JP7568476B2 - HOLLOW SEMICONDUCTOR PACKAGE, ITS MANUFACTURING METHOD, AND RESIN COMPOSITION SET FOR HOLLOW SEMICONDUCTOR PACKAGE - Google Patents

Description

The present invention relates to a hollow semiconductor package having a semiconductor element in a hollow structure and a method for manufacturing the same. The present invention also relates to a resin composition set for hollow semiconductor packages used to form spacers and sealants for hollow semiconductor packages.

A hollow package structure in which a semiconductor element is placed in a hollow structure is known as a structure for light-receiving semiconductor devices such as solid-state imaging devices and semiconductor lasers. In a hollow structure, a spacer is placed between a substrate such as a silicon substrate and a lid made of glass or the like, and the joints between the substrate and the spacer and between the lid and the spacer are sealed with a sealant to maintain airtightness.

Patent Document 1 proposes forming a spacer by applying a photosensitive resin composition that has thermocompression bonding properties to the substrate material onto the substrate and patterning it into a frame shape by photolithography. Patent Document 2 describes that by adding a moisture absorbent to the sealant, the sealant absorbs moisture inside the hollow structure in which the semiconductor element is placed, improving the reliability of the hollow semiconductor package.

JP 2011-116968 A JP 2002-124589 A

Hollow semiconductor packages require reflow resistance because they must go through a high-temperature reflow process during assembly. In addition, even if the temperature and humidity change in the device's operating environment, peeling or cracks must not occur at the joints between the spacer and the substrate or lid, or at the interface between the spacer and the sealant, and the hollow structure must remain sealed.

The spacer and sealant that form the hollow structure are made of a resin material, and so are prone to dimensional changes due to humidification and temperature changes. If the hygroscopicity of the sealant is increased as proposed in Patent Document 2, moisture absorption and expansion becomes significant, and peeling or cracks may occur at the interface due to differences in the amount of dimensional change between the spacer and the sealant.

In view of the above, the present invention aims to provide a hollow semiconductor package that suppresses the retention of moisture in the hollow structure and has excellent reliability in the joint between the spacer and the sealant.

The hollow semiconductor package has a semiconductor element in a hollow structure formed by a substrate, a lid, and a frame-shaped spacer disposed between the substrate and the lid. The joints between the substrate and the spacer and the joints between the lid and the spacer are sealed with a sealing part. Both the spacer and the sealing part preferably contain a polysiloxane resin.

The sealing portion may have a product of moisture permeability and thickness of 0.05 to 0.6 g/m24h. The glass transition temperature of the sealing portion may be 30 to 150°C.

The sealing portion is preferably formed by thermally curing a sealant made of a thermosetting resin composition containing a polysiloxane resin. The polysiloxane resin of the sealing portion (sealant after thermal curing) may contain either a cyclic polysiloxane structure or a chain polysiloxane structure, or may contain both.

The sealant may contain a polysiloxane polymer having two or more SiH groups in one molecule and a crosslinker having two or more alkenyl groups in one molecule. The polysiloxane polymer of the sealant may contain a cyclic polysiloxane structure, and the crosslinker may contain a linear polysiloxane structure. When this sealant is thermally cured, the polymer and the crosslinker react with each other, and the sealing portion formed by thermal curing contains a polymer having both a cyclic polysiloxane structure and a linear polysiloxane structure.

Spacers can also be made using a photosensitive resin composition. For example, a spacer having a frame-shaped pattern can be obtained by applying a photosensitive resin composition containing a polysiloxane resin and patterning it by photolithography.

As described above, the sealant (thermosetting resin composition) used to form the sealing portion and the photosensitive resin composition used to form the spacer both contain polysiloxane resin. These resin compositions can also be provided as a resin composition set for hollow semiconductor packages.

The hollow semiconductor package of the present invention has high moisture permeability because the spacer and sealing portion contain polysiloxane resin. Therefore, even if moisture penetrates into the hollow structure, the moisture is easily dissipated to the outside via the spacer and sealing agent, and moisture retention in the hollow structure can be suppressed. In addition, because the spacer and sealing portion are made of the same type of material, even if the humidity or temperature changes, the difference in the amount of dimensional change between the spacer and sealing agent is small, making it less likely for cracks or peeling to occur at the bonding interface, and providing excellent reliability.

1 is a cross-sectional view showing an example of the configuration of a hollow semiconductor package. FIG. 2 is a plan view showing an example of a hollow cell substrate. 2B is a cross-sectional view taken along line II-II in FIG. 2A. 4A to 4C are cross-sectional views showing examples of the configurations of chip pieces and semiconductor chips obtained by dicing a hollow cell substrate.

Figure 1 is a cross-sectional view showing an example of the configuration of a hollow semiconductor package. The hollow semiconductor package 100 includes a frame-shaped spacer 5 between a substrate 1 and a lid 3, and a hollow structure 6 is formed by the substrate 1, the lid 3, and the spacer 5. A semiconductor element 4 is disposed within this hollow structure 6. One end of a bonding wire 45 is connected to the semiconductor element 4. The other end of the bonding wire 45 is connected to an electrode (not shown) on the substrate 1.

The substrate 1 is a sensor substrate, and may be a semiconductor element substrate, a silicon wafer, a ceramic substrate, or the like. The lid 3 may be made of a transparent material such as glass or transparent plastic. The semiconductor element 4 may be, for example, a solid-state imaging element such as a CMOS or CCD, or a semiconductor laser element.

A sealing portion 7 made of a sealant is formed on the outer surface of the spacer 5. The sealing portion 7 is provided so as to cover at least the joint portion 51 between the substrate 1 and the spacer 5, and the joint portion 53 between the lid 3 and the spacer 5. As shown in FIG. 1, the sealing portion 7 may cover the entire outer surface of the spacer 5.

Figure 2A is a plan view of a hollow cell substrate used to fabricate a hollow semiconductor package. Figure 2B is a cross-sectional view taken along line II-II in Figure 2A. This hollow cell substrate 300 has a plurality of frame-shaped spacers 35 arranged in a matrix on a transparent substrate 30 made of glass, plastic, or the like. For example, a photosensitive resin composition is applied onto the substrate 30, and then patterned by photolithography to form the frame-shaped spacers 5.

By cutting this hollow cell substrate 300 along the dashed lines in Figures 2A and 2B, a chip piece 301 is obtained in which a frame-shaped spacer 5 is provided on the lid 3, as shown in Figure 3. The spacer 5 of the chip piece 301 is pressed onto a semiconductor chip 101 having a semiconductor element 4 provided on a substrate 1, and the joint is sealed with a sealant, thereby forming the hollow semiconductor structure shown in Figure 1. The sealant used in the sealing portion 7 is thermosetting, and after a composition is applied to the joint, it is cured by heating.

As described above, a photosensitive resin composition is used to form the spacer 5, and a thermosetting resin composition is used to form the sealing portion 7. In a preferred embodiment of the present invention, both the spacer 5 and the sealing portion 7 contain polysiloxane resin. By containing polysiloxane resin in both the spacer 5 and the sealing portion 7, the distortion (e.g., coefficient of linear thermal expansion) caused by temperature changes and the responsiveness to moisture (e.g., moisture permeability and water absorption rate) of the two are similar. Therefore, the reflow resistance is excellent, and even if the hollow semiconductor package is exposed to a high-humidity environment or a high-temperature environment, peeling or cracking between the spacer 5 and the sealing portion 7 is unlikely to occur. In addition, since polysiloxane resin has higher moisture permeability than general curable resins such as epoxy resin, moisture is unlikely to remain in the hollow structure 6. Therefore, there is a tendency to suppress deterioration of the semiconductor element due to moisture and condensation on the lid (transparent substrate).

[Polysiloxane resin]
The polysiloxane resin (polymer) contains a polysiloxane structure. The "polysiloxane structure" refers to a structural skeleton having siloxane units Si-O-Si. The polysiloxane structure may be a cyclic polysiloxane structure. The "cyclic polysiloxane structure" refers to a cyclic molecular structural skeleton having siloxane units (Si-O-Si) as ring components.

The polysiloxane polymer may contain a polysiloxane structure in the main chain or in the side chain. When the polymer contains a polysiloxane structure in the main chain, heat resistance tends to be improved.

Typical examples of polysiloxane polymers include silicones having a repeating unit of (-SiR ¹ R ² -O-). R ¹ and R ² bonded to Si are monovalent organic groups, such as an alkyl group or a phenyl group. Typical examples of these silicones include methyl silicones having a repeating unit of (-Si(CH ₃ ) ₂ -O-), phenyl methyl silicones having a repeating unit of (-Si(CH ₃ )(C ₆ H ₅ )-O-), and phenyl silicones having a repeating unit of (-Si(C ₅ H ₆ ) ₂ -O-).

These silicone resins may be modified silicones having amino groups, epoxy groups, carboxy groups, carbinol groups, methacryl groups, mercapto groups, phenols, hydrogen atoms, etc., introduced at the terminals and/or side chains. The silicone resins may also be hydrogen silicones having hydrogen atoms (SiH groups) bonded to Si at the terminals and/or side chains. For example, a composition containing vinyl modified silicone and hydrogen silicone can be used as a thermosetting silicone resin composition because Si-C bonds are generated by a hydrosilylation reaction between SiH groups and vinyl groups in the presence of a catalyst such as a platinum complex.

In one embodiment, the polysiloxane polymer is obtained by a hydrosilylation reaction between (α) a compound having at least two SiH groups (hydrosilyl groups) in one molecule and (β) a compound having at least two carbon-carbon double bonds (ethylenically unsaturated groups) in one molecule that are reactive with SiH groups. If either or both of (α) and (β) have a polysiloxane structure, a polymer having a polysiloxane structure is obtained by the hydrosilylation reaction of (α) and (β). By changing the types of (α) and (β), it is possible to prepare polymers having various functional groups.

(Compound (α): Polysiloxane compound having a SiH group)
Compound (α) is a compound having a SiH group, and is preferably a polysiloxane compound having a hydrogen atom bonded to the Si atom of polysiloxane structure.Specific examples of polysiloxane compound (α) having at least two SiH groups in one molecule include a hydrosilyl group-containing polysiloxane having a linear structure, a polysiloxane having a hydrosilyl group at the molecular end, and a cyclic polysiloxane containing a hydrosilyl group.Compared to a polymer containing only a chain-like polysiloxane structure, a polymer containing a cyclic polysiloxane structure tends to have excellent film-forming properties and heat resistance.

The cyclic polysiloxane may have a polycyclic structure, and the polycyclic ring may have a polyhedral structure. In order to form a film with high heat resistance and mechanical strength, it is preferable to use a cyclic polysiloxane compound having at least two SiH groups in one molecule as compound (α). Compound (α) preferably contains three or more SiH groups in one molecule. From the viewpoint of heat resistance and light resistance, it is preferable that the group present on the Si atom is either a hydrogen atom or a methyl group.

Examples of hydrosilyl group-containing polysiloxanes having a linear structure include copolymers of dimethylsiloxane units, methylhydrogensiloxane units, and terminal trimethylsiloxy units, copolymers of diphenylsiloxane units, methylhydrogensiloxane units, and terminal trimethylsiloxy units, copolymers of methylphenylsiloxane units, methylhydrogensiloxane units, and terminal trimethylsiloxy units, and polysiloxanes whose ends are blocked with dimethylhydrogensilyl groups.

Examples of polysiloxanes having hydrosilyl groups at the molecular terminals include polysiloxanes whose terminals are blocked with dimethylhydrogensilyl groups, and polysiloxanes composed of dimethylhydrogensiloxane units (H( _CH3 ) _{2SiO1 /2} units) and at least one siloxane unit selected from the group consisting of _SiO2 units, SiO3 _/2 units, and SiO units.

Examples of cyclic polysiloxane compounds include 1,3,5,7-tetrahydrogen-1,3,5,7-tetramethylcyclotetrasiloxane, 1-propyl-3,5,7-trihydrogen-1,3,5,7-tetramethylcyclotetrasiloxane, 1,5-dihydrogen-3,7-dihexyl-1,3,5,7-tetramethylcyclotetrasiloxane, 1,3,5-trihydrogen-1,3,5-trimethylcyclosiloxane, 1,3,5,7,9-pentahydrogen-1,3,5,7,9-pentamethylcyclosiloxane, and 1,3,5,7,9,11-hexahydrogen-1,3,5,7,9,11-hexamethylcyclosiloxane.

The compound (α) may be a polycyclic polysiloxane having multiple rings. The multiple rings may have a polyhedral structure. The polysiloxane having a polyhedral skeleton preferably has 6 to 24 silicon atoms constituting the polyhedral skeleton, and more preferably has 6 to 10 silicon atoms. A specific example of a polysiloxane having a polyhedral skeleton is silsesquioxane. The cyclic polysiloxane may be a silylated silicic acid having a polyhedral skeleton.

(Compound (β): Compound containing an ethylenically unsaturated group)
Compound (β) contains two or more carbon-carbon double bonds reactive with SiH groups in one molecule. Examples of the group containing a carbon-carbon double bond reactive with SiH groups (hereinafter, sometimes simply referred to as an "ethylenically unsaturated group" or an "alkenyl group") include a vinyl group, an allyl group, a methallyl group, an acryl group, a methacryl group, a 2-hydroxy-3-(allyloxy)propyl group, a 2-allylphenyl group, a 3-allylphenyl group, a 4-allylphenyl group, a 2-(allyloxy)phenyl group, a 3-(allyloxy)phenyl group, a 4-(allyloxy)phenyl group, a 2-(allyloxy)ethyl group, a 2,2-bis(allyloxymethyl)butyl group, a 3-allyloxy-2,2-bis(allyloxymethyl)propyl group, and a vinyl ether group.

Specific examples of compounds (β) having two or more alkenyl groups in one molecule include diallyl phthalate, triallyl trimellitate, diethylene glycol bisallyl carbonate, trimethylolpropane diallyl ether, trimethylolpropane triallyl ether, pentaerythritol triallyl ether, pentaerythritol tetraallyl ether, 1,1,2,2-tetraallyloxyethane, diarylidene pentaerythritol, triallyl cyanurate, triallyl isocyanurate, diallyl monobenzyl isocyanurate, diallyl monomethyl isocyanurate, 1,2,4-trivinylcyclohexane, 1,4-butanediol divinyl ether, nonanediol divinyl ether, 1,4-cyclohexane dimethanol divinyl ether, triethylene glycol divinyl ether, trimethylolpropane trivinyl ether, pentaerythritol tetravinyl ether ether, diallyl ether of bisphenol S, divinylbenzene, divinylbiphenyl, 1,3-diisopropenylbenzene, 1,4-diisopropenylbenzene, 1,3-bis(allyloxy)adamantane, 1,3-bis(vinyloxy)adamantane, 1,3,5-tris(allyloxy)adamantane, 1,3,5-tris(vinyloxy)adamantane, dicyclopentadiene, vinylcyclohexene, 1,5-hexadiene, 1,9-decadiene, diallyl ether, bisphenol A diallyl ether, 2,5-diallylphenol allyl ether, and oligomers thereof, 1,2-polybutadiene (1,2 ratio of 10 to 100%, preferably 1,2 ratio of 50 to 100%), allyl ether of novolak phenol, allylated polyphenylene oxide, and other conventionally known epoxy resins in which all of the glycidyl groups have been replaced with allyl groups. In addition, compounds in which the allyl group in the above example compounds is replaced with a (meth)acryloyl group (e.g., polyfunctional (meth)acrylates) can also be suitably used as compound (β).

Compound (β) may be a polysiloxane compound having two or more alkenyl groups. Examples of linear polysiloxanes having two or more alkenyl groups include methyl silicone having dimethylvinylsilyl groups at both ends, phenyl silicone having dimethylvinylsilyl groups at both ends, phenyl methyl silicone having dimethylvinylsilyl groups at both ends, and silicones containing multiple methylvinylsiloxane units in the molecular chain.

Specific examples of cyclic polysiloxane compounds include 1,3,5,7-tetravinyl-1,3,5,7-tetramethylcyclotetrasiloxane, 1-propyl-3,5,7-trivinyl-1,3,5,7-tetramethylcyclotetrasiloxane, 1,5-divinyl-3,7-dihexyl-1,3,5,7-tetramethylcyclotetrasiloxane, 1,3,5-trivinyl-1,3,5-trimethylcyclosiloxane, 1,3,5,7,9-pentavinyl-1,3,5,7,9-pentamethylcyclosiloxane, and 1,3,5,7,9,11-hexavinyl-1,3,5,7,9,11-hexamethylcyclosiloxane.

Compound (β) may be a compound having an alkenyl group at the end and/or side chain of a polymer chain such as polyether, polyester, polyarylate, polycarbonate, polyolefin, polyacrylic acid ester, polyamide, polyimide, or phenol-formaldehyde.

(Other Starting Materials)
In addition to the above-mentioned compound (α) and compound (β), a compound having only one functional group participating in the hydrosilylation reaction in one molecule may be used as a starting material for the hydrosilylation reaction. The functional group participating in the hydrosilylation reaction is a SiH group or an ethylenically unsaturated group. By using a compound having only one functional group participating in the hydrosilylation reaction, a specific functional group can be introduced at the end of a polymer.

A compound having a photopolymerizable functional group (photosensitive group) may be used as a starting material for the hydrosilylation reaction. Examples of the photopolymerizable functional group include cationic polymerizable functional groups and radical polymerizable functional groups. The term "cationically polymerizable functional group" refers to a functional group that undergoes polymerization and crosslinking due to an acidic active substance generated from a photoacid generator when irradiated with active energy rays. Examples of active energy rays include visible light, ultraviolet light, infrared rays, X-rays, α rays, β rays, and γ rays. Examples of the cationic polymerizable functional group include an epoxy group, a vinyl ether group, an oxetane group, and an alkoxysilyl group. By introducing these photopolymerizable functional groups, a photosensitive polysiloxane polymer can be obtained. From the viewpoint of photosensitivity, an epoxy group is preferred as the cationic polymerizable functional group, and among epoxy groups, an alicyclic epoxy group or a glycidyl group is preferred from the viewpoint of stability. In particular, an alicyclic epoxy group is preferred because of its excellent photocationic polymerization properties.

The cationic polymerizable functional group can be introduced into the polymer by using a compound having an alkenyl group and a cationic polymerizable functional group in one molecule as a starting material. Specific examples of compounds having an alkenyl group and an epoxy group as a cationic polymerizable functional group in one molecule include vinylcyclohexene oxide, allyl glycidyl ether, diallyl monoglycidyl isocyanurate, and monoallyl diglycidyl isocyanurate.

The polysiloxane polymer used in the photosensitive resin composition is preferably alkali-soluble. Alkali-solubility can be imparted to the polymer by introducing an alkali-solubility-imparting group. When the polymer has a photopolymerizable functional group and an alkali-soluble group, it is soluble in alkali before photocuring and becomes insoluble in alkali after photocuring, so it can be used as a negative-type photosensitive resin. Examples of alkali-solubility-imparting groups (acidic groups) include phenolic hydroxyl groups, carboxy groups, N-substituted isocyanuric acid, and N,N'-disubstituted isocyanuric acid.

By using a compound containing an acidic group and an alkenyl group and/or a SiH group as the starting material for the hydrosilylation reaction, an alkali-soluble polymer can be obtained. For example, by using monoallyl isocyanurate as the starting material, a siloxane polymer having N-substituted isocyanuric acid can be obtained. In addition, by using diallyl isocyanurate, monoallyl monoglycidyl isocyanurate, monoallyl monomethyl isocyanurate, etc. as the starting material, a siloxane polymer having N,N'-disubstituted isocyanuric acid can be obtained.

The polysiloxane polymer may be one in which the protecting group is eliminated in the presence of an acid, thereby exhibiting alkali solubility. A polymer in which the protecting group is eliminated in the presence of an acid, thereby exhibiting alkali solubility, can be used as a positive-type photosensitive resin, since the protecting group is eliminated (deprotected) by the reaction of the acid generated from the photoacid generator, thereby increasing the alkali solubility.

Examples of the acidic group include a phenolic hydroxyl group, a carboxyl group, an N-substituted isocyanuric acid, and an N,N'-disubstituted isocyanuric acid. Examples of the protecting group for the phenolic hydroxyl group include a tert-butoxycarbonyl group and a trialkylsilyl group. For example, the phenolic hydroxyl group can be protected with a tert-butoxycarbonyl group by a reaction using a Boc reagent. The alkyl group in the trialkylsilyl group as the protecting group for the phenolic hydroxyl group is preferably an alkyl group having 1 to 6 carbon atoms, and more preferably a methyl group, from the viewpoint of ease of deprotection with an acid. The phenolic hydroxyl group can be protected with a trimethylsilyl group by a reaction using a silylating agent such as hexamethyldisilazane or trimethylchlorosilane. The acidic group (NH group) of N-substituted isocyanuric acid and N,N'-disubstituted isocyanuric acid can also be protected with the same protecting group as the phenolic hydroxyl group. Examples of protective groups for carboxylic acids include tertiary alkyl esters and acetals. Examples of tertiary alkyl groups in tertiary alkyl esters of carboxylic acids include tert-butyl, adamantyl, tricyclodecyl, and norbornyl groups.

By using a compound having a structure with a protecting group that is eliminated in the presence of an acid and containing an alkenyl group and/or a SiH group as the starting material for the hydrosilylation reaction, a polysiloxane polymer that is alkali-soluble can be obtained by eliminating the protecting group in the presence of an acid.

(Hydrosilylation reaction)
The order and method of the hydrosilylation reaction are not particularly limited. The hydrosilylation reaction may be carried out by charging all starting materials in one pot and carrying out polymerization, or by charging the raw materials in multiple batches and carrying out the reaction in multiple stages.

In the hydrosilylation reaction, the ratio B/A of the total amount A of alkenyl groups to the total amount B of SiH groups in the starting materials is preferably greater than 1. In the hydrosilylation reaction, alkenyl groups and SiH groups react at a ratio of 1:1. If B/A is greater than 1 and there is an excess of SiH groups relative to the alkenyl groups, a polysiloxane polymer having unreacted SiH groups is obtained. The unreacted SiH groups in the polymer can serve as crosslinking reaction points in, for example, a thermosetting resin composition.

For the hydrosilylation reaction, a hydrosilylation catalyst such as chloroplatinic acid, a platinum-olefin complex, or a platinum-vinylsiloxane complex may be used. The hydrosilylation catalyst may be used in combination with a co-catalyst. The amount of the hydrosilylation catalyst added is not particularly limited, but is preferably 10 ⁻⁸ to 10 ⁻¹ times, and more preferably 10 ⁻⁶ to 10 ⁻² times, the total amount (number of moles) of alkenyl groups contained in the starting material.

The temperature of the hydrosilylation reaction may be set appropriately, and is preferably 30 to 200°C, and more preferably 50 to 150°C. The oxygen volume concentration in the gas phase during the hydrosilylation reaction is preferably 3% or less. From the viewpoint of promoting the hydrosilylation reaction by adding oxygen, the gas phase may contain approximately 0.1 to 3% by volume of oxygen.

A solvent may be used in the hydrosilylation reaction. Examples of the solvent include hydrocarbon solvents such as benzene, toluene, hexane, and heptane; ether solvents such as tetrahydrofuran, 1,4-dioxane, 1,3-dioxolane, and diethyl ether; ketone solvents such as acetone and methyl ethyl ketone; and halogen solvents such as chloroform, methylene chloride, and 1,2-dichloroethane. Toluene, tetrahydrofuran, 1,4-dioxane, 1,3-dioxolane, and chloroform are preferred because they are easy to remove by distillation after the reaction. A gelation inhibitor may be used in the hydrosilylation reaction, if necessary.

[Resin composition]
<Sealant>
The sealing agent used to form the sealing portion has thermosetting properties. The thermosetting resin composition containing a polysiloxane resin is preferably one in which the polysiloxane resin is involved in thermosetting. For example, a polysiloxane polymer has thermosetting properties because Si-Si bonds are generated by reacting SiH groups with each other when heated.

The thermosetting resin composition preferably contains, in addition to the polysiloxane polymer, a compound (crosslinking agent) having a functional group capable of bonding with the polysiloxane polymer to introduce a crosslinked structure. For example, when the polysiloxane polymer contains a SiH group, by containing a compound having multiple ethylenically unsaturated groups as a crosslinking agent, thermosetting (crosslinking) proceeds by a hydrosilylation reaction between the SiH group of the polymer and the ethylenically unsaturated group of the crosslinking agent. Specific examples of compounds having two or more ethylenically unsaturated groups in one molecule include compounds similar to the compound (β) exemplified above.

The crosslinking agent may or may not have a polysiloxane structure. As the crosslinking agent, a compound having a polysiloxane structure and a compound not having a polysiloxane structure may be used in combination.

The polymer obtained after the thermosetting resin composition (sealant) is thermally cured preferably has a cyclic polysiloxane structure. If either or both of the polysiloxane polymer and the crosslinking agent contain a cyclic polysiloxane structure, the cured polymer will contain a cyclic polysiloxane structure. In particular, it is preferable that the polysiloxane polymer contains a cyclic polysiloxane structure. When the polymer contains a cyclic polysiloxane structure, the coatability of the composition is improved, and outflow of the sealant when forming a sealing portion with the sealant tends to be suppressed.

The polymer obtained by thermally curing the thermosetting resin composition (sealant) preferably has a chain polysiloxane structure. By including a chain polysiloxane structure, the moisture permeability of the sealant (sealing portion) is improved, and the retention of moisture in the hollow structure tends to be suppressed. In addition, by including a chain polysiloxane structure, the reflow resistance in a moisture-absorbing state is improved, and the occurrence of peeling and cracks at the bonding interface tends to be suppressed. As a crosslinking agent having a chain polysiloxane structure, for example, a chain polysiloxane with both ends vinyl-modified (for example, a silicone oil modified with vinyl at both ends) is used. Silicone oil modified with vinyl at both ends is available from companies such as Shin-Etsu Chemical Co., Ltd., Dow, and Constuhl Chemical.

From the viewpoint of achieving both the applicability and durability of the sealant, it is preferable that the polymer after the sealant is heat-cured contains both a cyclic polysiloxane structure and a chain polysiloxane structure. For example, the thermosetting resin composition constituting the sealant contains a polymer containing a cyclic polysiloxane structure and a crosslinking agent containing a chain polysiloxane structure, so that the polymer after the sealant is heat-cured contains both a cyclic polysiloxane structure and a chain polysiloxane structure.

The resin composition that exhibits thermosetting properties due to a hydrosilylation reaction preferably contains a hydrosilylation catalyst. As the hydrosilylation catalyst, the above-mentioned catalysts are preferable. A commercially available product may be used as the thermosetting resin composition that constitutes the sealant.

<Resin composition for spacers>
The resin material used to form the spacer is a photosensitive resin composition containing a polysiloxane resin. The photosensitivity of the photosensitive resin composition may be positive or negative. By using the photosensitive resin composition, a spacer having a frame-shaped pattern as shown in Figures 2A and 2B can be formed by applying the resin composition in a film form on a substrate and then performing patterning by photolithography.

(Negative Photosensitive Resin Composition)
The negative photosensitive resin composition contains a polysiloxane polymer exhibiting alkali solubility. As described above, the polymer used in the negative photosensitive resin composition contains an alkali-soluble group and further contains a photopolymerizable functional group.

The negative photosensitive resin composition may further contain a crosslinking agent. For example, when the polysiloxane polymer has cationic polymerizability, if a compound having two or more alkenyl groups in one molecule is used as the crosslinking agent, the polymer and the crosslinking agent react with each other by exposure to light, and the crosslinking agent hardens, making the composition insoluble in alkali. As a crosslinking agent having cationic photopolymerizability, a compound having two or more alicyclic epoxy groups in one molecule is preferable. Specific examples of compounds having two or more alicyclic epoxy groups in one molecule include 3,4-epoxycyclohexylmethyl-3',4'-epoxycyclohexanecarboxylate (Daicel's "Celloxide 2021P"), ε-caprolactone-modified 3',4'-epoxycyclohexylmethyl 3,4-epoxycyclohexanecarboxylate (Daicel's "Celloxide 2081"), and bis(3,4-epoxycyclohexylmethyl)adipate. A compound having two or more alicyclic epoxy groups in one molecule may contain a chain siloxane structure, such as the compound of formula S1 below, or may contain a cyclic siloxane structure, such as the compound of formula S2 below.

(Positive Photosensitive Resin Composition)
The positive photosensitive resin composition includes a polysiloxane polymer that exhibits alkali solubility by elimination of a protective group in the presence of an acid. The polysiloxane polymer may further have thermosetting properties. The positive photosensitive resin composition may include a thermosetting crosslinking agent. For example, when the polysiloxane polymer includes a SiH group, if a compound having two or more ethylenically unsaturated groups in one molecule is included in the photosensitive resin composition as a crosslinking agent, a crosslinked structure is introduced by a hydrosilylation reaction with the polysiloxane polymer. As a specific example of a compound having two or more ethylenically unsaturated groups in one molecule, the same compound as the compound (β) exemplified above can be used.

(Photoacid generator)
The photosensitive resin composition used to form the spacer may contain a photoacid generator. When the photoacid generator is irradiated with active energy rays such as ultraviolet rays, an acid is generated. In a cationic polymerizable composition (e.g., a negative photosensitive resin composition), the photoacid generator acts as a polymerization initiator, and curing by cationic polymerization proceeds. In a positive photosensitive resin composition, the action of the acid generated from the photoacid generator causes the protective group bonded to the alkali-solubility-imparting group (acidic group) to be released, thereby increasing the alkali solubility.

The photoacid generator contained in the photosensitive resin composition is not particularly limited as long as it generates a Lewis acid upon exposure to light. Specific examples of photoacid generators include ionic photoacid generators such as sulfonium salts, iodonium salts, ammonium salts, and other onium salts; and nonionic photoacid generators such as imide sulfonates, oxime sulfonates, and sulfonyl diazomethanes.

The content of the photoacid generator in the photosensitive resin composition is preferably 0.1 to 20 parts by weight, more preferably 0.1 to 15 parts by weight, and even more preferably 0.5 to 10 parts by weight, per 100 parts by weight of the resin content of the composition.

(Sensitizer)
The photosensitive resin composition may contain a sensitizer. By using the sensitizer, the exposure sensitivity during patterning is improved. Examples of the sensitizer include naphthalene-based compounds, anthracene-based compounds, and thioxanthone-based compounds, and among them, anthracene-based sensitizers are preferred because of their excellent photosensitizing effect. Specific examples of anthracene-based sensitizers include anthracene, 2-ethyl-9,10-dimethoxyanthracene, 9,10-dimethylanthracene, 9,10-dibutoxyanthracene (DBA), 9,10-dipropoxyanthracene, 9,10-diethoxyanthracene, 9,10-bis(octanoyloxy)anthracene, 1,4-dimethoxyanthracene, 9-methylanthracene, 2-ethylanthracene, 2-tert-butylanthracene, 2,6-di-tert-butylanthracene, and 9,10-diphenyl-2,6-di-tert-butylanthracene.

The amount of sensitizer in the composition is not particularly limited and may be adjusted as appropriate within a range that allows the sensitizing effect to be exhibited. From the viewpoint of the balance between curability and physical properties, the amount is preferably 0.01 to 20 parts by weight, more preferably 0.1 to 15 parts by weight, and even more preferably 0.5 to 10 parts by weight, per 100 parts by weight of the resin content of the composition.

<Other components of resin composition>
The thermosetting resin composition constituting the sealant and the photosensitive resin composition used to form the spacer may contain resin components, solvents, additives, etc. other than those described above.

(Thermosetting resin)
The resin composition may contain a polymerizable compound (thermosetting resin) that does not show reactivity with the above-mentioned polysiloxane polymer and can be thermoset alone or by reacting with other compounds. Examples of the thermosetting resin include epoxy resin, oxetane resin, isocyanate resin, blocked isocyanate resin, bismaleimide resin, bisallylnadimide resin, acrylic resin, allyl cured resin, unsaturated polyester resin, etc. The thermosetting resin may be a side chain reactive group type thermosetting polymer having a reactive group such as an allyl group, a vinyl group, an alkoxysilyl group, or a hydrosilyl group on the side chain or end of the polymer chain.

(Thermoplastic resin)
The resin composition may contain resin components and additives other than those described above. For example, the resin composition may contain various thermoplastic resins for the purpose of improving properties. Examples of the thermoplastic resin include acrylic resins, polycarbonate resins, cycloolefin resins, olefin-maleimide resins, polyester resins, polyethersulfone resins, polyarylate resins, polyvinyl acetal resins, polyethylene resins, polypropylene resins, polystyrene resins, polyamide resins, silicone resins, fluororesins, natural rubber, and rubber-like resins such as EPDM. The thermoplastic resin may have a crosslinkable group such as an epoxy group, an amino group, a radically polymerizable unsaturated group, a carboxy group, an isocyanate group, a hydroxy group, and an alkoxysilyl group.

(solvent)
The resin composition may contain a solvent. The solvent may be any solvent capable of dissolving the polysiloxane polymer and other components, and specifically includes hydrocarbon solvents such as benzene, toluene, hexane, and heptane; ether solvents such as tetrahydrofuran, 1,4-dioxane, 1,3-dioxolane, and diethyl ether; ketone solvents such as acetone, methyl ethyl ketone, methyl isobutyl ketone, and cyclohexanone; glycol solvents such as propylene glycol-1-monomethyl ether-2-acetate (PGMEA), diethylene glycol dimethyl ether, diethylene glycol ethyl methyl ether, and ethylene glycol diethyl ether; and halogen-based solvents such as chloroform, methylene chloride, and 1,2-dichloroethane. From the viewpoint of film formation stability, propylene glycol-1-monomethyl ether-2-acetate and diethylene glycol dimethyl ether are preferred. The amount of the solvent used may be appropriately set. When the polymer is in a liquid state, a solvent may not be used.

(Additives)
The photosensitive composition may contain a filler or a colorant. Examples of the filler include silica-based fillers (quartz, fume silica, precipitated silica, silicic anhydride, fused silica, crystalline silica, and ultrafine amorphous silica), silicon nitride, silver powder, alumina, aluminum hydroxide, titanium oxide, glass fiber, carbon fiber, mica, carbon black, graphite, diatomaceous earth, white clay, clay, talc, calcium carbonate, magnesium carbonate, barium sulfate, and inorganic balloons. Examples of the colorant include organic pigments, inorganic pigments, and dyes.

In addition to the above, the resin composition may contain adhesion improvers, coupling agents such as silane coupling agents, deterioration inhibitors, hydrosilylation reaction inhibitors, polymerization inhibitors, polymerization catalysts (crosslinking accelerators), release agents, flame retardants, flame retardant assistants, surfactants, defoamers, emulsifiers, leveling agents, anti-repellent agents, ion trapping agents, thixotropy imparting agents, tackifiers, storage stability improvers, light stabilizers, thickeners, plasticizers, reactive diluents, antioxidants, heat stabilizers, electrical conductivity imparting agents, antistatic agents, radiation shielding agents, nucleating agents, phosphorus-based peroxide decomposers, lubricants, metal deactivators, thermal conductivity imparting agents, and physical property adjusters.

<Resin composition set>
The sealant (thermosetting resin composition) used to form the sealing portion and the spacer resin composition (photosensitive resin composition) used to form the spacer are both resin compositions containing a polysiloxane polymer. These resin compositions can also be provided as a resin composition set for hollow semiconductor packages.

[Formation of Spacers]
A photosensitive resin composition for spacers is applied onto the substrate 30 and heated to form a resin film. The method for applying the composition is not particularly limited as long as it allows uniform application, and general coating methods such as spin coating, slit coating, and screen coating can be used. The thickness of the resin film may be adjusted according to the height of the spacers (height of the hollow structure), and is, for example, 1 to 200 μm, and preferably 10 to 150 μm.

By exposing and developing the resin film formed on the substrate, the resin film is patterned to form a frame-shaped spacer. Before exposure, heating (pre-baking) may be performed for the purpose of removing the solvent, etc. The heating temperature may be set appropriately, and is preferably 50 to 150°C.

The light source for exposure may be selected according to the wavelength sensitivity of the photoacid generator and sensitizer contained in the photosensitive resin composition. Usually, a light source having a wavelength in the range of 200 to 450 nm (e.g., a high-pressure mercury lamp, an ultra-high-pressure mercury lamp, a metal halide lamp, a high-power metal halide lamp, a xenon lamp, a carbon arc lamp, or a light-emitting diode) is used. The amount of exposure is not particularly limited, and is, for example, about 1 to 10,000 mJ/ ^cm2 , preferably 10 to 4,000 mJ/ ^cm2 . In order to promote the photoreaction, post-exposure baking by heating may be performed after light irradiation and before development.

A typical photomask can be used for pattern exposure. For a negative photosensitive resin composition, a pattern mask with openings is used so that the areas where the spacers 5 are to be formed are selectively exposed. For a positive photosensitive resin composition, a pattern mask that can selectively block the areas where the spacers 5 are to be formed is used.

After exposure, the resin film is contacted with an alkaline developer by immersion or spraying, etc., to dissolve and remove the resin film, thereby performing patterning. In a negative-type photosensitive resin composition, the exposed areas are photocured and no longer alkaline soluble, so the film in the unexposed areas is selectively removed by alkaline development. In a positive-type photosensitive resin composition, the acid generated by irradiating the photoacid generator with light increases the alkaline solubility, so the film in the exposed areas is selectively removed.

The alkaline developer may be any commonly used one without any particular limitations. Specific examples of alkaline developers include organic alkaline aqueous solutions such as tetramethylammonium hydroxide (TMAH) aqueous solution and choline aqueous solution, and inorganic alkaline aqueous solutions such as potassium hydroxide aqueous solution, sodium hydroxide aqueous solution, potassium carbonate aqueous solution, sodium carbonate aqueous solution, and lithium carbonate aqueous solution. The alkaline concentration of the developer is preferably 0.01 to 25% by weight, more preferably 0.1 to 10% by weight, and even more preferably 0.3 to 5% by weight. The developer may contain a surfactant or the like for the purpose of adjusting the dissolution rate, etc.

The line width of the spacer 5 is, for example, 1 to 2000 μm. From the viewpoint of achieving both ensuring the strength of the spacer and miniaturizing the semiconductor package, the line width of the spacer 5 is preferably 10 to 1000 μm, more preferably 50 to 700 μm, and may be 70 to 500 μm or 100 to 300 μm. The pattern shape of the mask used during exposure may be adjusted so that the line width of the portion that remains without being dissolved in alkali during development falls within the above range.

The substrate provided with multiple frame-shaped spacers 5 is diced or otherwise divided into individual chip pieces 301 each provided with a frame-shaped spacer 5. The substrate may be divided into individual chip pieces 301 each provided with a frame-shaped spacer 5 after a hollow structure is formed in which a semiconductor element is disposed.

[Formation of hollow structure]
A hollow structure 6 is formed by the substrate 1, the lid 3 and the frame-shaped spacer 5, by pressing the spacer 5 of the chip piece onto a chip 101 having a semiconductor element 4 mounted on a substrate 1 such as a silicon substrate. An adhesive layer may be provided between the spacer 5 and the substrate 1. Since the spacer 5 containing a polysiloxane resin has adhesive properties, the spacer 5 can be fixed onto the substrate 1 by pressing, even without providing a separate adhesive.

There are no particular limitations on the conditions for compression, but the temperature is about 30°C to 300°C, preferably 60°C to 250°C, and more preferably 80°C to 250°C. The pressure applied to the bonding surface during compression is about 0.1 to 20 MPa, and preferably 0.2 to 10 MPa.

If the resin composition constituting the spacer 5 is thermosetting, it is preferable to thermally cure (post-bake) the resin composition by heating during or after thermocompression bonding. By thermally curing the resin composition, the adhesion between the spacer 5 and the substrate 1, and between the spacer 5 and the lid 3, is further improved. The spacer may be post-baked after or when the sealing portion is formed.

[Formation of sealing portion]
A sealant (thermosetting resin composition) is applied so as to cover the joint portion 51 between the substrate 1 and the spacer 5 and the joint portion 53 between the lid 3 and the spacer 5, and then thermally cured to form the sealing portion 7. The heating temperature during thermal curing may be set according to the composition of the sealant, and is, for example, 50 to 300°C, preferably 100 to 250°C, and more preferably 120 to 200°C.

The glass transition temperature of the sealing portion 7 (sealant after thermal curing) is preferably 30 to 150°C, and more preferably 35 to 100°C. If the glass transition temperature of the sealing portion is excessively high, the stress relaxation effect of the sealant is low due to the high elastic modulus at high temperatures, and peeling or cracks may occur at the interface when a heating test or a thermal cycle test is performed. On the other hand, if the glass transition temperature of the sealing portion is excessively low, the sealant is likely to flow when heated, resulting in reduced adhesion and causing contamination due to sealant protruding from the application area.

The product WD of the moisture permeability W and thickness D of the sealing portion 7 is preferably 0.05 to 0.6 g/m2·24h. The moisture permeability W and thickness D are inversely proportional, and the product WD of the moisture permeability and thickness is almost constant for sheets made of the same material. WD is an index that indicates the ease (movement speed) of moisture movement in a material, and the larger the WD, the faster the moisture moves in the sealing portion 7, meaning that the moisture is more easily transmitted. If the WD is within the above range, the sealing portion 7 has appropriate moisture permeability, and therefore moisture retention in the hollow structure 6 can be suppressed. If the WD is excessively large, the amount of moisture that penetrates into the hollow structure 6 in a high humidity environment increases, which may cause deterioration of the semiconductor element or peeling at the bonding interface.

The moisture permeability of the sealing portion 7 is measured using a measurement sample in which the sealant (thermosetting resin composition) constituting the sealing portion 7 is molded into a sheet shape with a thickness of 0.5 mm. A moisture permeability test is carried out for 5 hours in an environment of a temperature of 80 degrees and a relative humidity of 85%, and the moisture permeability (g/m ² ·5h) is measured from the amount of moisture that permeates the measurement sample, and this value is multiplied by 24/5 to calculate the moisture permeability W (g/m ² ·24h) for 24 hours. WD is calculated from the product of this moisture permeability W and the thickness D of the sample = 5 × 10 ^-4 m. The value of WD of the sealing portion is more preferably 0.07 to 0.5 g/m·24h, more preferably 0.1 to 0.4 g/m·24h, and may be 0.12 to 0.35 g/m·24h.

In resin compositions containing polysiloxane polymers, when the polymer contains a cyclic siloxane structure, the glass transition temperature tends to be high and the moisture permeability tends to be low. When both a cyclic polysiloxane structure and a linear polysiloxane structure are contained, the greater the proportion of cyclic polysiloxane structure, the higher the glass transition temperature and the lower the moisture permeability tends to be.

[Fabrication of hollow semiconductor package]
As described above, a frame-shaped spacer 7 is placed between a semiconductor chip having a semiconductor element 4 provided on a substrate 1 and a lid 3, and the sides of the spacer 7 are sealed to form a hollow semiconductor package 100 having a semiconductor element within a hollow structure 6.

In the above embodiment, the spacer 5 is formed using a photosensitive resin composition containing a polysiloxane resin, but the spacer 5 may be formed by screen printing or the like of a resin composition containing a polysiloxane resin. In the above embodiment, the cell substrate 300 on which multiple frame-shaped spacers 5 are formed on one glass substrate 30 is diced to form a chip piece in which one spacer 5 is provided on the lid 3 made of glass, but one spacer 5 may be formed on the lid 3. Also, instead of forming a spacer on the lid 3 (transparent substrate), a frame-shaped spacer may be formed on the sensor substrate 1 (e.g., a silicon substrate). When forming a spacer on a sensor substrate, multiple frame-shaped spacers may be formed on one substrate and then diced to form a semiconductor chip, or a spacer may be formed on the substrate after dicing.

Although FIG. 2A illustrates a spacer 5 that is a square in plan view, the shape of the frame-shaped spacer is not particularly limited and may be a quadrangle such as a rectangle, rhombus, or parallelogram, a polygon such as a triangle, pentagon, or hexagon, or may be a circle or ellipse. The spacer may also have a polygonal shape with rounded corners in plan view, for example, a square or rectangle with rounded corners. By having rounded corners of the polygon, even if dimensional changes occur due to humidity or temperature changes, the concentration of stress at the corners is mitigated, which tends to suppress cracks and peeling at the sealing portion or bonding interface.

The present invention will be described in more detail below with reference to examples, but the present invention is not limited to the following examples.

[Synthesis of polyorganosiloxane compound]
<Synthesis Example 1>
1,459 g of tetraethoxysilane was added to 1,803 g of a 48% aqueous choline solution (aqueous trimethyl-2-hydroxyethylammonium hydroxide solution) and vigorously stirred at room temperature for 2 hours. When the reaction system generated heat and the solution became homogeneous, the stirring was slowed down and the reaction was continued for another 12 hours. Next, 1,400 mL of methanol was added to the solid matter produced in the reaction system to make a homogeneous solution.

1,149 g of dimethylvinylchlorosilane and 830 g of trimethylsilyl chloride were dissolved in 1,400 mL of hexane, and the above solution was slowly added dropwise while vigorously stirring. After completion of the addition, the mixture was allowed to react for 1 hour, and then the organic layer was extracted and concentrated to obtain a solid. The resulting solid was washed by vigorously stirring in methanol, and then filtered to obtain 760 g of a cage polysiloxane compound, tetrakis(vinyldimethylsiloxy)tetrakis(trimethylsiloxy)octasilsesquioxane (Fw=1,175.8), as a white solid.

30.0 g of the above-mentioned cage polysiloxane compound was dissolved in 123.0 g of toluene, and 31.5 g of methyldiphenylvinylsilane and 1.46 μL of a xylene solution of platinum vinylsiloxane complex (Pt-VTSC-3X, manufactured by Umicore Precious Metals Japan, platinum content 3 wt%) were added. This solution was slowly dripped into a solution of 224.6 g of 1,3,5,7-tetrahydrogen-1,3,5,7-tetramethylcyclotetrasiloxane (hereinafter referred to as "TMCTS") and 24.6 g of toluene, and reacted at 105°C for 2 hours. After the reaction was completed, 2.8 μL of ethynylcyclohexanol and 0.65 μL of dimethyl maleate were added, and the toluene and unreacted components were distilled off to obtain 80.8 g of liquid polyorganosiloxane compound 1 (hydrosilyl valence 1.8 mol/kg).

<Synthesis Example 2>
626 g of TMCTS and 602 g of toluene were mixed uniformly and stirred under a nitrogen atmosphere at 105° C. A mixture of 90 g of triallyl isocyanurate, 90 g of toluene, and 0.1 g of a xylene solution of platinum vinylsiloxane complex was added dropwise to this solution over 40 minutes, and the reaction was carried out for 4 hours at 105° C. Unreacted components and toluene were distilled off under reduced pressure to obtain 310 g of liquid polyorganosiloxane compound 2 (hydrosilyl valence 8.60 mol/kg).

<Synthesis Example 3>
500 g of TMCTS and 1,800 g of toluene were mixed uniformly and stirred under a nitrogen atmosphere at 105° C. A mixture of 180 g of triallyl isocyanurate, 300 g of allyl glycidyl ether, 350 g of toluene, and 0.1 g of a xylene solution of platinum vinylsiloxane complex was added dropwise to this solution over 40 minutes, and the reaction was carried out for 4 hours at 105° C. Unreacted components and toluene were distilled off under reduced pressure to obtain 700 g of liquid polyorganosiloxane compound 3 (hydrosilyl valence 3.5 mol/kg).

<Synthesis Example 4>
44g of TMCTS and 88g of toluene were mixed uniformly and stirred at 105°C under a nitrogen atmosphere. A mixture of 14.5g of diallyl monomethyl isocyanurate, 20g of diallyl isocyanurate, 132g of dioxane, and 0.03g of a xylene solution of platinum vinyl siloxane complex was added dropwise to this solution over 40 minutes. After confirming that the allyl group had disappeared by ^1H -NMR, a mixture of 31g of toluene and 31g of vinylcyclohexene oxide was added dropwise. After confirming that the vinyl group had disappeared by ^1H -NMR, the reaction was terminated by cooling. Toluene and dioxane were distilled off under reduced pressure, and propylene glycol-1-monomethyl ether-2-acetate was added to obtain a solution of polyorganosiloxane compound 4 (concentration 75% by weight).

<Synthesis Example 5>
20 g of TMCTS and 40 g of toluene were mixed uniformly and stirred at 105° C. under a nitrogen atmosphere. A mixture of 12.2 g of diallyl monoglycidyl isocyanurate, 15.6 g of monoallyl isocyanurate, 100 g of dioxane, and 0.03 g of a xylene solution of platinum vinyl siloxane complex was added dropwise to this solution over 40 minutes. After confirming that the allyl group had disappeared by ¹ H-NMR, a mixture of 15 g of toluene and 12 g of vinylcyclohexene oxide was added dropwise. After confirming that the vinyl group had disappeared by ¹ H-NMR, the reaction was terminated by cooling. Toluene and dioxane were distilled off under reduced pressure, and propylene glycol-1-monomethyl ether-2-acetate was added to obtain a solution of polyorganosiloxane compound 5 (concentration 75% by weight).

[Preparation of Sealant]
The components were blended in the weight ratios shown in Table 1 and mixed with stirring to prepare sealant compositions (thermosetting resin compositions) 1 to 12.
The both-terminally vinyl-modified siloxane A used in compositions 1 to 3 was a both-terminally vinyl-modified polymethylphenylsiloxane (manufactured by Constur Chemical).
The vinyl-terminated siloxane B used in Composition 4 was 1,5-divinyl-1,1,5,5-tetramethyl-3,3-diphenyltrisiloxane.
The Pt catalyst solution used in compositions 1 to 8 was a xylene solution of platinum vinylsiloxane complex ("Pt-VTSC-3X" manufactured by Umicore Precious Metals Japan, platinum content 3% by weight).
The silicone compositions of Compositions 9 and 10 were two-liquid type methylsilicone elastomers ("DOWSIL JCR6140" manufactured by Dow), and 50 parts by weight each of Agent A and Agent B were used.
The epoxy composition of the sealant compositions 11 and 12 is a one-liquid type epoxy resin composition containing an alicyclic epoxy resin and an acid anhydride as main components ("EH1600G2" manufactured by Inabata Sangyo Kaisha).
The silica particles used in Compositions 7, 10, and 12 were fused spherical silica ("SF650" manufactured by Tatsumori).

[Evaluation of physical properties of sealant]
<Moisture permeability>
The sealant composition was poured into a mold prepared by sandwiching a 0.5 mm thick silicone rubber spacer between two glass substrates, and the sealant was cured by heating at 150°C for 3 hours to prepare an evaluation sample having a thickness of 0.5 mm.

A jig was made by fixing a 5 cm square frame-shaped polyisobutylene rubber sheet (3 mm thick, with a 3 cm square cut out in the center) to the surface of a 5 cm square glass plate, and 1 g of calcium chloride (for moisture measurement) was filled into the frame. The above evaluation sample was then fixed on top of the jig to obtain a test specimen.

The test specimen was left to stand for 5 hours in a thermohygrostat at a temperature of 80° C. and a relative humidity of 85%, and the total weight of the test specimen was measured before and after the test. The moisture permeability after 5 hours was calculated according to the following formula.
Moisture permeability (g/m ² ·5h)={(total weight of test specimen after test (g))−(total weight of test specimen before moisture permeability test (g))}/9×10 ⁻⁴ (m ² )
In addition, the polyisobutylene rubber used in the test specimen was confirmed to have a moisture permeability of 0 g/ ^m2 ·5 h as a result of similar moisture permeability tests.

From the moisture permeability (g/ ^m2 ·5h) of the 0.5 mm thick sample measured above for 5 hours, the product WD (g/m·24h) of the 24 hour moisture permeability W and the thickness D was calculated.

<Glass transition temperature>
A 2 mm-thick evaluation sample was prepared by pouring the sealant composition into a mold prepared by sandwiching a 2 mm-thick silicone rubber spacer between two glass substrates and curing the sealant by heating for 3 hours at 150° C. Dynamic viscoelasticity measurement of this sample was performed under the following conditions using a dynamic viscoelasticity measuring device (UBM's "Reogel E4000"), and the temperature at which the loss tangent was maximized was determined as the glass transition temperature (Tg).
Test mode: Tensile Measurement temperature: Room temperature to 200°C
Heating rate: 4° C./min Distortion: 4 μm
Frequency: 10Hz
Chuck distance: 25 mm

The formulations and evaluation results of sealant compositions 1 to 12 are shown in Table 1. Note that sealant compositions 9 and 10 did not show a maximum in loss tangent above room temperature, so the glass transition temperature was set to be below room temperature (RT).

[Preparation of Photosensitive Resin Composition for Spacers]
Photosensitive resin compositions for spacers 21 to 25 were prepared by mixing and stirring the components in the weight ratios shown in Table 2. The values shown in Table 2 are the weight ratios of solids (non-volatile contents) other than the organic solvent.

Epoxy compound 1 in Table 2 is ε-caprolactone-modified 3',4'-epoxycyclohexylmethyl-3,4-epoxycyclohexanecarboxylate (manufactured by Daicel under the name "Celloxide 2081"), and epoxy compound 2 is 3,4-epoxycyclohexylmethyl-3',4'-epoxycyclohexanecarboxylate (manufactured by Daicel under the name "Celloxide 2021P").

The photoacid generator in Table 2 is a sulfonium salt-based photoacid generator "CPI-310FG" manufactured by San-Apro.
The phenolic resin used in Composition 25 was polyparavinylphenol (Marukalinker M manufactured by Maruzen Petrochemicals), the photoradical polymerization initiator was Omnirad 184 manufactured by IGM Resins, the sensitizer was 9,10-dibutoxyanthracene, and the solvent was propylene glycol monomethyl ether acetate.

[Example 1]
The photosensitive resin composition 21 prepared above was spin-coated on a 0.4 mm thick glass substrate to a film thickness of 80 μm, and heated on a hot plate at 120 ° C. for 10 minutes. Furthermore, using a high-pressure mercury lamp, exposure was performed with an integrated light quantity of 1500 mJ / cm ² through a negative photomask in which rectangular frame-shaped openings of 6.23 mm in the horizontal direction, 5.18 mm in the vertical direction, and 0.39 mm in line width were arranged in a matrix. Thereafter, the substrate was immersed in an alkaline developer (2.38% tetramethylammonium hydroxide aqueous solution) for 300 seconds, washed with water for 30 seconds, and the surface moisture was removed with compressed air to obtain a cell pattern substrate in which frame-shaped spacers were arranged in a matrix on the glass substrate.

The cell pattern substrate obtained above was cut into individual pieces using a dicing device. The individualized cell spacers were placed on a silicon wafer cut into 1 cm squares so that they were in contact with each other, and the pieces were pressed against each other on a hot plate at 120°C with a load of 800 g. After pressing, the sample was heated in an oven at 200°C for 2 hours to post-bake (thermally cure) the photosensitive resin composition.

The sample was then placed on a hot plate at 60°C, and sealant composition 1 was applied to fill the gap between the glass substrate and the silicon wafer, and the sample was heated in an oven at 150°C for 3 hours to harden the sealant.

[Examples 2 to 13, Comparative Examples 1 to 3]
Samples having a hollow structure were prepared in the same manner as in Example 1, except that the types of photosensitive resin compositions used to form the sealant and spacers were changed as shown in Table 3.

[evaluation]
<Sealant Coating Properties>
The sealed portions of the samples prepared in the examples and comparative examples were visually inspected, and a rating of B was given if the sealant had flowed out onto the glass surface or outside the silicon chip, and a rating of A was given if the sealant had not flowed out.

<Moisture absorption reflow test>
The samples prepared in the examples and comparative examples were allowed to stand for 7 hours in a thermohygrostat at a temperature of 85°C and a relative humidity of 85% to absorb moisture, and then heated three times in a reflow furnace at 260°C for 1 minute. The samples after reflow were observed under a microscope to evaluate the presence or absence of peeling or cracking of the sealant. For each example and comparative example, evaluation was performed on 10 samples, and samples with 2 or less peeling or cracking were rated as "A", samples with 3 to 7 peeling or cracking were rated as "B", and samples with 8 or more peeling or cracking were rated as "C".

Table 3 shows the combinations of compositions used in the examples and comparative examples, as well as the evaluation results of the sealant's coatability and moisture absorption reflow test.

In both Comparative Example 1 and Comparative Example 2, which used a sealant made of an epoxy resin composition, cracks or peeling occurred in the sealing portion in many samples after the moisture absorption reflow test. In Comparative Example 3, which used a polysiloxane-based sealant composition 1 and a phenolic resin-based photosensitive resin composition 25 as the spacer, cracks or peeling occurred in the sealing portion in many samples after the moisture absorption reflow test.

In all of Examples 1 to 13, which used compositions containing polysiloxane polymers as both the sealant and the spacer material, peeling and cracking after the moisture absorption reflow test were suppressed compared to the comparative example.

In Examples 1 to 8 and 11 to 13, which used sealant compositions 1 to 8 containing cyclic polysiloxanes (compounds 1 to 3), there was no overflow of the sealant, and the applicability of the sealant was better than in Examples 9 and 10, which used compositions 9 and 10.

In Examples 1 to 4, 8 to 13, which used sealants 1 to 4, 8 to 10 containing a chain polysiloxane structure, the moisture absorption reflow resistance was further improved compared to Examples 5 and 6, which used sealants 5 and 6, which contained only a cyclic polysiloxane structure and did not contain a chain polysiloxane structure. Since sealants 1 to 4, 8 to 10 contain a chain siloxane structure, they have higher moisture permeability than sealants 5 and 6, and moisture within the hollow structure is easily released to the outside of the hollow structure during reflow, which is thought to have suppressed cracking and peeling in the sealing portion.

Sealant 7, which contains 150 parts by weight of filler (silica particles) per 100 parts by weight of resin, has the same resin composition as sealant 4, but the inclusion of filler reduces the moisture permeability of the sealant (see Table 1). In Example 7, which uses sealant 7, the moisture absorption reflow resistance was reduced compared to Example 4, suggesting that the moisture permeability of the sealant is involved in the reliability of the sealing part.

REFERENCE SIGNS LIST 100 Hollow semiconductor package 1 Substrate 3 Lid 4 Semiconductor element 45 Bonding wire 5 Spacer 6 Hollow structure 7 Sealing part 30 Substrate 300 Hollow cell substrate 101 Semiconductor chip 301 Chip piece

Claims (12)

substrate;
Lid;
a frame-shaped spacer disposed between the substrate and the lid;
a semiconductor element disposed in a hollow structure formed by the substrate, the lid, and the spacer; and a sealing portion that seals a joint between the substrate and the spacer and a joint between the lid and the spacer.
A hollow semiconductor package comprising:
the spacer comprises a polysiloxane resin;
the sealing portion includes a polysiloxane resin,
The lid and the spacer are in direct contact with each other.
Hollow semiconductor package. The hollow semiconductor package according to claim 1, wherein the sealing portion is made of a cured product of a thermosetting resin composition containing a polysiloxane resin. The hollow semiconductor package according to claim 1 or 2, wherein the polysiloxane resin of the sealing portion includes a cyclic polysiloxane structure. The hollow semiconductor package according to claim 1 or 2, wherein the polysiloxane resin of the sealing portion includes a cyclic polysiloxane structure and a chain polysiloxane structure. The hollow semiconductor package according to any one of claims 1 to 4, wherein the sealing portion has a product of moisture permeability and thickness of 0.05 to 0.6 g/m24h. The hollow semiconductor package according to any one of claims 1 to 5, wherein the glass transition temperature of the sealing portion is 30 to 150°C. A method for producing a hollow semiconductor package according to any one of claims 1 to 6, comprising the steps of:
The sealing portion is formed by thermally curing a thermosetting resin composition containing a polysiloxane resin.
A method for manufacturing a hollow semiconductor package. The method for producing a hollow semiconductor package according to claim 7, wherein the thermosetting resin composition contains a polysiloxane polymer having two or more SiH groups in one molecule and a crosslinking agent having two or more alkenyl groups in one molecule. The method for producing a hollow semiconductor package according to claim 8, wherein the polysiloxane polymer includes a cyclic polysiloxane structure. The method for producing a hollow semiconductor package according to claim 8 or 9, wherein the crosslinking agent contains a chain polysiloxane structure. The method for manufacturing a hollow semiconductor package according to any one of claims 7 to 10, in which the spacer is formed by applying a photosensitive resin composition containing a polysiloxane resin and patterning it by photolithography. A resin composition set for forming the hollow semiconductor package according to any one of claims 1 to 6 ,
the resin composition set includes a spacer resin composition used for producing the spacer and a sealant used for producing the sealing portion,
the spacer resin composition is a photosensitive resin composition containing a polysiloxane polymer,
The sealant is a thermosetting resin composition containing a polysiloxane polymer.
A resin composition set for hollow semiconductor packages.

Images