Composition for temporarily fixing materials, laminate, and method for manufacturing semiconductor device

Abstract

To provide a composition for temporarily fixing materials having superior film formability and lamination properties.SOLUTION: A composition for temporarily fixing materials comprises a polyamide acid and a solvent. A monomer constituted by a tetracarboxylic acid dianhydride and a diamine, which constitutes the polyamide acid, includes a monomer (A) having a structure represented by formula (1), at 10 mol% or more with respect to the total monomer, and the monomer (A) includes a diamine (a1) represented by formula (1-1), at 9 mol% or more and 40% or less with respect to the total monomer.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a temporary fixing material composition, a laminate, and a method for manufacturing a semiconductor device. [Background technology]

[0002] In recent years, technological developments for stacking semiconductor chips have been progressing in order to increase the integration and density of semiconductor elements. Furthermore, in the field of power semiconductors, there is a demand for lower conduction loss to save energy. These demands have led to a demand for thinner semiconductor wafers, less than 100 μm thick.

[0003] The process of thinning a semiconductor wafer (thinning process) is also called back-grinding. Back-grinding of semiconductor wafers involves polishing the semiconductor wafer while it is fixed to a rigid support substrate (e.g., a glass substrate) to prevent cracking of the semiconductor wafer, and then peeling the processed semiconductor wafer from the support substrate.

[0004] Various compositions for temporary fixing materials for fixing semiconductor wafers to support substrates are known, including compositions containing polyimide resins or precursors thereof (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Publication No. 2020-128452 Summary of the Invention [Problem to be solved by the invention]

[0006] Such a temporary fixing material composition is applied to a semiconductor wafer, and then the solvent is removed by heating to form a film-like temporary fixing material (temporary fixing material layer).The semiconductor wafer and a supporting substrate are then bonded together via the temporary fixing material layer.At this time, the temporary fixing material layer is heated to melt and soften the layer, thereby bonding the semiconductor wafer and the supporting substrate together.

[0007] However, a temporary fixing material composition containing a highly heat-resistant resin as shown in Patent Document 1 requires a high film-forming temperature when removing the solvent and forming a film. Furthermore, a high bonding temperature is required to melt or soften the temporary fixing material layer when bonding the support substrate. This could potentially damage devices formed on the semiconductor wafer. From the perspective of reducing such damage to devices, a temporary fixing material is desired that has good film-forming properties that allow film formation even at low film-forming temperatures and good bonding properties that allow the support substrate and semiconductor wafer to be bonded in close contact with each other even at low bonding temperatures.

[0008] The present invention has been made in view of the above-mentioned problems, and has an object to provide a composition for a temporary fixing material for obtaining a temporary fixing material having good film-forming properties and lamination properties, and also to provide a laminate obtained by using the composition and a method for manufacturing a semiconductor device. [Means for solving the problem]

[0009] The above problem can be solved by the following configuration. [1] A composition for a temporary fixing material comprising a polyamic acid and a solvent, wherein the polyamic acid comprises a polyaddition unit of a diamine and a tetracarboxylic dianhydride, and the monomer comprising the tetracarboxylic dianhydride and the diamine comprises a monomer (A) having a structure represented by formula (1) in an amount of 10 mol% or more relative to the total amount of the monomers, and The monomer (A) contains a diamine (a1) represented by formula (1-1) in an amount of 9 mol % or more and 40 mol % or less based on the total amount of the monomers. Temporary fixing composition. [ka] [ka] (In formula (1) and formula (1-1), R 1 ~R 3 are each a substituted or unsubstituted alkyl group having 1 to 3 carbon atoms or an alkoxy group having 1 to 3 carbon atoms, a to c are each an integer from 0 to 3, m and n are each an integer of 0 to 3. [2] The composition for temporary fixing material according to [1], wherein the content of the diamine (a1) relative to the total amount of the monomers is 10 mol % or more and 35 mol % or less. [3] The temporary fixing material composition according to [1], wherein the diamine further contains at least one of a diamine (a2) represented by formula (1-2) and a diamine (b) represented by formula (2). [ka] [ka] (In formula (1-2) and formula (2), R 1 ~R 5 are each a substituted or unsubstituted alkyl group having 1 to 3 carbon atoms or an alkoxy group having 1 to 3 carbon atoms, a to e are each an integer from 0 to 3, Z is an oxygen atom, a methylene group, or -CR c R d (R c and R d are divalent groups selected from the group consisting of substituted or unsubstituted alkyl groups each having 1 to 3 carbon atoms. m and n are each an integer of 0 to 3. [4] The temporary fixing material composition according to [3], wherein the molar ratio (a1 / a2+b) of the diamine (a1) to at least one of the diamine (a2) and the diamine (b) is 1 / 99 to 75 / 25. [5] The composition for a temporary fixing material according to any one of [1] to [4], wherein the composition for a temporary fixing material has a glass transition temperature of 120 to 165°C when heated to imidize the polyamic acid and form a film. [6] The temporary fixing material composition according to any one of [1] to [5], wherein the temporary fixing material composition has a melting temperature of 165 to 230°C in a melt viscoelasticity measurement when heated to imidize the polyamic acid and form a film. [7] The temporary fixing material composition according to any one of [1] to [6], wherein the temporary fixing material composition has a loss tangent (tanδ) of 1 to 10 at 250°C when heated to imidize the polyamic acid and form a film. [8] The temporary fixing material composition according to any one of [1] to [7], wherein when the temporary fixing material composition is heated to imidize the polyamic acid and form a film, the slope of the loss tangent (tanδ) at 250 to 300°C is 0.1 to 0.8. [9] A laminate having a substrate and a temporary fixing material layer disposed on the substrate, a laminate, wherein the temporary fixing material layer contains a polyimide containing a polycondensation unit of a diamine and a tetracarboxylic dianhydride, the monomer composed of the tetracarboxylic dianhydride and the diamine contains a monomer (A) having a structure represented by formula (1) in an amount of 10 mol % or more relative to the total amount of the monomers, and the monomer (A) contains a diamine (a1) represented by formula (1-1) in an amount of 9 mol % or more and 40 mol % or less relative to the total amount of the monomers. [ka] [ka] (In formula (1) and formula (1-1), R 1 ~R 3 are each a substituted or unsubstituted alkyl group having 1 to 3 carbon atoms or an alkoxy group having 1 to 3 carbon atoms, a to c are each an integer from 0 to 3, m and n are each an integer of 0 to 3.

[10] A method for manufacturing a semiconductor device, comprising: a step of applying the temporary fixing material composition according to any one of [1] to [8] onto a substrate, and then heating the composition to imidize the polyamic acid and form a temporary fixing material layer; a step of heating the temporary fixing material layer to a temperature equal to or higher than its melting temperature and bonding a support substrate to the temporary fixing material layer; and a step of grinding a surface of the substrate to which the support substrate has been bonded, the surface opposite to the temporary fixing material layer. [Effects of the Invention]

[0010] According to the present invention, it is possible to provide a composition for a temporary fixing material having good film-forming properties and laminating properties, and also to provide a laminate obtained by using the composition and a method for producing a semiconductor device. [Brief explanation of the drawings]

[0011] [Figure 1] 1A to 1F are schematic cross-sectional views illustrating a method for manufacturing a semiconductor device according to an embodiment of the present invention. [Figure 2] 2A to 2D are schematic cross-sectional views showing a method for manufacturing a semiconductor device according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0012] As a result of extensive investigations, the present inventors have found that a polyamic acid containing a predetermined amount or more of a monomer (monomer (A) having a structure represented by formula (1) described later) in which two ether bonds are bonded to a benzene ring at meta positions as a central skeleton, and containing a predetermined amount of a terminal meta-substituted monomer (diamine (a1) represented by formula (1-1) described later) in which an amino group and an ether group are bonded to a benzene ring at meta positions as a terminal skeleton, has good thermal decomposition resistance (T d5 ), while also having a low glass transition temperature (Tg) suitable for film formation and a low melting temperature suitable for lamination. As a result, it was found that a temporary fixing material with excellent film-forming properties and lamination properties could be obtained.

[0013] On the other hand, among the monomers (A), there are some terminal para-substituted monomers (e.g., diamine (a2) described later) in which an amino group or an acid dianhydride group and an ether group are bonded at para positions relative to the benzene ring as a terminal skeleton, and these have a flexible yet more rigid structure. In addition to the monomers (A), other terminal para-substituted monomers, such as pBAPP (e.g., diamine (b) described later), also have a flexible yet more rigid structure.

[0014] Therefore, it is preferable to further adjust the molar ratio of the terminal meta-substituted and terminal para-substituted monomers in the monomers constituting the polyamic acid (for example, the molar ratio of the diamine (a1) described below to the total amount of diamines (a2) and (b)), thereby further reducing the tangent loss (tan δ (250°C)) of the resulting polyimide in the high temperature range and its fluctuation with temperature. This makes it difficult for the temporary fixing material to melt and flow excessively, even in high-temperature processes at 250°C or higher, and makes it more difficult for voids (air bubbles) to occur. This makes it possible to further improve high-temperature adhesion and void resistance.

[0015] A temporary fixing material according to one embodiment of the present invention and a composition for the temporary fixing material therefor will be described in detail below. In this embodiment, a temporary fixing material used in the manufacture of a semiconductor device and a composition for the temporary fixing material for obtaining the same will be described as an example. In this specification, a numerical range expressed using "to" means a range that includes the numerical values ​​written before and after "to" as the lower and upper limits.

[0016] 1. Temporary fixing composition The temporary fixing material composition according to the present embodiment contains a polyamic acid and a solvent.

[0017] 1-1. Polyamic acid The polyamic acid contains polyaddition units of a tetracarboxylic dianhydride and a diamine.

[0018] (Monomer (A)) The monomer composed of a tetracarboxylic dianhydride and a diamine (hereinafter also simply referred to as "monomer") includes a monomer (A) having a structure represented by the following formula (1). [ka]

[0019] In formula (1), R 1 is a substituted or unsubstituted alkyl group having 1 to 3 carbon atoms or an alkoxy group having 1 to 3 carbon atoms. Of these, a substituted or unsubstituted alkyl group having 1 to 3 carbon atoms is preferred, and a methyl group is more preferred. Examples of the substituent include a halogen atom such as a fluorine atom. a is an integer of 0 to 3, and is preferably 0 or 1.

[0020] As shown in formula (1), the monomer (A) has a structure in which two ether bonds are bonded to a benzene ring at meta positions as a central skeleton. Such a monomer (A) has moderate rigidity and high flexibility. This improves the thermal decomposition resistance (T d5 In other words, it is possible to obtain a temporary fixing material having a low Tg suitable for film formation and a low melting temperature suitable for bonding.

[0021] The content of monomer (A) relative to the total amount of monomers is 10 mol% or more. When the content of monomer (A) is 10 mol% or more, the flexibility of the resulting polyimide can be further increased. Therefore, the Tg and melting temperature of the resulting polyimide can be further reduced. The content of monomer (A) is preferably 15 mol% or more. There is no particular upper limit to the content of monomer (A), but from the viewpoint of further suppressing melting or softening at high temperatures, for example, 250°C or higher, it is preferably 60 mol% or less.

[0022] The monomer (A) contains a diamine (a1) represented by formula (1-1). [ka]

[0023] R in formula (1-1) 1 ~R 3 and a to c are R in formula (1) 1 and a, respectively.

[0024] In formula (1-1), m and n are each an integer of 0 to 3. In particular, m and n are each preferably 0 or 1, and more preferably 0.

[0025] The content of diamine (a1) relative to the total amount of monomers is 9 mol% or more and 40 mol% or less. When the content of diamine (a1) is 9 mol% or more, the glass transition temperature (Tg) and melting temperature of the resulting polyimide can be further lowered. This allows the film formation temperature and lamination temperature of the temporary fixing material to be further lowered. When the content of diamine (a1) is 40 mol% or less, the melting or softening of the resulting polyimide at high temperatures can be further suppressed. From the same viewpoint, the content of diamine (a1) is preferably 10 mol% or more and 35 mol% or less, and more preferably 20 mol% or more and 30 mol% or less.

[0026] The diamine (a1) represented by formula (1-1) has a structure in which an amino group and an ether bond are bonded to a benzene ring at meta positions not only in the central skeleton but also in the terminal skeleton, which results in higher flexibility and allows the Tg and melting temperature of the resulting polyimide to be lowered.

[0027] Examples of the diamine (a1) represented by formula (1-1) include 1,3-bis(3-aminophenoxy)-4-trifluorobenzene, 1,3-bis(3-aminophenoxy)-5-trifluorobenzene, 1,3-bis(3-amino-5-trifluoromethylphenoxy)benzene, and 1,3-bis(3-amino-5-trifluoromethylphenoxy)-5-trifluoromethylbenzene.

[0028] The monomer (A) may further contain a diamine or a tetracarboxylic dianhydride other than those mentioned above.

[0029] For example, the monomer (A) may further contain a diamine (a2) represented by formula (1-2). The diamine (a2) has a terminal skeleton in which an amino group and an ether bond are bonded at para-positions relative to a benzene ring, and therefore has a more appropriate rigidity than the diamine (a1). This allows the tan δ (250°C) of the resulting polyimide to be appropriately reduced, and the slope of tan δ at 250 to 300°C to be further reduced. This makes it difficult for the temporary fixing material to melt and flow even during high-temperature processes, and makes it easier to maintain appropriate hardness, thereby further improving high-temperature adhesion. Furthermore, the formation of bubbles is also less likely, thereby further suppressing voids. [ka]

[0030] R in formula (1-2) 1 ~R 3 , a to c, m, and n are R in formula (1-1). 1 ~R 3 , a to c, m, and n, respectively.

[0031] Examples of the diamine (a2) represented by formula (1-2) include 1,3-bis(4-aminophenoxy)benzene (TPE-R), 1,3-bis(4-aminophenoxy)-4-trifluorobenzene, and the like.

[0032] The monomer (A) may further contain a tetracarboxylic dianhydride represented by formula (1-3). [ka]

[0033] R in formula (1-3) 1 ~R 3 , a to c, m, and n are R in formula (1-1). 1 ~R 3, a to c, m, and n, respectively.

[0034] (Other monomers) The monomers constituting the polyamic acid may further contain other monomers in addition to the monomer (A).

[0035] The other monomer is a monomer that does not have the structure represented by formula (1). From the viewpoint of further increasing the thermal decomposition resistance of the resulting polyimide and further suppressing melting or softening in a high temperature range, the other monomer preferably includes a monomer that includes an aromatic ring (aromatic monomer).

[0036] Among these, the other monomer preferably includes at least one of a diamine (b) represented by formula (2) and a tetracarboxylic dianhydride (b') represented by formula (2'). This can further enhance the thermal decomposition resistance and further suppress melting or softening at high temperatures while maintaining the flexibility of the resulting polyimide film. [ka] [ka]

[0037] R in formulas (2) and (2') 4 ~R 5 , d to e, m and n are R in formula (1-1) 1 ~R 3 , a to c, m, and n, respectively.

[0038] X and Y in formulas (2) and (2') are each an oxygen atom, a methylene group, and -CR a R b (R a and R b represents a divalent group selected from the group consisting of substituted or unsubstituted alkyl groups each having 1 to 3 carbon atoms; preferably -CR a R b , and more preferably -C(CH3)2.

[0039] Examples of the diamine (b) represented by formula (2) include bis[4-(4-aminophenoxy)phenyl]methane and 2,2-bis[4-(4-aminophenoxy)phenyl]propane.

[0040] Examples of the tetracarboxylic dianhydride (b') represented by the formula (2') include 4,4'-(4,4'-isopropylidenediphenoxy)bis(phthalic anhydride) (pBPADA).

[0041] The total amount of the diamine (b) represented by formula (2) and the tetracarboxylic dianhydride (b') represented by formula (2') is not particularly limited, but is preferably 30 to 90 mol% based on the total amount of monomers. When the total amount is 30 mol% or more, the flexibility of the polyimide is maintained while the thermal decomposition resistance is further improved and melting or softening at high temperatures can be reduced. From the same viewpoint, the total amount is more preferably 40 to 80 mol% based on the total amount of monomers.

[0042] The diamine (a1) represented by formula (1-1), the diamine (a2) represented by formula (1-2), the diamine (b) represented by formula (2), and the tetracarboxylic dianhydride represented by formula (2') all have an aromatic ring and an ether bond. Because aromatic rings easily absorb laser light, polyimides having these structures have ether bonds that are easily decomposed by heat generated by absorbing laser light, which can also improve the removability by LLO (laser lift-off).

[0043] The other monomer may include other diamines or other tetracarboxylic dianhydrides other than those mentioned above. Examples of other tetracarboxylic dianhydrides include aromatic tetracarboxylic dianhydrides having a biphenyl skeleton, such as 3,3',4,4'-biphenyltetracarboxylic dianhydride (BPDA); tetracarboxylic dianhydrides represented by the formula (3), such as 1,3-bis(3,4-dicarboxyphenoxy)benzene dianhydride, 1,4-bis(3,4-dicarboxyphenoxy)benzene dianhydride, 4,4'-oxydiphthalic anhydride (ODPA), 3,4'-oxydiphthalic anhydride, and 3,3'-oxydiphthalic anhydride. aromatic tetracarboxylic dianhydrides having a diphenyl ether skeleton that does not fall under the category of (1); aromatic tetracarboxylic dianhydrides having a hexafluoroisopropylidene skeleton such as 2,2-bis(2,3-dicarboxyphenyl)-1,1,1,3,3,3-hexafluoropropane dianhydride (6FDA); and aromatic tetracarboxylic dianhydrides having a fluorene skeleton such as 9,9-bis(3,4-dicarboxyphenyl)fluorene dianhydride (BPAF). These aromatic tetracarboxylic dianhydrides have a moderate rigidity, and therefore, the thermal decomposition resistance (T d5 ) is easier to increase.

[0044] (composition) Among the above monomers, the molar ratio (a1 / a2+b) of the diamine (a1) represented by formula (1-1) to at least one of the diamine (a2) represented by formula (1-2) and the diamine (b) represented by formula (2) is not particularly limited, but is preferably 1 / 99 to 75 / 25, and more preferably 20 / 80 to 70 / 30. When the molar ratio of (a1) is equal to or greater than the lower limit, the Tg and melting temperature of the resulting temporary fixing material can be lowered, thereby improving film-forming properties and lamination properties. When the molar ratio of (a1) is equal to or less than the upper limit, the molar ratio of (a2+b) becomes high, thereby making it possible to reduce the tan δ (250°C) and the slope of tan δ of the resulting temporary fixing material, thereby improving high-temperature adhesion and void resistance.

[0045] The content ratio of the aromatic monomer relative to the total amount of the above-mentioned monomers constituting the polyamic acid is not particularly limited, but from the viewpoint of further improving thermal decomposition resistance and further suppressing melting or softening in high temperature ranges, it is preferably 40 mol% or more, and may be 100 mol%.

[0046] (Physical Properties) The molecular terminals of the polyamic acid may be either acid anhydride groups or amino groups. From the viewpoint of increasing the solubility of the temporary fixing material in a solvent, it is preferable that the proportion of molecular terminals that are acid anhydride groups is higher than the proportion of molecular terminals that are amino groups. On the other hand, from the viewpoint of increasing heat resistance, it is preferable that the proportion of molecular terminals that are amino groups is higher than the proportion of molecular terminals that are acid anhydride groups.

[0047] For example, to increase the proportion of molecular terminals that are acid anhydride groups, the amount of tetracarboxylic dianhydride (a moles) can be increased relative to the amount of diamine (b moles). Specifically, the molar ratio of diamine (b moles) to tetracarboxylic dianhydride (a moles) contained in the polyamic acid is not particularly limited, but b / a is preferably 0.90 to 0.999, and may be 0.90 to 0.95. When b / a is 0.999 or less, the molecular terminals of the resulting polyimide are more likely to be acid anhydride groups, which makes it easier to increase the solubility of the film. b / a can be specified as the charging ratio of tetracarboxylic dianhydride (a moles) to diamine (b moles).

[0048] From the viewpoint of facilitating film formation, the intrinsic viscosity η of the temporary fixing material composition is preferably 0.3 to 2.0 dL / g, and more preferably 0.5 to 1.5 dL / g. The intrinsic viscosity (η) of the temporary fixing material composition is the average value measured three times using an Ubbelohde viscometer at 25°C when polyamic acid is dissolved in N-methyl-2-pyrrolidone (NMP) to a concentration of 0.5 g / dL.

[0049] The intrinsic viscosity (η) of the temporary fixing material composition can be adjusted by the molar ratio (b / a) of diamine (b moles) to tetracarboxylic dianhydride (a moles). By setting the molar ratio (b / a) within the above range, it is possible to achieve an appropriate solids concentration while keeping η appropriately small, making it possible to form a thicker film-like temporary fixing material.

[0050] 1-2.Solvent The solvent may be any solvent used in the preparation of polyamic acid, and is not particularly limited as long as it can dissolve the diamine and tetracarboxylic dianhydride. For example, aprotic polar solvents and alcoholic solvents can be used.

[0051] Examples of aprotic polar solvents include N-methyl-2-pyrrolidone, N,N-dimethylformamide, N,N-dimethylacetamide, dimethyl sulfoxide, hexamethylphosphoramide, 1,3-dimethyl-2-imidazolidinone, 3-methoxy-N,N-dimethylpropanamide, gamma-butyrolactone, epsilon-caprolactone; and ether compounds such as 2-methoxyethanol, 2-ethoxyethanol, 2-(methoxymethoxy)ethoxyethanol, 2-isopropoxyethanol, 2-butoxyethanol, tetrahydrofurfuryl alcohol, diethylene glycol, diethylene glycol monomethyl ether, diethylene glycol ... Examples of the alkyl ethers include ethylene glycol monoethyl ether, diethylene glycol monobutyl ether, triethylene glycol, triethylene glycol monoethyl ether, tetraethylene glycol, 1-methoxy-2-propanol, 1-ethoxy-2-propanol, dipropylene glycol, dipropylene glycol monomethyl ether, dipropylene glycol monoethyl ether, tripropylene glycol monomethyl ether, polyethylene glycol, polypropylene glycol, tetrahydrofuran, dioxane, 1,2-dimethoxyethane, diethylene glycol dimethyl ether, and diethylene glycol diethyl ether.

[0052] Examples of alcohol-based solvents include methanol, ethanol, 1-propanol, 2-propanol, tert-butyl alcohol, ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,3-butanediol, 1,4-butanediol, 2,3-butanediol, 1,5-pentanediol, 2-butene-1,4-diol, 2-methyl-2,4-pentanediol, 1,2,6-hexanetriol, and diacetone alcohol.

[0053] These solvents may be used alone or in combination of two or more, and among these, N,N-dimethylacetamide, N-methyl-2-pyrrolidone, 1,3-dimethyl-2-imidazolidinone, 3-methoxy-N,N-dimethylpropanamide, gamma-butyrolactone, dimethyl sulfoxide, or a mixed solvent of two or more of these is preferred.

[0054] The concentration of the polyamic acid in the temporary fixing material composition is preferably 5 to 50% by mass, and more preferably 10 to 35% by mass, from the viewpoint of improving the coatability.

[0055] 1-3. Properties of the temporary fixing material composition The temporary fixing material composition preferably has a low Tg and melting temperature from the viewpoint of improving film-forming properties and lamination properties when heated to imidize the polyamic acid to form a polyimide-containing film (temporary fixing material).

[0056] Furthermore, from the viewpoint of improving high-temperature adhesion and void resistance even under high-temperature processes when formed into the film, the temporary fixing material composition preferably has small loss tangent (tan δ) and small temperature-dependent fluctuations thereof. Furthermore, from the viewpoint of improving removability with a solvent when formed into the film, the temporary fixing material composition preferably further has good solubility.

[0057] That is, the film obtained by heating the temporary fixing material composition preferably satisfies the following (1) and (2), and more preferably further satisfies (3) to (6).

[0058] (1) Glass transition temperature (Tg) The Tg of the film is 120 to 165°C. When the Tg of the film is 120°C or higher, the molecules are less likely to move excessively during film formation, and the surface precision of the resulting coating film can be further improved. When the Tg of the film is 165°C or lower, the film formation temperature for removing the solvent and performing imidization can be lowered. From the same viewpoint, the Tg of the resulting film is preferably 125 to 165°C, and more preferably 130 to 160°C.

[0059] The Tg of the film can be measured by the following method. The temporary fixing material composition is applied to a glass plate, heated from 50°C to 250°C at a rate of 5°C / min in the atmosphere, and held at 250°C for 30 minutes to imidize the polyamic acid and obtain a film. The obtained film is cut into a size of 5 mm wide and 22 mm long. The Tg of the cut film is measured using a thermal analyzer (e.g., a TMA-50 manufactured by Shimadzu Corporation). Specifically, measurements are performed in the atmosphere at a heating rate of 5°C / min in a tensile mode (100 mN) to obtain a TMA curve. The glass transition temperature (Tg) of the obtained TMA curve is determined by extrapolating the curve before and after the inflection point of the TMA curve due to the glass transition.

[0060] The Tg of the film can be adjusted, for example, by the content of the monomer (A) or the molar ratio (a1 / (a2+b)) of the diamine (a1) to the diamine (a2) and / or diamine (b). For example, increasing the content of the monomer (A) or the molar ratio (a1 / (a2+b)) tends to lower the Tg of the film.

[0061] (2) Melting temperature The melting temperature of the film is 165 to 230°C. When the melting temperature is 230°C or lower, the film exhibits melt fluidity at a relatively low temperature, making it easier to spread the film more uniformly over the entire bonding surface during lamination, thereby further improving lamination properties. When the melting temperature is 165°C or higher, the film is less likely to melt during film formation, making it possible to further improve the thickness precision of the coating film. From the same viewpoint, the melting temperature of the film is more preferably 170 to 225°C.

[0062] (3) Complex viscosity As described above, the melt viscosity (complex viscosity) of the film at the melting temperature is 40,000 mPa·s or less. When the complex viscosity is 40,000 mPa·s or less, the viscosity is appropriately low when heated to or above the melting temperature. Therefore, when, for example, a support substrate and a substrate are thermocompression-bonded via the film, the film melts or softens easily, facilitating uniform spreading and adhesion. The lower limit of the complex viscosity is not particularly limited, but from the viewpoint of more stable support during substrate processing, it can be, for example, 1,000 mPa·s or more. From the same viewpoint, the complex viscosity of the film is preferably 1,000 to 30,000 mPa·s, more preferably 1,000 to 20,000 mPa·s, and even more preferably 2,000 to 15,000 mPa·s.

[0063] (4) Tangent loss (tanδ) and its slope The tan δ(250°C) of the film is preferably 1 to 10. When the tan δ(250°C) is 1 or more, the film can be more easily melted at the lamination temperature, thereby further improving lamination properties. On the other hand, when the tan δ(250°C) is 10 or less, the film is less likely to melt even in a high temperature range of 250°C or higher, thereby enabling more stable support of the substrate even in high-temperature processes. From the same viewpoint, the tan δ(250°C) is more preferably 2 to 9.

[0064] The slope of tan δ of the film at 250 to 300°C is preferably 0.1 to 1. When the slope of tan δ is 0.1 or more, the film can be more easily melted at the lamination temperature, thereby improving lamination properties. On the other hand, when the slope of tan δ is 1 or less, the melt fluidity is less likely to change with a slight temperature change, making it more unlikely that voids will occur even at high temperatures of 300°C or higher. From the same perspective, the slope of tan δ at 250 to 300°C is more preferably 0.1 to 0.8.

[0065] The melting temperature, complex viscosity and tan δ can be measured by melt viscoelasticity measurement. First, the film prepared for Tg measurement is cut into a plurality of pieces each having a diameter of 15 to 25 mm, and these pieces are stacked to form a sample having a thickness of 0.5 to 2 mm. The prepared sample is then placed in a TA Instruments ARES-G2 rheometer and heated to a predetermined temperature at a frequency of 1 Hz and a heating rate of 3°C / min, and the melt viscoelasticity is measured. In the measurement results obtained, the point at which the storage modulus and loss modulus are equal (the temperature at which tanδ = 1) in the temperature range higher than the glass transition temperature is the melting point, and the temperature at this melting point is defined as the melting temperature. The melt viscosity at the melting temperature (melting point) is defined as the complex viscosity.

[0066] The melting temperature, complex viscosity, and tan δ of the film can be adjusted, for example, by the content of diamine (a1) or the molar ratio (a1 / (a2+b)) of diamine (a1) to diamine (a2) and / or diamine (b). For example, increasing the content or molar ratio (a1 / (a2+b)) of diamine (a1) tends to lower the melting temperature and complex viscosity of the film. On the other hand, decreasing the content or molar ratio (a1 / (a2+b)) of diamine (a1) tends to lower the tan δ and its slope of the film.

[0067] (5) 5% weight loss temperature (T d5 ) The 5% weight loss temperature (Td5 ) is preferably 400°C or higher from the same viewpoint as above. d5 The upper limit of the temperature is not particularly limited, but may be, for example, 600°C.

[0068] The 5% weight loss temperature (T d5 The Tg can be measured using a thermogravimetric analyzer. Specifically, the film prepared for Tg measurement is cut into small pieces, and a sample (approximately 5 mg) is accurately weighed on the analyzer. The scanning temperature is set to 30 to 900°C, and the sample is heated at a temperature increase rate of 10°C / min in an air atmosphere while air gas is flowing at 50 mL / min. The temperature at which the sample loses 5% of its mass can be measured.

[0069] (6) Solubility The film preferably has high solubility in a solvent so that it can be easily removed from a substrate after use. Specifically, the film prepared for Tg measurement is immersed in N-methyl-2-pyrrolidone at 80°C for 5 minutes, and then filtered through filter paper to measure the dissolution rate, expressed by the following formula, which is preferably 90% or more, and more preferably 95% or more. Dissolution rate (%) = [1 - [(weight of filter paper after filtration and drying) - (weight of filter paper before use)] / (weight of film before immersion)] × 100

[0070] The solubility can be measured by the following procedure. First, the film is cut into a sample of 20 μm thick and 2.0 cm × 2.0 cm, and the weight of the sample (weight of the film before immersion) is measured in advance. The weight of the filter paper before use is also measured in advance. Next, the sample is added to N-methyl-2-pyrrolidone (NMP) to a concentration of 1% by mass to form a solution, and the resulting solution is left to stand in an oven heated to 80°C for 10 minutes. The solution is then removed from the oven, filtered through filter paper, and dried under reduced pressure at 100°C. The weight of the filter paper after filtration and drying is then measured. The measured values ​​are applied to the above formula to calculate the dissolution rate. These operations are carried out twice, and the average value is taken as the dissolution rate (%).

[0071] The solubility of the film tends to increase, for example, by increasing the content of the monomer (A) or by using the diamine (b) represented by formula (2) or the tetracarboxylic dianhydride (b') represented by formula (2'). Also, decreasing the diamine / acid dianhydride ratio tends to increase the solubility of the resulting film.

[0072] The film-like material obtained by heating a coating of the temporary fixing material composition to imidize the polyamic acid has an appropriately low Tg, as well as an appropriately low melting temperature and complex viscosity, as described above, and therefore can be preferably used as a temporary fixing material, for example, a temporary fixing material for semiconductor manufacturing.

[0073] 2. Manufacturing method of semiconductor device 1A to 1F and 2A to 2D are schematic diagrams showing a method for manufacturing a semiconductor device according to one embodiment of the present invention.

[0074] 1A to 1F and 2A to 2D, the method for manufacturing a semiconductor device according to this embodiment includes: 1) a step of applying a temporary fixing material composition onto a substrate 11, followed by heating to form a temporary fixing material layer 12 (see FIGS. 1A and 1B); 2) a step of bonding a support substrate 13 to the temporary fixing material layer 12 while heating the temporary fixing material layer 12 (see FIG. 1C); and 3) a step of grinding the surface of the bonded substrate 11 opposite to the temporary fixing material layer 12 (see FIGS. 1D and 1E). In this embodiment, the following steps may be further performed: 4) a step of further processing the back surface of the ground substrate 11 (see FIG. 1F); 5) a step of mounting the obtained substrate 11 on a dicing tape 15 fixed to a dicing frame (see FIG. 2A); 6) a step of irradiating the support substrate 13 with laser light to peel the support substrate 13 from the temporary fixing material layer 12 (see FIGS. 2B and 2C); and 7) a step of dissolving the remaining temporary fixing material layer 12 in a solvent and removing it (see FIG. 2D).

[0075] Step 1) The above-described temporary fixing material composition is applied onto a substrate 11, and then heated to form a temporary fixing material layer 12 (see FIGS. 1A and 1B). Specifically, a temporary fixing material composition is applied onto a substrate 11, and then heated to imidize the polyamic acid, thereby forming a temporary fixing material layer 12. In this way, a laminate L1 including the substrate 11 and the temporary fixing material layer 12 containing polyimide is obtained (see FIG. 1B).

[0076] The substrate 11 is preferably a semiconductor substrate containing at least one selected from the group consisting of silicon, silicon carbide, gallium nitride, gallium oxide, and sapphire. The semiconductor substrate may be a substrate on which devices such as diodes, transistors, integrated circuits (ICs), and power elements are formed. The temporary fixing material layer 12 may be disposed on the circuit-forming surface or on a surface different from the circuit-forming surface.

[0077] The temporary fixing material composition can be applied by, for example, spin coating or spray coating.

[0078] The applied temporary fixing material composition can be heated, for example, by an oven or a hot plate. The heating temperature may be any temperature at which the solvent can be removed to the extent that the polyamic acid contained in the temporary fixing material composition is imidized and becomes a self-supporting film.

[0079] When imidization is performed in one step, the imidization can be achieved by increasing the temperature from 20 to 50°C to a temperature range of 180 to 300°C and maintaining the temperature for a predetermined time. Specifically, the temperature to be reached is preferably 180 to 300°C, more preferably 200 to 300°C. The rate of temperature increase is preferably 1 to 20°C / min, more preferably 2 to 10°C / min. Furthermore, the time to maintain the temperature is preferably 20 to 60 minutes, more preferably 20 to 30 minutes.

[0080] When imidization is carried out in two stages, the first stage is preferably at 50 to 150°C, more preferably at 50 to 120°C. The second stage is preferably at 150 to 350°C, more preferably at 200 to 300°C. The holding time in each stage is preferably 2 to 15 minutes, more preferably 2 to 10 minutes. There are no particular limitations on the temperature change or time between each stage. The polyimide contained in the temporary fixing material layer 12 is an imidized version of the polyamic acid described above, and contains polycondensation units of diamine and tetracarboxylic dianhydride. The monomer composition is the same as above.

[0081] The thickness of the temporary fixing material layer 12 is not particularly limited as long as it is large enough to stably support the substrate 11 with the support substrate 13. The thickness of the temporary fixing material layer 12 can be, for example, about 1 to 100 μm.

[0082] Step 2) Next, the temporary fixing material layer 12 is heated to a temperature equal to or higher than its melting point, and a support substrate 13 is attached (see FIG. 1C).

[0083] The support substrate 13 may be any substrate having rigidity, such as a resin substrate, a ceramic substrate, or a glass substrate. Among these, from the viewpoint of performing LLO, the support substrate 13 is preferably a transparent support substrate such as a glass substrate. The thickness of the support substrate 13 is not particularly limited, but is preferably thicker than the thickness of the temporary fixing material layer 12, and may be, for example, 50 to 1000 μm.

[0084] The heating temperature of the temporary fixing material layer 12 may be equal to or higher than the melting temperature. The melting temperature means the melting temperature of the film obtained by heating the above-mentioned temporary fixing material composition. Specifically, the heating temperature during lamination may be equal to or higher than the melting temperature and 350°C or lower.

[0085] There are no particular limitations on the method for heating the temporary fixing material layer 12, and similarly to the above, it can be performed using an oven, a hot plate, etc. A predetermined pressure may be applied during lamination to perform thermocompression bonding.

[0086] Step 3) Next, the surface (back surface) of the substrate 11 to which the support substrate 13 is bonded, opposite to the temporary fixing material layer 12, is ground (see FIGS. 1D and 1E), thereby thinning the substrate 11 to a predetermined thickness or less.

[0087] Step 4) Next, the back surface of the ground substrate 11 is further processed. For example, after ion implantation or annealing is performed on the back surface of the ground substrate 11, a collector layer may be formed to form a transistor 14 (insulated gate bipolar transistor, IGBT) (see FIG. 1F). Alternatively, a resist may be formed on the back surface of the ground substrate 11, and patterning may be performed.

[0088] Step 5) Next, the ground substrate 11 is mounted on a dicing tape 15 attached to a dicing frame using, for example, a wafer mounter (see FIG. 2A).

[0089] Step 6) Next, a step of irradiating laser light through the support substrate 13 to peel the support substrate 13 from the temporary fixing material layer 12 (see FIGS. 2B and 2C).

[0090] The laser light may have a wavelength of 200 to 360 nm (preferably 355 nm). When the laser light is irradiated, the aromatic rings in the polyimide contained in the temporary fixing material layer 12 absorb the light and generate heat, which breaks the ether bonds and makes the layer more susceptible to peeling.

[0091] Step 7) After the support substrate 13 is peeled off, the remaining temporary fixing material layer 12 is brought into contact with a solvent, whereby the temporary fixing material layer 12 is dissolved in the solvent and removed (see FIG. 2D).

[0092] (action) In this embodiment, in step 1), the temporary fixing material layer 12 can be formed by applying a temporary fixing material composition and then heating it at a low film-forming temperature. In step 2), the temporary fixing material layer 12 has a low melting temperature, so it can be sufficiently melted even at a low bonding temperature, and the substrate 11 and the support substrate 13 can be favorably bonded together. As a result, the substrate 11 can be stably supported by the support substrate 13 during thinning processing without causing thermal damage to the substrate 11.

[0093] Furthermore, when the polyamic acid contained in the temporary fixing material composition further contains diamine (a2) or diamine (b), the temporary fixing material layer 12 can be made less likely to melt or soften excessively even at high temperatures, which makes it possible to obtain higher adhesion and void resistance even during high-temperature processes such as steps 3) and 4). [Example]

[0094] The present disclosure will be described below with reference to examples, which should not be construed as limiting the scope of the present disclosure.

[0095] 1. Material Preparation 1-1. Polyamic acid (Monomer (A)) APB-N: 1,3-bis(3-aminophenoxy)benzene (diamine (a1)) TPE-R: 1,3-bis(4-aminophenoxy)benzene (diamine (a2))

[0096] (Other monomers) p-BAPP: 2,2-bis(4-(4-aminophenoxy)phenyl)propane (diamine (b)) Bisaniline M: 1,3-bis[2-(4-aminophenyl)-2-propyl]benzene pBPADA: 4,4'-(4,4'-isopropylidenediphenoxy)bis(phthalic anhydride) (tetracarboxylic dianhydride (b'))

[0097] 1-2.Solvent NMP: N-methyl-2-pyrrolidone DMI: 1,3-dimethyl-2-imidazolidinone

[0098] 2. Preparation of temporary fixing material composition [Examples 1 to 9, Comparative Examples 1 to 6] The types and amounts (mol %) of tetracarboxylic dianhydrides and diamines shown in Table 1 were blended in a solvent shown in Table 1. The resulting mixture was stirred at 45°C for 5 hours or more in a flask into which dry nitrogen gas could be introduced. This resulted in a composition for temporary fixing material, which was a polyamic acid varnish with the concentration shown in Table 1.

[0099] 3. Evaluation 3-1. Evaluation of temporary fixing material composition (viscosity) The viscosity of the obtained temporary fixing material composition was measured at 25°C using an E-type viscometer.

[0100] (Intrinsic viscosity (η)) The obtained temporary fixing material composition was diluted with NMP so that the resin concentration was 0.5 g / dL, and the intrinsic viscosity η of the solution was measured three times at 25°C using an Ubbelohde viscometer (size number 1) in accordance with JIS K7367-1:2002, and the average value was used.

[0101] 3-2. Evaluation of temporary fixing materials (Preparation of temporary fixing material) The temporary fixing material composition was applied to a glass plate, and the temperature was increased from 50°C to 250°C at a rate of 5°C / min in the atmosphere, and then maintained at 250°C for 30 minutes. As a result, the polyamic acid contained in the temporary fixing material composition was imidized, and a temporary fixing material in the form of a polyimide film was obtained.

[0102] (glass transition temperature (Tg)) The prepared temporary fixing material was cut into a size of 5 mm wide and 22 mm long to prepare a sample. The glass transition temperature (Tg) of the obtained sample was measured using a thermal analyzer (e.g., TMA-50 manufactured by Shimadzu Corporation). Specifically, the sample was heated from below 50°C to 250°C at a heating rate of 5°C / min in an air atmosphere, and measurement was performed in a tensile mode (100 mN) to obtain a TMA curve. The glass transition temperature (Tg) of the obtained curve was determined by extrapolating the curves before and after the inflection point of the TMA curve due to the glass transition. The glass transition temperature is an index for evaluating film-forming properties. If the glass transition temperature was 120°C or higher and 165°C or lower, it was evaluated as ◯, and if it was higher than 165°C, it was evaluated as ×.

[0103] (5% weight loss temperature (T d5 )) The 5% weight loss temperature (T d5 ) was measured using a thermogravimetric analyzer (TGA-60) manufactured by Shimadzu Corporation. Specifically, the sample (approximately 5 mg) was accurately weighed on the analyzer, and the scanning temperature was set to 30 to 900°C. The sample was heated at a temperature increase rate of 10°C / min in an air atmosphere while air gas was flowing at 50 mL / min. The temperature at which the sample mass decreased by 5% was determined as T. d5 It was decided.

[0104] (melting temperature, complex viscosity, tanδ) The prepared temporary fixing material was cut into a plurality of pieces with a diameter of 15 to 25 mm, and these were stacked to form samples with a thickness of 0.5 to 2 mm. Next, the prepared sample was set in a TA Instruments ARES-G2 rheometer and heated to a predetermined temperature at a frequency of 1 Hz and a heating rate of 3°C / min, and the melt viscoelasticity was measured. In the obtained measurement results, the point where the storage modulus and loss modulus become equal (the temperature where tanδ = 1) in the temperature range above the glass transition temperature was determined as the melting point, and the temperature at this melting point was taken as the melting temperature. The melt viscosity at the melting temperature (melting point) was also taken as the complex viscosity. Furthermore, the values ​​of tanδ at 250°C and 300°C were read, and the slope of tanδ from 250 to 300°C was calculated from these values.

[0105] The melting temperature was used as an index for evaluating the lamination property. A melting temperature of 165°C or higher and 230°C or lower was evaluated as ◯, and a melting temperature lower than 165°C was evaluated as x. Tan δ (250°C) is an index for evaluating high-temperature adhesion. Tan δ (250°C) of 1 to 10 was judged as ◯, and tan δ (250°C) of less than 1 or more than 10 was judged as △. The slope of tan δ is an index for evaluating void resistance. If the slope of tan δ was 0.1 or more and 0.8 or less, it was judged as ◎, if it was more than 0.8 and 1 or less, it was judged as ○, and if it was less than 0.1, it was judged as △.

[0106] (Re-soluble) The prepared temporary fixing material was cut into a sample measuring 2.0 cm x 2.0 cm. Next, the sample was placed in N-methyl-2-pyrrolidone (in an amount such that the sample was 1% by mass), and the resulting solution was left to stand in an oven heated to 80°C for 10 minutes. The solution was then removed from the oven, and the state of dissolution of the sample was visually observed. If the solution did not shake or there was no sample residue when shaken, it was judged to be "soluble," and if there was any shaking or sample residue when shaken, it was judged to be "not soluble."

[0107] Table 1 shows the compositions and evaluation results of the temporary fixing material compositions of Examples 1 to 9 and Comparative Examples 1 to 6, and Table 2 shows the evaluation results of the temporary fixing materials. [Table 1]

[0108] [Table 2]

[0109] As shown in Table 1, the temporary fixing materials of Comparative Examples 1 to 6, which contain polyimides that do not contain at least monomer (A) or whose content is less than 10 mol%, have a high Tg of 170°C or higher and a high melting temperature.

[0110] In contrast, the temporary fixing materials of Examples 1 to 9, which contain polyimides containing 10 mol % or more of monomer (A) and 9 mol % or more and 40 mol % or less of diamine (a1), have a low Tg of 165°C or less and a relatively low melting temperature.

[0111] From these findings, it can be seen that the temporary fixing materials of Examples 1 to 9, which contain polyimide containing 10 mol % or more of monomer (A) and 9 mol % to 40 mol % of diamine (a1), have a low film formation temperature suitable for film formation and a low bonding temperature suitable for bonding.

[0112] In particular, it is clear that by setting the molar ratio a1 / (a2+b) to 25 / 75 or more, the high-temperature adhesion and void resistance can be further improved.

[0113] According to the present invention, it is possible to provide a composition for a temporary fixing material having good film-forming properties and laminating properties, and also to provide a laminate obtained by using the composition and a method for producing a semiconductor device. [Explanation of symbols]

[0114] 11 Circuit Board 12 Temporary fixing material layer 13 Support substrate 14 Transistor 15 Dicing tape L1 laminate

Claims

1. A temporary fixing material composition comprising a polyamic acid and a solvent, The polyamic acid contains polyaddition units of diamine and tetracarboxylic dianhydride, The monomer composed of the tetracarboxylic dianhydride and the diamine contains 10 mol % or more of a monomer (A) having a structure represented by formula (1) based on the total amount of the monomers, and The monomer (A) contains a diamine (a1) represented by formula (1-1) in an amount of 9 mol % or more and 40 mol % or less based on the total amount of the monomers. Temporary fixing composition. 【Chemical 1】 【Chemistry 2】 (In formula (1) and formula (1-1), R １ ~R ３ are each a substituted or unsubstituted alkyl group having 1 to 3 carbon atoms or an alkoxy group having 1 to 3 carbon atoms, a to c are each an integer of 0 to 3, m and n are each an integer of 0 to 3.

2. the content of the diamine (a1) relative to the total amount of the monomers is 10 mol % or more and 35 mol % or less; The temporary fixing material composition according to claim 1 .

3. The diamine further includes at least one of a diamine (a2) represented by formula (1-2) and a diamine (b) represented by formula (2), The temporary fixing material composition according to claim 1 . 【Chemistry 3】 【Chemistry 4】 (In formula (1-2) and formula (2), R １ ~R ５ are each a substituted or unsubstituted alkyl group having 1 to 3 carbon atoms or an alkoxy group having 1 to 3 carbon atoms, a to e each represent an integer of 0 to 3, X is an oxygen atom, a methylene group, or —CR ｃ R ｄ (R ｃ and R ｄ are divalent groups selected from the group consisting of substituted or unsubstituted alkyl groups each having 1 to 3 carbon atoms. m and n are each an integer of 0 to 3.

4. the molar ratio (a1 / a2+b) of the diamine (a1) to at least one of the diamine (a2) and the diamine (b) is 1 / 99 to 75 / 25; The temporary fixing material composition according to claim 3 .

5. The temporary fixing material composition has a glass transition temperature of 120 to 165°C when heated to imidize the polyamic acid and form a film. The temporary fixing material composition according to claim 1 .

6. The temporary fixing material composition has a melting temperature of 165 to 230°C in a melt viscoelasticity measurement when heated to imidize the polyamic acid and form a film. The temporary fixing material composition according to claim 1 .

7. the temporary fixing material composition has a loss tangent (tanδ) of 1 to 10 at 250°C when heated to imidize the polyamic acid and form a film; The temporary fixing material composition according to claim 1 .

8. The temporary fixing material composition has a slope of loss tangent (tanδ) of 0.1 to 0.8 at 250 to 300°C when the temporary fixing material composition is heated to imidize the polyamic acid and form a film. The temporary fixing material composition according to claim 1 .

9. A laminate, A substrate and a temporary fixing material layer disposed on the substrate, the temporary fixing material layer contains a polyimide containing a polycondensation unit of a diamine and a tetracarboxylic dianhydride, The monomer composed of the tetracarboxylic dianhydride and the diamine contains 10 mol % or more of a monomer (A) having a structure represented by formula (1) based on the total amount of the monomers, and The monomer (A) contains a diamine (a1) represented by formula (1-1) in an amount of 9 mol % or more and 40 mol % or less based on the total amount of the monomers. Laminate. 【Chemistry 5】 【Chemistry 6】 (In formula (1) and formula (1-1), R １ ~R ３ are each a substituted or unsubstituted alkyl group having 1 to 3 carbon atoms or an alkoxy group having 1 to 3 carbon atoms, a to c are each an integer of 0 to 3, m and n are each an integer of 0 to 3.

10. a step of applying the temporary fixing material composition according to any one of claims 1 to 8 onto a substrate, and then heating the composition to imidize the polyamic acid, thereby forming a temporary fixing material layer; a step of heating the temporary fixing material layer to a melting temperature or higher to bond a support substrate; grinding a surface of the substrate to which the support substrate is bonded, the surface being opposite to the temporary fixing material layer; Including, A method for manufacturing a semiconductor device.

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