KR20230062565A - Film-like adhesive, adhesive sheet, and semiconductor device and manufacturing method thereof - Google Patents

Abstract

A film adhesive for adhering a semiconductor element and a support member on which the semiconductor element is mounted is disclosed. The film adhesive contains a thermosetting resin, a curing agent and an elastomer. The elastomer includes an elastomer that satisfies the following condition (i) and the following condition (ii).
Condition (i): The glass transition temperature is 12°C or higher.
Condition (ii): The weight average molecular weight is 800,000 or less.

Description

Film-like adhesive, adhesive sheet, and semiconductor device and manufacturing method thereof

The present invention relates to a film adhesive, an adhesive sheet, a semiconductor device, and a manufacturing method thereof.

In recent years, stack MCPs (Multi Chip Packages) in which semiconductor elements (semiconductor chips) are stacked in multiple stages have become popular, and are mounted as memory semiconductor packages for mobile phones and portable audio devices. In addition, with the multifunctionalization of mobile phones and the like, high-speed, high-density, and high-integration of semiconductor packages are also promoted.

Currently, as a method for manufacturing a semiconductor device, a film adhesive and a dicing tape are attached to the back surface of a semiconductor wafer, and then a portion of the semiconductor wafer, the film adhesive, and the dicing tape is diced. A method of pasting the back of a semiconductor wafer to be cut is generally used. In this method, it is necessary to simultaneously cut the film adhesive at the time of dicing the semiconductor wafer, but in the general dicing method using a diamond blade, in that the semiconductor wafer and the film adhesive are simultaneously cut, the cutting speed is increased. It is necessary to slow down, and there is a possibility of causing an increase in cost.

On the other hand, as a method of classifying the semiconductor wafer, a process for easily classifying the semiconductor wafer, such as a method of forming a modified region by irradiating a laser beam into the inside of the semiconductor wafer on the line to be cut, is performed, and then the outer periphery is A method of cutting a semiconductor wafer by expanding it has recently been proposed (for example, Patent Literature 1). This method is called stealth dicing. Stealth dicing has an effect of reducing defects such as chipping, especially when the thickness of the semiconductor wafer is thin, and an effect of improving yield can be expected.

Patent Document 1: Japanese Unexamined Patent Publication No. 2002-192370

However, since the film adhesive is flexible and easy to spread, it tends to be difficult to part by expanding the dicing tape. In order to improve the parting property of the film adhesive by expansion (particularly, cooling expansion at low temperature (for example, in the range of -15°C to 0°C)), it is necessary to increase the amount of expansion of the dicing tape. Although there is a need, by increasing the amount of expansion, the amount of bending of the dicing tape also increases, so there is a possibility of adversely affecting the subsequent conveyance process and the like.

The present invention has been made in view of the above circumstances, and has as its main object to provide a film adhesive having excellent parting properties by cold expansion.

One aspect of the present invention provides a film adhesive for bonding a semiconductor element and a support member for mounting the semiconductor element. The film adhesive contains a thermosetting resin, a curing agent and an elastomer. The elastomer includes an elastomer that satisfies the following condition (i) and the following condition (ii). Such a film adhesive can be excellent in parting property by cold expansion.

Condition (i): The glass transition temperature is 12°C or higher.

Condition (ii): The weight average molecular weight is 800,000 or less.

According to the examination of the present inventors, in the film adhesive, it was discovered that there is a tendency that the flexibility of the film adhesive can be suppressed by using a specific elastomer. Therefore, the present inventors believe that by using such a specific elastomer, excessive improvement in the flexibility of the film adhesive can be suppressed, and consequently, the parting property of the film adhesive in cold expand can be improved. .

The film adhesive is a step of preparing a sample having a cross-sectional area A (mm ² ) from the film adhesive, and a cutting test under low temperature conditions in the range of -15 ° C to 0 ° C. mm), the step of obtaining the breaking strength P (N), and the elongation at break L (mm), the step of obtaining the cutting coefficient m represented by the following formula (1), and the cutting resistance R (N represented by the following formula (2) /mm ² ), in the method for evaluating splitting property performed under the following conditions, including the step of obtaining ), the cutting coefficient m is greater than 0 and 70 or less, and the cutting resistance R is greater than 0 N/mm ² and 40 N/mm ^{2 or less} ; A film-form adhesive may be sufficient.

m = W/[1000×(P×L)] (One)

R = P/A (2)

<condition>

Sample width: 5 mm

Sample length: 23 mm

Relative speed of indentation jig and sample: 10 mm/min

The film adhesive may further contain an inorganic filler.

Another aspect of the present invention provides an adhesive sheet comprising a base material and the film adhesive provided on one side of the base material.

Another aspect of the present invention includes a semiconductor element, a support member for mounting the semiconductor element, and an adhesive member provided between the semiconductor element and the support member to adhere the semiconductor element and the support member, wherein the adhesive member is provided as described above. A semiconductor device which is a cured product of a film adhesive is provided.

Another aspect of the present invention provides a method for manufacturing a semiconductor device comprising a step of bonding a semiconductor element and a support member using the film-like adhesive.

Another aspect of the present invention is a step of attaching the film adhesive of the adhesive sheet to a semiconductor wafer, and cutting the semiconductor wafer to which the film adhesive is attached, thereby producing a plurality of individual semiconductor devices with film adhesive A method for manufacturing a semiconductor device is provided, comprising a step of doing and a step of adhering a semiconductor element with a film-like adhesive to a supporting member.

ADVANTAGE OF THE INVENTION According to this invention, the film adhesive excellent in parting property by cooling expand is provided. Moreover, according to this invention, the adhesive sheet and semiconductor device using such a film adhesive are provided. Moreover, according to this invention, the manufacturing method of the semiconductor device using a film adhesive or adhesive sheet is provided.

1 is a schematic cross-sectional view showing one embodiment of a film adhesive.
Fig. 2 is a perspective view schematically showing a sample in a state fixed to a jig.
Fig. 3 is a cross-sectional view schematically showing a state in which a load is applied to a sample by means of a press-fitting jig.
4 is a graph schematically showing an example of the results of the cutting test.
5 is a schematic cross-sectional view showing an embodiment of an adhesive sheet.
6 is a schematic cross-sectional view showing another embodiment of the adhesive sheet.
7 is a schematic cross-sectional view showing another embodiment of an adhesive sheet.
8 is a schematic cross-sectional view showing one embodiment of a semiconductor device.
9 is a schematic cross-sectional view showing another embodiment of a semiconductor device.

EMBODIMENT OF THE INVENTION Hereinafter, embodiment of this invention is described, referring drawings suitably. However, this invention is not limited to the following embodiment. In the following embodiments, the constituent elements (including steps and the like) are not essential unless otherwise specified. The size of the components in each drawing is conceptual, and the relative relationship between the sizes of the components is not limited to what is shown in each drawing.

It is the same also about the numerical value and its range in this specification, and does not limit this invention. In this specification, the numerical range indicated using "-" shows the range which includes the numerical value described before and after "-" as a minimum value and a maximum value, respectively. In the numerical ranges stepwise described in this specification, the upper limit or lower limit of one numerical range may be replaced with the upper limit or lower limit of another stepwisely described numerical range. In addition, in the numerical range described in this specification, you may replace the upper limit value or the lower limit value of the numerical range with the value shown in the Example.

In this specification, (meth)acrylate means an acrylate or a methacrylate corresponding thereto. The same applies to other analogous expressions such as a (meth)acryloyl group and a (meth)acryl copolymer.

A film adhesive according to one embodiment is for bonding a semiconductor element and a support member on which the semiconductor element is mounted. The film adhesive is a thermosetting resin (hereinafter sometimes referred to as “component (A)”), a curing agent (hereinafter sometimes referred to as “component (B)”), and an elastomer (hereinafter sometimes referred to as “(A) component”). C) It is sometimes referred to as "component"). The film adhesive may further contain an inorganic filler (hereinafter sometimes referred to as "component (D)"). The film adhesive further contains a coupling agent (hereinafter sometimes referred to as "component (E)"), a curing accelerator (hereinafter sometimes referred to as "component (F)"), and other components. You can do it.

The film adhesive is (A) component, (B) component, and (C) component, and other components added as necessary ((D) component, (E) component, (F) component, other components, etc.) It can be obtained by molding an adhesive composition containing the into a film shape. The film adhesive (adhesive composition) may go through a semi-cured (B-stage) state and become a completely cured (C-stage) state after the curing treatment.

(A) component: thermosetting resin

(A) Component may be an epoxy resin from an adhesive viewpoint. As the epoxy resin, for example, bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol S type epoxy resin, phenol novolak type epoxy resin, cresol novolak type epoxy resin, bisphenol A novolak type epoxy resin, bisphenol F Novolak-type epoxy resin, stilbene-type epoxy resin, triazine skeleton-containing epoxy resin, fluorene skeleton-containing epoxy resin, biphenyl-type epoxy resin, xylylene-type epoxy resin, biphenylaralkyl-type epoxy resin, naphthalene-type epoxy resin, Diglycidyl ether compounds of polycyclic aromatics, such as functional phenols and anthracene, etc. are mentioned. You may use these individually by 1 type or in combination of 2 or more types. Among these, the epoxy resin may be a cresol novolac type epoxy resin.

The epoxy equivalent of the epoxy resin is not particularly limited, but may be 90 to 300 g/eq or 110 to 290 g/eq.

(B) component: curing agent

Component (B) is a component that acts as a curing agent for component (A). When the component (A) is an epoxy resin, the component (B) may be a phenol resin that can be a curing agent for the epoxy resin.

A phenolic resin can be used without particular limitation as long as it has a phenolic hydroxyl group in its molecule. Examples of the phenolic resin include phenols such as phenol, cresol, resorcin, catechol, bisphenol A, bisphenol F, phenylphenol, and aminophenol, and/or naphthols such as α-naphthol, β-naphthol, and dihydroxynaphthalene. Novolac-type phenolic resin obtained by condensation or co-condensation of a compound having an aldehyde group such as formaldehyde with acid catalyst under an acidic catalyst, allylated bisphenol A, allylated bisphenol F, allylated naphthalenediol, phenol novolak, phenols such as phenol, and and/or phenol aralkyl resins, naphthol aralkyl resins, biphenyl aralkyl type phenol resins, and phenyl aralkyl type phenol resins synthesized from naphthols and dimethoxyparaxylene or bis(methoxymethyl)biphenyl. . You may use these individually by 1 type or in combination of 2 or more types. Among these, the phenol resin may be a phenylaralkyl type phenol resin.

The hydroxyl equivalent of the phenol resin may be 70 g/eq or more or 70 to 300 g/eq. When the hydroxyl equivalent of the phenol resin is 70 g/eq or more, the storage modulus of the film tends to be improved, and when it is 300 g/eq or less, it is possible to prevent troubles caused by foaming, outgassing, and the like.

When component (A) is an epoxy resin and component (B) is a phenol resin, the ratio of the epoxy equivalent of the epoxy resin to the hydroxyl equivalent of the phenol resin (epoxy equivalent of the epoxy resin/hydroxyl equivalent of the phenol resin) is a curable viewpoint , may be 0.30/0.70 to 0.70/0.30, 0.35/0.65 to 0.65/0.35, 0.40/0.60 to 0.60/0.40, or 0.45/0.55 to 0.55/0.45. When the equivalence ratio is 0.30/0.70 or more, more sufficient curability tends to be obtained. When the equivalence ratio is 0.70/0.30 or less, excessive increase in viscosity can be prevented, and more sufficient fluidity can be obtained.

The content of the total of component (A) and component (B) is 5 to 50 parts by mass, 10 to 40 parts by mass, based on 100 parts by mass of the total amount of component (A), component (B), and component (C), Or you may apply 15-30 mass. If the content of the total of component (A) and component (B) is 5 parts by mass or more with respect to 100 parts by mass of the total amount of component (A), component (B), and component (C), the elastic modulus is further improved by crosslinking. there is a tendency When the content of the total of component (A) and component (B) is 50 parts by mass or less with respect to 100 parts by mass of the total amount of component (A), component (B), and component (C), the film handling property tends to be better. there is.

(C) Component: Elastomer

Examples of the component (C) include acrylic resins, polyester resins, polyamide resins, polyimide resins, silicone resins, butadiene resins; The modified body of these resins, etc. are mentioned. You may use these individually by 1 type or in combination of 2 or more types. Among these, the component (C) is a structural unit derived from (meth)acrylic acid ester in that it has less ionic impurities and is more excellent in heat resistance, easier to secure connection reliability of semiconductor devices, and more excellent in fluidity. It may be an acrylic resin (acrylic rubber) as a main component. (C) The content of the structural unit derived from the (meth)acrylic acid ester in the component may be, for example, 70% by mass or more, 80% by mass or more, or 90% by mass or more based on the total amount of the structural units do. The acrylic resin (acrylic rubber) may contain a structural unit derived from a (meth)acrylic acid ester having a crosslinkable functional group such as an epoxy group, an alcoholic or phenolic hydroxyl group, or a carboxyl group.

Among these, component (C) includes an elastomer (hereinafter sometimes referred to as "component (C1)") that satisfies conditions (i) and (ii).

Condition (i): The glass transition temperature is 12°C or higher.

Condition (ii): The weight average molecular weight is 800,000 or less.

Regarding condition (i), the glass transition temperature (Tg) of component (C1) is 12°C or higher, and may be 15°C or higher, 18°C or higher, or 20°C or higher. When the component (C1) has a Tg of 12°C or higher, it is possible to further improve the adhesive strength of the film adhesive, and consequently, the flexibility of the film adhesive tends to be prevented from becoming excessively high. Therefore, the parting property of the film adhesive in a cooling expand can be improved by using such a component (C1). The upper limit of the Tg of component (C1) is not particularly limited, but may be, for example, 55°C or lower, 50°C or lower, 45°C or lower, 40°C or lower, 35°C or lower, 30°C or lower, or 25°C or lower. When the component (C1) has a Tg of 55°C or lower, the decrease in flexibility of the film adhesive tends to be suppressed. This tends to make it easy to sufficiently fill the voids when attaching the film adhesive to the semiconductor wafer. In addition, it becomes possible to prevent chipping at the time of dicing due to a decrease in the adhesiveness of the semiconductor wafer. Here, the glass transition temperature (Tg) means a value measured using a DSC (thermal differential scanning calorimeter) (for example, Thermo Plus 2 manufactured by Rigaku Co., Ltd.). The Tg of the component (C1) is determined by adjusting the type and content of the structural unit constituting the component (C1) (a structural unit derived from (meth)acrylic acid ester when the component (C1) is an acrylic resin (acrylic rubber)). , can be adjusted to the desired range.

Regarding condition (ii), the weight average molecular weight (Mw) of component (C1) is 800,000 or less, and may be 700,000 or less, 600,000 or less, 500,000 or less, 400,000 or less, or 300,000 or less. The lower limit of the Mw of component (C1) is not particularly limited, but may be, for example, 10,000 or more, 50,000 or more, or 100,000 or more. When the Mw of the component (C1) is within such a range, it is possible to appropriately control the splitting property, film formability, film strength, flexibility, adhesiveness, etc. in the cold expand of the film, and excellent reflowability. Thus, the embedding property can be improved. Here, Mw means a value measured by gel permeation chromatography (GPC) and converted using a standard polystyrene calibration curve.

The content of component (C1) may be 50 to 100% by mass, 70 to 100% by mass, 90 to 100% by mass, or 95 to 100% by mass based on the total amount of component (C). The content of component (C1) may be 100% by mass based on the total amount of component (C).

Component (C) may contain, in addition to component (C1), an elastomer that does not satisfy the requirements of component (C1) (hereinafter sometimes referred to as "component (C2)").

The content of component (C2) may be 0 to 50% by mass, 0 to 30% by mass, 0 to 10% by mass, or 0 to 5% by mass based on the total amount of component (C). The content of component (C2) may be 0% by mass based on the total amount of component (C). That is, component (C) does not need to contain component (C2).

The content of component (C) is 50 to 95 parts by mass, 60 to 90 parts by mass, or 70 to 85 parts by mass relative to 100 parts by mass of the total amount of component (A), component (B), and component (C). do. When the content of component (C) is within such a range, a more elastic film can be obtained and the die shear strength tends to be further increased.

(D) Ingredient: inorganic filler

Examples of the component (D) include aluminum hydroxide, magnesium hydroxide, calcium carbonate, magnesium carbonate, calcium silicate, magnesium silicate, calcium oxide, magnesium oxide, aluminum oxide, aluminum nitride, aluminum borate whiskers, boron nitride, and silica. can be heard You may use these individually by 1 type or in combination of 2 or more types. Among these, the component (D) may be silica from the viewpoint of adjusting the melt viscosity. The shape of component (D) is not particularly limited, but may be spherical.

(D) The average particle size of the component may be 0.01 to 1 μm, 0.01 to 0.5 μm, 0.01 to 0.3 μm, or 0.01 to 0.1 μm from the viewpoint of fluidity. Here, the average particle diameter means a value obtained by converting from the BET specific surface area.

The content of component (D) is 0.1 parts by mass or more, 1 part by mass or more, 3 parts by mass or more, or 5 parts by mass with respect to 100 parts by mass of the total amount of component (A), component (B), and component (C). It may be more than 50 parts by mass or less, 30 parts by mass or less, 20 parts by mass or less, or 15 parts by mass or less may be sufficient.

Component (E): coupling agent

(E) Component may be a silane coupling agent. Examples of the silane coupling agent include γ-ureidopropyltriethoxysilane, γ-mercaptopropyltrimethoxysilane, 3-phenylaminopropyltrimethoxysilane, and 3-(2-aminoethyl). ) Aminopropyl trimethoxysilane etc. are mentioned. You may use these individually by 1 type or in combination of 2 or more types.

(F) component: curing accelerator

Component (F) is not particularly limited, and those generally used can be used. Examples of the component (F) include imidazoles and derivatives thereof, organophosphorus compounds, secondary amines, tertiary amines, and quaternary ammonium salts. You may use these individually by 1 type or in combination of 2 or more types. Among these, imidazoles and their derivatives may be sufficient as (F) component from a reactive viewpoint.

Examples of the imidazoles include 2-methylimidazole, 1-benzyl-2-methylimidazole, 1-cyanoethyl-2-phenylimidazole, and 1-cyanoethyl-2-methyl. Midazole etc. are mentioned. You may use these individually by 1 type or in combination of 2 or more types.

The film adhesive (adhesive composition) may further contain other components. As other components, a pigment, an ion trapping agent, an antioxidant, etc. are mentioned, for example.

The content of the total of component (E), component (F), and other components may be 0 to 30 parts by mass with respect to 100 parts by mass of the total amount of component (A), component (B), and component (C). .

1 is a schematic cross-sectional view showing one embodiment of a film adhesive. The film adhesive 1 (adhesive film) shown in Fig. 1 is obtained by molding an adhesive composition into a film shape. The film adhesive 1 may be in a semi-cured (B stage) state. Such a film-like adhesive 1 can be formed by apply|coating an adhesive composition to a support film. When using the varnish of the adhesive composition (adhesive varnish), (A) component, (B) component, and (C) component, and components added as necessary are mixed or kneaded in a solvent to prepare an adhesive varnish, obtained The film adhesive 1 can be obtained by applying an adhesive varnish to a support film and removing the solvent by heating and drying.

The support film is not particularly limited as long as it can withstand the drying by heating, and examples thereof include a polyester film, a polypropylene film, a polyethylene terephthalate film, a polyimide film, a polyetherimide film, a polyethylene naphthalate film, and a polymethyl film. A pentene film or the like may be used. The base material 2 may be a multilayer film in which two or more types are combined, or the surface may be treated with a release agent such as silicone or silica. The thickness of the support film may be, for example, 10 to 200 μm or 20 to 170 μm.

Mixing or kneading can be performed using a dispersing machine such as a normal stirrer, ramming machine, 3 roll, or ball mill, and combining these appropriately.

The solvent used for preparing the adhesive varnish is not particularly limited as long as it can uniformly dissolve, knead, or disperse each component, and conventionally known solvents can be used. Examples of such a solvent include ketone solvents such as acetone, methyl ethyl ketone, methyl isobutyl ketone, and cyclohexanone, dimethylformamide, dimethylacetamide, N-methylpyrrolidone, toluene, and xylene. etc. can be mentioned. The solvent may be methyl ethyl ketone or cyclohexanone from the viewpoint of drying rate and price.

As a method of applying the adhesive varnish to the supporting film, a known method can be used, and examples thereof include a knife coating method, a roll coating method, a spray coating method, a gravure coating method, a bar coating method, and a curtain coating method. there is. Heat drying is not particularly limited as long as the solvent used is sufficiently volatilized, but it can be performed by heating at 50 to 150°C for 1 to 30 minutes.

The thickness of the film adhesive 1 may be 50 μm or less, 40 μm or less, 30 μm or less, 20 μm or less, or 15 μm or less. Although the lower limit of the thickness of the film adhesive 1 is not specifically limited, For example, 1 micrometer or more may be sufficient.

The film adhesive 1 is a splitting evaluation method using the results of a cutting test conducted under the following conditions (under low-temperature conditions (for example, -15 ° C. to 0 ° C. range) in which cooling expand is performed) Method for Evaluating Breakability of Film-like Adhesive) WHEREIN: A film-like adhesive having a cutting coefficient m of greater than 0 and 70 or less and a cutting resistance R of greater than 0 N/mm ² and 40 N/mm ^{2 or} less may be used.

<condition>

Sample width: 5 mm

Sample length: 23 mm

Relative speed of indentation jig and sample: 10 mm/min

Hereinafter, the cutting test will be described. The cutting test is classified as a transverse strength test, and includes a process of pushing the central part of the sample until the sample is broken in a state where both ends of the sample are fixed. As shown in Fig. 2, the sample S is subjected to the cutting test in a state where it is inserted into and fixed to a pair of sample fixing jigs 14. A pair of sample fixing jigs 14 are made of thick paper having sufficient strength, for example, and each has a rectangular opening 14a in the center. A load is applied to the central portion of the sample S in a fixed state using a press-fitting jig 15 (see FIG. 3).

The sample S may be obtained by cutting out the film adhesive to be evaluated, and it is not necessary to prepare the sample by laminating a plurality of adhesive pieces cut out from the film adhesive. That is, the thickness of the sample S may be the same as the thickness of the film adhesive. The width (Ws in FIG. 2 ) of the sample S is, for example, 1 to 30 mm, and may be 3 to 8 mm. What is necessary is just to set it to an appropriate width according to the situation of a measuring device. The length of the sample S (Ls in FIG. 2 ) is, for example, 5 to 50 mm, and may be 10 to 30 mm or 6 to 9 mm. The length of the sample S depends on the size of the opening 14a of the sample fixing jig 14. In addition, the shape of the sample fixing jig 14 and the size of the sample S may be other than the above as long as the cutting test can be performed.

The press-fitting jig 15 is made of a columnar member having a conical tip 15a. The diameter of the press-fit jig 15 (R in Fig. 3) is, for example, 3 to 15 mm, and may be 5 to 10 mm. The angle (θ in FIG. 3 ) of the tip portion 15a is, for example, 40 to 120 degrees, and may be 60 to 100 degrees.

The cutting test is conducted in a thermostat set at a predetermined temperature. The thermostat may be set at a constant temperature (temperature of the cooling expander) in the range of -15°C to 0°C. As the thermostat, for example, TLF-R3-F-W-PL-S manufactured by I-Tech Co., Ltd. can be used. Using an autograph (for example, AZT-CA01 manufactured by A&D, load cell 50N, compression mode), work W at break, strength P at break, and elongation at break L are obtained.

The relative speed of the press-fitting jig 15 and the sample S is, for example, 1 to 100 mm/min, and may be 5 to 20 mm/min. If this relative speed is too fast, there is a tendency that sufficient data of the cutting process cannot be acquired, and if it is too slow, the stress is relieved and it is difficult to achieve cutting. The press-in distance of the press-fit jig 15 is, for example, 1 to 50 mm, and may be 5 to 30 mm. If the press-fitting distance is excessively short, there is a tendency not to reach splitting. For the film adhesive to be evaluated, it is preferable to prepare a plurality of samples and conduct a cutting test a plurality of times to confirm the stability of the test result.

4 is a graph showing an example of the results of the cutting test. As shown in Fig. 4, the cutting work W is the area covered when the vertical axis is the load and the abscissa is the pressing amount until the sample S is fractured when the graph is created. The breaking strength P is a load when the sample S is broken. The elongation at break L is the amount of elongation of the sample S when the sample S is broken. The cutting elongation L may be calculated using a trigonometric function from the press-in distance when the sample S is broken and the width of the opening 14a of the sample fixing jig 14.

From the values of breaking work W (N mm), breaking strength P (N), and breaking elongation L (mm) obtained by the cutting test, from Equations (1) and (2), the breaking coefficient m (dimensionless) and Find the cutting resistance R (N/mm ² ).

m = W/[1000×(P×L)] (One)

R = P/A (2)

According to the study of the present inventors, when a cutting test is performed under the following conditions, a film adhesive having a cutting coefficient m of more than 0 and 70 or less and a cutting resistance R of more than 0 N/mm ² and 40 N/mm ^{2 or less} is actually stealth In dicing, there is a tendency for excellent parting property when cooling expanding is performed.

<condition>

Sample width: 5 mm

Sample length: 23 mm

Relative speed of indentation jig and sample: 10 mm/min

As described above, the cutting coefficient m (dimensionless) may be greater than 0 and less than or equal to 70, or may be 10 to 60 or 15 to 55. The cutting coefficient m is a parameter related to the stretchability of the film adhesive under low temperature conditions. When the cutting coefficient m exceeds 70, excessive stretchability of the film-like adhesive tends to result in insufficient cutting ability by cold expand. In addition, when the cutting coefficient m is 15 or more, the stress propagation property tends to be good. The cutting resistance R may be greater than 0 N/mm ² and ^less than or equal to 40 N/mm 2 , greater than 0 N/mm ² and less than or equal to 35 N/mm ² , or 1 to 30 N/mm ² . When the cutting resistance R exceeds 40 N/mm ² , due to the excessive strength of the film adhesive, the splitting property by cold expand tends to be insufficient. In addition, when the cutting resistance R is 20 N/mm ² or more, better stress propagation in the cold expand tends to result in better cutting performance by the cold expand. A film adhesive having a cutting coefficient m and a cutting resistance R in the above ranges can be suitably used for stealth dicing. A film adhesive having a cleavage coefficient m and a cleavage resistance R within the above ranges can be applied to a semiconductor device manufacturing process in which cooling expand is performed.

5 is a schematic cross-sectional view showing an embodiment of an adhesive sheet. The adhesive sheet 100 shown in FIG. 5 includes a substrate 2 and a film adhesive 1 provided on the substrate 2 . 6 is a schematic cross-sectional view showing another embodiment of an adhesive sheet. The adhesive sheet 110 shown in FIG. 6 includes a substrate 2, a film adhesive 1 provided on the substrate 2, and the substrate 2 of the film adhesive 1 provided on opposite surfaces. A cover film (3) is provided.

For the base material 2, the same material as the support film described above can be used.

The cover film 3 is used to prevent damage or contamination of the film adhesive, and may be, for example, a polyethylene film, a polypropylene film, or a film treated with a surface release agent. The thickness of the cover film 3 may be, for example, 15 μm to 200 μm or 70 μm to 170 μm.

The adhesive sheets 100 and 110 can be formed by applying an adhesive composition (adhesive varnish) to the base material 2 in the same manner as in the method for forming the film-like adhesive described above. The method of applying the adhesive composition to the substrate 2 may be the same as the method of applying the above adhesive composition (adhesive varnish) to the supporting film.

The adhesive sheet 110 can be obtained by further laminating the cover film 3 on the film adhesive 1.

The adhesive sheets 100 and 110 can be formed using a previously prepared film adhesive. In this case, the adhesive sheet 100 can be formed by laminating to the substrate 2 under predetermined conditions (eg, room temperature (20° C.) or heated state) using a roll laminator, vacuum laminator, or the like. there is. Since the adhesive sheet 100 can be manufactured continuously and has excellent efficiency, it may be formed using a roll laminator in a heated state.

Another embodiment of the adhesive sheet is a dicing die-bonding integrated adhesive sheet in which the substrate 2 is a dicing tape. 7 is a schematic cross-sectional view showing another embodiment of an adhesive sheet. An adhesive sheet 120 (dicing/die bonding integrated adhesive sheet) shown in FIG. 7 includes a dicing tape 8 and a film adhesive 1 provided on the dicing tape 8 . If the dicing die-bonding integrated adhesive sheet is used, the efficiency of work can be improved because the lamination process to the semiconductor wafer becomes one time.

The dicing tape 8 is equipped with the base film 7 and the adhesive layer 6 provided on the base film 7 in one embodiment.

As the base film 7, plastic films, such as a polytetrafluoroethylene film, a polyethylene terephthalate film, a polyethylene film, a polypropylene film, a polymethylpentene film, and a polyimide film, etc. are mentioned, for example. These base films 7 may be subjected to surface treatment such as primer application, UV treatment, corona discharge treatment, polishing treatment, and etching treatment as needed.

The pressure-sensitive adhesive layer 6 is not particularly limited as long as it has sufficient adhesive strength so that semiconductor elements do not scatter during dicing and has low adhesive strength to the extent that semiconductor elements are not damaged in the subsequent pick-up process of semiconductor elements. Those conventionally known in the field of sing tapes can be used. The pressure-sensitive adhesive layer 6 may be either a pressure-sensitive adhesive or a radiation curing type.

The thickness of the dicing tape 8 (base film 7 and pressure-sensitive adhesive layer 6) may be 60 to 150 μm or 70 to 130 μm from the viewpoints of economy and film handleability.

The adhesive sheet 120 (dicing die-bonding integrated adhesive sheet) can be obtained by, for example, bonding the pressure-sensitive adhesive layer 6 of the dicing tape 8 and the film adhesive 1 together.

The film adhesive and the adhesive sheet may be those used in the manufacture of semiconductor devices, and the film adhesive and the dicing tape are bonded to a semiconductor wafer or a semiconductor element (semiconductor chip) that has already been pieced together at 0°C to 90°C. After combining, obtaining a semiconductor element with film adhesive by dividing with a rotating blade, laser, or stretching, and then bonding the semiconductor element with film adhesive on an organic substrate, a lead frame, or another semiconductor element. It may be used in the manufacture of semiconductor devices.

As a semiconductor wafer, compound semiconductors, such as single-crystal silicon, polycrystal silicon, various ceramics, and gallium arsenide, etc. are mentioned, for example.

Film adhesives and adhesive sheets are used for semiconductor devices such as ICs and LSIs, and lead frames such as 42 alloy lead frames and copper lead frames; plastic films such as polyimide resin and epoxy resin; materials obtained by impregnating and curing plastics such as polyimide resins and epoxy resins into substrates such as glass nonwoven fabrics; It can be used as an adhesive for attaching supporting members for semiconductor mounting, such as ceramics, such as alumina, etc.

Film adhesives and adhesive sheets are also suitably used as adhesives for adhering semiconductor elements to semiconductor elements in a Stacked-PKG having a structure in which a plurality of semiconductor elements are laminated. In this case, one semiconductor element serves as a support member for mounting the semiconductor element.

The film adhesive and the adhesive sheet can also be used as, for example, a protective sheet for protecting the back surface of a semiconductor element of a flip chip type semiconductor device, a sealing sheet for sealing between the surface of a semiconductor element of a flip chip type semiconductor device and an adherend, and the like. can

A semiconductor device manufactured using a film adhesive will be specifically described below with reference to drawings. In addition, semiconductor devices of various structures have been proposed in recent years, and the use of the film adhesive according to the present embodiment is not limited to the semiconductor devices of the structure described below.

8 is a schematic cross-sectional view showing an embodiment of a semiconductor device. The semiconductor device 200 shown in FIG. 8 is provided between a semiconductor element 9, a support member 10 on which the semiconductor element 9 is mounted, and the semiconductor element 9 and the support member 10, An adhesive member (cured product 1c of film-like adhesive) for adhering the semiconductor element 9 and the support member 10 is provided. A connection terminal (not shown) of the semiconductor element 9 is electrically connected to an external connection terminal (not shown) via a wire 11, and is sealed by a sealing material 12.

9 is a schematic cross-sectional view showing another embodiment of a semiconductor device. In the semiconductor device 210 shown in FIG. 9 , the first-stage semiconductor element 9a is attached to the support member 10 on which the terminal 13 is formed by means of an adhesive member (cured product 1c of film adhesive). Then, the second-stage semiconductor element 9b is further bonded to the first-stage semiconductor element 9a by means of an adhesive member (cured product 1c of film-like adhesive). The connection terminals (not shown) of the first-stage semiconductor element 9a and the second-stage semiconductor element 9b are electrically connected to an external connection terminal via a wire 11 and sealed by a sealing material 12. there is. In this way, the film adhesive according to the present embodiment can be suitably used also for a semiconductor device having a structure in which a plurality of semiconductor elements are superimposed.

In the semiconductor device (semiconductor package) shown in FIGS. 8 and 9, for example, a film adhesive is interposed between a semiconductor element and a support member or between a semiconductor element and a semiconductor element, and the two are bonded by heating and pressing. , and then, if necessary, it is obtained by passing through a wire bonding process, a sealing process with a sealing material, a heat melting process including reflow with solder, and the like. The heating temperature in the heat compression step is usually 20 to 250°C, the load is usually 0.1 to 200 N, and the heating time is usually 0.1 to 300 seconds.

As a method of interposing a film adhesive between a semiconductor element and a support member or between a semiconductor element and a semiconductor element, as described above, after producing a semiconductor element with a film adhesive in advance, attaching to the support member or semiconductor element It may be a method.

Next, one Embodiment of the manufacturing method of the semiconductor device in the case where the dicing die-bonding integrated adhesive sheet shown in FIG. 7 is used is demonstrated. In addition, the manufacturing method of the semiconductor device by the dicing die-bonding integrated adhesive sheet is not limited to the manufacturing method of the semiconductor device demonstrated below.

First, a semiconductor wafer is press-bonded to the film adhesive 1 in the adhesive sheet 120 (dicing and die-bonding integral adhesive sheet), and this is bonded and fixed (mount step). You may perform this process, pressing with pressing means, such as a crimping roll.

Next, dicing of the semiconductor wafer is performed. In this way, the semiconductor wafer is cut into a predetermined size to manufacture a plurality of individualized semiconductor elements (semiconductor chips) with adhesive film. Dicing can be performed according to a conventional method from the circuit surface side of a semiconductor wafer, for example. In addition, in this process, for example, a cutting method called full cut in which a cut is made to the dicing tape, a method in which a semiconductor wafer is cut in half and separated by cooling and drawing, a cutting method using a laser, etc. can be employed. there is. It does not specifically limit as a dicing apparatus used at this process, A conventionally well-known thing can be used.

In order to peel the semiconductor element adhesively fixed to the dicing die-bonding integrated adhesive sheet, the semiconductor element is picked up. The pick-up method is not particularly limited, and conventionally known various methods can be employed. For example, the method of pushing up each semiconductor element with a needle from the dicing die-bonding integrated adhesive sheet side, and picking up the pushed up semiconductor element with a pick-up device etc. are mentioned.

Here, pick-up is performed after radiation is irradiated to the pressure-sensitive adhesive layer when the pressure-sensitive adhesive layer is of a radiation (eg, ultraviolet ray) curing type. As a result, the adhesive force of the pressure-sensitive adhesive layer to the film adhesive is reduced, and the semiconductor element is easily separated. As a result, pickup is possible without damaging the semiconductor element.

Next, the semiconductor element with the film adhesive formed by dicing is adhered to the support member for mounting the semiconductor element via the film adhesive. Adhesion may be performed by crimping. The conditions for die bonding are not particularly limited and can be appropriately set as needed. Specifically, it can be performed within the range of, for example, a die bonding temperature of 80 to 160°C, a bonding load of 5 to 15 N, and a bonding time of 1 to 10 seconds.

If necessary, you may provide the process of thermally curing the film adhesive. By thermally curing the film adhesive that adheres the support member and the semiconductor element in the bonding step, more firmly adhesive fixation is possible. When performing thermal curing, you may apply pressure simultaneously and harden. The heating temperature in this process can be suitably changed according to the component of the film adhesive. The heating temperature may be, for example, 60 to 200°C. Further, the temperature or pressure may be changed step by step.

Next, a wire bonding step of electrically connecting the tip of the terminal portion (inner lead) of the supporting member and the electrode pad on the semiconductor element with a bonding wire is performed. As a bonding wire, a gold wire, an aluminum wire, a copper wire, etc. are used, for example. The temperature at the time of wire bonding may be in the range of 80 to 250°C or 80 to 220°C. The heating time may be several seconds to several minutes. The wiring may be performed by a combination of vibration energy by ultrasonic waves and pressing energy by applied pressure in a heated state within the above temperature range.

Next, a sealing step of sealing the semiconductor element with sealing resin is performed. This process is performed to protect the semiconductor element or bonding wire mounted on the support member. This process is performed by molding resin for sealing with a mold. As sealing resin, epoxy resin may be sufficient, for example. The substrate and the residue are buried by heat and pressure during sealing, and separation due to air bubbles at the bonding interface can be prevented.

Next, in the post-curing step, the insufficiently cured sealing resin is completely cured in the sealing step. In the sealing step, even when the film adhesive is not thermally cured, in this step, the film adhesive is thermally cured together with the curing of the sealing resin to enable adhesive fixation. The heating temperature in this step can be appropriately set according to the type of sealing resin, and may be, for example, in the range of 165 to 185°C, and the heating time may be about 0.5 to 8 hours.

Next, the semiconductor element with the film adhesive bonded to the supporting member is heated using a reflow furnace. In this process, you may surface mount the resin-sealed semiconductor device on the support member. Examples of the surface mounting method include reflow soldering in which solder is supplied on a printed wiring board in advance and then heated and melted by warm air or the like to perform soldering. As a heating method, hot-air reflow, infrared reflow, etc. are mentioned, for example. Moreover, the heating method may be heating the whole or heating a local part. The heating temperature may be in the range of 240 to 280°C, for example.

Example

Below, the present invention will be specifically described based on examples, but the present invention is not limited thereto.

[Production of film adhesive]

(Examples 1 to 6 and Comparative Example 1)

<Preparation of adhesive varnish>

Cyclohexanone was added to the composition consisting of component (A), component (B), and component (D) according to the components and contents (unit: parts by mass) shown in Table 1, and mixed with stirring. To this, component (C) (component (C1) or component (C2)) is added and stirred, and component (E) and component (F) are further added and stirred until each component becomes uniform, and an adhesive varnish is prepared. prepared In addition, the numerical value of (C) component shown in Table 1 means the mass part of solid content.

In addition, each component shown in Table 1 means the following.

(A) component: thermosetting resin

(A-1) YDCN-700-10 (trade name, manufactured by Nippon-Stetsu Sumikin Chemical Co., Ltd., o-cresol novolak type epoxy resin, epoxy equivalent: 209 g/eq)

(B) component: curing agent

(B-1) HE-100C-30 (trade name, manufactured by Air Water Co., Ltd., phenylaralkyl type phenolic resin, hydroxyl equivalent: 174 g/eq, softening point 77°C)

(C) Component: Elastomer

Component (C1): an elastomer that satisfies conditions (i) and (ii)

(C1-1) Acrylic rubber in acrylic rubber solution (SG-P3 (trade name, manufactured by Nagase Chemtex Co., Ltd., methyl ethyl ketone solution of acrylic rubber), acrylic rubber in which a part of the structural unit of the acrylic rubber is changed solution, measured Tg of acrylic rubber: 20 ° C, weight average molecular weight of acrylic rubber: 800,000)

(C1-2) In the acrylic rubber in the acrylic rubber solution (SG-P3 (trade name, manufactured by Nagase Chemtex Co., Ltd., methyl ethyl ketone solution of acrylic rubber), acrylic rubber in which a part of the structural unit of the acrylic rubber is changed solution, measured Tg of acrylic rubber: 25°C, weight average molecular weight of acrylic rubber: 800,000)

(C1-3) In acrylic rubber in an acrylic rubber solution (SG-P3 (trade name, manufactured by Nagase Chemtex Co., Ltd., methyl ethyl ketone solution of acrylic rubber), acrylic rubber in which a part of the structural unit of the acrylic rubber is changed solution, measured Tg of acrylic rubber: 12 ° C, weight average molecular weight of acrylic rubber: 500,000)

(C1-4) Acrylic rubber in acrylic rubber solution (SG-P3 (trade name, manufactured by Nagase Chemtex Co., Ltd., methyl ethyl ketone solution of acrylic rubber), in which a part of the structural unit of the acrylic rubber has been changed. solution, measured Tg of acrylic rubber: 20 ° C, weight average molecular weight of acrylic rubber: 500,000)

(C1-5) In acrylic rubber in an acrylic rubber solution (SG-P3 (trade name, manufactured by Nagase Chemtex Co., Ltd., methyl ethyl ketone solution of acrylic rubber), acrylic rubber in which a part of the structural unit of the acrylic rubber is changed solution, measured Tg of acrylic rubber: 20°C, weight average molecular weight of acrylic rubber: 200,000)

Component (C2): Elastomers other than component (C1)

(C2-1) Acrylic rubber in acrylic rubber solution (SG-P3 (trade name, manufactured by Nagase Chemtex Co., Ltd., methyl ethyl ketone solution of acrylic rubber), acrylic rubber in which a part of the structural unit of the acrylic rubber is changed solution, measured Tg of acrylic rubber: 3°C, weight average molecular weight of acrylic rubber: 800,000)

(D) Ingredient: inorganic filler

(D-1) R972 (trade name, manufactured by Nippon Aerosil Co., Ltd., silica particles, average particle diameter: 0.016 μm)

Component (E): Coupling agent

(E-1) A-189 (trade name, manufactured by Nippon Unica Co., Ltd., γ-mercaptopropyltrimethoxysilane)

(E-2) A-1160 (trade name, manufactured by Nippon Unica Co., Ltd., γ-ureidopropyltriethoxysilane)

(F) component: curing accelerator

(F-1) 2PZ-CN (trade name, manufactured by Shikoku Kasei Kogyo Co., Ltd., 1-cyanoethyl-2-phenylimidazole)

<Production of film adhesive>

The prepared adhesive varnish was filtered through a 100 mesh filter and vacuum defoamed. As a base material, a polyethylene terephthalate (PET) film having a thickness of 38 µm subjected to release treatment was prepared, and an adhesive varnish after vacuum defoaming was applied onto the PET film. The applied adhesive varnish was heated and dried in two stages, at 90°C for 5 minutes and then at 130°C for 5 minutes, to obtain film adhesives of Examples 1 to 3 and Comparative Example 1 in a B-stage state. In the film adhesive, the thickness of the film adhesive was adjusted to 10 µm according to the application amount of the adhesive varnish.

<Evaluation of splitting property by cooling expand of film adhesive>

Adhesive pieces (width 5 mm x length 100 mm) were cut out from the film adhesives of Examples 1 to 6 and Comparative Example 1, respectively. While fixing the adhesive piece to a pair of jigs (thick paper), the location of the adhesive piece protruding from the jig was removed. In this way, a sample to be evaluated (5 mm in width x 23 mm in length) was obtained. The cutting test was conducted in a thermostat (TLF-R3-F-W-PL-S manufactured by I-Tech Co., Ltd.) set to a predetermined temperature condition. That is, a cutting test was conducted using an autograph (AZT-CA01, load cell 50N, manufactured by A&D Co., Ltd.) under the conditions of a compression mode, a speed of 10 mm/min, and a press-in distance of 5 mm, and the cutting work W when the film adhesive was broken. , the breaking strength P, and the breaking elongation L were obtained. The cutting coefficient m and the cutting resistance R were calculated by the above formulas (1) and (2). In addition, 8 or more cutting tests were conducted for each Example and each Comparative Example. Table 1 shows the results. The values shown in Table 1 are average values of the results obtained by a plurality of cutting tests.

In order to confirm that the parting property evaluation matches the parting property in cold expand, dicing and die-bonding integrated films having the film adhesives of Examples 1 to 6 and Comparative Example 1 as an adhesive layer were prepared, respectively. , The parting property of the adhesive layer (film adhesive) was evaluated under the following conditions.

・Thickness of silicon wafer: 30 μm

· Tip size individualized by stealth dicing: length 10mm × width 10mm

Temperature of the cooling expander: the same temperature as the thermostat in the cutting test of Examples and Comparative Examples

・Push up by expand ring: 10 mm

- Evaluation criteria: The silicon wafer after being pushed up by the ring for expansion was irradiated with light. A case where light passes between adjacent chips with adhesive pieces (the silicon wafer and the adhesive layer are separated) is evaluated as "A", and a case where there is an area where light does not pass (the silicon wafer and the adhesive layer are divided) not) was rated as "B". The results are shown in Table 1.

[Table 1]

As shown in Table 1, the film adhesives of Examples 1 to 6 have a cutting coefficient m of 70 or less, a cutting resistance R of 40 N/mm ² or less, and an evaluation of the splitting property by cold expand of "A" was In contrast, the film adhesive of Comparative Example 1 had a cutting coefficient m of more than 70 and a cutting resistance R of more than 40 N/mm ² , and the evaluation of the cutting property by cold expand was “B”. From these results, it was confirmed that the film adhesive of the present invention was excellent in parting property by cold expand.

One… film adhesive
2… write
3... cover film
6... adhesive layer
7... base film
8… dicing tape
9, 9a, 9b... semiconductor device
10... support member
11... wire
12... sealing material
13... Terminals
14... Jig for fixing sample
14a... opening
15... press-fit jig
15a... distal end
100,110,120... adhesive sheet
200,210... semiconductor device
S... sample

Claims (8)

A film adhesive for bonding a semiconductor element and a support member for mounting the semiconductor element,
The film adhesive contains a thermosetting resin, a curing agent, and an elastomer;
A film-like adhesive, wherein the elastomer comprises an elastomer that satisfies the following condition (i) and the following condition (ii).
Condition (i): The glass transition temperature is 12°C or higher.
Condition (ii): The weight average molecular weight is 800,000 or less. The method of claim 1,
A step of preparing a sample having a cross-sectional area A (mm ² ) from the film-like adhesive;
A step of obtaining the work at break W (N mm), strength at break P (N), and elongation at break L (mm) of the sample by a cutting test under low temperature conditions in the range of -15 ° C to 0 ° C;
A step of obtaining the splitting coefficient m represented by the following formula (1);
In the method for evaluating the cutting property, which includes a step of obtaining the cutting resistance R (N/mm ² ) represented by the following formula (2) and is performed under the following conditions, the cutting coefficient m is more than 0 and 70 or less, and the cutting resistance R 0 N/mm ² to 40 N/mm ² or less, a film-like adhesive.
m = W/[1000×(P×L)] (1)
R= P/A (2)
<condition>
Sample width: 5 mm
Sample length: 23 mm
Relative speed of indentation jig and sample: 10 mm/min According to claim 1 or claim 2,
The film-like adhesive in which the said film-like adhesive further contains an inorganic filler. equipment and
An adhesive sheet provided with the film adhesive according to any one of claims 1 to 3 provided on one surface of the base material. The method of claim 4,
The adhesive sheet in which the said base material is a dicing tape. a semiconductor device,
a support member for mounting the semiconductor element;
An adhesive member provided between the semiconductor element and the support member to adhere the semiconductor element and the support member,
The semiconductor device in which the said adhesive member is a hardened|cured material of the film adhesive of any one of Claims 1-3. A method for manufacturing a semiconductor device comprising a step of adhering a semiconductor element and a support member using the film adhesive according to any one of claims 1 to 3. A step of attaching the film adhesive of the adhesive sheet according to claim 4 or 5 to a semiconductor wafer;
A step of producing a plurality of individualized semiconductor elements with film-like adhesive by cutting the semiconductor wafer to which the film-like adhesive has been affixed;
A method for manufacturing a semiconductor device comprising a step of adhering the semiconductor element with the film-like adhesive to a supporting member.

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