flow of the thermosetting resin mixture to the lead frame surface at the time of subsequent pressing, thereby preventing surface contamination.

The temperature for the heat treatment when producing the heat conductive substrate may be appropriately selected depending on the thermosetting resin to be used, but is generally 100 to 230 ° C. If it is lower than this, curing may be insufficient, and if it is higher than this, decomposition of the resin may start. Preferred temperatures are between 130 and 180C, for example 140C. The pressure at the time of pressing is not particularly limited.
It is preferably in the range of 20 to 20 MPa, for example, 14 MPa. If it is lower than this, the pressure will be insufficient, and the adhesive force between the heat conductive resin sheet member and the lead frame or the metal radiating plate will be easily reduced and peeled. On the other hand, if the pressure is too high, the risk of damaging the substrate increases. In the heat treatment step without pressing, the heat treatment time is generally 1 to 60.
Seconds, preferably 5 to 30 seconds, more preferably 10 to 20 seconds
Seconds, for example 15 seconds. In the heat treatment step involving pressing, the heat treatment time is generally 1 to 120 minutes, preferably 5 to 60 minutes, and more preferably 8 to 30 minutes.

The degree of curing of the thermosetting resin of the heat conductive substrate obtained by the above-described manufacturing method may not always be sufficient depending on the use of the heat conductive substrate. In such a case, by further heat-treating the thermally conductive substrate obtained by the above-described method, the curing can be accelerated and substantially completely cured.

(Embodiment 6) FIGS. 8 (a) to 8 (e)
It is sectional drawing which shows typically the process of another manufacturing method of the heat conductive substrate of this invention. The details described above can be applied to the materials and conditions to be used unless otherwise specified.

FIG. 8A shows a heat conductive resin sheet member 80.
1 indicates that, when used, a heat treatment is performed using a drying oven or the like so that the gel has a predetermined gel time.
The thermosetting resin contained is adjusted so as to be in a semi-cured state. After this step, it is preferable to process such a heat conductive resin sheet member 801 into a predetermined shape as described above. Thereby, the thickness and / or weight of the heat conductive resin sheet member can be controlled.

Next, as shown in FIG. 8 (b), the metal heat sink 803 and the heat conductive resin sheet 801 are overlapped, and then, as shown in FIG. Heat and pressurize the resin sheet member at a temperature at which curing does not proceed,
The heat conductive resin sheet member is pressure-bonded to the metal heat sink, that is, integrated. The temperature and pressure conditions in this case are:
The manufacturing conditions of the lead frame with a thermally conductive resin sheet member of the present invention may be the same as the conditions used for integrating the lead frame with the thermally conductive resin sheet member.

Next, as shown in FIG. 8 (d), a lead frame 802 is arranged on a heat conductive resin sheet member to which a metal heat radiator plate is crimped, and the metal heat radiator plate 803 is connected to the heat conductive resin sheet member 801. And are overlapped so as to face the lead frame 802 via the.

Thereafter, these are pressed while being heat-treated as shown in FIG.
01 fills the through-opening of the leadframe 802 and integrates with the leadframe so that they together form a single surface. Also, a metal heat sink 803
Is already integrated with the heat conductive resin sheet member 801, but the heating and pressurizing at this time makes it more firmly adhered to the heat conductive resin sheet member 801 to obtain an integrated heat conductive substrate. In this case, the heating and pressurizing may be performed by performing heat treatment without first pressing and then pressing, as described with respect to the integration with the metal heat sink in Embodiment 5. Heat treatment and pressing may be performed. The conditions of the heat treatment and the pressing may be the same as those in the case where the heat treatment and the pressing are performed together at the time of integration with the metal heat sink in the fifth embodiment. In some cases, the obtained thermally conductive substrate may be further heat-treated to ensure sufficient curing of the thermally conductive resin sheet member.

[0103]

Hereinafter, the present invention will be described in more detail with reference to examples.

Example 1 A thermally conductive resin sheet member used in this example was manufactured. First, a slurry-like thermosetting resin mixture was prepared by mixing an inorganic filler, a thermosetting resin, and other components described below. The composition of the thermosetting resin mixture is shown below:

(1) Inorganic filler: 89 parts by weight of Al ₂ O ₃ (AS-40, manufactured by Showa Denko KK, average particle size: 12 μm) (2) Thermosetting resin: brominated polyfunctional epoxy resin ( NVR-1010, manufactured by Nippon Lec Co., Ltd., containing a curing agent) 10 parts by weight (3) Other additives: curing accelerator (imidazole, manufactured by Nippon Lec Co., Ltd.) 0.05 part by weight Carbon black (Toyo Carbon (Toyo Carbon) Co., Ltd.) 0.4 parts by weight Coupling agent (Prenact KR-46B, manufactured by Ajinomoto Co.) 0.55 parts by weight

In addition to these components, MEK was added as a solvent and mixed with a kneader (Matsuo Sangyo Co., Ltd.). Note that M
The addition of EK lowers the viscosity of the mixture and allows the mixture to be processed into a slurry, but is not included in the above composition because it is removed by evaporation in the subsequent drying step.

Using this slurry, a film was formed by a doctor blade method on a release film of polyethylene terephthalate (PET) whose surface was subjected to a release treatment. Thereafter, drying was performed at 90 ° C. for 60 minutes, and the solvent was evaporated to obtain a thermally conductive resin sheet member (150 mm × 150 mm) having a thickness of 1.0 mm and containing a thermosetting resin in a semi-cured state.

Next, a lead frame with a thermally conductive resin sheet member was manufactured. A 0.5 mm-thick copper plate (manufactured by Kobe Steel Ltd.) was etched by a known method to form a circuit pattern, and a nickel-plated lead frame was prepared. Thereafter, one surface of the lead frame was roughened by sand blasting (polishing powder: Al ₂ O ₃ , Morundum A-40 (trade name), manufactured by Showa Denko KK).

Next, the heat conductive resin sheet member obtained by the above method was heat-treated at 100 ° C. in a dryer. The heat treatment time was changed variously so as to have different gel times (experiment numbers a to f). The temperature of the heat treatment is a set temperature of the dryer, and the heat treatment time is a time during which the thermally conductive resin sheet member is held in the dryer.

An outer 250 mm × 250 mm frame-shaped spacer (0.8 mm thick) having a 160 mm × 160 mm through opening at the center was placed between two 250 mm × 250 mm SUS304 flat plates and heated to 70 ° C. . A 75 μm thick PET film is placed on both sides of the thermally conductive resin sheet member whose gel time has been adjusted, and then placed in the through opening of the spacer to bring the flat plates close to each other and conduct heat at a pressure of 3 MPa. The conductive resin sheet member was pressed for one minute. Thereafter, the heat conductive resin sheet member was taken out to obtain a heat conductive resin sheet member having a controlled thickness. Thereafter, the PET film is peeled off from one surface of the heat conductive resin sheet member, and is punched into a 100 mm × 100 mm mold while being heated at 70 ° C. Obtained. At 70 ° C., the curing of the thermosetting resin did not substantially proceed.

Next, the obtained thermally conductive resin sheet member and the above-mentioned lead frame were heated and pressed at 65 ° C. and a pressure of 10 MPa for 60 seconds at 65 ° C. in the same manner as in FIG. 2B. As a result, the heat conductive resin sheet member flows into the pattern gap of the lead frame, that is, the through opening, fills the surface of the lead frame, and is integrated, as shown in FIG. 2C. A lead frame with members was obtained. However, a PET film is attached to the other surface of the thermally conductive resin sheet member (not shown).

Next, an aluminum plate having a thickness of 1 mm was prepared as a metal radiator plate, and both surfaces thereof were subjected to sandblasting in the same manner as a lead frame. The release film is peeled off from the lead frame with the heat conductive resin sheet member obtained as described above, and the lead frame and the aluminum plate are positioned so as to face the heat conductive resin sheet member as shown in FIG. 7B. They were put together and overlapped.

First, they are heated without pressure at a temperature of 140 ° C. for 15 seconds, and then at a pressure of 14 MPa for 10 seconds.
Pressurized for minutes. As a result, the thermosetting resin in the heat conductive resin sheet member is hardened to be rigid, and the metal radiator plate is bonded to the heat conductive resin sheet member.
A thermally conductive substrate as shown in (c) was obtained. Further, after that, a heat treatment was performed at 175 ° C. for 6 hours, and the curing of the thermosetting resin was sufficiently advanced to complete the heat conductive substrate. Thereafter, the components are mounted on the heat conductive substrate through steps such as solder resist processing, frame cutting, and terminal processing. These steps can be performed using a known technique. Since it is not directly involved in the description, the description is omitted.

As described above, various heat conductive resin sheet members having different gel times (Experiment Nos. A to f) were used to integrate with a lead frame, and then further integrated with a metal heat radiating plate. A thermally conductive substrate was manufactured. The obtained heat conductive substrate was evaluated. In particular, the degree of filling of the thermally conductive resin sheet member into the through-opening of the lead frame, and the presence and dirt of resin burrs on the exposed surface of the lead frame were visually evaluated. In addition, the adhesion between the lead frame and the metal radiator plate is evaluated by observing the interface between the heat conductive resin sheet member and the lead frame or the metal radiator plate in each of the heat conductive substrates using an ultrasonic imager (SAT). did. The gel time is
A part of the heat conductive resin sheet member was obtained from each of the obtained lead frames with the heat conductive resin sheet member, and 155 was obtained.
The gel time at ° C was measured. (Table 1)
Shown in

[0115]

[Table 1]

In the table, evaluation indices “X”, “many” and “excess” are used. These are the results of relative comparison with other evaluation indices. It should be noted that a thermally conductive substrate, which merely means poor performance, and which produces such relatively poor results, cannot always be used for any application.

If the gel time of the heat conductive resin sheet member at the stage of the lead frame with the heat conductive resin sheet member is too short, the curing reaction proceeds too much. )
Since the heat conductive resin sheet member did not flow into the metal radiating plate, the surface was not sufficiently filled, and the adhesiveness to the metal radiating plate was not always sufficient when the heat conductive resin sheet member was integrated with the metal radiating plate.

On the other hand, if the gel time is long, the bleeding of the thermosetting resin mixture around the heat conductive substrate, particularly on the exposed lead frame surface, increases the resin burrs and the surface dirt. In particular, at the stage of a lead frame with a thermally conductive resin sheet member, the thermally conductive resin sheet member is
In the case of having a gel time at 155 ° C. in the range of 20 seconds to 120 seconds, the filling property of the opening of the lead frame,
It was confirmed that the adhesion of the lead frame and the adhesion of the metal radiator plate were particularly good, and that the occurrence of surface dirt and resin burrs was small.

Therefore, when the gel time of the heat conductive resin sheet member is in the above-mentioned range, particularly when the gel time is in the range of 50 seconds to 90 seconds, a very good heat conductive substrate can be manufactured. In addition, the substrate (gel time 2) thus obtained was used.
A reflow test was performed at a maximum temperature of 260 ° C. for 10 seconds to evaluate the reliability of the sample (0 to 120 seconds). At this time, no particular abnormality was observed at the interface between the thermally conductive resin sheet member of the substrate and the lead frame and the metal plate by visual observation and observation with the SAT, and it was confirmed that strong adhesion was maintained. .

Incidentally, in manufacturing the heat conductive substrate as described above, the heat conductive substrates having different thicknesses of the used heat conductive resin sheet members were manufactured by varying the thickness of the spacer. The thickness of the central portion of the obtained heat conductive substrate was measured with a micrometer. FIG. 9 shows the relationship between the spacer thickness and the measured substrate thickness.
As can be seen from this figure, by changing the thickness of the spacer, the thickness of the heat conductive resin sheet member, and hence the amount of the heat conductive sheet member, can be controlled correctly, and the thickness and, therefore, the weight per sheet can be stabilized. It can be seen that a thermally conductive substrate can be manufactured.

Example 2 Using a thermosetting resin mixture having the composition used in Example 1 above, P
A heat conductive resin sheet member having a thickness of about 0.4 mm was formed on the ET film. Next, the heat conductive resin sheet member was heat-treated at 100 ° C. in a dryer to set the gel time to 60 seconds.

[0122] Three such thermally conductive resin sheet members were prepared, and of these two PET films were peeled off, and as shown in FIG. The PET films were placed so as to be in contact with each other, and a PET film was further disposed on the uppermost surface. These are placed in a mold heated to 60 ° C. and having a set of plates that can be pressed at regular intervals, and pressed at a pressure of 5 MPa to control the thickness as shown in FIG. A heat conductive resin sheet member was produced. Thereafter, the sheet was punched into a predetermined size by a mold to obtain a thermally conductive resin sheet member whose amount was controlled as shown in FIG.

Next, a circuit pattern was formed by punching a 42-alloy plate having a thickness of 0.5 mm, and a lead frame plated with nickel and solder was prepared. One surface of the lead frame was subjected to a surface roughening treatment in the same manner as in Example 1.

The obtained thermally conductive resin sheet member and the lead frame were placed at 65 ° C. and 10 M, as shown in FIG.
A lead frame with a thermally conductive resin sheet member was obtained by heating and pressing at a temperature and pressure of Pa for 60 seconds. However, a PET film is attached to the surface of the heat conductive resin sheet member.

Next, an aluminum plate having a thickness of 1 mm was prepared as a metal radiator plate, and both surfaces thereof were subjected to sandblasting in the same manner as the lead frame. Then, the release film is peeled off from the lead frame with the heat conductive resin sheet member obtained as described above, and as shown in FIG. 7B, the lead frame and the aluminum plate are interposed via the heat conductive resin sheet member. They were positioned so as to face each other and overlapped.

First, without pressurizing these, 14
Heating was performed at a temperature of 0 ° C. for 15 seconds, and thereafter, pressure was applied at a pressure of 14 MPa for 10 minutes to obtain a thermally conductive substrate having a thickness of about 2.5 mm as shown in FIG. 7C. After this, 17
Heat treatment was performed at 5 ° C. for 6 hours to sufficiently cure the thermosetting resin to obtain a final heat conductive substrate.

In order to examine the adhesiveness between the lead frame and the aluminum plate on the obtained thermally conductive substrate, the adhesiveness of each interface was examined by SAT, but no peeling was found at any of the interfaces. In addition, in order to confirm the reliability of the substrate, a temperature cycle test at −55 to + 125 ° C. was performed 1,000 times, and then the adhesion of the interface was examined. However, no peeling was observed at the interface. From this, it was found that the thermally conductive substrate manufactured by the method of the present invention has high reliability.

Example 3 A heat conductive resin sheet member used in this example was manufactured. First, a slurry-like thermosetting resin mixture was prepared by mixing an inorganic filler, a thermosetting resin, and other components described below. The composition of the thermosetting resin mixture is shown below:

(1) Inorganic filler: 88 parts by weight of Al ₂ O ₃ (AS-40, manufactured by Showa Denko KK, average particle size: 12 μm) (2) Thermosetting resin: epoxy resin (XNR5002, Nagase Chiba Co., Ltd.) 1) parts by weight (3) Other additives: 0.3 parts by weight of silane coupling agent (A-187, manufactured by Nippon Unicar Co., Ltd.) carbon black (manufactured by Toyo Carbon Co., Ltd.) 2 parts by weight

After these components were blended and a small amount of MEK was added to lower the viscosity, a kneading machine (Matsuo Sangyo Co., Ltd.)
And kneaded with a three-roll kneader, followed by vacuum drying to evaporate the MEK to obtain a clay-like thermosetting resin mixture. This was extruded by extrusion molding to form a polyethylene terephthalate (PE)
A thermally conductive resin sheet member having a thickness of 1.2 mm was obtained on the release film of T).

Thereafter, the obtained heat conductive resin sheet member was heat-treated in a dryer at 125 ° C. for 50 minutes.
After cooling to room temperature, the gel time was set to 70 seconds.

Next, a lead frame having a wiring pattern formed by punching a copper plate having a thickness of 0.8 mm was prepared.
As shown in (b), the lead frame and the obtained heat conductive resin sheet member (however, one sheet in this embodiment) are overlapped and heated to 50 ° C. to form a predetermined gap. As shown in FIG. 5 (c), pressure is applied in a mold made of a set of iron plates that can be brought close to each other, and the thickness is regulated as shown in FIG. A conductive resin sheet member was obtained. After that, while heating the heat conductive resin sheet member to 60 ° C., an unnecessary portion of the heat conductive resin sheet member was cut off and processed into a predetermined shape as shown in FIG.

Thereafter, as in FIG. 7B, a thickness of 3 mm
The copper plate and the obtained lead frame with a heat conductive resin sheet member are overlapped, and pressed at 140 ° C. without applying pressure.
Heating was performed for 5 seconds, and thereafter, pressure was applied at a pressure of 14 MPa for 10 minutes to obtain a heat conductive substrate having a thickness of 4.5 mm as shown in FIG. 7C. Thereafter, a heat treatment was further performed at 175 ° C. for 6 hours to advance the curing of the thermosetting resin, thereby completing a heat conductive substrate.

The same tests as in Example 2 were performed, but with substantially the same results. From this, it was found that the heat conductive substrate obtained by the manufacturing method of the present invention has high reliability.

(Example 4) A thermoconductive resin sheet member having a thickness of about 1.2 mm was formed on a PET film in the same manner as in Example 1 using the thermosetting fat mixture having the composition used in Example 3. Produced. Thereafter, the heat conductive resin sheet member was heat-treated in a dryer at 125 ° C. to set the gel time to 70 seconds.

An aluminum plate having a thickness of 1 mm was prepared as a metal radiator plate, and both surfaces thereof were subjected to a surface roughening treatment in the same manner as in Example 1. Next, the obtained heat conductive resin sheet member and the metal heat radiating plate were superposed in the same manner as in FIG.
Heating and pressurizing was performed at a temperature and pressure of 0 MPa for 5 minutes. At this time, in order to prevent generation of voids, a vacuum (degree of vacuum: 1 ×
10 ⁻⁴ MPa).

As a result, an aluminum plate with a heat conductive resin sheet member was obtained as shown in FIG. 8 (c) in which the heat conductive resin sheet member was pressed against the metal radiator plate. However, the PET film adheres to the surface of the heat conductive resin sheet member. Next, a 0.5 mm thick copper plate (manufactured by Kobe Steel Co., Ltd.) is etched by a known method to form a circuit pattern, and a nickel-plated lead frame is prepared. The same roughening treatment was carried out.

The release film was peeled off from the aluminum plate with the heat conductive resin sheet member obtained as described above, and as shown in FIG. 8D, the aluminum plate and the lead frame were interposed via the heat conductive resin sheet member. Were superposed on each other, and they were pressed at 175 ° C. and a pressure of 14 MPa for 10 minutes. As a result, the heat conductive resin sheet member fills the pattern gap of the lead frame, forms a single surface with the lead frame, and cures.
(E) a thickness of 2.5 to which a metal heat sink is bonded
mm of a thermally conductive substrate (the thickness of the insulating layer was 1.0 mm).

Further, after that, heat treatment was performed at 175 ° C. for 6 hours, and the curing of the thermosetting resin was advanced to complete the heat conductive substrate. The substrate thus obtained has little resin burrs and surface dirt, and when observed with the naked eye and SAT, there is no particular abnormality at the interface between the thermally conductive resin sheet member of the substrate and the lead frame and metal radiator plate. It was not recognized, and it was confirmed that strong adhesion was obtained. Further, as a reliability evaluation, a reflow test was performed at a maximum temperature of 260 ° C. for 10 seconds, but no abnormality was found.

On the other hand, as a comparative example, the same heat conductive resin sheet member was cured without heat treatment, that is, without adjusting the gel time, integrated with the aluminum plate, and subsequently formed into a lead frame. In the case where the heat conductive substrate is integrally formed with the lead frame, if the time of the heating and pressurizing to be integrated with the lead frame is 10 minutes, the hardening of the heat conductive resin sheet member is insufficient. Was needed.

Therefore, a plurality of heat conductive resin sheet members are heat-treated collectively before production of the heat conductive substrate, so that the gel time suitable for the production of the heat conductive substrate is adjusted in advance. The curing of the thermally conductive resin sheet member by heating, which is performed in a subsequent step, can be performed in a short time, and the tact of manufacturing the thermally conductive substrate can be reduced.

[0142]

As described above, a lead frame with a thermally conductive resin sheet member according to the present invention is used in the production of a thermally conductive substrate comprising a thermally conductive resin sheet member, a lead frame and a metal radiator plate. By doing so, it becomes possible to suppress the generation of resin burrs due to the exudation of the thermosetting resin mixture and the occurrence of surface contamination of the lead frame. In addition, since a large number of heat conductive resin sheet members can be heat-treated together when adjusting the gel time before manufacturing the heat conductive substrate, the heat conductive resin sheet members can be cured in a short time by heating in the subsequent steps. After that, it becomes possible to shorten the tact time of manufacturing the heat conductive substrate and to suppress the occurrence of resin burrs, dirt, and the like on the surfaces of the lead frame and the heat dissipating metal plate. Furthermore, the thickness is stabilized by controlling the amount per unit area of the heat conductive resin sheet member by pressing the heat conductive resin sheet member with the adjusted gel time and processing it to have a uniform thickness. This makes it possible to manufacture a thermally conductive substrate.

Furthermore, since the heat conductive resin sheet member immediately after being formed (therefore, before adjusting the gel time) has a long gel time, the heat conductive resin sheet member can be stably stored for a long time. And since the gel time can be adjusted for many heat conductive sheet members together, the production tact time of the heat conductive substrate is improved as a whole, and the heat conductive substrate with excellent heat dissipation and high reliability can be efficiently manufactured. Can be manufactured.

In the present specification, the heat conductive substrate (also referred to as “heat conductive substrate”) is formed from a material containing a filler for the purpose of heat conduction, as can be understood from the above description. It is a substrate. Usually, a wiring pattern is arranged on one side of the substrate, and a heat sink is arranged on the other side. The heat conductive resin sheet material is a sheet-like material used for manufacturing such a heat conductive substrate,
It is obtained by curing a sheet material obtained from a thermosetting resin mixture.

Incidentally, the present invention relates to Japanese Patent Application No. 2000-39765.
0 and Japanese Patent Application No. 2000-397651 (both 200
The content disclosed in these applications is incorporated herein by reference.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view schematically showing one embodiment of a lead frame with a thermally conductive resin sheet member of the present invention.

FIGS. 2A to 2C are cross-sectional views schematically showing steps of one embodiment of a method for manufacturing a lead frame with a thermally conductive resin sheet member according to the present invention.

FIGS. 3A to 3D are a cross-sectional view and a top view schematically showing steps of one embodiment of a method for manufacturing a thermally conductive resin sheet member.

FIGS. 4A to 4D are a cross-sectional view and a top view schematically showing the steps of another embodiment of the method for manufacturing a thermally conductive resin sheet member.

5 (a) to 5 (d) are cross-sectional views schematically showing steps of another embodiment of the method for manufacturing a lead frame with a thermally conductive resin sheet member of the present invention.

FIGS. 6 (a) to 6 (d) are a top view and a sectional view schematically showing steps of still another embodiment of the method for manufacturing a lead frame with a thermally conductive resin sheet member of the present invention. .

FIGS. 7A to 7C are cross-sectional views schematically showing the steps of one embodiment of the method for producing a thermally conductive substrate according to the present invention.

8 (a) to 8 (e) are cross-sectional views schematically showing steps of another embodiment of the method for producing a heat conductive substrate of the present invention.

FIG. 9 is a graph showing the relationship between the thickness of a heat conductive substrate manufactured in one example of the present invention and the thickness of a spacer used for manufacturing the same.

[Explanation of symbols]

101, 201, 301, 401, 501, 601, 7
01, 801 Thermal conductive resin sheet member 102, 202, 502, 602, 702, 802 Lead frame 302, 402, 503 A set of plates 303, 403 having a predetermined thickness of gap 303, 403 Thermal conductive resin having a predetermined thickness Sheet members 304, 404 Thermal conductive resin sheet member with controlled amount per unit area 600 Independent terminal of lead frame 603 Through hole 604 Pin 605 Die 610 Outer frame 612 Common terminal 700 Lead with thermal conductive resin sheet member Frame 703, 803 Metal heat sink

 ──────────────────────────────────────────────────の Continuing on the front page (72) Inventor Seiichi Nakatani 1006 Kadoma Kadoma, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. F term (reference) 4J002 AA021 CD041 CD051 DE076 DE146 DF016 DK006 FD016 FD140 GQ00 GQ05 5F036 BA23 BB08 BB21 5F067 AA03 BA06 BC01 BD08 CA08 CC07 DA05

Claims (36)

[Claims] 1. It has a thermally conductive resin sheet member,
A lead frame positioned thereon and integrated therewith, wherein the thermally conductive resin sheet member comprises an inorganic filler 7;
0 to 95 parts by weight and a thermosetting resin mixture containing 5 to 30 parts by weight of a thermosetting resin composition containing a thermosetting resin, and the thermosetting resin is in a semi-cured state. A lead frame with a thermally conductive resin sheet member. 2. The heat conductive resin sheet member has a length of 20 seconds to 1 hour.
The lead frame of claim 1 having a gel time at 155 ° C in the range of 20 seconds. 3. The heat conductive resin sheet member has a size of 10 ² to 1
The lead frame of claim 1 or 2 having a viscosity in the range of 0 5 ^Pa · s. 4. The lead frame has a through opening, and the heat conductive resin sheet member fills the through opening of the lead frame so that the heat conductive resin sheet member and the lead frame are flush with each other. The lead frame according to any one of claims 1 to 3, which is integrated so as to form a lead frame. 5. The thermosetting resin composition according to claim 1, wherein at least one selected from the group consisting of a bisphenol A epoxy resin, a bisphenol F epoxy resin and a liquid phenol resin is used as a main component. The lead frame described in Crab. 6. An inorganic filler comprising Al ₂ O ₃ , MgO,
The lead frame according to any one of claims 1 to 5, wherein the lead frame is at least one selected from the group consisting of BN and AlN. 7. The heat conductive resin sheet member is integrated with a part of a lead frame.
7. The lead frame according to claim 1, wherein all other terminals are electrically connected to the outer frame portion via a common terminal connected to the outer frame portion. 8. The heat conductive resin sheet member has at least one electrically independent sheet on the same side as the lead frame.
The lead frame according to any one of claims 1 to 7, further comprising two terminals. 9. A heat conductive material which is formed from a thermosetting resin mixture containing a thermosetting resin composition containing a thermosetting resin and an inorganic filler, and wherein the thermosetting resin is in a semi-cured state. A method for producing a lead frame with a thermally conductive resin sheet member, comprising: a lead frame located on and integrated with a conductive resin sheet member, comprising: (a) a thermosetting resin; Obtaining a thermoconductive resin sheet member from a thermosetting resin mixture comprising the thermosetting resin composition and an inorganic filler, and (b) heat treating the thermoconductive resin sheet member to have a predetermined gel time. And (c) arranging a lead frame on the thermally conductive resin sheet member and pressing them toward each other at a temperature at which curing of the thermosetting resin does not proceed, thereby integrating them. A method for manufacturing a lead frame, comprising: 10. The lead frame manufacturing method according to claim 9, wherein the predetermined gel time is within a range of 20 seconds to 120 seconds at 155 ° C. 11. The lead frame has a through opening, and in step (c), the thermally conductive resin sheet member fills the through opening of the lead frame, and the thermally conductive resin sheet member and the lead frame are filled. 11. The method for manufacturing a lead frame according to claim 9 or 10, wherein the steps are integrated so as to form a flush surface. 12. After step (b) and before step (c),
The method for manufacturing a lead frame according to claim 9, further comprising a step of forming the heat conductive resin sheet member into a predetermined shape. 13. The step of forming the heat conductive resin sheet member into a predetermined shape includes sandwiching the heat conductive resin sheet member between two plates and bringing the plates closer to each other so as to have a predetermined distance between the plates. The method according to claim 12, comprising pressing the heat conductive resin sheet member to obtain a heat conductive resin sheet member having a predetermined thickness, and thereafter, processing the heat conductive resin sheet member into a predetermined shape. Lead frame manufacturing method. 14. The method for manufacturing a lead frame according to claim 9, further comprising, after the step (c), removing a part of the lead frame integrated with the thermally conductive resin sheet member. 15. In the step (c), a heat conductive resin sheet member and a lead frame are laminated and sandwiched between two plates, and the plates are brought close to each other so as to have a predetermined distance between the plates. The conductive resin sheet member and the lead frame are pressed toward each other to obtain a heat conductive resin sheet member having a predetermined thickness integrated with the lead frame. (D) Then, the thermal conductive resin member integrated with the lead frame is obtained. The method for manufacturing a lead frame according to claim 9, further comprising a step of processing the resin sheet member into a predetermined shape. 16. The method according to claim 15, wherein the predetermined gel time is in a range of 20 seconds to 120 seconds at 155 ° C. 17. The lead frame has a through opening, and in step (c), the heat conductive resin sheet member fills the through opening of the lead frame, and the heat conductive resin sheet member and the lead frame 17. The method for manufacturing a lead frame according to claim 15 or 16, wherein the steps are integrated so as to form a flush surface. 18. The method for manufacturing a lead frame according to claim 15, further comprising, after step (d), removing a part of the lead frame integrated with the heat conductive resin sheet member. 19. A method for manufacturing a heat conductive substrate comprising a heat conductive resin sheet member, a lead frame, and a metal heat radiating plate, wherein: (1) the lead frame and the metal heat radiating plate are formed of a heat conductive resin sheet; 15. A step of arranging a metal radiator plate on a lead frame with a thermally conductive resin sheet member manufactured by the method according to any one of claims 9 to 14 so as to face the member via a member. A step of heat-treating the lead frame with the sheet member and the metal heat radiating plate at a temperature higher than the temperature at which the curing of the thermosetting resin proceeds without being pressed toward each other for a predetermined time; and (3) continuing the heat treatment thereafter While pressing the lead frame and the metal radiator plate toward each other with a predetermined pressure, the curing of the thermosetting resin further proceeds, and the metal radiator plate and the heat conductive resin sheet member are attached. A method for manufacturing a thermally conductive substrate, comprising a step of integrating a lead frame. 20. The thermal method according to claim 19, wherein the gel time of the thermally conductive resin sheet member of the lead frame with the thermally conductive resin sheet member in the step (1) is in a range of 20 seconds to 120 seconds at 155 ° C. A method for manufacturing a conductive substrate. 21. The lead frame with a thermally conductive resin sheet member in the step (1), wherein the lead frame has a through opening, and in the step (c), the thermally conductive resin sheet member is inserted through the lead frame. 21. The method of manufacturing a heat conductive substrate according to claim 19, wherein the opening is filled, and the heat conductive resin sheet member and the lead frame are integrated so as to form a flush surface. 22. The method according to claim 19, wherein the step (1) includes a step of forming the heat conductive resin sheet member into a predetermined shape after the step (b) and before the step (c). The method described in. 23. A step of forming a heat conductive resin sheet member into a predetermined shape, wherein the plates are brought closer to each other so as to have a predetermined distance between the two plates with the heat conductive resin sheet member interposed therebetween. 23. The method according to claim 22, comprising pressing the heat conductive resin sheet member to obtain a heat conductive resin sheet member having a predetermined thickness, and thereafter processing the heat conductive resin sheet member into a predetermined shape. A method for manufacturing a conductive substrate. 24. The heat conduction according to claim 19, further comprising, after the step (c) in the step (1), removing a part of the lead frame integrated with the heat conductive resin sheet member. Of manufacturing a flexible substrate. 25. The heat conductive substrate according to claim 19, further comprising, after the step (3), a step of further heat-treating the heat conductive substrate to sufficiently cure the thermosetting resin. Manufacturing method. 26. A method for manufacturing a heat conductive substrate comprising a heat conductive resin sheet member, a lead frame and a metal heat radiating plate, wherein: (1) the lead frame and the metal heat radiating plate are made of a heat conductive resin sheet; 19. A step of arranging a metal radiator plate on a lead frame with a thermally conductive resin sheet member manufactured by the method according to any one of claims 15 to 18 so as to face the member via a member, (2) a thermally conductive resin A step of subjecting the lead frame with the sheet member and the metal radiator plate to a heat treatment at a temperature higher than the temperature at which the curing of the thermosetting resin proceeds without being pressed toward each other for a predetermined time; and (3) continuing heating thereafter While pressing the lead frame and the metal radiator plate toward each other with a predetermined pressure, the curing of the thermosetting resin further proceeds, and the metal radiator plate and the heat conductive resin sheet member are attached. A method for manufacturing a thermally conductive substrate, comprising a step of integrating a lead frame. 27. The thermal method according to claim 26, wherein the gel time of the thermally conductive resin sheet member of the lead frame with the thermally conductive resin sheet member in the step (1) is in a range of 20 seconds to 120 seconds at 155 ° C. A method for manufacturing a conductive substrate. 28. The lead frame with a thermally conductive resin sheet member in the step (1), wherein the lead frame has a through opening, and in the step (c), the thermally conductive resin sheet member is inserted through the lead frame. 28. The method of manufacturing a heat conductive substrate according to claim 26, wherein the opening is filled, and the heat conductive resin sheet member and the lead frame are integrated so as to form a flush surface. 29. The method according to claim 26, further comprising, after the step (d) in the step (1), removing a part of the lead frame integrated with the thermally conductive resin sheet member. A method for manufacturing a conductive substrate. 30. The method for producing a thermally conductive substrate according to claim 26, further comprising a step of further heat-treating the thermally conductive substrate to promote sufficient curing after the step (3). . 31. A method for producing a heat conductive substrate having a heat conductive resin composition, a lead frame and a metal heat sink, comprising: (A) a thermosetting resin composition containing a thermosetting resin. Obtaining a thermally conductive resin sheet member from a thermosetting resin mixture comprising a material and an inorganic filler; (B) heat treating the thermally conductive resin sheet member to have a predetermined gel time; (C) a step of arranging a metal radiator plate on the thermally conductive resin sheet member and pressing them toward each other at a temperature at which curing of the thermosetting resin does not proceed, thereby integrating them; (D) a lead frame Disposing the lead frame on the heat conductive resin sheet member integrated with the metal heat radiator plate such that the metal frame and the metal heat radiator plate face each other via the heat conductive resin sheet member; and (E) integrating with the metal heat radiator plate Heat transfer Heat treatment of the conductive resin sheet member and the lead frame at a temperature higher than the temperature at which the curing of the thermosetting resin proceeds, and pressing the lead frame and the metal radiator plate toward each other with a predetermined pressure to integrate them. And a method of manufacturing a heat conductive substrate, which comprises a step of promoting the curing of a thermosetting resin. 32. The method according to claim 31, wherein the predetermined gel time is within a range of 20 seconds to 120 seconds at 155 ° C. 33. The lead frame has a through-opening, and in the step (E), the heat-conductive resin sheet member fills the through-opening of the lead frame, and the heat-conductive resin sheet member and the lead frame 33. The method for producing a thermally conductive substrate according to claim 31, wherein the substrate and the substrate are integrated so as to form a flush surface. 34. After the step (B) and before the step (C),
The method for manufacturing a heat conductive substrate according to any one of claims 31 to 33, comprising a step of forming the heat conductive resin sheet member into a predetermined shape. 35. A step of forming the heat conductive resin sheet member into a predetermined shape, the step of forming a gap between the plates so as to have a predetermined distance between the two plates with the heat conductive resin sheet member interposed therebetween. 35. The method according to claim 34, comprising controlling and pressing the heat conductive resin sheet member to obtain a heat conductive resin sheet member having a predetermined thickness, and thereafter processing the heat conductive resin sheet member into a predetermined shape. A method for manufacturing a thermally conductive substrate. 36. The heat conductive substrate according to claim 31, further comprising, after the step (E), a step of further heat-treating the heat conductive substrate to sufficiently cure the thermosetting resin. Manufacturing method.