JP2013211348A - Chip protection coat formation film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a chip protection coat formation film excellent in adhesiveness with a wafer and capable of satisfactory suppressing warp of the wafer.SOLUTION: A chip protection coat formation film includes a protection coat formation layer 1 containing: a bismaleimide compound having annular imide bond and (a) a bivalent hydrocarbon group derived from dimer acid; a thermal polymerization initiator; and a spherical type inorganic filler having an average particle size of 1-15 μm.

Description

  The present invention relates to a film for forming a protective film for a chip for forming a protective film on the back surface of a semiconductor chip, and in particular, for a chip used for manufacturing a semiconductor chip mounted by a so-called face down method. The present invention relates to a protective film-forming film.

In recent years, semiconductor devices have been manufactured using a so-called face-down mounting method. The face-down method uses a semiconductor chip in which convex portions called bumps for ensuring conduction are formed on the circuit surface side, and the semiconductor chip is mounted on the base so that the circuit surface side is in contact with the base. The method of obtaining a semiconductor device generally includes the following steps (1) to (4).
(1) A circuit is formed on the surface of the semiconductor wafer by an etching method or the like, and bumps are formed at predetermined positions on the circuit surface.
(2) The back surface of the semiconductor wafer is ground to a predetermined thickness.
(3) The back surface of the semiconductor wafer is fixed to a dicing sheet stretched on a ring frame, and a circuit is cut and separated (diced) for each circuit by a dicing saw to obtain a semiconductor chip.
(4) A semiconductor chip is picked up and mounted on a predetermined base by a face-down method, and a semiconductor device is applied by applying resin sealing or resin coating on the back surface of the chip to protect the semiconductor chip as necessary. obtain.

  The grinding in the step (2) is usually performed by mechanical grinding. However, a minute streak may be formed on the back surface of the semiconductor wafer by the mechanical grinding, and such a fine scratch is formed in the step (3). May cause cracks during dicing or after semiconductor device packaging. Therefore, conventionally, it may be necessary to perform chemical etching to remove such fine flaws after the mechanical grinding, which has the problem that equipment costs and operating costs increase, leading to cost increase. It was.

  Examples of the resin sealing in the step (4) include a potting method in which an appropriate amount of resin is dropped and cured on a chip, a molding method using a mold, and the like. However, in the potting method, it is difficult to drop an appropriate amount of resin, and in the molding method, it is necessary to clean the mold. Had. Furthermore, the resin coating has a problem in that it is difficult to uniformly apply an appropriate amount of resin, resulting in variations in quality.

  Therefore, even if a minute scratch is formed on the back surface of the chip by mechanical grinding, it is possible to eliminate the adverse effects caused by the scratch, and a highly uniform protective film can be easily applied to the back surface of the chip. Development of a technique that can be formed is demanded. Examples of such a technique include Japanese Patent Laid-Open No. 2002-280329 (Patent Document 1), Japanese Patent Application Laid-Open No. 2004-214288 (Patent Document 2), and Japanese Patent Application Laid-Open No. 2004-2004. In No. 260190 (Patent Document 3), a protective film forming sheet for a chip comprising a release sheet and a protective film forming layer is attached to the back surface of a semiconductor wafer, and then the protective film forming layer is cured and the semiconductor wafer is diced. Describes a method for manufacturing a semiconductor chip on which a protective film is formed and a protective film-forming sheet for chips. However, in the protective film forming layer described in Patent Documents 1 to 3, it is necessary to contain a binder polymer component in order to form a sheet, and the protection obtained by using such a binder polymer component. When the solvent resistance of the film is lowered or the protective film forming layer is cured, a very small amount of oligomer contained in the binder polymer component is volatilized, thereby contaminating the equipment or the semiconductor chip material.

  Further, the protective film formed in this way is usually subjected to laser marking that marks the product number by scraping the surface of the protective film by irradiation with laser light. As a film for forming a protective film for a chip having such a laser marking property, in JP-A-2004-331728 (Patent Document 4), an epoxy resin, a phenoxy resin, an epoxy resin curing agent, silica, and carbon black are used. A film for covering electronic components is described. As a curable component used for the protective film-forming film for chips described in Patent Documents 3 to 4, in addition to the epoxy resin described in Patent Document 4, generally acrylic resin, phenol resin, melamine resin Etc. are known.

  In JP-T-2006-526014 (Patent Document 5) and US Patent Application Publication No. 2011/0049731 (Patent Document 6), the amide acid structure is closed in advance as a curable compound, and polymerization is performed. Polymaleimide compounds with maleimide groups introduced as functional groups are described, and these compounds can be applied to adhesives and semiconductor wafer passivation films (films with low elastic modulus to protect circuit surfaces) However, there is no description about using the protective film formed on the back surface of the semiconductor chip as described above.

JP 2002-280329 A JP 2004-214288 A JP 2004-260190 A JP 2004-331728 A JP 2006-526014 A US Patent Application Publication No. 2011/0049731

  When the present inventors examined, in the protective film formation film for chips etc. which were described in patent documents 1-4, the difference in the linear thermal expansion coefficient of the protective film and wafer obtained, and the film in the case of hardening It has been found that the wafer tends to warp due to the shrinkage, and in particular, the tendency becomes more prominent as the thickness of the wafer becomes thinner. Such warpage of the wafer causes a reduction in handling performance of semiconductor chips and a reduction in connection reliability in the manufacture of semiconductor devices. In addition, if the wafer is warped in this way when laser marking is performed, the laser beam is not focused and marking accuracy is lowered.

  Furthermore, when an inorganic filler is added for the purpose of improving the strength and physical properties of the protective film-forming film for chips, adhesion between the protective film-forming film for chips and the wafer (laminate property) and the resulting protective film The present inventors have also found that the problem that the adhesion to the wafer is significantly reduced occurs.

  In addition, when a polymaleimide compound as described in Patent Documents 5 to 6 is used in the protective film-forming film for a chip instead of an epoxy resin or a phenol resin, the tensile elastic modulus after curing is too low, The inventors have also found that problems such as insufficient strength as a protective film and insufficient adhesion and heat resistance of the obtained protective film to the wafer occur.

  The present invention has been made in view of the above-described problems of the prior art, and can provide a protective film having excellent adhesion to the wafer, and excellent laminating properties with the wafer, so that the wafer is sufficiently warped. It aims at providing the protective film formation film for a chip | tip which can be suppressed to this.

  As a result of intensive studies to achieve the above object, the present inventors have found that a protective film for a chip containing a specific bismaleimide compound, a thermal polymerization initiator, and a specific spherical inorganic filler in combination in the protective film forming layer. The formed film has excellent laminating properties with the wafer, and can sufficiently suppress the warpage of the wafer. Furthermore, by using such a protective film forming film for chips, it has excellent adhesion to the wafer. The inventors have found that a protective film can be obtained, and have completed the present invention.

  That is, the protective film-forming film for chips of the present invention includes a bismaleimide compound having a cyclic imide bond and a divalent hydrocarbon group (a) derived from dimer acid, a thermal polymerization initiator, and an average particle size of 1 to 15 μm. A protective film forming layer containing the spherical inorganic filler is provided.

  In the protective film-forming film for chips of the present invention, the bismaleimide compound was obtained by reacting a diamine (A) derived from dimer acid, tetracarboxylic dianhydride, and maleic anhydride. A bismaleimide compound, a diamine (A) derived from a dimer acid, an organic diamine (B) other than the diamine (A) derived from a dimer acid, a tetracarboxylic dianhydride, and a maleic anhydride It is preferably at least one selected from the group consisting of bismaleimide compounds obtained by reacting

  In the protective film-forming film for chips of the present invention, the bismaleimide compound has the following general formula (1):

[In Formula (1), R ¹ represents a divalent hydrocarbon group (a) derived from dimer acid, and R ² represents a divalent other than the divalent hydrocarbon group (a) derived from dimer acid. R ³ represents a divalent organic group other than the divalent hydrocarbon group (a) derived from dimer acid and the divalent hydrocarbon group (a) derived from dimer acid. (B) represents any one selected from the group consisting of R ⁴ and R ^{5, which} may be the same or different, each represents a tetravalent organic group, and m is an integer of 1 to 30. , N is an integer of 0-30, and when m is 2 or more, a plurality of R ¹ and R ⁴ may be the same or different, and when n is 2 or more, a plurality of R ² and R 4 are present. ⁵ may be the same or different. ]
It is preferable that it is a bismaleimide compound represented by these.

  Furthermore, as the protective film-forming film for chips of the present invention, the protective film-forming layer preferably further contains a fine inorganic filler having an average particle diameter of 0.1 μm or more and less than 1 μm, and the fine film in the protective film-forming layer It is more preferable that the content of the inorganic filler is 5 to 50% by mass with respect to the total amount of the spherical inorganic filler and the fine inorganic filler in the protective film forming layer.

  Moreover, as a protective film formation film for chips of this invention, in the said protective film formation layer, content of the said bismaleimide compound is 10-45 mass%, and content of the said spherical inorganic filler is 30-80 mass. It is preferable that the content of the thermal polymerization initiator is 0.05 to 25% by mass with respect to the content of the bismaleimide compound in the protective film forming layer, and further includes a release layer. preferable.

  Moreover, as a protective film formation film for chips of this invention, the said protective film formation layer further contains the black pigment, and content of the said black pigment in the said protective film formation layer is 0.1-15 mass% Preferably, the protective film forming layer further contains a silane coupling agent, and the content of the silane coupling agent in the protective film forming layer is 0.1 to 5% by mass. preferable.

  In addition, although the reason that the said objective is achieved by the protective film formation film for chips of this invention is not necessarily certain, the present inventors guess as follows. That is, since a maleimide compound usually has poor homopolymerizability, when used as a thermosetting component, it is necessary to use it in combination with a thermosetting resin such as a cyanate resin and a curing catalyst. However, since cyanate resin or the like is a resin having a very high tensile modulus after curing, use as a protective film-forming film for a chip is not preferable from the viewpoint of suppressing wafer warpage. Furthermore, since the polymaleimide compounds described in Patent Documents 5 to 6 have a flexible skeleton containing a structure derived from dimer acid, the tensile elastic modulus is sufficiently small even when cured, In the case of a protective film, the present inventors speculate that the tensile elastic modulus is too low and the strength is not sufficient, and the polar group is hardly present in the molecule, so that the adhesion to the wafer is lowered.

  On the other hand, in the protective film-forming film for chips of the present invention, a specific bismaleimide compound and a thermal polymerization initiator are combined with a specific inorganic filler, that is, a spherical inorganic filler having an average particle diameter of 1 to 15 μm. By using it, an excellent laminating property with the wafer is exhibited, and further, a warp of the wafer can be sufficiently suppressed, and a protective film having excellent adhesion to the wafer while exhibiting strength as a protective film. The inventors speculate that it can be obtained. Furthermore, when a black pigment is further contained in the protective film-forming film for chips of the present invention, since warpage of the wafer is sufficiently suppressed in this way, visual recognition when laser markking is performed on the obtained protective film This improves the marking accuracy.

  According to the present invention, there is provided a protective film-forming film for a chip that can provide a protective film excellent in adhesion to a wafer, has excellent laminating properties with the wafer, and can sufficiently suppress warpage of the wafer. It becomes possible to provide.

It is sectional drawing which shows typically suitable 1st Embodiment of the protective film formation film for chips of this invention. It is a schematic diagram which shows suitable 2nd Embodiment of the protective film formation film for chips of this invention.

  Hereinafter, the present invention will be described in detail with reference to preferred embodiments thereof. The protective film-forming film for chips of the present invention has a bismaleimide compound having a cyclic imide bond and a divalent hydrocarbon group (a) derived from dimer acid, a thermal polymerization initiator, and an average particle size of 1 to 15 μm. A protective film forming layer containing a spherical inorganic filler is provided.

<Bismaleimide compound>
The bismaleimide compound according to the present invention is a compound having two maleimide groups and has a divalent hydrocarbon group (a) derived from dimer acid and a cyclic imide bond. Such a bismaleimide compound can be obtained by reacting a diamine (A) derived from dimer acid, tetracarboxylic dianhydride, and maleic anhydride.

  The divalent hydrocarbon group (a) derived from the dimer acid refers to a divalent residue obtained by removing two carboxy groups from the dicarboxylic acid contained in the dimer acid. In the present invention, such a divalent hydrocarbon group (a) derived from dimer acid is a diamine (A) obtained by substituting two carboxy groups of dicarboxylic acid contained in dimer acid with amino groups. ) And a tetracarboxylic dianhydride and maleic anhydride, which will be described later, to form an imide bond, which can be introduced into the bismaleimide compound.

  In the present invention, the dimer acid is obtained by dimerizing unsaturated bonds of unsaturated carboxylic acids such as linoleic acid, oleic acid, and linolenic acid, and then distilled and purified. It mainly contains a dicarboxylic acid, and usually contains about 54% by mass of a tricarboxylic acid having 54 carbon atoms and about 5% by mass of a monocarboxylic acid. The diamine (A) derived from dimer acid according to the present invention (hereinafter sometimes referred to as dimer acid-derived diamine (A)) has two carboxy groups of each dicarboxylic acid contained in the dimer acid as amino groups. It is a diamine obtained by substitution and is usually obtained as a mixture. In the present invention, examples of the dimer acid-derived diamine (A) contained in such a mixture include [3,4-bis (1-aminoheptyl) 6-hexyl-5- (1-octenyl)] cyclohexane, and the like. And diamines obtained by further adding hydrogen to these diamines to saturate unsaturated bonds.

  When the bismaleimide compound according to the present invention is obtained using such a dimer acid-derived diamine (A), two or more kinds having different compositions can be used even if one kind is used alone as the dimer acid-derived diamine (A). You may use it in combination. Further, as the dimer acid-derived diamine (A), for example, a commercially available product such as “PRIAMINE 1074” (manufactured by Croda Japan Co., Ltd.) may be used.

  In the present invention, the cyclic imide bond refers to a bond in which two imide bonds are linked in a cyclic manner. In the present invention, such a cyclic imide bond is formed by reacting a tetracarboxylic dianhydride with the dimer acid-derived diamine (A) and / or the organic diamine (B) described below to form an imide bond. It can be introduced into the bismaleimide compound.

  Examples of the tetracarboxylic dianhydride include pyromellitic dianhydride, 2,2 ′, 3,3′-, 2,3,3 ′, 4′- or 3,3 ′, 4,4 ′. -Benzophenone tetracarboxylic dianhydride, 2,3,6,7-, 1,2,4,5-, 1,4,5,8-, 1,2,6,7- or 1,2,5 , 6-Naphthalene-tetracarboxylic dianhydride, 4,8-dimethyl-1,2,3,5,6,7-hexahydronaphthalene-1,2,5,6-tetracarboxylic dianhydride, 2 , 6- or 2,7-dichloronaphthalene-1,4,5,8-tetracarboxylic dianhydride, 2,3,6,7- (or 1,4,5,8-) tetrachloronaphthalene-1 , 4,5,8- (or 2,3,6,7-) tetracarboxylic dianhydride, 3,3 ', 4,4'-, 2,2', 3,3'- Is 2,3,3 ′, 4′-biphenyltetracarboxylic dianhydride, 3,3 ″, 4,4 ″-, 2,3,3 ″, 4 ″-or 2,2 ″ , 3,3 ″ -p-terphenyltetracarboxylic dianhydride, 2,2-bis (2,3- or 3,4-dicarboxyphenyl) -propane dianhydride, bis (2,3-di Carboxyphenyl) ether dianhydride, bis (2,3- or 3.4-dicarboxyphenyl) methane dianhydride, bis (2,3- or 3,4-dicarboxyphenyl) sulfone dianhydride, 1, 1-bis (2,3- or 3,4-dicarboxyphenyl) ethane dianhydride, 2,3,8,9-, 3,4,9,10-, 4,5,10,11- or 5 , 6,11,12-perylene-tetracarboxylic dianhydride, 1,2,7,8-, 1,2,6,7- 1,2,9,10-phenanthrene-tetracarboxylic dianhydride, cyclopentane-1,2,3,4-tetracarboxylic dianhydride, pyrazine-2,3,5,6-tetracarboxylic dianhydride Pyrrolidine-2,3,4,5-tetracarboxylic dianhydride, thiophene-2,3,4,5-tetracarboxylic dianhydride, 4,4′-oxydiphthalic dianhydride.

  Among these, the tetracarboxylic dianhydride is preferably pyromellitic dianhydride from the viewpoint of obtaining a protective film having excellent heat resistance. Moreover, when obtaining the bismaleimide compound based on this invention using these tetracarboxylic dianhydrides, even if it uses individually 1 type of these tetracarboxylic dianhydrides, it combines 2 or more types May be used.

  Furthermore, as the bismaleimide compound according to the present invention, the dimer acid-derived diamine (A), the organic diamine (B) other than the dimer acid-derived diamine (A), the tetracarboxylic dianhydride, and the malee It may be a bismaleimide compound obtained by reacting with an acid anhydride. By copolymerizing the organic diamine (B) other than the dimer acid-derived diamine (A), it is possible to control the required physical properties as required, such as reducing the tensile elastic modulus of the protective film obtained.

  In the present invention, the organic diamine (B) other than the dimer acid-derived diamine (A) refers to a diamine other than the diamine contained in the dimer acid-derived diamine (A). Such an organic diamine is not particularly limited, and examples thereof include aliphatic diamines such as 1,6-hexamethylenediamine; alicyclic diamines such as 1,4-diaminocyclohexane; 4,4′-diaminodiphenyl ether, 3 , 4′-diaminodiphenyl ether, 1,4-bis (4-aminophenoxy) benzene, 1,3-bis (4-aminophenoxy) benzene, 1,3-bis (3-aminophenoxy) benzene, 1,4- Aromatic diamines such as diaminobenzene, 1,3-diaminobenzene, 2,4-diaminotoluene, 4,4′-diaminodiphenylmethane; 4,4′-diaminodiphenyl sulfone; 3,3′-diaminodiphenyl sulfone; 4-diaminobenzophenone; 4,4-diaminodiphenyl sulfide; 2,2-bis [ - (4-aminophenoxy) phenyl] propane. Among these, from the viewpoint of further suppressing warpage of the wafer, an aliphatic diamine having 6 to 12 carbon atoms such as 1,6-hexamethylenediamine; diaminocyclohexane such as 1,4-diaminocyclohexane; An aromatic diamine having an aliphatic structure having 1 to 4 carbon atoms in an aromatic skeleton such as 2,2-bis [4- (4-aminophenoxy) phenyl] propane is more preferable. Moreover, when obtaining the bismaleimide compound based on this invention using these organic diamine (B), even if it uses individually by 1 type in these organic diamine (B), it uses it in combination of 2 or more types. May be.

  A method of reacting the dimer acid-derived diamine (A), the tetracarboxylic dianhydride, and the maleic anhydride, or the dimer acid-derived diamine (A) and the organic diamine (B), The method for reacting the tetracarboxylic dianhydride and the maleic anhydride is not particularly limited, and a known method can be appropriately employed. For example, first, the dimer acid-derived diamine (A) And the tetracarboxylic dianhydride and, if necessary, the organic diamine (B), a solvent such as toluene, xylene, tetralin, N, N-dimethylacetamide, N-methyl-2-pyrrolidone, or the like Polyamic acid was synthesized by stirring for 30 to 60 minutes at room temperature (about 23 ° C.) in a solvent such as a mixed solvent. Added in acid to synthesize a polyamic acid at both ends maleic acid was added with stirring for 30-60 minutes at room temperature (about 23 ° C.). To this polyamic acid, a solvent such as toluene that is azeotroped with water is further added, and the desired bismaleimide compound is obtained by refluxing at a temperature of 100 to 160 ° C. for 3 to 6 hours while removing water generated during imidization. Can be obtained. In such a method, a catalyst such as pyridine may be further added.

  As a mixing ratio of the raw materials in the reaction, (total number of moles of all diamines and organic diamine (B) contained in dimer acid-derived diamine (A)): ([total number of moles of tetracarboxylic dianhydride] + [ It is preferable that 1/2 of the number of moles of maleic anhydride]) is 1: 1. Moreover, when using the said organic diamine (B), the softness | flexibility derived from a dimer acid expresses and it exists in the tendency which can suppress the curvature of a wafer more, (Mole of organic diamine (B)) Number) / (number of moles of all diamines contained in the dimer acid-derived diamine (A)) is preferably 1 or less, and more preferably 0.4 or less. In addition, when using the said organic diamine (B), the amide acid unit which consists of dimer acid origin diamine (A) and tetracarboxylic dianhydride, and organic diamine (B) and tetracarboxylic dianhydride The polymerization form with the acid unit may be random polymerization or block polymerization.

  The bismaleimide compound thus obtained includes the following general formula (1):

It is preferable that it is a bismaleimide compound represented by these. In the formula (1), R ¹ represents a divalent hydrocarbon group (a) derived from dimer acid, and R ² represents a divalent other than the divalent hydrocarbon group (a) derived from dimer acid. R ³ represents a divalent organic group other than the divalent hydrocarbon group (a) derived from dimer acid and the divalent hydrocarbon group (a) derived from dimer acid. Any one selected from the group consisting of (b) is shown, and R ⁴ and R ⁵ may be the same or different and each represents a tetravalent organic group.

  The divalent hydrocarbon group (a) derived from the dimer acid in the formula (1) is as described above. In the present invention, the divalent organic group (b) other than the divalent hydrocarbon group (a) derived from the dimer acid in the formula (1) refers to two amino acids from the organic diamine (B). This refers to a divalent residue excluding a group. However, in the same compound, the divalent hydrocarbon group (a) derived from the dimer acid and the divalent organic group (b) are not the same. Furthermore, the tetravalent organic group in the formula (1) refers to a tetravalent residue obtained by removing two groups represented by -CO-O-CO- from the tetracarboxylic dianhydride.

  In the formula (1), m is the number of repeating units containing the divalent hydrocarbon group (a) derived from the dimer acid (hereinafter sometimes referred to as dimer acid-derived structure), and an integer of 1 to 30 Indicates. When the value of m exceeds the upper limit, the number of maleimide groups that are curable groups is insufficient, and curing failure tends to occur, and the surface hardness of the resulting protective film tends to decrease. Moreover, since the ratio of the flexible structure originating in a dimer acid increases, it exists in the tendency for the tensile elasticity modulus of the protective film obtained to fall. Moreover, as a value of m, the viewpoint of making the reactivity of a bismaleimide compound and the tensile elasticity modulus of the protective film obtained compatible, and when the value of m is small, the solubility in a solvent is lowered by the imide structure. From the viewpoint of tendency, it is particularly preferably 3 to 10.

  In said Formula (1), n is the number of the repeating units (henceforth organic diamine origin structure depending on the case) containing the said bivalent organic group (b), and shows the integer of 0-30. When the value of n exceeds the upper limit, the flexibility of the protective film obtained is lowered and it becomes hard and brittle. Furthermore, since the imide structure derived from the organic diamine (B) has low solubility in a solvent, there is a concern that insolubilization in the solvent occurs. In addition, as the value of n, from the viewpoint that the physical properties such as the solubility in a solvent, the surface hardness of the obtained protective film, and the tensile elastic modulus capable of sufficiently suppressing the warpage of the wafer are obtained. It is especially preferable that it is 0-10.

Further, when m in the formula (1) is 2 or more, R ¹ and R ⁴ may be the same or different, respectively, and when n in the formula (1) is 2 or more, R ² and R ⁵ may be the same or different. Furthermore, as the bismaleimide compound represented by the formula (1), the dimer acid-derived structure and the organic diamine-derived structure may be random or block.

  In the case of obtaining the bismaleimide compound according to the present invention from the dimer acid-derived diamine (A), the maleic anhydride, the tetracarboxylic dianhydride and, if necessary, the organic diamine (B), the reaction rate Is 100%, n and m in the formula (1) are all diamines contained in the dimer acid-derived diamine (A), the organic diamine (B), the maleic anhydride and the tetracarboxylic acid. It can be represented by the mixed molar ratio of dianhydrides. That is, (m + n): (m + n + 2) is (total number of moles of all diamines and organic diamine (B) contained in dimer acid-derived diamine (A)): (total moles of maleic anhydride and tetracarboxylic dianhydride) M: n is represented by (number of moles of all diamines contained in dimer acid-derived diamine (A)): (number of moles of organic diamine (B)), and 2: (m + n) is (Mole number of maleic anhydride): (Mole number of tetracarboxylic dianhydride).

  Furthermore, in the bismaleimide compound according to the present invention, as the sum (m + n) of m and n in the formula (1), from the viewpoint that a protective film having a more suitable tensile elastic modulus tends to be obtained, It is preferable that it is 2-30. Further, the ratio of m to n (n / m) is 1 or less from the viewpoint that flexibility derived from dimer acid is expressed and a protective film having a more preferable tensile elastic modulus tends to be obtained. It is preferable that the ratio is 0.4 or less.

  As the bismaleimide compound according to the present invention, a commercially available compound may be used as appropriate. For example, “BMI-3000” (manufactured by DESIGNER MOLECURES Inc.); dimer diamine, pyromellitic dianhydride and maleic anhydride What was synthesize | combined; m + n can use 4-7) suitably. Moreover, as a bismaleimide compound based on this invention, you may use individually by 1 type or in combination of 2 or more types.

  In the protective film-forming film for chips of the present invention, the content of the bismaleimide compound in the protective film-forming layer is preferably 10 to 45% by mass, and more preferably 15 to 40% by mass. When the content of the bismaleimide compound is less than the lower limit, the viscosity of the protective film forming layer tends to increase and the laminating property with the wafer tends to decrease. On the other hand, when the content exceeds the upper limit, it is obtained. The tensile elastic modulus of the protective film is lowered, and the strength of the protective film on the back surface of the chip is insufficient, and the heat resistance tends to be insufficient.

<Thermal polymerization initiator>
The thermal polymerization initiator according to the present invention is not particularly limited as long as it is a compound capable of initiating radical polymerization by heat, and any conventionally used one can be appropriately employed. For example, methyl ethyl ketone peroxide, cyclohexanone peroxide, methylcyclohexanone peroxide, methyl acetoacetate peroxide, acetyl acetate peroxide, 1,1-bis (t-hexylperoxy) -3,3,5-trimethylcyclohexane, 1, 1-bis (t-hexylperoxy) -cyclohexane, 1,1-bis (t-butylperoxy) -3,3,5-trimethylcyclohexane, 1,1-bis (t-butylperoxy) -2- Methylcyclohexane, 1,1-bis (t-butylperoxy) -cyclohexane, 1,1-bis (t-butylperoxy) cyclododecane, 1,1-bis (t-butylperoxy) butane, 2,2 -Bis (4,4-di-t-butylperoxycyclohexyl ) Propane, p-menthane hydroperoxide, diisopropylbenzene hydroperoxide, 1,1,3,3-tetramethylbutyl hydroperoxide, cumene hydroperoxide, t-hexyl hydroperoxide, t-butyl hydroperoxide, α, α′-bis (t-butylperoxy) diisopropylbenzene, dicumyl peroxide, 2,5-dimethyl-2,5-bis (t-butylperoxy) hexane, t-butylcumyl peroxide, di- t-butyl peroxide, 2,5-dimethyl-2,5-bis (t-butylperoxy) hexyne-3, isobutyryl peroxide, 3,5,5-trimethylhexanoyl peroxide, octanoyl peroxide, Lauroyl peroxide, Aroyl peroxide, succinic acid peroxide, m-toluoylbenzoyl peroxide, benzoyl peroxide, di-n-propyl peroxydicarbonate, diisopropyl peroxydicarbonate, bis (4-t-butylcyclohexyl) peroxydicarbonate Di-2-ethoxyethyl peroxydicarbonate, di-2-ethoxyhexyl peroxydicarbonate, di-3-methoxybutyl peroxydicarbonate, di-s-butylperoxydicarbonate, di (3-methyl- 3-methoxybutyl) peroxydicarbonate, α, α′-bis (neodecanoylperoxy) diisopropylbenzene, cumylperoxyneodecanoate, 1,1,3,3-tetramethylbutylperoxyneodecano Eate 1-cyclohexyl-1-methylethylperoxyneodecanoate, t-hexylperoxyneodecanoate, t-butylperoxyneodecanoate, t-hexylperoxypivalate, t-butylperoxypivalate 1,1,3,3-tetramethylbutylperoxy-2-ethylhexanoate, 2,5-dimethyl-2,5-bis (2-ethylhexanoylperoxy) hexanoate, 1-cyclohexyl-1- Methylethylperoxy-2-ethylhexanoate, t-hexylperoxy-2-ethylhexanoate, t-butylperoxy-2-ethylhexanoate, t-hexylperoxyisopropylmonocarbonate, t-butyl Peroxyisobutyrate, t-butyl peroxymalate, t-butyl peroxy -Oxy-3,5,5-trimethylhexanoate, t-butyl peroxylaurate, t-butyl peroxyisopropyl monocarbonate, t-butyl peroxy-2-ethylhexyl monocarbonate, t-butyl peroxyacetate, t-butylperoxy-m-toluylbenzoate, t-butylperoxybenzoate, bis (t-butylperoxy) isophthalate, 2,5-dimethyl-2,5-bis (m-toluylperoxy) hexane, t -Hexylperoxybenzoate, 2,5-dimethyl-2,5-bis (benzoylperoxy) hexane, t-butylperoxyallyl monocarbonate, t-butyltrimethylsilyl peroxide, 3,3 ', 4,4'- Tetra (t-butylperoxycarbonyl) benzofe Emissions, organic peroxide initiators such as 2,3-dimethyl-2,3-diphenyl butane.

  2-phenylazo-4-methoxy-2,4-dimethylvaleronitrile, 1-[(1-cyano-1-methylethyl) azo] formamide, 1,1′-azobis (cyclohexane-1-carbonitrile), 2,2′-azobis (2-methylbutyronitrile), 2,2′-azobisisobutyronitrile, 2,2′-azobis (2,4-dimethylvaleronitrile), 2,2′-azobis ( 2-methylpropionamidine) dihydrochloride, 2,2′-azobis (2-methyl-N-phenylpropionamidine) dihydrochloride, 2,2′-azobis [N- (4-chlorophenyl) -2-methylpropionamidine] Dihydride chloride, 2,2′-azobis [N- (4-hydrophenyl) -2-methylpropionamidine] dihydrochloride 2,2′-azobis [2-methyl-N- (phenylmethyl) propionamidine] dihydrochloride, 2,2′-azobis [2-methyl-N- (2-propenyl) propionamidine] dihydrochloride, 2, 2′-azobis [N- (2-hydroxyethyl) -2-methylpropionamidine] dihydrochloride, 2,2′-azobis [2- (5-methyl-2-imidazolin-2-yl) propane] dihydrochloride, 2,2′-azobis [2- (2-imidazolin-2-yl) propane] dihydrochloride, 2,2′-azobis [2- (4,5,6,7-tetrahydro-1H-1,3-diazepine) -2-yl) propane] dihydrochloride, 2,2′-azobis [2- (3,4,5,6-tetrahydropyrimidin-2-yl) propane] Dihydrochloride, 2,2′-azobis [2- (5-hydroxy-3,4,5,6-tetrahydropyrimidin-2-yl) propane] dihydrochloride, 2,2′-azobis [2- [1- ( 2-hydroxyethyl) -2-imidazolin-2-yl] propane] dihydrochloride, 2,2′-azobis [2- (2-imidazolin-2-yl) propane], 2,2′-azobis [2-methyl -N- [1,1-bis (hydroxymethyl) -2-hydroxyethyl] propionamide], 2,2'-azobis [2-methyl-N- [1,1-bis (hydroxymethyl) ethyl] propionamide ], 2,2'-azobis [2-methyl-N- (2-hydroxyethyl) propionamide], 2,2'-azobis (2-methylpropionamide), 2,2 ' Azobis (2,4,4-trimethylpentane), 2,2'-azobis (2-methylpropane), dimethyl-2,2-azobis (2-methylpropionate), 4,4'-azobis (4- Also included are azo initiators such as cyanopentanoic acid) and 2,2′-azobis [2- (hydroxymethyl) propionitrile]. As the thermal polymerization initiator according to the present invention, one of these may be used alone, or two or more may be used in combination, or another known thermal polymerization initiator may be used in further combination. .

  The content of the thermal polymerization initiator according to the present invention in the protective film forming layer may be an amount stoichiometrically required with respect to the amount of the bismaleimide compound, It is preferable that it is 0.05-25 mass% with respect to content of the said bismaleimide compound, and it is more preferable that it is 1-20 mass%. When the content of the thermal polymerization initiator is less than the lower limit, curing of the bismaleimide compound tends to be insufficient. On the other hand, when the content exceeds the upper limit, the protective film-forming film for chips is used at room temperature. There is a possibility that the long-term storage stability of the product is impaired.

<Spherical inorganic filler>
The spherical inorganic filler according to the present invention is a spherical inorganic filler having an average particle diameter of 1 to 15 μm. If the average particle size is less than the lower limit, the local dispersibility of the filler is reduced, so local abnormalities such as filler aggregates are likely to occur on the surface of the protective film-forming film for chips and the protective film obtained, On the other hand, when the above upper limit is exceeded, the coarse particles increase the surface roughness of the protective film-forming film for chips and the protective film to be obtained and lower the surface smoothness. The average particle diameter is particularly preferably 3 to 10 μm from the viewpoint of achieving both uniform dispersibility and surface smoothness of the filler. In the present invention, such an average particle size can be determined by measuring using a particle size distribution meter (for example, “Microtrac MT3000” manufactured by Nikkiso Co., Ltd.).

  The spherical inorganic filler according to the present invention needs to be spherical rather than crushed. When the crushed filler is used in the present invention, the viscosity of the protective film forming layer is remarkably increased, so that the laminating property with the wafer is lowered or the adhesion between the obtained protective film and the wafer is remarkably lowered. In the present invention, the spherical shape refers to a true sphere or a rounded particle state having substantially no corners, and the crushed shape refers to a particle state having an arbitrary shape with corners of the crushed particles. Some say, and can be confirmed with an electron microscope or other microscope.

  Examples of the material for the spherical inorganic filler according to the present invention include silica, alumina, aluminum nitride, and the like. Among these, silica is preferable.

  As the spherical inorganic filler according to the present invention, one of these may be used alone, or two or more may be used in combination. In the present invention, by using such a spherical inorganic filler, the warpage of the wafer can be sufficiently suppressed, and it has excellent adhesion to the wafer while sufficiently exhibiting the strength as a protective film. A protective film can be obtained. Furthermore, the visibility of laser marking is further improved when a black pigment described later is further contained in the protective film forming layer.

  In the protective film-forming film for chips of the present invention, the content of the spherical inorganic filler in the protective film-forming layer is preferably 30 to 80% by mass, and more preferably 40 to 70% by mass. When the content of the spherical inorganic filler is less than the lower limit, the moisture absorption rate of the obtained protective film increases, and the adhesion to the wafer particularly under high humidity conditions decreases, or the surface hardness decreases and the mechanical strength decreases. There is a tendency that scratches or the like against friction are likely to occur. On the other hand, if the upper limit is exceeded, the viscosity of the protective film forming layer tends to increase, and the laminating property on the wafer tends to decrease.

  Moreover, as the protective film-forming film for chips of the present invention, in addition to the spherical inorganic filler having an average particle diameter of 1 to 15 μm, a fine inorganic filler having an average particle diameter of 0.1 μm or more and less than 1 μm is used. It is preferable to further contain it. By including such a fine inorganic filler in the protective film forming layer, the laminating property to the wafer is further improved, and the surface state of the film tends to be improved. Examples of the material for such a fine inorganic filler include those similar to the spherical inorganic filler, and silica is particularly preferable. Further, the fine inorganic filler is preferably the above-mentioned spherical shape from the viewpoint that the filler component is closely packed in the protective film forming layer.

  When such a fine inorganic filler is contained in the protective film forming layer according to the present invention, the content thereof is based on the total amount of the spherical inorganic filler and the fine inorganic filler in the protective film forming layer. It is preferable that it is 50 mass% or less, and it is preferable that it is 5-50 mass%. When the content of the fine inorganic filler is less than the above lower limit, the effect of improving the laminating property by the fine inorganic filler is not exhibited, and the surface state of the protective film-forming film tends to deteriorate or cracking tends to occur. On the other hand, when the upper limit is exceeded, the laminating property on the wafer tends to be lowered.

  As the protective film-forming film for chips of the present invention, it is preferable that the protective film-forming layer further contains a black pigment for the purpose of imparting light-shielding properties or applying laser marking to the resulting protective film. Although it does not restrict | limit especially as said black pigment, Carbon black is preferable and powdery carbon black with an average particle diameter of 10-500 nm which is an arithmetic mean of the measured value of the diameter of the primary particle observed with an electron microscope is more preferable. Furthermore, from the viewpoint of further improving the accuracy of laser marking, it is more preferable that carbon black powder having a low volume resistivity such as acetylene black is contained in the carbon black in an amount of 50% by mass or more.

  When such a black pigment is contained in the protective film forming layer according to the present invention, the content in the protective film forming layer is preferably 0.1 to 15% by mass. When the content of the black pigment is less than the lower limit, the light shielding property and laser marking accuracy tend to be remarkably lowered. On the other hand, when the content exceeds the upper limit, the chip protective film-forming film becomes hard. As a result, the laminate property with the wafer decreases, or the volume resistivity tends to decrease, making it difficult to maintain the insulation performance.

  In addition, the protective film-forming film for a chip of the present invention reinforces the interface between the black pigment or the filler component and the resin component described above to develop a high breaking strength and further improve the laminating property with the wafer. For the purpose, it is preferable that the protective film forming layer further contains a silane coupling agent. Such a silane coupling agent is not particularly limited and may be appropriately selected from known ones. From the viewpoint of further improving the adhesion at the interface between the filler component and the resin component, epoxy group, vinyl A group containing at least one of a group, a styryl group, an acrylic group, and a methacryl group is preferable.

  When such a silane coupling agent is contained in the protective film forming layer according to the present invention, the content in the protective film forming layer is preferably 0.1 to 5% by mass. When the content of the silane coupling agent is less than the lower limit, the adhesiveness to the wafer tends to be insufficient. On the other hand, when the content exceeds the upper limit, an excess of the silane coupling agent causes a weak layer. In order to form, there exists a tendency for adhesiveness with a wafer to become inadequate.

  The protective film-forming layer according to the present invention further contains additives such as antioxidants and flame retardants; stress relaxation agents such as butadiene rubber and silicone rubber, etc., as long as the effects of the present invention are not impaired. May be.

  The protective film-forming film for chips of the present invention is provided with a release layer for the purpose of improving the handleability of the protective film-forming film for chips or protecting the protective film-forming film for chips until use. It is preferable to further provide. As a form provided with such a release layer, a release layer 1 is further provided on one surface of the protective film forming layer 2 as in the preferred second embodiment of the present invention shown in FIG. Alternatively, as in the first preferred embodiment of the present invention shown in FIG. 1, the protective film forming layer 2 may be further provided with a release layer 1 on each side.

  Examples of the release layer include a base film having a release surface having peelability on at least one surface, and the surface tension of the release surface is preferably 40 mN / m or less, and 35 mN / m or less. It is more preferable that Further, such a release layer can be obtained by appropriately selecting the material of the base film, and also by applying a release treatment by applying a silicone resin or the like to the surface of the base film. Can be obtained. The thickness of the release layer is usually 5 to 300 μm, preferably 10 to 200 μm, more preferably about 20 to 150 μm.

  Examples of the material of the base film include polyethylene film, polypropylene film, polybutene film, polybutadiene film, polymethylpentene film, polyphenyl chloride film, vinyl chloride copolymer film, polyethylene terephthalate film, polyethylene naphthalate film, and polybutylene. Terephthalate film, polyurethane film, ethylene / vinyl acetate copolymer film, ionomer resin film, ethylene / (meth) acrylic acid copolymer film, ethylene / (meth) acrylic acid ester copolymer film, polystyrene film, polycarbonate film, Examples thereof include a polyimide film and a fluororesin film. Moreover, the bridge | crosslinking film and laminated | multilayer film which combined 1 type (s) or 2 or more types of these films may be sufficient.

  Examples of the method for producing a protective film-forming film for chips of the present invention include, for example, dissolving the bismaleimide compound, the thermal polymerization initiator, and the spherical inorganic filler in a solvent, and further, if necessary, the fine inorganic filler and the black Forming the protective film by applying the protective film-forming composition obtained by adding a pigment, the silane coupling agent, etc. onto the release surface of the release layer and drying to obtain the protective film-forming layer The method of obtaining the protective film formation film for chips (FIG. 2) of the said 2nd Embodiment provided with a layer and the said peeling layer laminated | stacked on one surface of the said protective film formation layer is mentioned. Moreover, as a protective film forming film for chips of the present invention, a release layer is further laminated on the other surface of the protective film forming layer, and on both surfaces of the protective film forming layer and the protective film forming layer. It is good also as a protective film formation film (FIG. 1) for chips of the said 1st Embodiment provided with the laminated peeling layer.

  Examples of the solvent include aromatic hydrocarbon solvents such as toluene and xylene; ketone solvents such as cyclohexanone; ether solvents such as THF; and mixed solvents thereof. As solid content concentration in such a composition for protective film formation, it is preferable that it is 50-90 mass%.

  The drying temperature may be any temperature as long as it is lower than the curing temperature of the protective film forming layer and can volatilize the solvent, and is usually 80 to 120 ° C. Moreover, as thickness of the protective film formation layer concerning this invention, it is preferable that it is 10-300 micrometers, and it is more preferable that it is 25-100 micrometers. When the thickness is less than the lower limit, it tends not to function sufficiently as a protective film for a semiconductor chip. On the other hand, when the thickness exceeds the upper limit, a useless volume increases, which is not preferable.

  By using the chip protective film-forming film of the present invention, for example, a protective film can be formed on the back surface of a wafer level package chip. As a method for forming such a protective film, for example, the chip protective film-forming film of the present invention is laminated on the wafer so that the back surface of the semiconductor wafer is in contact with the protective film-forming layer, and then heat treatment is performed thereon. And a method of curing the protective film forming layer and forming a protective film on the entire back surface of the semiconductor wafer. The obtained wafer with a protective film can be made into a semiconductor chip with a protective film by being separated into pieces by dicing.

  As the laminating method, heating is preferably performed at 40 ° C. or higher and lower than the curing temperature of the protective film forming layer, and it is more preferable to apply a pressure of 0.05 to 0.5 MPa. The conditions for the heat treatment for curing cannot be generally described because they differ depending on the composition of the protective film forming layer. For example, it is preferable to heat at 100 to 200 ° C. for 0.5 to 3 hours. In the case of the first embodiment in which the protective film-forming film for chips of the present invention further includes a release layer, at least one release layer is peeled off and the lamination is performed. The peeling of the other peeling layer and the peeling layer of the second embodiment may be before or after curing.

  In this way, by using the protective film-forming film for chips, a semiconductor chip with a protective film can be obtained while sufficiently suppressing the warp of the semiconductor wafer. Furthermore, the protective film thus obtained has excellent adhesion to the wafer. The protective film preferably has a tensile modulus of 500 to 5000 MPa. In the present invention, the tensile elastic modulus is determined by using a viscoelasticity measuring device (for example, “Rheogel-E4000” manufactured by UBM Co., Ltd.) at a frequency of 11 Hz and a temperature rising condition of 5 ° C./min at 0 to 300 ° C. It means the storage elastic modulus at a temperature of 25 ° C. obtained by measuring viscoelasticity by mode.

  EXAMPLES Hereinafter, although this invention is demonstrated more concretely based on an Example and a comparative example, this invention is not limited to a following example. In addition, the elastic modulus measurement, wafer warpage measurement, laser marking accuracy evaluation, moisture absorption rate measurement, moisture absorption reflow resistance evaluation, and laminating property evaluation in each example and comparative example were performed as follows.

<Elastic modulus measurement>
First, the PET film was peeled from the protective film-forming film for chips obtained in each Example and Comparative Example, and this was superposed to a thickness of 100 μm, and cured by heat treatment at a temperature of 130 ° C. for 2 hours. The obtained cured film (protective film) was used as a measurement sample. About the obtained measurement sample, viscoelasticity by a tensile mode was measured at 0 to 300 ° C. at a frequency of 11 Hz and a temperature rising condition of 5 ° C./min using a viscoelasticity measuring device (“Rheogel-E4000” manufactured by UBM). The storage elastic modulus (MPa) at a temperature of 25 ° C. obtained by this measurement was taken as the elastic modulus value.

<Wafer warpage measurement>
First, the protective film-forming film for chips obtained in each Example and Comparative Example was used at a temperature of 70 ° C. using a manual laminator (manufactured by Technovision, “FM-114”) on a mirror wafer (8 inches, 100 μm thickness). After laminating, a heat treatment was performed at a temperature of 130 ° C. for 2 hours to cure to obtain a wafer with a protective film. Next, the obtained wafer with a protective film was placed on a smooth table with the protective film surface as the upper surface, and the height (mm) of the portion farthest from the table was measured due to warpage of the wafer.

<Laser marking accuracy evaluation>
The protective film of the wafer with protective film obtained in the same manner as in the wafer warpage measurement is marked using a marking device (manufactured by Keyence Corporation, “MDS-9900A”), and the following standard is visually observed:
A: Printing is performed uniformly on the entire surface of the protective film. B: Printing is performed on the entire surface of the protective film, but the printing is not uniform as it goes toward the outer periphery of the wafer. C: Printing is performed because the laser beam is not focused as it goes toward the outer periphery of the wafer. Evaluation was based on the absence.

<Moisture absorption measurement>
A measurement sample obtained in the same manner as in the elastic modulus measurement was allowed to stand for 168 hours under conditions of a temperature of 85 ° C. and a humidity of 85% RH to absorb moisture. %).

<Moisture absorption reflow resistance evaluation (JEDEC L-1)>
First, a wafer with a protective film obtained in the same manner as in the wafer warpage measurement was divided into chips of 10 mm × 10 mm size using a dicing apparatus to produce a chip with a protective film. Next, this chip with protective film was allowed to stand for 168 hours under conditions of a temperature of 85 ° C. and a humidity of 85% RH to absorb moisture, and an IR reflow (Asahi Electronics Co., Ltd.) was set so that the region at a temperature of 255 ° C. or higher was 20 seconds. Manufactured, “Ba-250N2”). The chip with a protective film after three IR reflows was observed with an optical microscope, and the peeling state was confirmed. Among the 10 samples, the ones where peeling occurred were counted. The moisture absorption reflow resistance is indicated by the number of samples where peeling occurred / the total number of samples.

<Laminate evaluation>
A cross-cut test according to JIS-K5400 was performed on each wafer with a protective film obtained in the same manner as the wafer warpage measurement except that the lamination temperature was 80 ° C. and 100 ° C., and the number of grids peeled off from the wafer after the test. Counted. The laminating property is indicated by the number of cells where peeling occurred / the number of all cells.

Example 1
First, 100 parts by mass of bismaleimide compound 1 (manufactured by DESIGNER MOLECURES Inc., “BMI-3000”, solid content 100%) and 100 parts by mass of solvent (xylene) were stirred at room temperature for 2 hours to obtain a resin varnish. Next, the total amount of this resin varnish, 10 parts by mass of dicumyl peroxide (manufactured by NOF Corporation, “Permicle D”), spherical filler 1 (silica, average particle size 3 μm, manufactured by Denki Kagaku, “FB-3SDX”) 320 Part by weight, planetary filler 11 parts by weight, spherical filler 2 (silica, average particle size 0.7 um, manufactured by Admatechs, "SO-25R-75C"), carbon black (Mitsubishi Chemical Co., "MA100") A mixture prepared using a Lee mixer ("PVM-5" manufactured by Asada Tekko Co., Ltd.) is kneaded with a three roll mill ("NR-84A" manufactured by Noritake Co., Ltd.) and vacuum degassed to form a protective film forming composition. Got. Next, the resulting protective film-forming composition was applied onto a 50 μm-thick release PET film so that the thickness after removal of the solvent was 25 μm, and dried with hot air at a temperature of 100 ° C. for 10 minutes. The protective film-forming layer was formed by removing the solvent to obtain a protective film-forming film for chips.

(Example 2)
A protective film-forming film for a chip was obtained in the same manner as in Example 1 except that the spherical filler 1 was 136 parts by mass and the spherical filler 2 was 34 parts by mass.

(Example 3)
A protective film-forming film for a chip was obtained in the same manner as in Example 1 except that the spherical filler 1 was 200 parts by mass and the spherical filler 2 was not used.

(Comparative Example 1)
A protective film-forming film for chips was obtained in the same manner as in Example 1 except that the spherical filler 1 and the spherical filler 2 were not used.

(Comparative Example 2)
First, 60 parts by mass of dicyclopentadiene type epoxy resin (manufactured by Nippon Kayaku Co., Ltd., “XD-1000”), 20 parts by mass of phenoxy resin (manufactured by Nippon Steel Chemical Co., Ltd., “YP-50S”), bisphenol A type epoxy resin (Mitsubishi Chemical Co., Ltd., “JER-828”) 44 parts by mass and solvent (methyl isobutyl ketone) 70 parts by mass were heated and stirred at a temperature of 110 ° C. for 2 hours to make a comparative mixed resin 1 (dicyclopentadiene type epoxy resin, phenoxy) Resin varnish of resin, bisphenol A type epoxy resin) was obtained. Next, the total amount of the resin varnish, 160 parts by mass of spherical filler 1 (silica, average particle size 3 μm, manufactured by Denki Kagaku Co., “FB-3SDX”), spherical filler 2 (silica, average particle size 0.7 μm, manufactured by Admatex) , "SO-25R-75C") 40 parts by mass, carbon black (Mitsubishi Chemical Co., "MA100") 7 parts by mass using a planetary mixer (Asada Tekko Co., "PVM-5") Is mixed with a three-roll mill (manufactured by Noritake, “NR-84A”), and 7 parts by mass of an imidazole-based curing agent (manufactured by Shikoku Kasei Kogyo Co., “2PHZ”) is added to the resulting kneaded product. Were further kneaded and vacuum degassed to obtain a protective film-forming composition. Next, the resulting protective film-forming composition was applied onto a 50 μm-thick release PET film so that the thickness after removal of the solvent was 25 μm, and dried with hot air at a temperature of 100 ° C. for 10 minutes. The protective film-forming layer was formed by removing the solvent to obtain a protective film-forming film for chips.

(Comparative Example 3)
Instead of 320 parts by weight of spherical filler 1, 136 parts by weight of crushed filler 1 (silica, average particle size 3 μm, manufactured by Tatsumori Co., Ltd., “FUSELEX-X”) was used except that spherical filler 2 was 34 parts by weight. A protective film-forming film for chips was obtained in the same manner as in Example 1.

  Using the protective film-forming films for chips obtained in Examples 1 to 3 and Comparative Examples 1 to 3, elastic modulus measurement, wafer warpage measurement, laser marking accuracy evaluation, moisture absorption rate measurement, moisture absorption reflow resistance evaluation, laminating property The evaluation results are shown in Table 1 together with the composition of the protective film-forming film for each chip.

  As is apparent from the results shown in Table 1, the protective film-forming film for chips of the present invention obtained in Examples 1 to 3 is excellent in laminating properties with the wafer, and sufficiently suppresses the warpage of the wafer. It was confirmed that Moreover, it was confirmed that the protective film obtained using the protective film-forming film for chips of the present invention has excellent adhesion to the wafer. Furthermore, it was confirmed that the accuracy of laser marking on the protective film is increased by sufficiently suppressing the warpage of the wafer by the protective film-forming film for chips of the present invention.

  As described above, according to the present invention, a chip capable of obtaining a protective film excellent in adhesion to the wafer, excellent in laminating properties with the wafer, and sufficiently suppressing warpage of the wafer. It is possible to provide a protective film-forming film.

  In addition, according to the present invention, since the warpage of the wafer can be sufficiently suppressed, marking accuracy can be increased even when laser marking is performed on the obtained protective film, and the connection reliability of the semiconductor device can be improved. Can be improved.

DESCRIPTION OF SYMBOLS 1 ... Protective film formation layer, 2 ... Release layer.

Claims (9)

  A bismaleimide compound having a cyclic imide bond and a divalent hydrocarbon group (a) derived from dimer acid, a thermal polymerization initiator, and a protective film forming layer containing a spherical inorganic filler having an average particle diameter of 1 to 15 μm A protective film-forming film for a chip, characterized in that   The bismaleimide compound was derived from a dimer acid and a bismaleimide compound obtained by reacting a diamine (A) derived from dimer acid, tetracarboxylic dianhydride, and maleic anhydride. It consists of a bismaleimide compound obtained by reacting a diamine (A), an organic diamine (B) other than the diamine (A) derived from dimer acid, a tetracarboxylic dianhydride, and a maleic anhydride. The film for forming a protective film for a chip according to claim 1, wherein the film is at least one selected from the group. The bismaleimide compound has the following general formula (1):

[In Formula (1), R ¹ represents a divalent hydrocarbon group (a) derived from dimer acid, and R ² represents a divalent other than the divalent hydrocarbon group (a) derived from dimer acid. R ³ represents a divalent organic group other than the divalent hydrocarbon group (a) derived from dimer acid and the divalent hydrocarbon group (a) derived from dimer acid. (B) represents any one selected from the group consisting of R ⁴ and R ^{5, which} may be the same or different, each represents a tetravalent organic group, and m is an integer of 1 to 30. , N is an integer of 0-30, and when m is 2 or more, a plurality of R ¹ and R ⁴ may be the same or different, and when n is 2 or more, a plurality of R ² and R 4 are present. ⁵ may be the same or different. ]
The protective film-forming film for chips according to claim 1, wherein the film is a bismaleimide compound represented by the formula:   The said protective film formation layer further contains the fine inorganic filler with an average particle diameter of 0.1 micrometer or more and less than 1 micrometer, The protective film formation film for chips as described in any one of Claims 1-3 characterized by the above-mentioned.   The content of the fine inorganic filler in the protective film forming layer is 5 to 50% by mass with respect to the total amount of the spherical inorganic filler and the fine inorganic filler. Protective film forming film for chips.   In the protective film forming layer, the content of the bismaleimide compound is 10 to 45% by mass, the content of the spherical inorganic filler is 30 to 80% by mass, and the content of the thermal polymerization initiator is The protective film formation for chips according to any one of claims 1 to 5, wherein the content of the bismaleimide compound in the protective film forming layer is 0.05 to 25% by mass. the film.   The protective film-forming film for chips according to any one of claims 1 to 6, further comprising a release layer.   The protective film forming layer further contains a black pigment, and the content of the black pigment in the protective film forming layer is from 0.1 to 15% by mass. The protective film formation film for chips as described in any one of these.   The protective film forming layer further contains a silane coupling agent, and the content of the silane coupling agent in the protective film forming layer is 0.1 to 5% by mass. The protective film formation film for chips as described in any one of -8.

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