TW201420639A - Method for forming protective film, protective film, cured composition and laminated body - Google Patents

Abstract

A method for forming a protective film for a wafer-level package is provided, wherein a cured composition is coated on a wafer having a semiconductor element, and an obtained coating film is cured to form the protective film. The cured composition contains: a polysiloxane containing an alkenyl group (A), a hydrogen polysiloxane (B) and a catalyst for a hydrosilylation reaction (C), while a specific condition is satisfied. According to a method for forming a passivation film of the invention, even in a situation that the protective film is formed over a wide area in a wafer-level packaging technique, a warp of the wafer and a crack of the protective film can be restrained.

Description

Method for forming protective film, protective film, curable composition, and laminate

The present invention relates to a method for forming a protective film, a protective film, and a curable composition, and more particularly to a method for forming a protective film for forming a protective film on a wafer in a wafer level packaging method. The protective film obtained by the method and the hardenable composition used in the method.

In recent years, the miniaturization, weight reduction, and high functionality of electronic products such as mobile phones, mobile computers, personal digital assistants (PDAs), and digital still cameras (DSCs) have made great progress. With such market trends, there is a strong demand for miniaturization, thinning, weight reduction, and high-density mounting of mounting substrates for semiconductor packages mounted on electronic products.

Based on this background, new semiconductor packaging technologies called wafer level packaging are receiving attention. The wafer-level package is a packaging technology that obtains a semiconductor wafer by performing rewiring, formation of a protective film such as a passivation film, formation of an electrode, and the like in a wafer state. According to this technique, the size of the semiconductor wafer obtained by cutting the wafer directly becomes the size of the package, so that it can be made small Modeling and weight reduction.

Patent Document 1 describes a method of manufacturing a light-emitting device including a light-emitting diode (LED), a drive circuit unit that drives the LED, and a light detecting element that detects the optical power of the LED, and A control circuit portion that performs feedback control of a current flowing from the driving circuit portion to the LED, and the manufacturing method of the light emitting device not only provides the photodetecting element on the mounting substrate, but also achieves miniaturization, and can be applied in the manufacturing method Wafer-level packaging technology is further miniaturized.

[Previous Technical Literature]

[Patent Literature]

[Patent Document 1] Japanese Patent Laid-Open Publication No. 2008-113039

In the case of forming a protective film on a wafer in a wafer level package, the area of the formed film is significantly wider than that in the case of forming a protective film on each wafer, and thus is easily affected by the difference in thermal expansion between the wafer and the protective film. It is easy to cause warpage of the wafer after the formation of the protective film and cracking of the protective film. Therefore, in the wafer level package, it is strongly required to develop a method of forming a protective film that does not cause warpage of the wafer and cracking of the protective film as described above.

An object of the present invention is to develop a method for forming a protective film in which wafer warpage and cracking of a protective film are less likely to occur when a protective film is formed by a wafer level packaging technique.

The inventors have found that by using a polyoxane and satisfying specific conditions The composition is to solve the problem, thereby completing the present invention. That is, the present invention relates to the following [1] to [6].

[1] A method of forming a protective film for wafer level packaging, comprising: applying a curable composition onto a wafer having a semiconductor element, and curing the obtained coating film to form a protective film, wherein the curable composition The product contains at least one alkenyl group-containing polyoxyalkylene (A) represented by the following chemical formula (1), at least one hydrogenated polyoxyalkylene (B) represented by the following chemical formula (2), and hydrogenation reaction of hydrazine The catalyst (C) is used, and the conditions shown by the following formula (3) and the following formula (4) are satisfied: (R ¹ R ² ₂ SiO _1/2 ) _a1 (R ³ ₃ SiO _1/2 ) _b1 (R) ⁴ ₂ SiO _2/2 ) _c1 (R ⁵ SiO _3/2 ) _d1 (SiO _4/2 ) _e1 (OX ¹ ) _f1 (1)

(wherein R ¹ is an alkenyl group, R ^{2 is} independently an alkyl group, an aryl group or an aralkyl group, and R ³ , R ⁴ and R ⁵ are each independently an alkyl group, an aryl group, an arylalkyl group or a ring; The group of the oxy group, X ¹ each independently represents a hydrogen atom or an alkyl group having 1 to 3 carbon atoms; the symbol a1, the symbol b1, the symbol c1, the symbol d1, the symbol e1, and the symbol f1 indicate that the one molecule contains The number of structural units of the symbol, a1 is an integer of 2 or more, and b1, c1, d1, e1, and f1 are each independently an integer of 0 or more; (HR ⁶ ₂ SiO _1/2 ) _a2 (R ⁷ ₃ SiO _1/2 ) _b2 (R ⁸ ₂ SiO _2/2 ) _c2 (R ⁹ SiO _3/2 ) _d2 (SiO _4/2 ) _e2 (OX ² ) _f2 (2)

(wherein R ^{6 is} independently an alkyl group, an aryl group or an aralkyl group, and R ⁷ , R ⁸ and R ⁹ are each independently an alkyl group, an aryl group, an arylalkyl group or a group having an epoxy group, X ² independently represents a hydrogen atom or an alkyl group having 1 to 3 carbon atoms; the symbol a2, the symbol b2, the symbol c2, the symbol d2, the symbol e2, and the symbol f2 represent a structural unit containing the symbol contained in one molecule. For the number, a2 is an integer of 2 or more, and b2, c2, d2, e2, and f2 are each an integer of 0 or more, respectively; 0.1<[Σ[(d1+e1)×L ₁ ]+Σ[(d2+e2 )×L ₂ 〕]/[Σ[(a1+b1+c1+d1+e1)×L ₁ ]+Σ[(a2+b2+c2+d2+e2)×L ₂ ]]<0.6 (3)

(wherein a1 to e1 have the same meanings as a1 to e1 in the formula (1), respectively, and represent a1 to e1; a2 related to each alkenyl group-containing polyoxane (A) contained in the curable composition; ~e2 has the same meaning as a2 to e2 in the formula (2), and represents a2 to e2 related to each hydrogenated polyoxyalkylene (B) contained in the curable composition; L ₁ is a hardening composition. The content of each of the alkenyl group-containing polyoxyalkylene (A) contained is expressed by parts by weight, and L ₂ is the weight of each hydrogenated polyoxyalkylene (B) contained in the curable composition. when the value represented by the parts (L wherein the total of the sum of L ₁ silicon poly siloxane (a) each of the alkenyl group-containing silicon with the hydrogenated poly siloxane (B) and ₂ to 100); [[Sigma sum (d1 + e1) × L _1] represents (d1 + e1) curable silicone composition of poly siloxane (a) containing alkenyl groups each contained in the × L _1, Σ [(d2 + E2) × L ₂ ] represents the sum of (d2+e2) × L ₂ in each hydrogenated polyoxyalkylene (B) contained in the curable composition, Σ [(a1 + b1 + c1 + d1 + e1) ×L ₁ ] represents the sum of (a1+b1+c1+d1+e1)×L ₁ in each alkenyl group-containing polyoxane (A) contained in the curable composition, Σ[(a2+b2) + c2 + d2 + e2) × L 2 ] Each composition shown hydride curable poly silicon contained in siloxane (a2 + b2 + c2 + d2 + e2) (B) the sum of ₂ × L); 0.05 <[Σ [c1 × L _1] + Σ [c2×L ₂ ]]/[Σ[(a1+b1+c1+d1+e1)×L ₁ ]+Σ[(a2+b2+c2+d2+e2)×L ₂ ]]<0.5 (4)

(In the formula, the same as in a1 ~ e1 respectively of formula (3) a1 ~ e1 meaning the same as in a2 ~ e2 respectively of formula (3) a2 ~ e2 meaning; of L ₁ and L ₂ respectively of formula (3) L ₁ and L ₂ have the same meaning; Σ [c1 × L ₁ ] represents the sum of c1 × L ₁ in each alkenyl group-containing polyoxane (A) contained in the curable composition, Σ [c2 × L ₂ ] represents the sum of c2 × L ₂ in each of the hydrogenated polyoxyalkylenes (B) contained in the curable composition, and Σ [(a1 + b1 + c1 + d1 + e1) × L ₁ ] represents hardenability The sum of (a1+b1+c1+d1+e1)×L ₁ in each alkenyl group-containing polyoxane (A) contained in the composition, Σ[(a2+b2+c2+d2+e2) ×L ₂ ] represents the sum of (a2+b2+c2+d2+e2)×L ₂ in each of the hydrogenated polyoxyalkylene oxides (B) contained in the curable composition.

[2] The method of forming a protective film for wafer level packaging according to [1], wherein the semiconductor element is a light emitting diode.

[3] A protective film for a wafer level package, which is formed by the method for forming a protective film for wafer level packaging according to [1].

[4] A curable composition for wafer-level encapsulation, comprising the alkenyl group-containing polyoxane (A) represented by the chemical formula (1) according to [1], The hydrogenated polyoxyalkylene (B) represented by the chemical formula (2) described in [1] and the catalyst (C) for hydrogenation reaction, and satisfying the formula (3) and the formula (1) according to the above [1] 4) The conditions shown.

[5] A protective film for wafer level encapsulation, which is obtained by the curable composition according to [4] above.

[6] A laminate comprising a protective film for a wafer level package, a wafer, and a semiconductor device according to the above [3] or [5].

According to the method for forming a protective film of the present invention, even when a protective film is formed over a wide area in the wafer level packaging technique, warpage of the wafer and generation of cracks in the protective film can be suppressed.

[Method of Forming Protective Film for Wafer Level Packaging]

The method for forming a protective film for wafer level packaging according to the present invention is characterized in that a curable composition is applied onto a wafer having a semiconductor element, and the obtained coating film is thermally cured to form a protective film. The object contains: at least one alkenyl group-containing polyoxyalkylene (A) represented by the following chemical formula (1), and the following chemical formula (2) At least one hydrogenated polyoxyalkylene (B) and a catalyst for hydrogenation reaction (C) are shown, and the conditions shown by the following formula (3) and the following formula (4) are satisfied.

(R ¹ R ² ₂ SiO _1/2 ) _a1 (R ³ ₃ SiO _1/2 ) _b1 (R ⁴ ₂ SiO _2/2 ) _c1 (R ⁵ SiO ₃ / ₂ ) _d1 (SiO _4/2 ) _e1 (OX ¹ ) _f1 (1)

(wherein R ¹ is an alkenyl group, R ^{2 is} independently an alkyl group, an aryl group or an aralkyl group, and R ³ , R ⁴ and R ⁵ are each independently an alkyl group, an aryl group, an arylalkyl group or a ring; The group of the oxy group, X ¹ each independently represents a hydrogen atom or an alkyl group having 1 to 3 carbon atoms; the symbol a1, the symbol b1, the symbol c1, the symbol d1, the symbol e1, and the symbol f1 indicate that the one molecule contains The number of structural units of the symbol, a1 is an integer of 2 or more, and b1, c1, d1, e1, and f1 are each independently an integer of 0 or more.)

(HR ⁶ ₂ SiO _1/2 ) _a2 (R ⁷ ₃ SiO _1/2 ) _b2 (R ⁸ ₂ SiO _2/2 ) _c2 (R ⁹ SiO _3/2 ) _d2 (SiO _4/2 ) _e2 (OX ² ) _F2 (2)

(wherein R ^{6 is} independently an alkyl group, an aryl group or an aralkyl group, and R ⁷ , R ⁸ and R ⁹ are each independently an alkyl group, an aryl group, an arylalkyl group or a group having an epoxy group, X ² independently represents a hydrogen atom or an alkyl group having 1 to 3 carbon atoms; the symbol a2, the symbol b2, the symbol c2, the symbol d2, the symbol e2, and the symbol f2 represent a structural unit containing the symbol contained in one molecule. The number, a2 is an integer of 2 or more, and b2, c2, d2, e2, and f2 are each independently an integer of 0 or more.)

0.1<[Σ[(d1+e1)×L ₁ ]+Σ[(d2+e2)×L ₂ ]]/[Σ[(a1+b1+c1+d1+e1)×L ₁ ]+Σ[( A2+b2+c2+d2+e2)×L ₂ 〕]<0.6 (3)

(wherein a1 to e1 have the same meanings as a1 to e1 in the formula (1), respectively, and represent a1 to e1; a2 related to each alkenyl group-containing polyoxane (A) contained in the curable composition; ~e2 has the same meaning as a2 to e2 in the formula (2), and represents a2 to e2 related to each hydrogenated polyoxyalkylene (B) contained in the curable composition; L ₁ is a hardening composition. The content of each of the alkenyl group-containing polyoxyalkylene (A) contained is expressed by parts by weight, and L ₂ is the weight of each hydrogenated polyoxyalkylene (B) contained in the curable composition. when the value represented by the parts (L wherein the total of the sum of L ₁ silicon poly siloxane (a) each of the alkenyl group-containing silicon with the hydrogenated poly siloxane (B) and ₂ to 100).

[[Sigma sum (d1 + e1) × L _1] represents (d1 + e1) curable silicone composition of poly siloxane (A) containing alkenyl groups each contained in the × L _1, Σ [(d2 + E2) × L ₂ ] represents the sum of (d2+e2) × L ₂ in each hydrogenated polyoxyalkylene (B) contained in the curable composition, Σ [(a1 + b1 + c1 + d1 + e1) ×L ₁ ] represents the sum of (a1+b1+c1+d1+e1)×L ₁ in each alkenyl group-containing polyoxane (A) contained in the curable composition, Σ[(a2+b2) +c2+d2+e2)×L ₂ ] represents the sum of (a2+b2+c2+d2+e2)×L ₂ in each hydrogenated polyoxyalkylene (B) contained in the curable composition. )

0.05<[Σ[c1×L ₁ ]+Σ[c2×L ₂ ]]/[Σ[(a1+b1+c1+d1+e1)×L ₁ ]+Σ[(a2+b2+c2+d2+ E2)×L ₂ 〕]<0.5 (4)

(In the formula, the same as in a1 ~ e1 respectively of formula (3) a1 ~ e1 meaning the same as in a2 ~ e2 respectively of formula (3) a2 ~ e2 meaning; of L ₁ and L ₂ respectively of formula (3) L ₁ and L ₂ have the same meaning; Σ [c1 × L ₁ ] represents the sum of c1 × L ₁ in each alkenyl group-containing polyoxane (A) contained in the curable composition, Σ [c2 × L ₂ ] represents the sum of c2 × L ₂ in each of the hydrogenated polyoxyalkylenes (B) contained in the curable composition, and Σ [(a1 + b1 + c1 + d1 + e1) × L ₁ ] represents hardenability The sum of (a1+b1+c1+d1+e1)×L ₁ in each alkenyl group-containing polyoxane (A) contained in the composition, Σ[(a2+b2+c2+d2+e2) ×L ₂ ] represents the sum of (a2+b2+c2+d2+e2)×L ₂ in each of the hydrogenated polyoxyalkylenes (B) contained in the curable composition.

In the present invention, the wafer-level package is obtained by cutting the wafer into a wafer shape, performing rewiring, forming a protective film, and forming an electrode in a wafer state, and then cutting the wafer. Packaging technology for semiconductor wafers.

The protective film in the present invention refers to a film formed on a wafer for protecting a semiconductor element provided on a wafer, and is a concept including a passivation film, a sealing film, and the like.

The wafer refers to a thin substrate (having an area of 5 cm ² or more with respect to a thickness of 1 mm). The wafer is usually formed of an inorganic compound such as ruthenium, sapphire, gallium nitride or glass, or an organic compound such as an epoxy resin or a polyimide. In addition, the wafer may have irregularities.

The semiconductor element is not particularly limited, and examples thereof include a light-emitting diode (LED).

In the method for forming a protective film of the present invention, the curable composition is applied onto a wafer having a semiconductor element.

Examples of the coating method include a spin coating method and a screen printing method.

The curable composition contains an alkenyl group-containing polysiloxane (A), a hydrogenated polyoxyalkylene (B), and a rhodium hydrogenation catalyst (C), and may further contain an additive or the like as necessary.

The alkenyl group-containing polyoxyalkylene (A) is hardened by hydrogenation reaction with a hydrogenated polyoxyalkylene (B) to form a main component of the protective film.

The alkenyl group-containing polyoxyalkylene (A) is represented by the above formula (1). The alkenyl group-containing polysiloxane (A) may be used singly or in combination of two or more.

In the chemical formula (1), R ¹ is an alkenyl group. Examples of the alkenyl group include a vinyl group, an allyl group, a propenyl group, an isopropenyl group, a butenyl group, an isobutenyl group, a pentenyl group, a heptenyl group, a hexenyl group, and a cyclohexenyl group. Among these alkenyl groups, a vinyl group, an allyl group, and a hexenyl group are preferable.

R ^{2 is} independently an alkyl group, an aryl group or an aralkyl group. Examples of the alkyl group include a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, a hexyl group, a heptyl group and the like. Examples of the aryl group include a phenyl group, a tolyl group, a xylyl group, and a naphthyl group. The aralkyl group may, for example, be a benzyl group, a 2-phenylethyl group, a 2-naphthylethyl group or a diphenylmethyl group.

R ³ , R ⁴ and R ⁵ are each independently an alkyl group, an aryl group, an aralkyl group or a group having an epoxy group. The alkyl group, the aryl group and the aralkyl group are the same as those of the alkyl group, the aryl group and the aralkyl group described for R ² . Examples of the group having an epoxy group include glycidoxyalkyl groups such as glycidoxy group and 3-glycidoxypropyl group, and 3,4-epoxycyclopentyl group and 3,4-epoxy ring. An epoxycycloalkyl group such as a hexyl group, a 2-(3,4-epoxycyclopentyl)ethyl group or a 2-(3,4-epoxycyclohexyl)ethyl group.

X ^{1 is} independently a hydrogen atom or an alkyl group having 1 to 3 carbon atoms. Examples of the alkyl group having 1 to 3 carbon atoms include a methyl group, an ethyl group, and a propyl group.

In the chemical formula (1), the symbol a1, the symbol b1, the symbol c1, the symbol d1, the symbol e1, and the symbol f1 represent the number of structural units in which the symbol is included in one molecule, and a1 is an integer of 2 or more, b1. C1, d1, e1, and f1 are each independently an integer of 0 or more.

The polystyrene-equivalent weight average molecular weight measured by gel permeation chromatography of the alkenyl group-containing polyoxyalkylene (A) is usually in the range of from 100 to 50,000, preferably in the range of from 500 to 5,000. When the weight average molecular weight of the alkenyl group-containing polysiloxane (A) is within the above range, the workability of the curable composition is improved, and the protective film obtained from the curable composition has sufficient strength.

The hydrogenated polyoxyalkylene (B) is a crosslinking agent for the alkenyl group-containing polyoxyalkylene (A), and is hardened by hydrogenation reaction with an alkenyl group-containing polyoxyalkylene (A) to form a protective film.

The hydrogenated polyoxyalkylene (B) is represented by the above formula (2). The hydrogenated polyoxyalkylene (B) may be used singly or in combination of two or more.

R (2) in the chemical formula ^6, R ^7, R ^8, with the formula R (1) is ^{6, R 7, R 8,} R , and X are the same as R ⁹ and ⁹ X.

In the chemical formula (2), the symbol a2, the symbol b2, the symbol c2, the symbol d2, the symbol e2, and the symbol f2 represent the structural unit in which the symbol is included in one molecule. The number, a2 is an integer of 2 or more, and b2, c2, d2, e2, and f2 are each independently an integer of 0 or more.

In the present curable composition, since the conditions shown in the above formulas (3) and (4) are satisfied, the alkenyl group-containing polyoxane (A) contained in the curable composition is contained. D1 and e1 and d2 and e2 in each hydrogenated polyoxyalkylene (B) are not all 0, c1 in each alkenyl group-containing polyoxane (A) and each hydrogenated polyoxyalkylene (B) The c2 in it will not all be 0.

The conditions shown in the above formula (3) and formula (4) are satisfied in the curable composition.

A1 to e1 in the formula (3) and the formula (4) have the same meanings as a1 to e1 in the formula (1), respectively, and represent each alkenyl group-containing polyoxane contained in the present curable composition (A). ) related to a1~e1. A2 to e2 have the same meanings as a2 to e2 in the formula (2), and represent a2 to e2 related to each of the hydrogenated polyoxyalkylenes (B) contained in the present curable composition.

L ₁ in the formula (3) and the formula (4) is a value obtained by expressing the content of each alkenyl group-containing polyoxyalkylene (A) contained in the curable composition in parts by weight, and L ₂ is The content of each hydrogenated polyoxyalkylene (B) contained in the curable composition is a numerical value expressed by parts by weight. Wherein the sum of L ₁ Silicon poly siloxane (A) each of the alkenyl group-containing silicon oxide with hydrogenated poly L alkoxy total of (B) and ₂ to 100.

In the formula (3), Σ[(d1+e1)×L ₁ ] represents the sum of (d1+e1)×L ₁ in each alkenyl group-containing polyfluorene oxide (A) contained in the curable composition. .

Σ[(d2+e2)×L ₂ ] represents the sum of (d2+e2)×L ₂ in each of the hydrogenated polyoxyalkylenes (B) contained in the curable composition.

Σ[(a1+b1+c1+d1+e1)×L ₁ ] represents (a1+b1+c1+d1+e1) in each alkenyl group-containing polyoxane (A) contained in the curable composition ) The sum of × L ₁ .

Σ[(a2+b2+c2+d2+e2)×L ₂ ] represents (a2+b2+c2+d2+e2)×L in each hydrogenated polyoxyalkylene (B) contained in the curable composition The sum of ₂ .

In the formula (4), Σ[c1 × L ₁ ] represents the sum of c1 × L ₁ in each alkenyl group-containing polyoxane (A) contained in the curable composition.

Σ [c2 × L ₂ ] represents the sum of c2 × L ₂ in each of the hydrogenated polyoxyalkylenes (B) contained in the curable composition.

Σ[(a1+b1+c1+d1+e1)×L ₁ ] represents (a1+b1+c1+d1+e1) in each alkenyl group-containing polyoxane (A) contained in the curable composition ) The sum of × L ₁ .

Σ[(a2+b2+c2+d2+e2)×L ₂ ] represents (a2+b2+c2+d2+e2)×L in each hydrogenated polyoxyalkylene (B) contained in the curable composition The sum of ₂ .

For example, suppose that the present curable composition contains only one polyoxynitane (A1) as an alkenyl group-containing polyoxyalkylene (A), and contains only one polyoxyalkylene (B1) as a hydrogenated polyoxyalkylene. (B). In this case, L ₁ is a value when the content of the polyoxyalkylene (A1) in terms of the total content of the polyoxyalkylene (A1) and the polyoxyalkylene (B1) is 100 parts by weight, and is expressed by parts by weight. L ₂ is a numerical value when the content of the polysiloxane (B1) in terms of the total content of the polyoxyalkylene (A1) and the polyoxyalkylene (B1) is 100 parts by weight. For example, when the content of the polyoxyalkylene (A1) is 70 parts by weight and the content of the polyoxyalkylene (B1) is 30 parts by weight, L ₁ is 70 and L ₂ is 30.

Under the circumstances, (3) [in the formula [Sigma (d1 + e1) × L _1] represents a poly siloxane silicon (A1) in a _{(d1 + e1) × L 1} , Σ [(a1 + b1 + c1 + D1 + e1) × L ₁ ] represents (a1 + b1 + c1 + d1 + e1) × L _{1 in the} polyoxyalkylene (A1). Further, the formula (3) [Sigma [(d2 + e2) × L _2] represented by _{(d2 + e2) × L 2} , Σ [(a2 + b2 + c2 + d2 + e2 poly-silicon siloxane (B1) of ) × L ₂ ] represents (a2+b2+c2+d2+e2)×L _{2 in the} polyoxyalkylene (B1). The same applies to the formula (4).

Further, it is assumed that the present curable composition contains two kinds of polyoxyalkylene oxide (A1) and polyoxyalkylene oxide (A2) as an alkenyl group-containing polyoxyalkylene (A), and contains polyoxyalkylene (B1) and Two kinds of polyoxyalkylene (B2) are used as the hydrogenated polyoxyalkylene (B). In this case, L ₁ is a polycondensation when the total content of polyoxydecan (A1), polyoxyalkylene (A2), polyoxyalkylene (B1), and polyoxyalkylene (B2) is 100 parts by weight. The content of the decane (A1) and the polyoxyalkylene (A2) is expressed by parts by weight, and L ₂ is a polyaluminoxane (A1), a polyoxyalkylene (A2), or a polyoxyalkylene (B1). And the content of the polyoxydecane (B1) and the polyoxyalkylene (B2) when the total content of the polyoxyalkylene (B2) is 100 parts by weight, expressed as parts by weight. For example, when the content of the polyoxyalkylene (A1) is 40 parts by weight, the content of the polyoxyalkylene (A2) is 30 parts by weight, the content of the polyoxyalkylene (B1) is 20 parts by weight, and the polyoxyalkylene oxide when the content of (B2) is 10 parts by weight, on the poly silicon siloxane (A1), L ₁ is 40, the polylactic silicon siloxane (A2), L ₁ is 30, the polylactic silicon siloxane (B1), L ₂ 20, the L ₂ for polyoxyalkylene (B2) is 10.

The case where the formula (3) Σ [(d1 + e1) × L _1] represents a poly siloxane silicon (A1) in a (d1 + e1) × L ₁ with a poly silicon alumoxane (A2) of (d1+e1)×the sum of L ₁ , Σ[(a1+b1+c1+d1+e1)×L ₁ ] represents (a1+b1+c1+d1+e1)× in the polyoxyalkylene (A1)× ₁ L siloxane poly silicon (A2) in (a1 + b1 + c1 + d1 + e1) × L ₁ and a sum. Further, the formula (3) Σ [(d2 + e2) × L _2] represents a poly silicon siloxane (B1) of (d2 + e2) × L ₂ with a poly silicon alumoxane (B2) in (d2 + e2) × L, and ₂ of, Σ [(a2 + b2 + c2 + d2 + e2) × L 2 ] represents a poly silicon siloxane (B1) of (a2 + b2 + c2 + d2 + e2) × L 2 and The sum of (a2+b2+c2+d2+e2)×L ₂ in polyoxyalkylene (B2). The same applies to the formula (4).

When the curable composition contains three or more kinds of polyoxyalkylene oxides as the alkenyl group-containing polyoxyalkylene oxide (A) or three kinds of polyoxyalkylene oxides as the hydrogenated polyoxyalkylene oxide (B), The same.

Formula (3) is a 4-functional structural unit (Q unit) and a trifunctional group contained in the alkenyl group-containing polyoxane (A) as a main component and a hydrogenated polyoxyalkylene (B) as a crosslinking agent The content ratio of the structural unit (T unit) is specified. The Q unit and the T unit are units that contribute to the branching of the polyoxane. Therefore, the formula (3) is a parameter indicating the degree of branching of the crosslinked body obtained from the present curable composition.

The content ratio of the alkenyl group-containing polyoxane (A) as a main component and the bifunctional structural unit (D unit) contained in the hydrogenated polyoxyalkylene (B) as a crosslinking agent is carried out in the formula (4). Provisions. The D unit is a linear unit that contributes to polyoxyalkylene. Therefore, the formula (4) becomes a parameter indicating the degree of linearity.

In other words, the present curable composition satisfies the conditions of the formulae (3) and (4), and means that the balance of the ratio of the branch portion to the linear portion in the crosslinked body obtained from the curable composition is in a specific range. Inside. As a result, when the present curable composition is used and the protective film is formed on the wafer by the wafer level packaging technique, the wafer warpage and the protective film are obtained even when the film is formed over a wide area. of The effect of cracking is small.

[Σ[(d1+e1)×L ₁ ]+Σ[(d2+e2)×L ₂ ]]/[Σ[(a1+b1+c1+d1+e1)×L ₁ ] in the formula (3) +Σ[(a2+b2+c2+d2+e2)×L ₂ ]] (hereinafter also referred to as (3) value) is preferably more than 0.25 and less than 0.55, particularly preferably more than 0.3 and less than 0.5. When the value of (3) is within the above range, it is possible to obtain a protective film having less adhesion, occurrence of warpage of the wafer, and generation of cracks in the protective film.

[Σ[c1×L ₁ ]+Σ[c2×L ₂ ]]/[Σ[(a1+b1+c1+d1+e1)×L ₁ ]+Σ[(a2+b2+) in the formula (4) C2+d2+e2)×L ₂ ]] (hereinafter also referred to as (4) value) is preferably more than 0.07 and less than 0.3, and particularly preferably more than 0.1 and less than 0.2. When the value of (4) is within the above range, it is possible to obtain a protective film having less adhesiveness and less warpage of the wafer.

Further, in the formulas (3) and (4), a1 to e1 and a2 to e2 represent the number of structural units in which the symbol is included in one molecule, and the (3) value and (4) are obtained. In the case of the value shown in the following examples, the contents (unit: mmol/g, etc.) of each structural unit contained in the polyoxyalkylene may be used instead of a1 to e1 and a2 to e2.

In the present curable composition, the content of the hydrogenated polyoxyalkylene (B) is usually 10 parts by weight to 50 parts by weight, preferably 15 parts by weight to 45 parts by weight (wherein the alkenyl group-containing polydecane oxide (A) The content is set to 100 parts by weight). In the case where the curable composition contains two or more kinds of alkenyl group-containing polyoxoxanes (A), the content of the alkenyl group-containing polyoxane (A) means that the curable composition is The total content (L ₁ part by weight) of each of the alkenyl group-containing polysiloxanes (A) contained. In the case where the curable composition contains two or more kinds of hydrogenated polyoxyalkylene oxides (B), the content of the hydrogenated polyoxyalkylene (B) means each hydrogenated polyfluorene contained in the curable composition. The total content (L ₂ parts by weight) of the oxyalkylene (B).

The method for producing the alkenyl group-containing polyoxane (A) and the hydrogenated polyoxyalkylene (B) is exemplified by Japanese Patent Laid-Open No. Hei 6-9659, Japanese Patent Laid-Open No. 2003-183582, and Japanese Patent Laid-Open A known method described in, for example, JP-A-2007-106798, JP-A-2007-169427, and JP-A-2010-059359, for example, A method of co-hydrolysis of chlorodecane or alkoxysilane, or a method of performing a balance reaction of a co-hydrolyzate by an alkali metal catalyst or the like.

When the alkenyl group-containing polyoxyalkylene (A) and the hydrogenated polyoxyalkylene (B) are produced, the ratio of the tetrafunctional decane compound, the trifunctional decane compound, and the bifunctional decane compound to be used is appropriately adjusted. The produced alkenyl group-containing polyoxyalkylene (A) and hydrogenated polyoxyalkylene (B) were produced, whereby a composition satisfying the conditions of the above formula (3) and formula (4) was obtained.

The catalyst for hydrogenation reaction (C) is a catalyst for the hydrogenation reaction of an alkenyl group-containing polyoxyalkylene (A) with a hydrogenated polyoxyalkylene (B).

The catalyst for the hydrogenation reaction (C) can be used without any particular limitation as long as it is a catalyst used as a catalyst for the hydrogenation reaction in the conventional hydrogenated decane-based polyoxane composition.

Specific examples of the catalyst (C) for the hydrogenation reaction include a platinum catalyst, a rhodium catalyst, and a palladium catalyst. Among these catalysts, the present hardenable composition From the viewpoint of promoting the hardening of the substance, a platinum-based catalyst is preferable. Examples of the platinum-based catalyst include a platinum-alkenyl alkane complex and the like. Examples of the alkenyl oxirane include 1,3-divinyl-1,1,3,3-tetramethyldioxane and 1,3,5,7-tetramethyl-1,3,5. , 7-tetravinylcyclotetraoxane, and the like. Particularly, from the viewpoint of the stability of the complex, 1,3-divinyl-1,1,3,3-tetramethyldioxane is preferred.

The catalyst (C) for the hydrogenation reaction of the hydrazine in the curable composition of the present invention is an amount in which a hydrogenation reaction of an alkenyl group-containing polyoxyalkylene (A) and a hydrogenated polyoxyalkylene (B) is carried out in practice.

Examples of the additives which may be contained in the curable composition include finely divided cerium oxide such as fumed silica and quartz powder, inorganic fillers such as titanium oxide and zinc oxide, and cyclo-tetramethyltetravinyltetrasiloxane. A diluent such as a retarder, a diphenyl bis(dimethylvinyl decyloxy) decane, a phenyl tris(dimethylvinyl decyloxy) decane, a phosphor, a pigment, and a hindrance A fuel, a heat resistant agent, an antioxidant, and the like.

When the inorganic filler is contained in the polyoxane composition for forming a protective film, it is known that the thermal expansion coefficient of the protective film containing the composition is lowered, and when the protective film is formed on the wafer using the composition, the coating can be reduced. Warpage of the wafer and generation of cracks in the protective film. However, in the case of a wafer-level package, since a film is uniformly formed over a wide area on a substrate having a low thermal expansion coefficient, warpage of the wafer is particularly likely to occur. Therefore, in wafer level packaging, in order to suppress warpage by blending an inorganic filler in a composition, it is necessary to increase the amount of the inorganic filler. When the amount of the inorganic filler is increased, it becomes difficult to uniformly coat the film due to thixotropy of the curable composition.

However, since the protective film obtained from the curable composition has high performance for suppressing warpage of the wafer, warpage can be suppressed even if the inorganic filler is not blended in the curable composition, and the inorganic filler can be formulated. In the case of the case, the amount of the mixture can be suppressed to a small amount. When the inorganic filler is blended in the curable composition, the amount thereof is usually 30% by weight or less, preferably 0.01% by weight to 10% by weight, and more preferably 0.1% by weight in the curable composition. 5 wt%.

The curable composition can be prepared by uniformly mixing the above components by a known method such as a mixer.

The viscosity of the curable composition of the present invention at 25 ° C is preferably 1 mPa. s~1000000mPa. s, more preferably 10 mPa. s~10000mPa. s. When the viscosity is within this range, the workability of the curable composition is improved.

The curable composition can be prepared as one type of liquid, or can be prepared by dividing into two kinds of liquids, and when used, two kinds of liquids are mixed and used. A small amount of a hardening inhibitor such as a fast alcohol may be added as needed.

The method of applying the curable composition to a wafer having a semiconductor element is not particularly limited, and a spin coating method in which a protective film forming composition is applied when a protective film is formed on a wafer can be used. The thickness and the like of the coating film obtained by applying the curable composition are not particularly limited as long as the protective film can be formed by curing the coating film.

The method of hardening the coating film is, for example, a method of heating the coating film at 100 ° C to 180 ° C for 1 hour to 13 hours. In addition, it is also possible to employ a two-stage heating in which the second heating is performed at a temperature higher than the first heating after the first heating. Hardening method.

A protective film for wafer level encapsulation is obtained by curing the curable composition. By providing the wafer-level packaging protective film on a wafer having a semiconductor element, a laminate including a wafer-level packaging protective film, a wafer, and a semiconductor element is obtained.

As described above, the protective film obtained by curing the coating film has characteristics of suppressing warpage or cracking of the wafer even when it is formed over a wide area in the wafer level packaging technique.

[Examples]

1. Preparation of alkenyl-containing polyoxyalkylene (A) and hydrogenated polyoxyalkylene (B)

1-1. Structural Analysis

The structures of the compounds synthesized in the following synthesis examples were analyzed by ²⁹ Si nuclear magnetic resonance (NMR) and ¹³ C NMR.

1-2. Synthesis of polyoxyalkylene

[Synthesis Example A1 to Synthesis Example A57] Synthesis of Alkenyl Group-Containing Polyoxane (A)

The decane compound shown in Table 1 was added to a four-necked flask equipped with a stirrer, a reflux cooling tube, an inlet, and a thermometer, and further, water, trifluoromethanesulfonic acid, and toluene were added and mixed. Reflux. After cooling, a 0.5 wt% potassium hydroxide aqueous solution was added to the reaction liquid, and after heating under reflux, the remaining water was removed by azeotropic dehydration. After cooling, the reaction solution was neutralized with acetic acid and washed with water. From The solvent was removed from the reaction mixture to obtain a polyoxyalkylene (A1)-polyoxane (A57) having the structural unit shown in Table 1 in the amounts shown in Table 1.

[Synthesis Example B1 to Synthesis Example B19] Synthesis of Hydrogenated Polyoxane (B)

The decane compound shown in Table 2 was added to a four-necked flask equipped with a stirrer, a reflux cooling tube, an inlet, and a thermometer, and further mixed with water, trifluoromethanesulfonic acid, acetic acid, and toluene. Heat to 50 °C. After heating, liquid separation extraction was carried out using toluene and water to obtain a polyoxyalkylene (B1)-polyoxane (B19) having the structural unit shown in Table 2 in the amounts shown in Table 2.

The details in the table are as follows.

Decane compound

M1: 1,3-divinyl-1,1,3,3-tetramethyldioxane

M2: 1,1,3,3-tetramethyldioxane

M3: methylvinyldimethoxydecane

M4: diphenyldimethoxydecane

M5: 3-glycidoxypropylmethyldimethoxydecane

M6: dimethyldimethoxydecane

M7: phenyltrimethoxydecane

M8: methyltrimethoxydecane

M9: tetramethoxy decane

Structural units

M(Vi)-A: a structural unit equivalent to (R ¹ R ² ₂ SiO _1/2 ) of the formula (1)

MA: a structural unit equivalent to (R ³ ₃ SiO _1/2 ) of the formula (1)

DA: a structural unit equivalent to (R ⁴ ₂ SiO _2/2 ) of the formula (1)

TA: a structural unit equivalent to (R ⁵ SiO _3/2 ) of the formula (1)

QA: a structural unit equivalent to (SiO _4/2 ) of the formula (1)

M(H)-B: a structural unit equivalent to (HR ⁶ ₂ SiO _1/2 ) of the formula (2)

MB: a structural unit equivalent to (R ⁷ ₃ SiO _1/2 ) of the formula (2)

DB: a structural unit equivalent to (R ⁸ ₂ SiO _2/2 ) of the formula (2)

TB: a structural unit equivalent to (R ⁹ SiO _3/2 ) of the formula (2)

QB: a structural unit equivalent to (SiO _4/2 ) of the formula (2)

2. Preparation and evaluation of the composition

2-1. Preparation of the composition

The polysiloxanes shown in the following Table 3 were mixed at a ratio shown in the following Table 3 to prepare Composition 1 to Composition 3, Composition 5, and Composition 7 to Composition 12 as Examples. As a comparative example, the composition 4, the composition 6 and the composition 13 to the composition 19 were used. The (3) value and the (4) value of the composition 1 to the composition 19 are shown in Table 3.

2-2. Wafer warpage

Each of the composition 1 to the composition 19 was applied to a different 5 cm square copper clad laminate (printed substrate manufactured by Mitsubishi Gas Chemical Co., Ltd., "CCL-HL950K"), and then heated at 100 ° C. After 1 hour, it was heated at 150 ° C for 5 hours to form 19 kinds of protective films having a thickness of 0.5 mm including any one of the composition 1 to the composition 19. After the formation of the protective film, the substrate was placed on a stage, and the interval between the angle between the stage and the substrate was measured as the lift height, and the warpage of the wafer was evaluated in accordance with the following evaluation criteria. The evaluation results are shown in Table 3.

"A": Lift height is less than 1mm

"B": The lifting height is 1mm or more and less than 3mm

"C": the lifting height is 3mm or more and less than 10mm

"D": The lifting height is 10mm or more

2-3. Crack resistance of protective film

The composition 1 to the composition 19 were respectively applied to a ruthenium wafer having a diameter of 8 inches, and then heated at 100 ° C for 1 hour, and then heated at 150 ° C for 5 hours to form a composition 1 to composition. 19 kinds of protective films having a film thickness of 1 mm. The obtained protective film was observed with an optical microscope, and the crack resistance of the protective film was evaluated in accordance with the following evaluation criteria. The evaluation results are shown in Table 3.

"A": No cracks on the protective film.

"B": There is crack on the protective film.

2-4. Adhesion of protective film

After the composition 1 to the composition 19 were respectively applied to different 5 cm square copper-clad laminates (printed substrates manufactured by Mitsubishi Gas Chemical Co., Ltd., CCL-HL950K), The film was heated at 100 ° C for 1 hour, and then heated at 150 ° C for 5 hours to form 19 kinds of passivation films having a thickness of 0.5 mm including any one of the composition 1 to the composition 19. For the adhesion evaluation, a tacking tester (manufactured by Rhesca Co., Ltd., TAC-1000) was used. The probe was pressed against the protective film, and the adhesion at the time of peeling was measured by the test machine, and the adhesiveness was evaluated. The evaluation results are shown in Table 3. When the adhesion is small, in the wafer level packaging method, problems such as adhesion of wafer fragments at the time of wafer cutting can be prevented.

"A": adhesion is less than 40gf

"B": the adhesion is 40gf or more and less than 100gf

"C": the adhesion is 100gf or more and less than 500gf

"D": Adhesive force is 500gf or more

"-": not evaluated

Claims (6)

A method for forming a protective film for a wafer-level package, comprising: applying a curable composition to a wafer having a semiconductor element, and curing the obtained coating film to form a protective film, wherein the curable composition contains At least one alkenyl group-containing polyoxane (A) represented by the following chemical formula (1), at least one hydrogenated polyoxyalkylene (B) represented by the following chemical formula (2), and a catalyst for hydrogenation reaction of hydrazine (C), and satisfying the conditions of the following formula (3) and the following formula (4): (R ¹ R ² ₂ SiO _1/2 ) _a1 (R ³ ₃ SiO _1/2 ) _b1 (R ⁴ ₂ SiO _2/2 ) _c1 (R ⁵ SiO _3/2 ) _d1 (SiO _4/2 ) _e1 (OX ¹ ) _f1 (1) (wherein R ¹ is an alkenyl group, and R ^{2 is} independently an alkyl group, an aromatic group Or an alkyl group, R ³ , R ⁴ and R ⁵ are each independently an alkyl group, an aryl group, an arylalkyl group or a group having an epoxy group, and X ¹ independently represents a hydrogen atom or a carbon number of 1 to 3; The alkyl group; the symbol a1, the symbol b1, the symbol c1, the symbol d1, the symbol e1, and the symbol f1 represent the number of structural units in which the symbol is included in one molecule, and a1 is an integer of 2 or more, b1, c1. , d1, e1, and f1 are each independently 0 or more _{^{); (HR 6 2 SiO 1/2}} ) a2 (R 7 3 SiO 1/2) b2 (R 8 2 SiO 2/2) c2 (R 9 SiO 3/2) d2 (SiO 4/2) e2 (OX ² ) _f2 (2) (wherein R ^{6 is} independently alkyl, aryl or aralkyl, respectively, and R ⁷ , R ⁸ and R ⁹ are each independently alkyl, aryl, aralkyl or have a ring The group of the oxy group, X ² independently represents a hydrogen atom or an alkyl group having 1 to 3 carbon atoms; the symbol a2, the symbol b2, the symbol c2, the symbol d2, the symbol e2, and the symbol f2 indicate that the one molecule contains The number of structural units of the symbol, a2 is an integer of 2 or more, and b2, c2, d2, e2, and f2 are each independently an integer of 0 or more); 0.1<[Σ[(d1+e1)×L ₁ ] +Σ[(d2+e2)×L ₂ ]]/[Σ[(a1+b1+c1+d1+e1)×L ₁ ]+Σ[(a2+b2+c2+d2+e2)×L ₂ ] <0.6 (3) (wherein a1 to e1 have the same meanings as a1 to e1 in the formula (1), respectively, and represent each of the alkenyl group-containing polyoxoxanes contained in the curable composition. (A) The related a1~e1; a2~e2 have the same meanings as a2~e2 in the formula (2), respectively, and are related to each of the hydrogenated polyoxane (B) contained in the curable composition. A2~e2; L ₁ is the hardenable composition The content of each of the alkenyl group-containing polyoxyalkylene (A) contained in the above is expressed by parts by weight, and L ₂ is the respective hydrogenated polyoxynitride contained in the curable composition. The content of (B) is a numerical value expressed by parts by weight (wherein the total of L ₁ in each of the alkenyl group-containing polyoxyalkylenes (A) and each of the hydrogenated polyoxyalkylenes (B) The sum of the total of L ₂ is set to 100); Σ [(d1 + e1) × L ₁ ] represents each of the alkenyl group-containing polyoxoxanes (A) contained in the curable composition ( the sum d1 + e1) × L ₁ is, Σ [(d2 + e2) × L _2] representing the hydrogenation of each of the curable composition contained in the poly silicon siloxane (B) of (d2 + e2) ₂ × L sum, Σ [(a1 + b1 + c1 + d1 + e1) × L 1 ] represents the poly silicon siloxane (a) each of the alkenyl group-containing curable composition contained in the the sum (a1 + b1 + c1 + d1 + e1) × L 1 is, Σ [(a2 + b2 + c2 + d2 + e2) × L 2 ] represents each of the hydrogenation of the curable composition contained in the poly (a sum of (a2+b2+c2+d2+e2)×L ₂ in the oxane (B)); 0.05<[Σ[c1×L ₁ ]+Σ[c2×L ₂ ]]/[Σ[( a1 + b1 + c1 + d1 + e1) × L 1 ] + Σ [(a2 + b2 + c2 + d2 + e2) × L 2 ]] <0.5 (4) (formula , A1 ~ e1 respectively formulas a1 ~ e1 same meaning as (3), a2 ~ e2 respectively formulas a2 ~ e2 the same meaning as (3); in L ₁ and L ₂ respectively of formula (3) L ₁ And L ₂ have the same meaning; Σ [c1 × L ₁ ] represents the sum of c1 × L ₁ in each of the alkenyl group-containing polyoxyalkylenes (A) contained in the curable composition, Σ [c2 ×L ₂ ] represents the sum of c2 × L ₂ in each of the hydrogenated polyaluminoxanes (B) contained in the curable composition, Σ [(a1 + b1 + c1 + d1 + e1) × L ₁ ] represents the sum of (a1+b1+c1+d1+e1)×L ₁ in each of the alkenyl group-containing polyoxosiloxanes (A) contained in the curable composition, Σ[(a2) +b2+c2+d2+e2)×L ₂ ] represents (a2+b2+c2+d2+e2)×L in each of the hydrogenated polyoxyalkylenes (B) contained in the curable composition The sum of ₂ ). The method of forming a protective film for wafer level packaging according to claim 1, wherein the semiconductor element is a light emitting diode. A protective film for wafer level packaging, characterized in that: The method for forming a protective film for wafer level packaging according to the first aspect of the invention. A hardenable composition for wafer level packaging, comprising: an alkenyl group-containing polyoxyalkylene (A) represented by the chemical formula (1) according to claim 1 of the patent application, as claimed in the patent application The hydrogenated polyoxyalkylene (B) represented by the chemical formula (2) and the catalyst (C) for hydrogenation reaction according to the first aspect, and satisfying the formula (3) and the formula (1) as described in the first aspect of the patent application ( 4) The conditions shown. A protective film for wafer level encapsulation, which is obtained by the curable composition according to item 4 of the patent application. A laminate comprising a protective film for a wafer level package, a wafer, and a semiconductor device according to claim 3 or 5.