JP2016219600A - Die attach paste for semiconductor and semiconductor device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a die attach paste that suppresses bleed-out, prevents dripping and bleeding, and has excellent storage stability and workability, and a reliable semiconductor device.SOLUTION: The die attach paste for semiconductor is improved in thixotropic properties by including as essential components an epoxy resin, a hardening agent, a hardening accelerator, a polymer ion dispersant containing polycarboxylic acid as a main skeleton, and a spherical filler. The semiconductor device is formed by fixing a semiconductor element 2 and a lead frame 1 through an adhesive layer 3 formed by hardening the die attach paste for semiconductor.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a die attach paste for semiconductor used when bonding and fixing a semiconductor element on a support member such as a metal frame, and a semiconductor device obtained using the same.

  Conventionally, semiconductor elements such as IC and LSI are mounted on a metal piece called a lead frame and fixed with an adhesive called Au / Si eutectic method or die attach paste, and then the lead part of the lead frame and the semiconductor element These electrodes are generally connected to each other by a fine wire (bonding wire), and then these are housed in a package to obtain a semiconductor product. Moreover, in order to express the performance requested | required according to the objective, the 1 type or several types of additive is used for the die attach paste according to the use.

  Here, when the thixotropic property of the die attach paste is low, a phenomenon called so-called bleed out occurs in which the resin component contained in the paste oozes out to the substrate depending on the state of the substrate surface. In order to solve this problem, a technique is known in which silicone rubber fine powder or silica particles are added as an additive in order to sufficiently develop thixotropic properties, thereby suppressing the occurrence of bleeding out and improving workability. (See Patent Documents 1 and 2).

  Further, in the thermosetting resin, by containing a specific amount of cellulose resin, it is excellent in thixotropic property and has good coating suitability, so-called conductive filler oozes out together with the resin in the conductive paste to the substrate. A technique for suppressing bleed-out is known (see Patent Document 3).

  In addition, a technique for suppressing bleed-out to a substrate by improving the affinity between the resin and the filler by adding an organotitanium compound containing 憐 atoms in the molecule is also known (see Patent Document 4). ).

  In addition, for the purpose of imparting thixotropic properties, it is known to use fatty acid amide wax or bentonite as an additive (see Patent Document 5),

  Although not related to suppression of bleed out, it is known to use a polymeric ionic dispersant as an additive in the conductive paste for the purpose of enhancing the dispersibility of the conductive powder in the conductive paste. (See Patent Document 6).

JP-A-5-335353 JP-A-7-102225 JP 2012-84440 A JP 2008-283199 A International Publication No. 2005/108493 JP 2010-135180 A

  However, since the additives as described above are often added as powders, dispersion into the added resin is a very important factor. When a poor dispersion occurs, there is a risk that a sufficient effect cannot be obtained or a defect such as a poor appearance occurs.

  Even when an additive is added to the thermosetting resin in order to improve the thixotropic property of the resin composition, the present invention exhibits excellent dispersibility, prevents bleeding and bleeding by suppressing bleeding out, It is another object of the present invention to provide a die attach paste having excellent storage stability and workability, and to provide a highly reliable semiconductor device using such a die attach paste.

  As a result of diligent research to solve the above problems, the present invention has found that a die attach paste containing an epoxy resin containing a specific additive as a main component can achieve the above object. It came to complete.

  That is, the die attach paste for semiconductor of the present invention comprises (A) an epoxy resin, (B) a curing agent, (C) a curing accelerator, and (D) a polymer ionic dispersion having a polycarboxylic acid as a main skeleton. An agent and (E) a spherical filler are contained as essential components.

  The semiconductor device of the present invention is a semiconductor device in which a semiconductor element is fixed on a support member, and the semiconductor element and the support member are fixed via the semiconductor die attach paste. Features.

The die attach paste for semiconductor of the present invention is a die attach paste having excellent workability and storage stability and good adhesiveness, and is suitable for semiconductor bonding applications.
According to the semiconductor device of the present invention, the semiconductor element is bonded onto the support substrate using the semiconductor die attach paste having the above characteristics, and a highly reliable semiconductor device with high solder reflow resistance can be obtained. .

It is sectional drawing which shows the semiconductor device which is one Embodiment of this invention.

  Hereinafter, the die attach paste for semiconductor of the present invention, the manufacturing method thereof, and the semiconductor device will be described in detail.

  As described above, the semiconductor die attach paste of the present invention contains the components (A) to (E) as essential components. First, these essential components will be described.

  The (A) epoxy resin used in the semiconductor die attach paste of the present invention is not particularly limited as long as it is a known epoxy resin having two or more epoxy groups in one molecule. That is, any epoxy resin that exhibits adhesiveness can be used without limitation.

  As this (A) epoxy resin, for example, bisphenol A type epoxy resin, bisphenol F type epoxy resin, biphenyl type epoxy resin, novolac type epoxy resin, polyfunctional type epoxy resin, alicyclic epoxy resin, aliphatic epoxy resin, Naphthalene type epoxy resin, glycidyl modified polybutadiene resin, glycidyl modified triazine resin, aminophenol type epoxy resin, flexible epoxy resin, methacrylic modified epoxy resin, acrylic modified epoxy resin, dicyclopentadiene type epoxy resin, and the like. This (A) epoxy resin may be used individually by 1 type, and may use 2 or more types together.

  The (A) epoxy resin is preferably liquid at normal temperature, but may be solid at normal temperature. When the epoxy resin is solid, it can be diluted with another liquid epoxy resin or a reactive diluent or solvent and used in a liquid state.

  In addition, it is preferable that the said (A) epoxy resin contains 2-45 mass% of flexible epoxy resins in resin, Especially as a flexible epoxy resin, an epoxy equivalent is a flexible of the range of 200-2000. It is preferable that it is a conductive epoxy resin.

  A die attach paste for semiconductors with good workability can be obtained by including 2 to 45 mass% of the flexible epoxy resin in the epoxy resin (A). If the amount of the flexible epoxy resin is less than 2% by mass, the adhesive strength may be inferior. If the amount of the flexible epoxy resin is more than 45% by mass, the dispensing property may be inferior.

  Specific examples of this flexible epoxy resin include diglycidyl ether of polyethylene glycol, diglycidyl ether of polypropylene glycol, polyoxyalkylene glycol and polytetraalkylene containing an alkylene group having 2 to 9 carbon atoms (preferably 2 to 4 carbon atoms). Polyglycidyl ethers of long-chain polyols including methylene ether glycol, copolymers of glycidyl (meth) acrylate and radical polymerizable monomers such as ethylene, vinyl acetate or (meth) acrylate, (co) of conjugated diene compounds Epoxidized unsaturated carbon bond in polymer or its partially hydrogenated (co) polymer, polyester resin having epoxy group, urethane modified epoxy or polycaprolactone introduced with urethane bond or polycaprolactone bond Epoxy resin, dimer acid-modified epoxy resin in which epoxy group is introduced into the molecule of dimer acid or derivative thereof, acrylonitrile butadiene rubber (NBR), butadiene-acrylonitrile copolymer rubber (CTBN) having a carboxyl group at the terminal, polybutadiene, acrylic Examples thereof include rubber-modified epoxy resins having an epoxy group introduced into the molecule of a rubber component such as rubber.

（式中、ｎは繰り返し単位数を表し、１〜１０の整数である。Ａは（ＣＨ_２）_ｒのアルキレン基であって、ｒは繰り返し単位数を表し、１〜２０の整数である。ＢはＣＨ_２及びＣ（ＣＨ_３）_２から選ばれる有機基である。）で示されるエポキシ樹脂が挙げられる。 As a more specific example, the following general formula (1)

(In the formula, n represents the number of repeating units and is an integer of 1 to 10. A is an alkylene group of (CH ₂ ) _r , and r represents the number of repeating units and is an integer of 1 to 20. B is an organic group selected from CH ₂ and C (CH ₃ ) ₂ ).

  Specific examples include YL7175-500 (trade name; epoxy equivalent 487), YL7150-1000 (trade name; epoxy equivalent 1000) manufactured by Mitsubishi Chemical Corporation, and DIC Corporation, which is a bisphenol A-type modified epoxy resin. EP-4003 (trade name; epoxy equivalent 412), EP-4000S (trade name; epoxy equivalent 260), and the like.

  Moreover, in this invention, you may mix | blend resin components other than (A) component in order to improve stress relaxation property, adhesiveness, etc. further. Examples of the resin that can be used in combination include acrylic resin, polyester resin, polybutadiene resin, phenol resin, polyimide resin, silicone resin, polyurethane resin, and xylene resin. These resins may be used alone or in combination with an epoxy resin, or may be used in combination of two or more.

  Thus, when using other resins other than an epoxy resin together, another resin can be mixed to 50 mass parts with respect to 100 mass parts of epoxy resins.

  The (B) curing agent used in the die attach paste for semiconductor of the present invention is a curing agent for epoxy resin, and any known curing agent can be used without particular limitation.

  Examples of the curing agent for component (B) include dicyandiamide, phenol resin, amine compound, latent amine compound, cationic compound, acid anhydride, and special epoxy curing agent. This (B) hardening | curing agent may be used individually by 1 type, and may use 2 or more types of multiple types together. From the viewpoint of curability and adhesiveness, dicyandiamide and phenol resin are more preferable, and it is more preferable to use dicyandiamide and phenol resin in combination.

  The content of the component (B) is not particularly limited, but is preferably in the range of 0.1 to 10 parts by mass for dicyandiamide with respect to a total of 100 parts by mass of the epoxy resin as the component (A). Moreover, in a phenol resin, 5-100 mass parts is preferable with respect to a total of 100 mass parts of the epoxy resin which is (A) component.

  The (C) curing accelerator used in the semiconductor die attach paste of the present invention is not particularly limited as long as it is used as an epoxy resin curing accelerator, and a known curing accelerator can be used.

  Examples of the (C) curing accelerator include imidazole curing accelerators, amine curing accelerators, triphenylphosphine curing accelerators, diazabicyclo curing accelerators, urea curing accelerators, and borate salt curing accelerators. And polyamide curing accelerators. This (C) hardening accelerator may be used individually by 1 type, or may use 2 or more types together. From the viewpoints of curability and adhesiveness, an imidazole curing accelerator and an amine curing accelerator are preferable, and an imidazole curing accelerator is more preferable.

  Specific examples of the imidazole curing accelerator include, for example, 2-methylimidazole, 2-ethylimidazole, 2-isopropylimidazole, 2-n-propylimidazole, 2-undecyl-1H-imidazole, 2-ethyl-4-methyl. Examples include imidazole (2E4MZ), 2-phenyl-4-methylimidazole (2P4MZ), 2-phenyl-4,5-dihydroxymethylimidazole, and 2-phenyl-4-methyl-5-hydroxymethylimidazole.

  Specific examples of the amine curing accelerator include aliphatic amines such as ethylenediamine, trimethylenediamine, tetramethylenediamine, hexamethylenediamine, diethylenetriamine, triethylenetetramine, tetraethylenepentamine; piperidine, piperazine, Cycloaliphatic and heterocyclic amines such as menthanediamine, isophoronediamine, 1,8-diazabicyclo (4.5.0) undecene-7; o-phenylenediamine, m-phenylenediamine, p-phenylenediamine, diaminodiphenylmethane , M-xylenediamine, pyridine, picoline and other aromatic amines; modification of epoxy compound-added polyamine, Michael-added polyamine, Mannich-added polyamine, thiourea-added polyamine, ketone-capped polyamine, etc. Riamin acids; dicyandiamide; guanidine; organic acid hydrazide; diaminomaleonitrile; amine imide; boron trifluoride - piperidine complex; boron trifluoride - such as monoethyl amine complex.

  From the viewpoint of curability, imidazole curing accelerators 2-ethyl-4-methylimidazole (2E4MZ), 2-phenyl-4-methylimidazole (2P4MZ), 2-phenyl-4,5-dihydroxymethylimidazole (2PHZ) 2-phenyl-4-methyl-5-hydroxymethylimidazole (2P4MHZ) is more preferred.

  Although content of this (C) component is not restrict | limited in particular, 0.5-2.0 mass parts is preferable with respect to a total of 100 mass parts of the epoxy resin which is (A) component.

  The polymer ionic dispersant (D) having a polycarboxylic acid as the main skeleton used in the semiconductor die attach paste of the present invention has a hydrocarbon chain or an ether bond (-O-) in which oxygen is interposed in the hydrocarbon chain. A compound having a main chain and having two or more carboxyl groups. Moreover, the mass average molecular weight is 500 or more.

  In addition, (D) the polymeric ionic dispersant has a mass average molecular weight in the range of 500 to 10000, because workability such as dispensing properties is improved, and is preferably in the range of 1000 to 3000.

  In addition, (D) the polymeric ionic dispersant has a large number of carboxyl groups, so that the hydrogen atoms are dissociated in the dispersion medium to become negative ions and exhibit anionic properties. The acid value of this (D) polymer ionic dispersant is preferably 10 to 300 mgKOH / g. If the acid value is less than 10 mgKOH / g, the dispersibility may be poor and sufficient thixotropic properties may not be obtained, and if it exceeds 300 mgKOH / g, the storage stability may be poor.

  This (D) polymeric ionic dispersant imparts sufficient thixotropic properties to the die attach paste by adsorbing to the surface of the filler contained in the die attach paste to form a crosslinked structure. is there. Therefore, even if the die attach paste is applied to the substrate surface that is the support member, the occurrence of dripping or bleeding can be effectively suppressed. And the effect that sedimentation of a filler can be prevented and dispersion stability improves is also acquired.

  That is, the inclusion of the dispersant improves the dispersibility of the filler and improves the workability, storage stability (pot life), and bleed resistance of the die attach paste.

  Examples of the polymer ionic dispersant (D) include, for example, Aron A-6330 (trade name, manufactured by Toa Gosei Co., Ltd.), Hypermer KD-4, Hypermer KD-8, Hypermer KD-9 (above, Croda Japan Co., Ltd.) Company name, product name), and the like.

（式中、ｐ及びｍは繰り返し単位数を表し、ｐは１〜２０、ｍは１〜５の整数である。
Ｒ^１は置換基を有してもよい炭素数１〜１０のアルキル基を含む１価の有機基である。）で表されるものが好ましく、具体的には、Ｈｙｐｅｒｍｅｒ ＫＤ−４、Ｈｙｐｅｒｍｅｒ ＫＤ−８、Ｈｙｐｅｒｍｅｒ ＫＤ−９（以上、クローダジャパン社製、商品名）を挙げることができる。 Especially, the following general formula (2)

(In formula, p and m represent the number of repeating units, p is 1-20, m is an integer of 1-5.
R ¹ is a monovalent organic group containing a C 1-10 alkyl group which may have a substituent. ) Are preferred, and specific examples include Hypermer KD-4, Hypermer KD-8, and Hypermer KD-9 (trade name, manufactured by Croda Japan Co., Ltd.).

  The content of the polymer ionic dispersant (D) is preferably 0.01 to 10% by mass in 100% by mass of the die attach paste. When the content is less than 0.01% by mass, the storage stability may be lowered. When the content is more than 10% by mass, the viscosity becomes high and workability such as dispensing property may be lowered.

  The (E) spherical filler used in the die attach paste for semiconductors of the present invention is not particularly limited as long as it is a known spherical filler used in die attach paste. The (E) spherical filler may be either conductive or non-conductive, and is selected according to its application.

  As this (E) spherical filler, as the conductive material, spherical silver powder such as spherical silver powder, spherical copper powder and spherical aluminum powder, spherical silver-coated powder such as spherical silver-coated copper powder and spherical silver-coated inorganic particles Moreover, metal oxide powders, such as spherical silica powder, spherical alumina powder, and spherical titania powder, can be cited as non-conductive ones. Of these, spherical silver powder and spherical silver-coated powder are preferable as the conductive filler, and spherical silica powder and spherical alumina powder are preferably used as the non-conductive filler.

The (E) spherical filler preferably has an average particle size of 1 to 30 μm. When this average particle diameter is smaller than 1 μm, the viscosity of the resin composition increases, and workability may be reduced. On the other hand, if the average particle size is larger than 30 μm, there is a possibility that nozzle clogging may occur at the syringe tip during dispensing. The average particle size here is the volume-based particle size distribution by a laser diffraction scattering particle size distribution measuring method, a 50% cumulative value D _50.

  In addition, in this specification, the spherical shape of the spherical filler (E) means that the aspect ratio defined by (the maximum long diameter of the particles / the width orthogonal to the maximum long diameter) is in the range of 1.0 to 1.2. is there.

  By using spherical particles having an aspect ratio in this range, even when the content is increased, the viscosity is hardly increased and workability is not adversely affected. Furthermore, a resin composition having excellent storage stability compared to flaky particles and irregularly shaped particles can be obtained. If the aspect ratio is greater than 1.2, the filling rate may be reduced, and the intended function may not be exhibited.

  Moreover, in this invention, it is preferable to use spherical silver coating powder as (E) spherical filler. By using the spherical silver-coated powder, the specific gravity of the die attach paste for semiconductor can be made smaller than when the spherical silver powder is used alone. The application mass of the die attach paste for semiconductor per unit use volume can be reduced, and since the amount of silver used is reduced, there is an effect of reducing the manufacturing cost of the semiconductor device.

  Here, the specific gravity of the (E) spherical filler is preferably 2.0 to 5.0. When the specific gravity is within this range, a die attach paste that suppresses sedimentation and has excellent dispersibility can be obtained.

  The manufacturing method of this (E) spherical filler should just apply the manufacturing method of a well-known spherical particle according to the raw material to be used. For example, in the case of metal powder, a spray method using a gas as a spray medium, a centrifugal spray method in which a molten metal is dropped on a rotating disk at a high speed, metal powder and metal oxide powder in a high temperature region such as plasma. Examples thereof include a method of solidifying after melt spheroidization. Moreover, if it is a metal oxide powder, it can be manufactured by the spraying spheroidization method by a flame, the sol-gel method, etc.

  In addition, spherical silver-coated powder, etc., the surface of inorganic particles and heat-resistant resin particles such as spherical silica powder and alumina powder obtained as described above, vapor deposition method, sputtering method, electroplating method, displacement plating method, It can be obtained by performing a coating treatment with silver using an electroless plating method or the like. Furthermore, by using spherical particles with an aspect ratio in the above range as the core, the surface of the particles can be uniformly coated as compared with flakes and irregular shapes, so there are problems such as peeling of the coated silver and cracks There is an effect that is difficult to occur.

  (E) It is preferable to contain 30-90 mass% of spherical fillers in the die attach paste of this invention. When the content of the component (E) is less than 30% by mass, the paste viscosity may be reduced, and workability may be reduced due to liquid dripping at the time of dispensing. The workability is likely to be insufficient.

  As described above, the die attach paste for semiconductor of the present invention has thixotropic properties by using a combination of (D) a polymeric ionic dispersant having a polycarboxylic acid as a main skeleton and (E) a spherical filler. It is a resin composition that is good and suppresses bleeding.

  In the present invention, (F) a coupling agent may be further contained. The coupling agent used here is not particularly limited as long as it is a known coupling agent that modifies the surface of the filler.

  Examples of the coupling agent (F) include 3-methacryloxypropyltrimethoxysilane, 3-acryloxypropyltrimethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, vinyltris (β-methoxyethoxy) silane, β -(3,4-epoxycyclohexyl) ethyltrimethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, 3-aminopropyltriethoxysilane, N-phenyl-3 -Aminopropyltrimethoxysilane, 3-mercaptopropyltrimethoxysilane, titanate coupling agent, aluminum coupling agent, zirconate coupling agent, zircoaluminate coupling agent and the like.

（式中、Ｒ^２及びＲ^３はそれぞれ独立に炭素数１〜４のアルキル基であり、Ｄは置換基を有してもよい炭素数３〜１２の２価の炭化水素基又は該炭化水素基の主鎖において酸素原子が挿入されたエーテル結合を有する有機基であり、ｑは１〜３の整数である。）で表されるエポキシ基を含有するエポキシシランカップリング剤が好ましく用いられる。 Especially, the following general formula (3)

(In the formula, R ² and R ³ each independently represent an alkyl group having 1 to 4 carbon atoms, and D represents a divalent hydrocarbon group having 3 to 12 carbon atoms which may have a substituent or the hydrocarbon. An epoxy silane coupling agent containing an epoxy group represented by the formula (1) is an organic group having an ether bond having an oxygen atom inserted in the main chain of the group, and q is an integer of 1 to 3.

Here, examples of R ² and R ³ include a methyl group, an ethyl group, a propyl group, an isopropyl group, an n-butyl group, a sec-butyl group, a tert-butyl group, and the like. Good. R ² is preferably a methyl group or an ethyl group. R ³ is preferably a methyl group.

  Examples of the divalent organic group for D include a hydrocarbon group or an organic group having an ether bond (—O—) with oxygen interposed in the main chain of the hydrocarbon group. The divalent organic group represented by D preferably has 3 to 12 carbon atoms. When the carbon number is 3 or more, the adhesiveness of the die attach paste, in particular, the adhesiveness at high temperature and the adhesiveness at high temperature after moisture absorption are improved. Moreover, when carbon number is 12 or less, the viscosity of a die attach paste becomes low and a dispersibility becomes favorable. As for this carbon number, 5-12 are more preferable, and 7-12 are more preferable.

The hydrocarbon group of D is preferably an alkylene group having 3 to 12 carbon atoms, and the organic group having an ether bond is —C ₆ H ₁₂ —O—CH ₂ — or —C ₈ H ₁₆ —O—. CH ₂ —, —C ₁₀ H ₂₀ —O—CH ₂ — and the like are preferable. In the divalent hydrocarbon group of D, one or more hydrogen atoms may be substituted with a halogen atom such as a fluorine atom or a chlorine atom. As q, 2 or 3 is preferable, and 3 is more preferable.

  (F) As for content of the coupling agent which is a component, the range of 0.01-5 mass% is preferable in the die-attach paste for semiconductors, and the range of 0.05-4 mass% is more preferable. If it is less than 0.01% by mass, the effect of improving the adhesiveness cannot be obtained, and if it exceeds 5% by mass, a bleeding phenomenon may occur at the time of applying the paste, such being undesirable.

  Furthermore, the die attach paste for semiconductors of the present invention can contain a diluent for the purpose of improving workability. As a diluent, in addition to solvents, a (meth) acrylate compound can be used.

  Examples of the solvent include diethylene glycol diethyl ether, n-butyl glycidyl ether, t-butylphenyl glycidyl ether, allyl glycidyl ether, 2-ethylhexyl glycidyl ether, styrene oxide, phenyl glycidyl ether, cresyl glycidyl ether, dioxane, hexane, methyl Cellosolve, cyclohexane, butyl cellosolve, butyl cellosolve acetate, butyl carbitol, butyl carbitol acetate, diethylene glycol dimethyl ether, diacetone alcohol, N-methylpyrrolidone, dimethylformamide, dimethylacetamide, γ-butyrolactone, and 1,3-dimethyl-2-imidazo Lysinone and the like can be mentioned.

  Examples of (meth) acrylate compounds include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, and 2-hydroxybutyl (meth) aglycerin mono (meth) acrylate. Glycerin di (meth) acrylate, trimethylolpropane mono (meth) acrylate, trimethylolpropane di (meth) acrylate, pentaerythritol mono (meth) acrylate, pentaerythritol di (meth) acrylate, pentaerythritol tri (meth) acrylate, (Meth) acrylate having a hydroxyl group such as neopentyl glycol mono (meth) acrylate, methyl (meth) acrylate, ethyl (meth) acrylate, n-butyl (meth) acrylate Relate, isobutyl (meth) acrylate, t- butyl (meth) acrylate, 3-hydroxybutyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, and the like. These may be used individually by 1 type, and may mix and use 2 or more types.

  This diluent is preferably added to the die attach paste for semiconductor in an amount of 1 to 20% by mass, and the viscosity at 25 ° C. is preferably in the range of 5 to 200 Pa · s.

  This die attach paste includes (A) an epoxy resin, (B) a curing agent, (C) a curing accelerator, (D) a polymer ionic dispersant having a polycarboxylic acid as a main skeleton, and (E) a spherical filling. After mixing the material and (F) silane coupling agent, diluent and other components blended as necessary using a high speed mixer, etc., using a disperse, kneader, three rolls, etc. It can be easily prepared by kneading and then defoaming.

  The die attach paste for semiconductors of the present invention is excellent in storage stability at room temperature, has little stringing and liquid dripping at the time of dispensing, and is excellent in workability because there is little oozing to the support member. Also, a combination of a semiconductor element and a copper frame has excellent adhesive strength.

  The semiconductor device of the present invention can be manufactured by a known method using the semiconductor die attach paste. For example, a semiconductor element is mounted on a lead frame or the like as a supporting member via the die attach paste for semiconductor of the present invention, and the die attach paste is heated and cured at 200 ° C. for 2 minutes, and then the lead frame lead. The part and the electrode on the semiconductor element are connected by wire bonding, and then these are sealed with a sealing resin.

  Examples of the bonding wire include wires made of copper, gold, aluminum, gold alloy, aluminum-silicon, and the like. Moreover, the temperature at the time of hardening an electrically conductive paste is 100-230 degreeC normally, Preferably it is 100-200 degreeC, and when using a copper lead frame, 190 degrees C or less is especially preferable, and heating time Is preferably about 0.5 to 2 hours.

  FIG. 1 shows an example of the semiconductor device thus obtained. In this semiconductor device, a lead frame 1 such as a copper frame or PPF (palladium preplenting lead frame) and a semiconductor element 2 are bonded together via an adhesive layer 3 that is a cured product of the die attach paste for semiconductor of the present invention. It has been fixed. Further, the electrode 4 on the semiconductor element 2 and the lead portion 5 of the lead frame 1 are connected by a bonding wire 6, and these are further sealed by a sealing resin 7. In addition, as thickness of the adhesive bond layer 3, about 10-30 micrometers is preferable.

In the above description, the lead frame is exemplified as the support member of the semiconductor element. However, the lead frame is not limited as long as it is a target to which the semiconductor element is fixed, and can be applied to, for example, a circuit board or a heat dissipation member.
The semiconductor device of the present invention has good solder reflow resistance and high reliability.

  EXAMPLES Hereinafter, although an Example demonstrates this invention, this invention is not limited to these Examples.

<Examples 1 to 10, Comparative Examples 1 to 4>
Each component was sufficiently mixed at a blending ratio shown in Tables 1 and 2, and kneaded with three rolls to prepare a semiconductor die attach paste. After defoaming this semiconductor die attach paste with a vacuum pump, various performances were evaluated. Each component used is as follows.

(A) Epoxy resin / epoxy resin 1: flexible epoxy resin (YL7175-500, manufactured by Mitsubishi Chemical Corporation; epoxy equivalent 487)
Epoxy resin 2: bisphenol A type epoxy resin (EP828, manufactured by Mitsubishi Chemical Corporation; epoxy equivalent 185)
Epoxy resin 3: bisphenol F type epoxy resin (YL983U, manufactured by Mitsubishi Chemical Corporation; epoxy equivalent 170)

(B) Curing agent / curing agent 1: bisphenol F (manufactured by Honshu Chemical Industry Co., Ltd.)
Curing agent 2: Diciadiamide (DICY)
(C) Curing accelerator / curing accelerator: 2-ethyl-4-methylimidazole (2E4MZ, manufactured by Shikoku Kasei Kogyo Co., Ltd.)

(D) Polymeric ionic dispersant / polymeric ionic dispersant having a polycarboxylic acid as a main skeleton 1: Hypermer KD-4 (trade name; mass-average molecular weight 1700, acid value 33 mgKOH / g, manufactured by Croda Japan Co., Ltd.) )
-Polymeric ionic dispersant 2: Hypermer KD-8 (trade name; mass average molecular weight 1700, acid value 33 mgKOH / g, manufactured by Croda Japan Co., Ltd.)
Polymeric ionic dispersant 3: Hypermer KD-9 (trade name; mass-average molecular weight 760, acid value 74 mgKOH / g, manufactured by Croda Japan Co., Ltd.)
Other dispersants

(Other dispersants and additives)
Additive 4: Fumed silica (manufactured by Nippon Aerosil Co., Ltd., trade name: R972)
Dispersant 5: Polyester-modified polydimethylsiloxane (manufactured by Big Chemie Japan, trade name: BYK-310)
-Dispersant 6: Hypermer KD-2 (trade name; polyamine main skeleton polymer ion dispersant, mass average molecular weight 2000, base equivalent 1725 meq / kg, manufactured by Croda Japan Co., Ltd.)

(E) Spherical filler / filler 1: spherical silver-coated silica (manufactured by Toyo Aluminum Co., Ltd., trade name: RD10-1204) (D ₁₀ = 2.6 μm, D ₅₀ = 4.3 μm, D ₉₀ = 6.9 μm) , Specific gravity 2.88, silver content 30% by mass)
Filler 2: Spherical silver-coated copper powder (Fukuda Metal Foil Powder Co., Ltd., trade name: silver-coated Cu-HWQ) (average particle size 4.34 μm, silver content 20 mass%)
Filler 3: spherical fused silica (manufactured by Tatsumori Co., Ltd., trade name: SO-E5; average particle size 1.5 μm)
Filler 4: spherical alumina (manufactured by Showa Denko KK, trade name: CB-P05; average particle size 4.0 μm)

(F) Silane coupling agent / Silane coupling agent: Glycidoxyoctyltrimethoxysilane (manufactured by Shin-Etsu Chemical Co., Ltd., trade name: KBM-4803)

Other components / Reactive diluent: Butyl carbitol acetate (BCA, Wako Pure Chemical Industries, Ltd.)

Various characteristics in each example were determined according to the following methods.
<Characteristics of die attach paste>
1. Viscosity Using an E-type viscometer (3 ° cone) manufactured by Toki Sangyo Co., Ltd., the viscosity was measured at 25 ° C. and 0.5 rpm.

2. Thixotropic (thixotropic)
Using an E-type viscometer (3 ° cone) manufactured by Toki Sangyo Co., Ltd., measuring the viscosity at 25 ° C. and 2.5 rpm, and combining the results of (1) with the ratio of the viscosity measured at different rotational speeds (0.5 rpm viscosity / 2.5 rpm viscosity) was calculated as thixotropic property. The thixotropic property was determined according to the following criteria.
○: 3.5 or more and 7.0 or less ×: Less than 3.5 or more than 7.0

3. After preparing the normal temperature life, the normal temperature viscosity change rate was calculated based on the viscosity measured by thawing the die attach paste for semiconductor that was stored frozen (−20 ° C.) for one day and the viscosity after storing for 72 hours at normal temperature. . Each viscosity was measured using an E-type viscometer (3 ° cone) at 25 ° C. and 0.5 rpm. Moreover, the normal temperature viscosity change rate was calculated by (normal temperature storage viscosity / frozen storage viscosity), and judged according to the following criteria.
○: Room temperature viscosity change rate less than ± 10% △: Room temperature viscosity change rate ± 10 to 20%
×: Room temperature viscosity change rate exceeds ± 20%

4). Leaving bleed: When a die attach paste for semiconductor is applied on a copper frame and left for 24 hours under conditions of a temperature of 25 ° C. and a humidity of 35% RH, ○ indicates no bleed, and × indicates when it occurs. Judged as.

5. Dispensing 10 g of semiconductor die attach paste is filled in a syringe, using a shot master manufactured by Musashi Engineering Co., Ltd., temperature 25 ° C., humidity 35% RH, needle diameter φ = 0.3 mm, discharge pressure 7.85 N (0. A dispense test was performed on the silicon wafer substrate under the conditions of 8 kgf) and a gap of 100 μm. Using an optical microscope, the number of ejection failures was measured by setting the angle collapse due to stringing after 300 shots and no ejection due to syringe clogging or liquid dripping as ejection failure. The dispensing property was calculated from the following formula.
Dispensing property [%] = (300−number of ejection defects) / 300 × 100
Moreover, the obtained dispensing property was determined according to the following criteria.
○: 95% or more △: 90% or more and less than 95% ×: less than 90%

6). Tensile bond strength A die attach paste for semiconductor was applied to a copper frame to a thickness of 20 μm, a 4 mm × 4 mm silicon chip was mounted thereon, and cured at 120 ° C. for 1 hour and 175 ° C. for 1 hour. After curing, a hexagonal nut was mounted on a silicon chip using a two-component quick-drying epoxy adhesive (manufactured by J-B WELD) and cured at 120 ° C. Thereafter, the tensile adhesive strength during heating at 260 ° C. and after moisture absorption was measured using a tensile adhesive strength measuring device (moisture absorption conditions were 85 ° C. and 85% RH for 24 hours and 168 hours).

7). Solder reflow resistance A silicon chip of 4 mm × 4 mm was mounted on a copper frame using the obtained die attach paste, and heat cured at 200 ° C. for 2 minutes. Using this epoxy resin sealing material (trade name: KE-G3000D (K)) manufactured by Kyocera Chemical Co., Ltd., a package formed under the following conditions is subjected to moisture absorption treatment at 85 ° C. and a relative humidity of 60% for 168 hours. After the application, IR reflow treatment (at 260 ° C. for 10 seconds) was performed. After this IR reflow treatment, the occurrence of external cracks (cracks on the package surface) of the package was observed with a microscope (magnification: 15 times), and the number of occurrences was examined. Also, the number of internal cracks in the package was examined with an ultrasonic microscope. The number of samples in which cracks occurred was shown for five samples.

<Molding condition>
80pQFP, 14mm x 20mm x 2mm
Chip size: 4mm x 4mm (surface aluminum wiring only)
Lead frame: Copper Molding of sealing material: 175 ° C, 1 minute Post mold cure: 175 ° C, 6 hours

  As described above, the die attach paste for semiconductors of the present invention has good room temperature life, neglected bleeding, dispensing properties, etc. and good workability. Moreover, it turned out that the hardened | cured material is what was excellent in adhesive strength and reflow resistance. Therefore, a semiconductor device obtained using this semiconductor die attach paste has high reliability.

DESCRIPTION OF SYMBOLS 1 ... Lead frame, 2 ... Semiconductor element, 3 ... Adhesive layer, 4 ... Electrode, 5 ... Lead part, 6 ... Bonding wire, 7 ... Sealing resin

Claims (7)

(A) an epoxy resin;
(B) a curing agent;
(C) a curing accelerator;
(D) a polymeric ionic dispersant having a polycarboxylic acid as a main skeleton;
(E) a spherical filler;
As an essential component, a die attach paste for semiconductors. (D) The polymer ionic dispersant having a polycarboxylic acid as a main skeleton contains a compound represented by the following general formula (2), and 0.1 to 1 in the die attach paste for semiconductor The die attach paste for semiconductor according to claim 1, containing 0.0 mass%.

(In the formula, p and m represent the number of repeating units, p is an integer of 1 to 20, and m is an integer of 1 to 5. R ¹ represents an alkyl group having 1 to 10 carbon atoms which may have a substituent. Containing monovalent organic groups.) The die attach paste for semiconductor according to claim 1 or 2, wherein the epoxy resin (A) contains 2 to 45 mass% of an epoxy resin represented by the following general formula (1).

(In the formula, n represents the number of repeating units and is an integer of 1 to 10. A is an alkylene group represented by (CH ₂ ) _r, where _r represents the number of repeating units and is an integer of 1 to 20) B is an organic group selected from CH ₂ and C (CH ₃ ) ₂ .   The said (E) spherical filler is a spherical particle by which the surface was silver-coated, Comprising: 30-90 mass% is contained in the said die attach paste for semiconductors, The any one of Claims 1-3 characterized by the above-mentioned. The die attach paste for semiconductor as described in the item.   The semiconductor die attach paste according to any one of claims 1 to 4, further comprising (F) a coupling agent. The (F) coupling agent contains 0.1 to 5.0% by mass of an epoxysilane coupling agent represented by the following general formula (3) in the die attach paste for semiconductor. The die attach paste for semiconductor according to claim 5.

(In the formula, R ² and R ³ each independently represent an alkyl group having 1 to 4 carbon atoms, and D represents a divalent hydrocarbon group having 3 to 12 carbon atoms which may have a substituent or the hydrocarbon. An organic group having an ether bond with an oxygen atom inserted in the main chain of the group, q is an integer of 1 to 3.) A semiconductor device in which a semiconductor element is fixed on a support member,
The semiconductor device, wherein the semiconductor element and the support member are fixed via the die attach paste for semiconductor according to any one of claims 1 to 6.

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