JP2010067637A - Heat dissipation member, semiconductor device using the same, and methods of manufacturing the heat dissipation member and the semiconductor device - Google Patents

Abstract

A heat dissipating member that improves the adhesion of an amorphous carbon film with poor adhesion and has excellent adhesion to a member that is more easily bonded to the surface of the amorphous carbon film, and uses the heat dissipating member Further, the present invention provides a semiconductor device and a manufacturing method thereof.
SOLUTION: A base material having thermal conductivity, at least a part of the surface of the base material, carbon as a main component, and silicon present more in the surface layer portion on the side opposite to the base material than on the base material side. Insulating amorphous carbon coating, and fixed on the surface of the amorphous carbon coating, and Si—O—M bonds with silicon in the amorphous carbon coating (M = Si, Ti, Al, or Zr) M And a bonding layer made of a resin containing.
[Selection figure] None

Description

  The present invention relates to a heat radiating member that can be suitably used as a heat radiating member for radiating and cooling heat generated in a semiconductor element, a semiconductor device using the same, and a method for manufacturing the same.

  Conventionally, in order to solve the increase in the amount of heat generated due to high output and miniaturization of a semiconductor element accompanied by power control, the semiconductor element is mounted on a substrate made of an insulator to electrically isolate it, and this insulating substrate is mounted on a heat sink The module was built in. In order to improve the heat dissipation characteristics of such a heat sink, a semiconductor element may be mounted on a heat sink coated with an insulating amorphous carbon film.

  In this case, an electrode is formed on the amorphous carbon film. However, if the adhesion between the amorphous carbon film and the heat sink substrate and the amorphous carbon film and the electrode is not sufficient, peeling occurs on the bonding surface. Conventionally, since an amorphous carbon film has poor adhesion, various studies have been conducted in order to improve adhesion to a base material and to improve adhesion to an electrode.

  Patent Document 1 and Patent Document 2 disclose an amorphous carbon coating having a characteristic structure for the purpose of improving adhesion. For example, in Patent Document 1, silicon whose main component is carbon and whose concentration is continuously inclined so as to have the highest concentration on the substrate side and hydrogen whose concentration is continuously inclined so as to have the lowest concentration on the substrate side are disclosed. And an amorphous carbon coating that is a graded composition coating. Patent Document 2 discloses a DLC gradient structure hard coating having a first layer containing titanium coated on a substrate surface and an outermost layer of a diamond-like carbon (DLC) film.

Patent Document 3 discloses a method for improving the adhesion between an amorphous carbon coating and a metal layer serving as an electrode. In Patent Document 3, metal nanoparticles are formed on the surface of the amorphous carbon coating, and the surface of the amorphous carbon coating is locally etched using the metal nanoparticles as a mask to form irregularities on the surface of the amorphous carbon coating. And the method of improving the adhesiveness of an amorphous carbon film and a metal layer is disclosed by the anchor effect.
JP 2006-291355 A JP 2004-137541 A JP 2007-327081 A

  However, the methods disclosed in Patent Document 1 and Patent Document 2 are carried out in order to improve the adhesion of the amorphous carbon film to the substrate, and other members that are bonded on the surface of the amorphous carbon film There has been no study on improving the adhesion. The method disclosed in Patent Document 3 is a method in which nanoparticles are formed, etching is performed, and a metal layer is formed by electroless plating, which is troublesome.

  In view of the above problems, the present invention improves the adhesion of an amorphous carbon film having poor adhesion, and has a superior heat dissipation property for a member that is more easily bonded to the surface of the amorphous carbon film. An object is to provide a member. Another object of the present invention is to provide a semiconductor device using the heat dissipating member and a method for manufacturing the same.

  The heat-dissipating member of the present invention is coated on at least a part of the surface of the base material having thermal conductivity and the surface of the base material, and is present more in the surface layer portion on the side opposite to the base side than carbon as the main component. An insulating amorphous carbon coating containing silicon, and fixed to the surface of the amorphous carbon coating, and Si—O—M bonds with silicon in the amorphous carbon coating (M = Si, Ti, Al or And a bonding layer made of a resin containing Zr) M.

  The amorphous carbon film contains silicon and is bonded to the bonding layer by Si—O—M bonds. Therefore, the adhesion between the amorphous carbon coating and the bonding layer can be improved by increasing the amount of silicon on the surface of the amorphous carbon coating on the bonding layer side. However, if the amorphous carbon film contains excessive silicon, defects are generated and the insulating property is lowered. Therefore, the bonding layer is formed without degrading the overall insulation of the amorphous carbon coating by increasing the silicon content of the surface layer portion of the amorphous carbon coating on the side opposite to the substrate to the silicon content on the substrate side. The amount of silicon on the side can be increased. As a result, the adhesion between the amorphous carbon film and the bonding layer can be improved.

  At this time, it is preferable that the thickness of the surface layer portion on the side opposite to the base material side of the amorphous carbon coating containing more silicon than the base material side is 0.01 μm or more and 10 μm or less. When the surface layer has the above thickness, the adhesion between the amorphous carbon coating and the bonding layer can be improved.

  The silicon content in the surface layer is preferably 5 atomic% to 50 atomic%, assuming that all components in the surface layer are 100 atomic%. Adhesiveness can be improved by setting it as the silicon content of the said range.

  Further, the silicon content of the portion excluding the surface layer portion of the amorphous carbon coating is 1 atomic% to 20 atomic% and the hydrogen content is 20 to 60 atomic when all the components of the amorphous carbon coating are 100 atomic%. % Is preferable. By making it within this range, insulation can be maintained.

  The amorphous carbon film is preferably formed by a direct current plasma CVD method.

  A desired amorphous carbon film can be formed more easily by forming a film by a direct current plasma CVD method.

  Furthermore, it is preferable that the amorphous carbon film and the bonding layer are chemically bonded by a coupling reaction via a coupling agent. By using a coupling agent, the adhesiveness according to the adhesive to be used can be improved.

  The semiconductor device of the present invention includes the above-described heat dissipation member and a semiconductor element mounted on the bonding layer of the heat dissipation member via a wiring material.

  By using the heat dissipation member, a semiconductor device having excellent adhesion can be obtained.

  The semiconductor element can be a power device or a semiconductor chip of a large scale integrated circuit.

  Further, in the method for producing a heat radiating member of the present invention, at least part of the surface of the base material having thermal conductivity, carbon as a main component and silicon present more in the surface layer portion on the side opposite to the base side than the base side. Including an amorphous carbon film forming step for forming an insulating amorphous carbon film, a surface oxidation step for oxidizing the surface of the amorphous carbon film to form a silanol group, A fixing step of fixing the crystalline carbon film and an adhesive made of resin.

  Further, in the method for producing a heat radiating member of the present invention, at least part of the surface of the base material having thermal conductivity, carbon as a main component and silicon present more in the surface layer portion on the side opposite to the base side than the base side. An amorphous carbon film forming step for forming an insulating amorphous carbon film, a surface oxidation step for oxidizing the surface of the amorphous carbon film to form a silanol group, and a surface of the amorphous carbon film -M-X group (M = Si, Ti, Al or Zr; X = hydrolyzable substituent or hydrophilic group) of the adhesive composed of resin reacts with the amorphous carbon coating. A fixing step of fixing the agent.

  The oxidation treatment is preferably UV treatment, plasma treatment or corona treatment.

  By using such a manufacturing method, a heat radiation member with high adhesion can be manufactured.

  Further, the method for manufacturing a semiconductor device of the present invention includes carbon as a main component on at least a part of the surface of a base material having thermal conductivity and silicon present in a surface layer portion on the side opposite to the base material rather than the base material side. Including an amorphous carbon film forming step for forming an insulating amorphous carbon film, a surface oxidation step for oxidizing the surface of the amorphous carbon film to form a silanol group, Fixing process for fixing crystalline carbon film and resin adhesive, wiring material bonding process for bonding low thermal expansion wiring material to the surface of the adhesive, and fixing semiconductor elements using solder on the wiring material And a semiconductor element fixing step.

  Further, the method for manufacturing a semiconductor device of the present invention includes carbon as a main component on at least a part of the surface of a base material having thermal conductivity and silicon present in a surface layer portion on the side opposite to the base material rather than the base material side. An amorphous carbon film forming step for forming an insulating amorphous carbon film, a surface oxidation step for oxidizing the surface of the amorphous carbon film to form a silanol group, and a surface of the amorphous carbon film -M-X group (M = Si, Ti, Al or Zr; X = hydrolyzable substituent or hydrophilic group) of the adhesive composed of resin reacts with the amorphous carbon coating. A fixing step of fixing the agent, a wiring material bonding step of bonding a low thermal expansion wiring material to the surface of the adhesive, and a semiconductor element fixing step of fixing the semiconductor element using solder on the wiring material It is characterized by that.

  By adopting such a manufacturing method, a semiconductor device with high adhesion can be manufactured.

  ADVANTAGE OF THE INVENTION According to this invention, the heat radiating member which has the amorphous carbon film excellent in adhesiveness, the semiconductor device excellent in adhesiveness, and those manufacturing methods can be provided.

(Heat dissipation member)
The heat dissipating member of the present invention includes a base material having thermal conductivity, an insulating amorphous carbon film coated on at least a part of the surface of the base material, and a chemical bond to the surface of the amorphous carbon film. And a bonding layer made of resin.

  A base material will not be specifically limited if it consists of a well-known metal material which has heat conductivity.

  Here, having thermal conductivity means a substrate made of a metal having a thermal conductivity of 50 W / m · K or more. Further, the thermal conductivity of the base material is preferably 100 W / m · K or more, and more preferably 200 W / m · K or more.

  In the heat radiating member of the present invention, this base material serves as a heat radiating plate. In order to dissipate heat efficiently, the higher the thermal conductivity of the base material, the better. From this point of view, the base material includes a single metal selected from Al, Cu, Mo, W, Si and Fe or these. A composite material, a mixture or an alloy is preferred. The shape of the substrate is not particularly limited.

  The insulating amorphous carbon coating coated on at least a part of the substrate contains carbon as a main component and silicon that is present more in the surface layer portion on the side opposite to the substrate than on the substrate.

Since the amorphous carbon coating is thin, it hardly affects the thermal conductivity of the heat dissipation member. The amorphous carbon coating is insulative, and is used to electrically insulate between the base material and the object to be radiated which is bonded on the bonding layer. The degree of insulation is preferably 10 ¹⁰ Ωm or more. The thickness of the amorphous carbon film is preferably 5 to 30 μm because if it is thin, the thermal conductivity is improved but the voltage resistance is deteriorated.

  Moreover, this amorphous carbon film contains more silicon present in the surface layer portion on the side opposite to the substrate than on the substrate. Therefore, the silicon content of the portion excluding the surface layer portion of the amorphous carbon film is 1 atomic% to 20 atomic%, further 3 atomic% to 8 atomic%, assuming that all the components of the amorphous carbon film are 100 atomic%. It is preferable. When the silicon content is within this range, the amorphous carbon coating can electrically insulate between the base material and the object to be radiated.

  And the adhesiveness with a joining layer can be improved by containing more silicon than the base material side in the surface layer part by the side of an anti-base material. The reason for this will be described later.

  Here, the thickness of the surface layer portion on the side opposite to the substrate of the amorphous carbon coating containing more silicon than the substrate is preferably 0.01 μm or more and 10 μm or less, more preferably 0.05 μm or more and 1 μm or less.

  If the thickness of the surface layer portion with a large silicon content is smaller, the insulation property of the entire amorphous carbon film can be prevented from being lowered. However, if there is not a certain thickness, the effect of the surface oxidation treatment described later can be sufficiently obtained. I can't.

  The silicon content in the surface layer is preferably 5 atomic% to 50 atomic%, more preferably 10 atomic% to 30 atomic%, assuming that all components in the surface layer are 100 atomic%. The silicon content in the surface layer portion is preferably higher from the viewpoint of adhesion to the bonding layer, and from the viewpoint of insulation, it is preferable not to contain excessively. Therefore, if the silicon content in the surface layer portion is 10 atomic% to 30 atomic%, it is possible to obtain a heat radiating member with better insulation and adhesion.

  As described above, the amorphous carbon film having different silicon contents on the base material side and the non-base material side has the highest concentration on the surface layer side in addition to the multilayer film composed of two or more layers having different silicon contents. A gradient composition film containing silicon having a continuously gradient concentration may be used.

  A method for forming the amorphous carbon film as described above is not particularly limited, and a known film formation method such as a sputtering method or a vacuum film formation method can be used. Among these, the amorphous carbon film is preferably formed by a direct current plasma CVD method.

  In the direct-current plasma CVD method, glow discharge is generated by applying electric power between two electrodes, a positive electrode and a negative electrode. Using this glow discharge, the processing gas introduced between the electrodes is activated to deposit a thin film on the negative potential side electrode. That is, an amorphous carbon film can be formed by connecting a conductive substrate disposed in a film forming furnace to the negative electrode and causing the substrate to glow discharge.

In order to form an amorphous carbon film using the direct current plasma CVD method, the base material needs to be a conductive material. The conductive material desirably has a volume resistivity of 10 ⁴ Ωm or less. Moreover, since there is no limitation in particular also in the shape of a base material, it can form into a film on the base material of various shapes.

A known apparatus can be used as the apparatus for the direct current plasma CVD method. As a processing gas, as a raw material gas for supplying carbon and hydrogen, for example, saturated hydrocarbons such as methane, ethane, and cyclohexane, and unsaturated hydrocarbons such as ethylene and acetylene. Aromatic hydrocarbons such as benzene can be used, and these gases may be mixed with hydrogen gas. As a source gas for supplying silicon, silicon compounds such as tetramethylsilane (Si (CH ₃ ) ₄ : TMS), silane, and silicon chloride can be used. In addition to an inert gas such as nitrogen as a dilution gas, A rare gas such as argon can be used. The type, mixing ratio, or flow rate ratio of the processing gas may be appropriately selected so that the composition of the obtained amorphous carbon film has a desired composition.

  And in order to make the amorphous carbon film in which the silicon content in the surface layer portion on the side opposite to the base material side is larger than that on the base material side, by forming two or more layers under different conditions, a multilayer film is formed. Can be done. Further, for example, the flow rate of tetramethylsilane (TMS) serving as a silicon raw material is controlled during film formation, and the temperature is controlled during film formation, thereby forming a gradient composition film.

  The bonding layer is made of a resin containing M that is fixed on the surface of the amorphous carbon coating and that has Si—OM bonding with silicon in the amorphous carbon coating (M = Si, Ti, Al, or Zr). The bonding layer and the amorphous carbon film are firmly bonded by being chemically bonded by the Si—OM bond. At this time, the amorphous carbon film and the bonding layer are preferably chemically bonded by a coupling reaction via a coupling agent.

  Thus, in order for the bonding layer and the amorphous carbon film to be chemically bonded by the Si-OM bond, silicon in the amorphous carbon film is oxidized to a silanol group, and reactive M is used as the bonding layer. It can be carried out by including both of them and reacting them to chemically bond silicon in the amorphous carbon film and M in the bonding layer.

  For example, reactive M in the bonding layer may be introduced by a coupling agent, or -M-X group (M = Si, Ti, Al or Zr; X = hydrolyzable substituent or hydrophilic group). You may use the adhesive which has. The adhesive having the -MX group (M = Si, Ti, Al or Zr; X = hydrolyzable substituent or hydrophilic group) may be used in combination with a coupling agent.

  A coupling agent is an organic compound having a functional group that can chemically bond to both inorganic and organic materials, which are generally unfamiliar with each other.

  As the coupling agent, a coupling agent such as a silane coupling agent, a titanate coupling agent, an aluminate coupling agent, or a silazane can be used.

For example silane coupling agent _has the general formula _{Y n -Si (OR) (4} -n) (n = 1~3 integer). OR is an alkoxy group such as a methoxy group or an ethoxy group bonded to Si, and is a hydrolyzable inorganic reactive group.

Y represents a functional group (Y ^1- ) (for example, vinyl group, epoxy group, amino group, aminopropyl group, glycidoxy group, methacryloxy group, mercapto group, etc.) and a linking group (—Y ² —) (for example, alkylene). Group) and a group (for example, 3-glycidoxypropyl group, 3-aminopropyl group, 3-methacryloxypropyl group, etc.) having a structure (Y ¹ -Y ² —) bonded to the organic substance It is an organic reactive group.

  A silane coupling agent hydrolyzes and generates a silanol group when an alkoxysilyl group (—Si—OR) comes into contact with water.

_{-Si (OR) + H 2 O} → -Si (OH) + ROH
The produced silanol group is chemically bonded to the OH group on the substrate surface by a dehydration condensation reaction. On the other hand, Y is firmly bonded to the resin component in the bonding layer by chemical bonding or crosslinking. The silane coupling reaction refers to the entire reaction caused by such a silane coupling agent.

  FIG. 1 shows an explanatory diagram of the silane coupling reaction via the silane coupling agent described above.

As shown in FIG. 1, the —Si (OH) ₃ group generated by hydrolysis of the alkoxysilyl group of the silane coupling agent undergoes a dehydration condensation reaction with a silanol group on the surface of the amorphous carbon film to form a Si—O—Si bond. Join. Further, the unreacted —Si (OH) ₃ group is bonded to the silanol group on the surface of the amorphous carbon film by hydrogen bonding.

  In FIG. 1, Y has an amino group, and the amino group is covalently bonded to the functional group on the adhesive side. For this reason, the amorphous carbon film and the adhesive which is the resin component in the bonding layer can be firmly bonded via the silane coupling agent.

  Usable silane coupling agents include 3-methacryloxypropyltrimethoxysilane, 2- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3- (2-amino Ethyl) -aminopropyltrimethoxysilane, 3- (2-aminoethyl) aminopropylmethyldimethoxysilane, 3-aminopropyltriethoxysilane, 3-aminopropyltrimethoxysilane, 3-mercaptopropylmethoxysilane, vinyltriethoxysilane Vinyltris (methoxyethoxy) silane, 3-glycidoxypropylmethyldiethoxysilane, and the like.

Particularly, 3-glycidoxypropyltrimethoxysilane in which an epoxy group is present in Y of Y _n -Si- (OR) _(4-n) in the general chemical formula of a silane coupling agent, and 3- Aminopropyltrimethoxysilane is preferably used. This is because the compatibility and reactivity with the epoxy adhesive generally used for the bonding layer is excellent.

  As described above as coupling agents other than silane coupling agents, titanate coupling agents, aluminate coupling agents, coupling agents such as silazanes can also be used, but with Si in the amorphous carbon coating In the case of bonding, the bonding becomes stronger by using a silane coupling agent.

  When an adhesive having a -MX group (M: Si, Ti, Al or Zr, X: hydrolyzable substituent or hydrophilic group) is used, it is preferable that M = Si and X = OR ( R = methyl group or ethyl group). At this time, like the silane coupling agent, this adhesive hydrolyzes to form silanol groups when it comes into contact with water, and the silanol groups are polymerized by self-condensation, and at the same time, dehydration condensation reaction with OH groups on the substrate surface. Chemically bond with

  As for the joining layer (henceforth an adhesive agent) which consists of resin used by this invention, it is desirable that the heat conductivity of the hardened | cured material is at least 5 W / mK or more. Adhesives having such characteristics are, for example, nitriding to thermosetting resins such as epoxy, silicone, urethane, polyimide, BT resin, and resins mainly composed of thermoplastic resins such as polyetherimide and polyimide. It can be obtained by blending high thermal conductive insulating powder such as aluminum, boron nitride, alumina, silica, diamond and / or metal powder such as silver, copper, aluminum and the like. The blending amount of the high thermal conductive insulating powder and / or metal powder is preferably 80% by weight or more.

  The thinner the adhesive, the better in terms of thermal conductivity. However, since the adhesive is filled with the above-mentioned powder in order to impart high thermal conductivity, if the thickness is too thin, the coatability is deteriorated. Therefore, it is desirable that the adhesive thickness is 10 to 100 μm considering both. If the thickness of the adhesive layer exceeds 100 μm, the heat generated in the power device cannot be efficiently conducted even if the thermal conductivity of the adhesive is 5 W / mK or more.

The heat dissipating member of the present invention can be used for a heat dissipating member of a semiconductor element, a substrate for mounting an electronic component (resistor, capacitor) or a housing.
(Semiconductor device)
The semiconductor device of the present invention includes the heat dissipating member described above and a semiconductor element mounted on the bonding layer of the heat dissipating member via a wiring member.

  When a semiconductor element is mounted on a heat dissipation member, a wiring material is formed on a bonding layer to form an electrode, and the electrode and the semiconductor element are bonded with solder or the like to form a semiconductor device.

  The wiring material used in the present invention has an important condition that it can be used as a heat radiating and supporting plate of the power module, and that it can be joined by soldering and heat conductivity and strength.

Examples of such wiring materials include copper and its alloy nickel-plated, aluminum and its alloy nickel-plated, and iron nickel-plated.
Of these, copper plated with nickel and alloys plated with nickel are preferable from the viewpoint of thermal conductivity, and Cu-W, Cu-Mo, Cu-Cr are also preferable from the viewpoint of bonding reliability. It is preferable to use a low thermal expansion wiring material such as that because thermal stress at the bonding interface can be reduced.

  The thickness of the wiring material is preferably 0.5 to 3 mm, and preferably 0.5 to 1.5 mm from the viewpoint of heat conduction.

  Moreover, you may process a silane coupling agent on plating. The adhesive which is the resin component in the bonding layer and the plating can be firmly bonded via the silane coupling agent.

  At this time, the same silane coupling agent as that described above can be used as the silane coupling agent. For example, 3-methacryloxypropyltrimethoxysilane, 2- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3- (2-aminoethyl) -aminopropyltrimethoxysilane, 3- (2-aminoethyl) aminopropylmethyldimethoxysilane, 3-aminopropyltriethoxysilane, 3-aminopropyltrimethoxysilane, 3-mercaptopropylmethoxysilane, vinyltriethoxysilane, vinyltris (methoxyethoxy) silane, 3 -Glycidoxypropylmethyldiethoxysilane can be used.

Particularly, 3-glycidoxypropyltrimethoxysilane in which an epoxy group is present in Y of Y _n -Si- (OR) _(4-n) in the general chemical formula of a silane coupling agent, and 3- Aminopropyltrimethoxysilane is preferably used. This is because the compatibility and reactivity with the epoxy adhesive generally used for the bonding layer is excellent.

  As the semiconductor element, a bipolar transistor such as an IGBT, a diode, a power device such as a power MOS, and a semiconductor chip of a large scale integrated circuit can be used. Since such a semiconductor element generates a large amount of heat generated by switching, the temperature range of the cooling / heating cycle is increased, and the bonded portion is easily peeled off. Since the semiconductor device of the present invention is coated with an amorphous carbon film on the base material, the heat dissipation is high, and the semiconductor element can be prevented from reaching a high temperature. Further, since the adhesion between the amorphous carbon film and the semiconductor element is high, the bonded portion is hardly peeled even under severe cooling and cycling conditions.

  FIG. 2 is a schematic cross-sectional view of the semiconductor device. However, the semiconductor device of the present invention is not limited to the following configuration.

  As shown in FIG. 2, the semiconductor device 10 includes a heat radiating member 1, a wiring member 5, solder 6, and a semiconductor element 7. The heat dissipating member 1 includes a base material 2, an amorphous carbon coating 3, and a bonding layer 4. As can be seen from FIG. 2, an amorphous carbon coating 3 is coated on the base material 2, and a bonding layer 4 is formed on the amorphous carbon coating 3. Further, the amorphous carbon coating 3 and the wiring member 5 are bonded via the bonding layer 4. A semiconductor element 7 is fixed on the wiring member 5 via solder 6.

  In FIG. 2, a power device is provided as the semiconductor element 7. Further, the semiconductor device 10 may be provided by adhering an air cooling or liquid cooling type cooling member for forcibly cooling the heat conducted to the heat dissipation member 10 so as to be in contact with the lower surface of the heat dissipation member 1. By providing such a cooling member, the heat generated in the semiconductor element 7 can be dissipated more effectively. In addition, as an adhesive material used for adhesion at this time, for example, grease or wax can be used. It is preferable to use wax with lower thermal resistance.

In the semiconductor device 10 of the present invention, since the amorphous carbon coating 3 and the wiring member 5 are firmly chemically bonded via the bonding layer 4, the adhesion between the amorphous carbon coating 3 and the wiring member 5 is high. The resistance to temperature changes caused by switching of the semiconductor element 7 is enhanced, and a highly reliable module can be formed.
(Manufacturing method of heat dissipation member)
The manufacturing method of the heat radiating member of this invention has an amorphous carbon film formation process, a surface oxidation process, and the fixing process which fixes an amorphous carbon film and an adhesive agent, It is characterized by the above-mentioned.

  The amorphous carbon film forming step is an insulating process in which at least a part of the surface of the base material having thermal conductivity contains carbon as a main component and silicon present more in the surface layer portion on the side opposite to the base than on the base. This is a step of forming a conductive amorphous carbon film. The method for forming the amorphous carbon film is not particularly limited, and a known film formation method such as a sputtering method or a vacuum film formation method can be used. In particular, the amorphous carbon film is preferably formed by the direct-current plasma CVD method described for the heat dissipation member.

  The surface oxidation step is a step of oxidizing the surface of the amorphous carbon coating to form silanol groups. The oxidation treatment is preferably UV treatment, plasma treatment or corona treatment. In particular, UV treatment is more preferable.

  As the UV treatment, UV ozone treatment is preferably used. The UV ozone treatment is a method in which ozone is generated by ultraviolet rays and the surface is oxidized by the oxidizing power of excited oxygen atoms decomposed and generated from the ozone. The mechanism is explained as follows.

  For example, when a low-pressure mercury lamp whose main emitted light is ultraviolet rays having wavelengths of 185 nm and 254 nm is used as the ultraviolet light source, the ultraviolet rays of 185 nm generate ozone by decomposing oxygen molecules in the air (reaction formulas 1 and 2 below). Since ultraviolet rays of 254 nm decompose the generated ozone to generate excited active oxygen atoms (O.) (the following reaction formula 3), a cycle reaction represented by the following reaction formulas 1 to 3 occurs.

(Reaction Formula 1)
O ₂ + hν (185 nm) → O + O
(Reaction Formula 2)
O ₂ + O → O ₃
(Reaction Formula 3)
O ₃ + hν (254 nm) → O · + O ₂
When an active oxygen atom generated by the above reaction formula 3 is present, a polar functional group such as a highly hydrophilic —OH group or —COOH group is formed by its strong oxidizing action.

  UV ozone treatment (ultraviolet ray / ozone process) can be performed using a known apparatus. Since UV ozone treatment requires high-energy short-wave UV, low-pressure mercury lamps emitting 185 nm and 254 nm and xenon excimer lamps emitting 172 nm are used as light sources. At this time, the energy of the excimer lamp is high, but light is strongly absorbed by oxygen, and the irradiation distance is extremely short in the atmosphere. Therefore, the low-pressure mercury lamp is more preferably used.

  By performing the oxidation treatment as described above, -OH groups and -COOH groups can be imparted to the surface of the amorphous carbon film, and impurities on the treated surface can also be removed.

  The fixing step of fixing the amorphous carbon coating and the adhesive may be a step of fixing the amorphous carbon coating and the adhesive made of resin via a silane coupling agent, or amorphous carbon. Amorphous carbon is produced by reacting silanol groups on the surface of the coating with -MX groups (M = Si, Ti, Al or Zr; X = hydrolyzable substituents or hydrophilic groups) of the resin adhesive. It may be a step of fixing the film and the adhesive.

Further, the fixing in the fixing step may be performed by performing a treatment such as heat treatment or UV treatment according to the fixing conditions of each adhesive.
(Method for manufacturing semiconductor device)
The method for manufacturing a semiconductor device of the present invention includes an amorphous carbon film forming step, a surface oxidation step, a fixing step, a wiring material bonding step, and a semiconductor element fixing step. Since the amorphous carbon film forming step, the surface oxidation step, and the fixing step have been described above, description thereof will be omitted.

  The wiring material bonding process is a process of bonding a low thermal expansion wiring material to the surface of the adhesive. A wiring material is installed on the adhesive and, for example, heat treatment, UV processing, etc. according to the fixing conditions of the adhesive. To fix. This step may be performed simultaneously with the fixing step described above.

  In the semiconductor element fixing step, the semiconductor element may be fixed on the wiring material using solder. This may be fixed by a known method using solder, and is not particularly limited.

Embodiments of the present invention will be described below with reference to the drawings. In this example, the adhesion between the surface of the amorphous carbon film and the adhesive was evaluated. Therefore, in this example, evaluation was performed by forming an amorphous carbon film containing a large amount of silicon corresponding to the surface layer portion on the bonding layer side. Therefore, the amorphous carbon film in this example is formed only on the surface layer portion on the bonding layer side, and in the heat dissipating member of the present invention, the silicon content is reduced before forming the amorphous carbon film containing a large amount of silicon. It is necessary to form an amorphous carbon film with a reduced concentration.
(Creation of amorphous carbon film)
FIG. 3 is an explanatory view of a film forming apparatus using the direct current plasma CVD method. 4 is an explanatory view showing a state of glow discharge during film formation as seen from the cutting line XX ′ side in FIG.

  An amorphous carbon film deposition apparatus 400 shown in FIG. 3 uses a cylindrical, stainless steel chamber 411 as a deposition furnace, and has an exhaust system 413 that communicates with the chamber 411 through an exhaust passage 412.

  The exhaust system 413 includes an oil rotary pump, a mechanical booster pump, and an oil diffusion pump, and adjusts the processing pressure in the chamber 411 by opening and closing an exhaust adjustment valve 415 disposed in the exhaust passage 412.

  In the chamber 411, a cathode 420 and a gas supply unit 430 are disposed which are energized to the negative electrode of the plasma power source 416.

  The cathode 420 includes a support base 421 connected to the negative electrode of the plasma power source 416 and a conductive substrate 422 on which an amorphous carbon film is formed. The support base 421 has a disk shape made of stainless steel, and is fixed to the bottom of the chamber 411 coaxially with the cylindrical chamber 411. The support base 421 holds the conductive substrate 422 in an arbitrary arrangement state.

  In addition, the film forming apparatus includes a gas supply unit 430. The gas supply means 430 supplies a mixed gas of the source gas and the dilution gas to the chamber 411 at an arbitrary flow rate ratio. The mixed gas is supplied to the inside of the chamber 411 through the gas supply valve 434 and the gas supply pipe 435 after adjusting the flow rate by the mass flow controller (MFC) 433. The gas supply pipe 435 has a plurality of holes at equal intervals in the length direction. The gas supply pipe 435 is installed so as to be positioned at the center of the chamber 411, and the mixed gas is uniformly supplied to the conductive substrate 422 held by the support base 421.

The positive electrode of the plasma power source 416 is connected to the chamber 411 and the ground, and the wall surface of the chamber 411 serves as a ground electrode (anode).

  The amorphous carbon film forming apparatus having the above-described configuration was operated to form an amorphous carbon film on the surface of the conductive substrate 422. In this example, four conductive substrates (50 mm long, 10 mm wide, 3 mm thick) made of aluminum alloy 3003 were used as the conductive substrate 422. As shown in FIGS. 3 and 4, these conductive bases 422 were arranged on the support base 421 in parallel and in parallel with the thickness direction. The distance D between the opposing surfaces of the two adjacent conductive substrates 422 was 10 mm.

Next, a film forming procedure will be described. First, the inside of the chamber 411 was exhausted by the exhaust system 413 until the degree of vacuum became 1 × 10 ⁻² Pa. Next, the gas supply valve 434 was opened, and hydrogen gas as a dilution gas was introduced. The gas flow rate was adjusted with MFC433. Thereafter, the opening degree of the exhaust adjustment valve 415 was adjusted, and the processing gas pressure in the chamber 411 was set to 400 Pa.

  Next, a voltage of −100 V was applied to the cathode 420 by the plasma power source 416. When voltage was applied, glow discharge was generated around the cathode 420 to heat the cathode. The output of the plasma power supply was increased and the substrate temperature was adjusted to 350 ° C.

Next, when hexane (C ₆ H ₁₄ ) and tetramethylsilane (TMS, Si (CH ₃ ) ₄ ), which are source gases, were introduced, an amorphous carbon film grew on the surface of the conductive substrate 422. The film forming temperature was 350 ° C. A radiation thermometer was used to measure the substrate temperature. The flow rates of the mixed gas were hexane: 11.5 sccm: tetramethylsilane (TMS): 10 sccm, and hydrogen gas: 100 sccm.

The state of glow discharge during film formation is shown in FIG. D represents the distance between the opposing surfaces of the conductive substrate. Around the conductive substrate 422, a sheath 425 having a sheath width S was formed along the conductive substrate 422. The sheath 425 approached between the opposing surfaces, and a negative glow 424 overlapped at a portion indicated by 426. A portion indicated by 426 is a glow discharge brighter than a portion where other negative glows 424 do not overlap. The discharge was stabilized by overlapping the negative glow, resulting in a glow discharge with a low voltage and high current density.

  By discharging for 40 minutes, an amorphous carbon film having a thickness of 3 μm was formed on the surface of the conductive substrate 422.

The silicon content of this amorphous carbon coating was 13 atomic% (total). Silicon content was measured by Rutherford backscattering analysis (RBS) / hydrogen forward scattering analysis (HFS).
(Oxidation treatment of amorphous carbon coating)
The surface of the amorphous carbon film obtained above was subjected to UV ozone treatment.

  The UV treatment device capable of performing UV ozone treatment is equipped with a general-purpose UV cleaning and reforming device OC2506 (manufactured by synthetic quartz glass arc tube 25W (model QOL25SY) 6 lamps), batch-type treatment. ) Was used.

The UV-ozone treatment using the ultraviolet treatment apparatus was performed for 30 minutes under the condition of ultraviolet illuminance of about 5 mW / cm ² .
(Evaluation of oxidized surface)
The surface of the amorphous carbon film subjected to the UV ozone treatment was subjected to XPS analysis to check whether silanol groups were formed.

  FIG. 5 shows a graph representing the surface analysis result of the oxidized surface. The peak shown on the left side of FIG. 5 is the XPS analysis result of the amorphous carbon film subjected to the UV ozone treatment, and the peak shown on the right side of FIG. 5 is the XPS analysis result of the untreated product. The peak shown on the right side shows the peak of Si—C group and Si—CH group, and the peak shown on the left side shows the peak of the oxidized functional group of Si. From this, it was observed that the peak moved to the left side of the figure as shown by the arrow in FIG. 5 by UV ozone treatment. From this, it was confirmed that an oxidized functional group of Si containing a Si—OH group was formed on the surface by UV ozone treatment.

(Shear test)
A shear test was performed to measure the shear strength between the amorphous carbon coating and the adhesive. FIG. 6 is an explanatory diagram for explaining the shape of the shear test piece.
(Preparation of amorphous carbon coating specimen for shear test)
A conductive base (thickness 3 mm, width 10 mm, length 50 mm) made of aluminum alloy 3003 was used as the lower shear test piece shown in FIG. 6, and an amorphous carbon film was formed in the same manner as described above.
An amorphous carbon film having a thickness of 3 μm and a silicon content of 13 atomic% could be formed.
(Preparation of bright Ni plating test piece for shear test)
A bright Ni plating was applied to a copper C1100 base (thickness 3 mm, width 10 mm, length 50 mm) to obtain an upper shear test piece shown in FIG.
(Surface oxidation treatment)
The upper and lower shear test pieces were subjected to UV ozone treatment for 30 minutes at an irradiation distance of 40 mm using a UV ozone treatment apparatus (general type UV cleaning / modification apparatus OC2506 manufactured by Iwasaki Electric Co., Ltd.).

Example 1
(Adjustment of silane coupling agent coating solution)
3-glycidoxypropyltrimethoxysilane (Z-6040 manufactured by Toray Dow Corning Co.), which is an epoxy silane coupling agent, is used as a raw material, and a mixed solution of acetic acid and ethanol (acetic acid: ethanol = 7: 2) at room temperature. ) To obtain a coating solution (pH about 4) having a solid content concentration of 0.5 wt%.
(Formation of silane coupling layer)
The upper and lower test pieces treated with UV ozone were immersed in the coating solution and pulled up to apply the silane coupling agent, followed by heat drying at 100 ° C. for 30 minutes and cooling to room temperature. Next, excess silane coupling agent was washed away with ethanol and dried again.
(Shear test piece preparation)
A high thermal conductivity epoxy adhesive (CT2512 manufactured by Kaken Tech Co., Ltd.) is applied to the obtained upper test piece and lower test piece with a dispenser, combined as shown in FIG. 6, and heat-cured at 180 ° C. for 1 hour. A shear test piece of Example 1 was obtained.

(Example 2)
(Adjustment of silane coupling agent coating solution)
Application using 3-aminopropyltrimethoxysilane (Z-6610 manufactured by Toray Dow Corning Co., Ltd.), which is an amino silane coupling agent, as a raw material, diluted with pure water at room temperature, and having a solid content concentration of 0.5 wt% Liquid.

  A shear test piece of Example 2 was produced in the same manner as in Example 1 except that the silane coupling agent coating solution was changed to the above coating solution.

(Comparative Example 1)
A shear test piece of Comparative Example 1 was produced in the same manner as in Example 1 except that the silane coupling layer was not formed.
(Shear test result)
In order to confirm the adhesive improvement effect, the high-temperature and high-humidity test was performed using the shear test pieces of Example 1, Example 2, and Comparative Example 1, and compared with the initial value.
(Initial shear tensile test)
The shear tensile strength of the shear test piece was measured at a test speed of 0.2 mm / min using an autograph manufactured by Shimadzu Corporation, and the initial adhesive strength was evaluated by the measured value of the shear tensile strength.
(Shear tensile test after leaving at high temperature and high humidity)
Moisture resistance was evaluated from the shear tensile strength measured in the same manner as in the initial shear tensile test after leaving the shear test piece in a constant temperature and humidity chamber at 85 ° C. and 85% RH for 500 hours.

  FIG. 7 shows a graph comparing the shear test strengths of Example 1, Example 2 and Comparative Example 1. Moreover, the photograph which observed the surface of the test piece after a shear test visually is shown in FIG.

  The initial shear strengths of Example 1, Example 2, and Comparative Example 1 were all about 9 to 10 MPa. After leaving at high temperature and high humidity, the shear strength of the test piece of Comparative Example 1 was significantly reduced to 0.4 MPa, whereas the shear strength after leaving high temperature and high humidity in Example 1 was 6.6 MPa, which was the high temperature of Example 2. The shear strength after leaving at high humidity was not so low as 8.6 MPa.

  Further, from FIG. 8, in the test piece after being left at high temperature and high humidity in Comparative Example 1, no white layer of adhesive was observed on the black surface of the amorphous carbon coating, and the fracture surface was the same as that of the amorphous carbon coating. It was found to be an interface with the resin layer. On the other hand, in the test pieces after leaving at high temperature and high humidity in Example 1 and Example 2, the black surface of the amorphous carbon film is covered with the white surface of the resin, and the fracture surface is in the vicinity of the Ni plating side. I understood.

  From this, it was found that in Example 1 and Example 2, the amorphous carbon film and the adhesive were firmly adhered.

Explanatory drawing about the silane coupling reaction through a silane coupling agent is shown. The schematic cross section of the semiconductor device of this invention is shown. An explanatory view of a film forming apparatus using a DC plasma CVD method is shown. The state of glow discharge during film formation is shown. The graph showing the surface analysis result of an oxidation process surface is shown. Explanatory drawing explaining the shape of a shear test piece is shown. The graph which compares the shear test intensity | strength of Example 1, Example 2, and the comparative example 1 is shown. The observation photograph of the shear test piece after a test is shown.

Explanation of symbols

1: heat dissipation member, 2: base material, 3: amorphous carbon coating, 4: bonding layer, 5: wiring member,
6: solder, 7: semiconductor element, 10: semiconductor device, 400: film forming device,
411: chamber, 413: exhaust system, 416: plasma power source, 420: cathode,
422: conductive substrate, 430: gas supply means.

Claims (14)

A substrate having thermal conductivity;
An insulating amorphous carbon film that is coated on at least a part of the surface of the base material and contains silicon as a main component and silicon that is present more in the surface layer portion on the side opposite to the base material than on the base material side;
A bonding layer made of a resin containing M (M = Si, Ti, Al, or Zr) fixed to the surface of the amorphous carbon film and bonded to Si-OM bond with silicon in the amorphous carbon film;
A heat dissipating member comprising:   The heat radiating member according to claim 1, wherein a thickness of the surface layer portion is 0.01 μm or more and 10 μm or less.   3. The heat radiating member according to claim 2, wherein the silicon content of the surface layer portion is 5 atomic% to 50 atomic% when all the components of the surface layer portion are 100 atomic%.   The silicon content of the portion of the amorphous carbon film excluding the surface layer is 1 atomic% to 20 atomic% when the total components of the amorphous carbon film are 100 atomic%, and the hydrogen content is 20 The heat radiating member according to any one of claims 2 and 3, wherein the heat radiating member is in a range of -60 atomic%.   The heat radiating member according to claim 1, wherein the amorphous carbon film and the bonding layer are chemically bonded by a coupling reaction via a coupling agent.   The heat radiating member according to claim 1, wherein the amorphous carbon film is formed by a direct-current plasma CVD method.   A semiconductor device comprising: the heat radiating member according to claim 1; and a semiconductor element mounted on the bonding layer of the heat radiating member via a wiring member.   The semiconductor device according to claim 7, wherein the semiconductor element is a power device or a semiconductor chip of a large-scale integrated circuit. Forms an insulating amorphous carbon coating containing carbon as the main component and silicon, which is present more in the surface layer on the side opposite to the base than on the base, on at least part of the surface of the base that has thermal conductivity An amorphous carbon film forming step,
A surface oxidation step of oxidizing the surface of the amorphous carbon film to form a silanol group;
A fixing step of fixing the amorphous carbon film and an adhesive made of resin through a coupling agent;
The manufacturing method of the heat radiating member characterized by having. Forms an insulating amorphous carbon coating containing carbon as the main component and silicon, which is present more in the surface layer on the side opposite to the base than on the base, on at least part of the surface of the base that has thermal conductivity An amorphous carbon film forming step,
A surface oxidation step of oxidizing the surface of the amorphous carbon film to form a silanol group;
The silanol group on the surface of the amorphous carbon coating is reacted with the -MX group (M = Si, Ti, Al or Zr; X = hydrolyzable substituent or hydrophilic group) of the adhesive made of resin. Fixing step of fixing the amorphous carbon film and the adhesive,
The manufacturing method of the heat radiating member characterized by having.   The method for manufacturing a heat dissipation member according to claim 9 or 10, wherein the oxidation treatment is UV treatment, plasma treatment, or corona treatment.   The heat radiating member manufactured with the manufacturing method of Claim 9 or 10. Forms an insulating amorphous carbon coating containing carbon as the main component and silicon, which is present more in the surface layer on the side opposite to the base than on the base, on at least part of the surface of the base that has thermal conductivity An amorphous carbon film forming step,
A surface oxidation step of oxidizing the surface of the amorphous carbon film to form a silanol group;
A fixing step of fixing the amorphous carbon film and an adhesive made of resin through a coupling agent;
A wiring material bonding step of bonding a low thermal expansion wiring material to the surface of the adhesive;
A semiconductor element fixing step of fixing a semiconductor element using solder on the wiring material;
A method for manufacturing a semiconductor device, comprising: Forms an insulating amorphous carbon coating containing carbon as the main component and silicon, which is present more in the surface layer on the side opposite to the base than on the base, on at least part of the surface of the base that has thermal conductivity An amorphous carbon film forming step,
A surface oxidation step of oxidizing the surface of the amorphous carbon film to form a silanol group;
The silanol group on the surface of the amorphous carbon coating is reacted with the -MX group (M = Si, Ti, Al or Zr; X = hydrolyzable substituent or hydrophilic group) of the adhesive made of resin. Fixing step of fixing the amorphous carbon film and the adhesive,
A wiring material bonding step of bonding a low thermal expansion wiring material to the surface of the adhesive;
A semiconductor element fixing step of fixing a semiconductor element using solder on the wiring material;
A method for manufacturing a semiconductor device, comprising: