Photothermal conversion ink composition and laminate

Abstract

An ink composition capable of forming a photothermal conversion layer with high heat resistance and chemical resistance is provided. According to one embodiment, the photothermal conversion layer ink composition comprises a thermally decomposable light absorber and a binder or precursor thereof, wherein the binder or precursor comprises at least one of an organosilicon partial condensate or an alkali metal silicate.

Description

Technical Field

[0001] This disclosure relates to a photothermal conversion layer ink composition and a laminate including a photothermal conversion layer. This disclosure also relates to a method for manufacturing a thinned substrate, a method for manufacturing a semiconductor chip, and a method for manufacturing a semiconductor substrate laminate and using the laminate. Background Technology

[0002] In the semiconductor industry, to meet the demands for thinning and densification of packages through chip lamination technology, semiconductor wafer thinning via so-called back-side grinding is advocated. In back-side grinding, the surface opposite to the patterned surface is ground. Known techniques where the wafer is carried solely by a protective tape during back-side grinding and transport steps are insufficient to meet the requirements of various newly proposed manufacturing steps. Therefore, a technique has been proposed in which, during back-side grinding and, if necessary, in subsequent steps, the semiconductor wafer is carried on a hard, transparent carrier (such as a glass substrate) with a photothermal conversion (LTHC) layer via an adhesive. Finally, the photothermal conversion layer is destroyed by laser scanning, thereby separating the semiconductor wafer, or the semiconductor chip obtained by slicing the semiconductor wafer, from the carrier without stress.

[0003] JP 2004-064040 A discloses "a laminate comprising: a substrate to be ground; an adhesive layer in contact with the substrate to be ground; a photothermal conversion layer comprising a light absorber and a thermolytically decomposable resin; and a light-transmitting carrier, wherein after grinding the surface of the substrate to be ground on the side opposite to the adhesive layer, the photothermal conversion layer is decomposed by irradiation with radiation energy to separate the ground substrate from the light-transmitting carrier."

[0004] JP 2013-534721 T discloses "a laminate comprising: a substrate; an adhesive layer adjacent to the substrate; a photothermal conversion layer adjacent to the adhesive layer and including a metal absorbing layer; and a light-transmitting carrier adjacent to the photothermal conversion layer".

[0005] JP 2019-189868 A discloses "a method for bonding workpieces, the method comprising: forming an adhesive layer on the surface of at least one substrate and / or at least one workpiece; bonding the at least one substrate and the at least one workpiece through the adhesive layer; processing the at least one workpiece; and separating the at least one workpiece from the at least one substrate by irradiating the adhesive layer with a laser, wherein the adhesive layer is formed by an adhesive comprising a polymer and a light-absorbing material, the polymer being present in a solid fraction of the adhesive in the range of 50% to 98% by weight, the light-absorbing material being present in a solid fraction of the adhesive in the range of 2% to 50% by weight, the polymer being a polyimide or a copolymer of ammonium acid / imide, the polymer backbone containing hydroxyl units in the range of 5% to 45% by weight, the polymer backbone containing aliphatic ether units or siloxane units in the range of 5% to 40% by weight, and the polymer having a cyclization rate greater than or equal to 90%".

[0006] JP 2015-199794 A discloses "a peeling method comprising irradiating a laminate comprising a carrier and an adhesive from one side of the laminate with an energy beam to separate the carrier and the adhesive, the side facing the carrier, the carrier being translucent and the adhesive being fixed to the carrier by an adhesive, wherein the adhesive comprises a condensation resin and boron-containing carbon particles, and the adhesive comprises at least one of an inorganic material or an organic material."

[0007] JP 2012-052031 A discloses "a method for processing a layer to be processed, the method comprising: (1) forming an adhesive layer on a carrier, the adhesive layer comprising a polymer (A) and a photoradical generator (B), wherein the content of the polymeric compound in 100% by weight of the adhesive layer is less than 10% by weight; (2) forming a layer to be processed on the adhesive layer; (3) processing the layer to be processed; (4) irradiating the adhesive layer with light from one side of the adhesive layer facing the carrier; and (5) peeling the processed layer to be processed off the carrier in this order." Summary of the Invention

[0008] Technical issues

[0009] The technologies disclosed in JP 2004-064040 A, JP 2013-534721 T, JP 2019-189868 A, JP 2015-199794 A and JP 2012-052031 A can solve problems such as substrate thickness non-uniformity during back-side grinding, wafer warping after back-side grinding, and wafer breakage due to stress applied during back-side grinding.

[0010] With the rapid development of power semiconductors and high-density packaging, there is a growing demand for heat and / or chemical resistance in adhesive materials that can be temporarily bonded and subsequently peeled off. The required heat and chemical resistance depends entirely on the processing steps the adhesive material undergoes. Examples of processing steps include chemical mechanical polishing (CMP), resin molding, etching such as wet and dry etching, vapor deposition, physical vapor deposition (PVD) such as sputtering, chemical vapor deposition (CVD), plating such as electrolytic plating and chemical plating, patterning by photolithography, and oxide film formation on silicon wafer surfaces. In processing steps where the processing temperature reaches above 350°C (such as sputtering), the adhesive material needs to be stable at that temperature for several hours. When plating and / or wet etching are performed, the adhesive material needs to be stable in a variety of chemicals such as acids, alkaline solutions, organic solvents, and inorganic solvents. In particular, in some semiconductor processes, such as the RDL (redistribution layer) first process, the entire surface of the layer constituting the adhesive material (e.g., a photothermal conversion layer) is exposed to a high-temperature atmospheric environment or chemicals.

[0011] This disclosure provides ink compositions capable of forming photothermal conversion layers with high heat resistance and chemical resistance.

[0012] Solution to the problem

[0013] According to one embodiment of the present disclosure, a photothermal conversion layer ink composition is provided, the photothermal conversion layer ink composition comprising a light absorber having thermal decomposability and a binder or precursor thereof, wherein the binder or precursor thereof comprises at least one of an organosilicon partial condensate or an alkali metal silicate.

[0014] According to another embodiment of this disclosure, a laminate is provided, the laminate comprising a light-transmitting carrier and a photothermal conversion layer, the photothermal conversion layer comprising a light absorber having thermal decomposability and a binder, wherein the binder comprises at least one of an organosilicon condensate or an alkali metal silicate.

[0015] According to another embodiment of the present disclosure, a laminate (laminate B) is provided, which further includes an adhesive layer disposed on the photothermal conversion layer and a substrate to be ground disposed on the adhesive layer, wherein the photothermal conversion layer and the substrate to be ground are bonded together by the adhesive layer.

[0016] According to another embodiment of this disclosure, a method for manufacturing a thinned substrate is provided, the method comprising: preparing a laminate B; grinding a substrate to be ground until the substrate to be ground has a desired thickness; irradiating a photothermal conversion layer with radiant energy through a light-transmitting carrier to decompose the photothermal conversion layer, thereby separating the ground substrate having an adhesive layer from the light-transmitting carrier; and optionally, removing the adhesive layer from the ground substrate.

[0017] According to another embodiment of the present disclosure, a laminate (laminate C) is provided, the laminate including a patterned metal layer disposed on a photothermal conversion layer, a patterned insulating layer disposed on the metal layer, a semiconductor device disposed on or above the insulating layer, and a sealing material covering the semiconductor device.

[0018] According to another embodiment of this disclosure, a method for manufacturing a semiconductor chip is provided, the method comprising: preparing a laminate C; irradiating a photothermal conversion layer with radiation energy through a light-transmitting carrier to decompose the photothermal conversion layer, thereby separating a metal layer and the light-transmitting carrier from each other; and optionally, removing residues of the photothermal conversion layer from the surface of the metal layer.

[0019] According to another embodiment of the present disclosure, a laminate (laminate D) is provided, the laminate further comprising an adhesive layer disposed on a photothermal conversion layer and a semiconductor substrate disposed on the adhesive layer, wherein the semiconductor substrate includes an insulating layer disposed on a surface of the semiconductor substrate opposite to the adhesive layer, and one or more conductive connectors electrically connected to the semiconductor substrate through the insulating layer.

[0020] According to another embodiment of this disclosure, a method for manufacturing a semiconductor substrate laminate is provided, the method comprising: preparing a laminate D; preparing a second semiconductor substrate, the second semiconductor substrate including a second insulating layer disposed on a surface of the second semiconductor substrate, and one or more second conductive connectors electrically connected to the second semiconductor substrate through the second insulating layer; forming a semiconductor substrate laminate, wherein the conductive connectors are bonded to each other and the insulating layer is bonded to each other by making the conductive connectors of the semiconductor substrate face each other and the second conductive connectors of the second semiconductor substrate facing each other, and by hot-pressing the semiconductor substrate and the second semiconductor substrate together; irradiating a photothermal conversion layer with radiation energy through a light-transmitting carrier to decompose the photothermal conversion layer, thereby separating the semiconductor substrate laminate including the adhesive layer from the light-transmitting carrier; and optionally, removing the adhesive layer from the surface of the semiconductor substrate laminate.

[0021] Beneficial effects of the invention

[0022] According to this disclosure, a photothermal conversion layer ink composition capable of forming a photothermal conversion layer with high heat resistance and chemical resistance can be provided. Laminates including photothermal conversion layers formed using the photothermal conversion layer ink composition can be used in various processes for manufacturing semiconductor devices, particularly in processes involving high-temperature or chemical processing steps.

[0023] The above description should not be construed as indicating that all embodiments of the present invention and all advantages of the present invention are disclosed. Attached Figure Description

[0024] Figure 1 It is a schematic cross-sectional view of the laminate according to the first embodiment.

[0025] Figure 2 This is a schematic cross-sectional view of the laminate according to the second embodiment.

[0026] Figure 3 This is an illustrative diagram of a method for manufacturing a thinned substrate according to one embodiment.

[0027] Figure 4 It is a schematic cross-sectional view of the laminate according to the third embodiment.

[0028] Figure 5 This is an illustration of a method for manufacturing a laminate according to the third embodiment.

[0029] Figure 6 This is an illustrative diagram of a method for manufacturing a semiconductor chip according to one embodiment.

[0030] Figure 7 It is a schematic cross-sectional view of the laminate according to the fourth embodiment.

[0031] Figure 8 This is an illustrative diagram of a method for manufacturing a semiconductor substrate laminate according to one embodiment. Detailed Implementation

[0032] Representative embodiments of the invention will now be described in more detail with reference to the accompanying drawings necessary for illustrating the embodiments, but the invention is not limited to these embodiments.

[0033] One embodiment of the photothermal conversion layer ink composition comprises a thermally decomposable light absorber and a binder or precursor thereof. The binder or precursor thereof comprises at least one of an organosilicon partial condensate or an alkali metal silicate.

[0034] The photothermal conversion layer formed using the ink composition contains an inorganic binder, thus exhibiting high heat resistance and minimal mass loss at high temperatures. Therefore, the photothermal conversion layer can be used in high-temperature processing steps in semiconductor device manufacturing, for example, in the temperature range of 350°C to 400°C. Furthermore, because the photothermal conversion layer contains an inorganic binder, it possesses high chemical resistance and is stable relative to organic solvents, acids, and most alkaline solutions.

[0035] Another layer, such as a redistribution layer (RDL), can be formed directly on the photothermal conversion layer formed using the photothermal conversion layer ink composition, without the need for an adhesive layer. In the first RDL process, the photothermal conversion layer is directly exposed to a high-temperature atmospheric environment or various chemicals, but because the photothermal conversion layer has high heat resistance and chemical resistance as described above, it can also be used in the first RDL process.

[0036] A thermally decomposable light absorber (hereinafter referred to as "light absorber") is a substance that absorbs radiant energy, such as laser irradiation, converts it into heat, and undergoes thermal decomposition. For example, in the case of carbon black particles, which are a type of thermally decomposable light absorber, combustion (in the presence of oxygen) or graphitization occurs when the temperature rises due to light absorption, and the carbon black particles decompose, generating gases and losing their particle shape. Therefore, voids are generated in the photothermal conversion layer, and the photothermal conversion layer decomposes and separates into two layers. This allows for easy separation of the carrier and substrate on both sides of the photothermal conversion layer without applying unnecessary stress.

[0037] As a light absorber, a light absorber that absorbs the radiation energy of the wavelength to be used can be selected. As the radiation energy, lasers with wavelengths typically from 150 nm to 2000 nm, preferably from 300 nm to 1100 nm, can be used, and specific examples of such lasers include YAG lasers with a wavelength of 1064 nm, second-harmonic YAG lasers with a wavelength of 532 nm, semiconductor lasers with wavelengths from 780 nm to 1300 nm, KrF excimer lasers (wavelength 248 nm), ArF excimer lasers (wavelength 193 nm), F2 excimer lasers (wavelength 157 nm), XeCl lasers (wavelength 308 nm), XeF lasers (wavelength 351 nm), and solid-state UV lasers (wavelength 355 nm). As the radiation energy, ultraviolet light (wavelengths above 254 nm and below 436 nm) generated by high-pressure mercury lamps can also be used, such as gamma rays (wavelength 436 nm), h-rays (wavelength 405 nm), or i-rays (wavelength 365 nm).

[0038] Examples of light absorbers include black pigments such as carbon black, graphite powder, and black titanium dioxide; inorganic materials that specifically absorb laser wavelengths, such as cesium-doped tungsten oxide (CWO); aromatic diamine metal complexes, aromatic diamine metal complexes, aromatic dithiol metal complexes, mercaptophenol metal complexes, squaric acid cyanine compounds, black dyes, red dyes, or purple dyes such as cyanine dyes, methylene dyes, naphthoquinone dyes, and anthraquinone dyes; and ultraviolet-absorbing compounds such as octyl methoxycinnamate, octyl dimethoxybenzyldioxazolidinyl propionate, hexyl diethylaminohydroxybenzoylbenzoate, tert-butylmethoxydibenzoylmethane, octyl triazine, 2-ethylhexyl p-methoxycinnamate, and dihydroxybenzophenone.

[0039] In the photothermal conversion layer ink composition, the light absorber is preferably particulate. In other words, the particulate light absorber has low compatibility with the binder and its precursors or the solvent of the photothermal conversion layer ink composition, and is preferably dispersed rather than dissolved in the photothermal conversion layer ink composition. Even when the particulate light absorber's temperature increases during the absorption of light and conversion of light into heat, changes such as oxidation, decomposition, and phase transitions gradually occur from the particle surface to the particle interior, thereby temporarily maintaining light absorption capacity within the particles. Therefore, when the particulate light absorber is observed on a particle-by-particle basis, photothermal conversion continues for a longer period at the location of the particulate light absorber within the photothermal conversion layer, and voids can be effectively generated within the photothermal conversion layer. From this perspective, the particulate light absorber is preferably a black pigment.

[0040] The average primary particle size of the particulate light absorber is preferably about 10 nm or more, or about 20 nm or more, and about 400 nm or less, or about 300 nm or less. When a more precise smooth surface is required in the photothermal conversion layer, for example, when the photothermal conversion layer is used in the first process of RDL, the average primary particle size of the particulate light absorber is preferably about 10 nm or more, or about 30 nm or less. In this disclosure, the average primary particle size of the particulate material refers to the value obtained by forming primary particles from aggregates using an ultrasonic disperser in a solvent in which the material is not dissolved, and then randomly measuring the particle size (equivalent circle diameter) of more than 1000 primary particles in an image taken using a transmission electron microscope at a magnification of 50,000 to 200,000x, and calculating their average value.

[0041] In one embodiment, the light absorber comprises carbon black particles. Examples of carbon black particles include thermal black particles, acetylene black particles, gas furnace black particles, oil furnace black particles, and channel black particles. Carbon black particles can significantly reduce the force required to separate the substrate and the light-transmitting carrier after irradiation with radiation energy.

[0042] Depending on the mass of the light absorber, the content of carbon black particles in the light absorber can be more than about 40% by mass, more than about 50% by mass, or more than about 60% by mass. In one embodiment, the light absorber is carbon black particles.

[0043] The average primary particle size of the carbon black particles is preferably between about 10 nm and about 400 nm. When a more accurate smooth surface is required in the photothermal conversion layer, such as in the first process for the redistribution layer (RDL), the average primary particle size of the carbon black particles is preferably between about 10 nm and about 30 nm.

[0044] The carbon black particles preferably comprise hydrophilic carbon black particles. Hydrophilic carbon black particles have hydrophilic functional groups, such as carboxyl groups on their surface. Therefore, hydrophilic carbon black particles can exhibit self-dispersibility and be highly dispersed in the photothermal conversion layer ink composition. By using hydrophilic carbon black particles, the storage stability of the photothermal conversion layer ink composition can be enhanced, while avoiding the use of dispersants that may cause the binder or its precursors to gel in the photothermal conversion layer ink composition.

[0045] Dyes that selectively absorb wavelengths of radiation energy while transmitting other wavelengths can be used in combination with carbon black particles. This is useful for forming a photothermal conversion layer that selectively transmits aligned light during the slicing process.

[0046] The content of the light absorber in the photothermal conversion layer ink composition varies depending on the type, particle form, and dispersibility of the light absorber, and can be approximately 20% by volume or more, approximately 30% by volume or more, approximately 35% by volume or more, approximately 70% by volume or less, approximately 60% by volume or less, or approximately 55% by volume or less, based on the volume of the solid fraction. When the content of the light absorber is approximately 20% by volume or more, voids are generated more effectively in the photothermal conversion layer, and the substrate and the light-transmitting carrier can be separated from each other with low stress. By setting the content of the light absorber to approximately 70% by volume or less, the film-forming properties of the photothermal conversion layer and its adhesion to adjacent layers can be ensured. When the adhesive used to form the adhesive layer is a UV-curable adhesive and UV light is irradiated through the photothermal conversion layer, the content of the light absorber is ideally 60% by volume or less, so that the UV transmittance of the photothermal conversion layer is set to a level sufficient to cure the adhesive.

[0047] The content of the light absorber in the photothermal conversion layer ink composition varies depending on the type, particle form, and dispersibility of the light absorber, and can be about 20% by mass or more, about 30% by mass or more, about 35% by mass or more, about 65% by mass or less, about 55% by mass or less, or about 50% by mass or less, based on the mass of the solids. When the content of the light absorber is about 20% by mass or more, voids are generated more effectively in the photothermal conversion layer, and the substrate and the light-transmitting carrier can be separated from each other with low stress. By setting the content of the light absorber to about 65% by mass or less, the film-forming properties of the photothermal conversion layer and its adhesion to adjacent layers can be ensured. When the adhesive used to form the adhesive layer is a UV-curable adhesive and UV light is irradiated through the photothermal conversion layer, the content of the light absorber is ideally 65% ​​by mass or less, so that the UV transmittance of the photothermal conversion layer is set to a level sufficient to cure the adhesive.

[0048] The binder or its precursor includes at least one of an organosilicon partial condensate or an alkali metal silicate. At least a portion of the organosilicon partial condensate may condense during the formation of the photothermal conversion layer to form an organosilicon condensate. The alkali metal silicate may also condense during the formation of the photothermal conversion layer to form a more advanced crosslinked structure. The organosilicon condensate and the alkali metal silicate form the matrix of the photothermal conversion layer and serve as a binder for a thermally decomposable light absorber. When the light absorber is thermally decomposed by laser irradiation or the like, the organosilicon condensate and alkali metal silicate in the photothermal conversion layer lose their structure or integrity as the matrix. During the thermal decomposition of the light absorber, alcohols may be generated and volatilized through the decomposition of the organic groups of the organosilicon partial condensate or the organosilicon condensate. Therefore, the interior of the photothermal conversion layer is decomposed to separate the substrate and the carrier. The organosilicon partial condensate and the alkali metal silicate are also used as transparent fillers, particularly silica, as described below, as optional components.

[0049] Examples of organosilicon partial condensates include partial condensates of alkyl silicates, such as methyl silicate, ethyl silicate, n-propyl silicate, isopropyl silicate, and n-butyl silicate. The partial condensates of alkyl silicates are obtained by hydrolysis and condensation of the alkyl silicates in the presence of an acidic catalyst, such as sulfuric acid, hydrochloric acid, nitric acid, phosphoric acid, or an organic acid, with the addition of water and, if desired, an alcohol, such as methanol, ethanol, or isopropanol. The partial condensates can be obtained as a solution of a mixed solvent of water and a byproduct alcohol, or optionally, a solution of the alcohol used.

[0050] The organosilicon partial condensate preferably includes tetraethyl orthosilicate. Tetraethyl orthosilicate can improve film-forming properties while maintaining the storage stability of the photothermal conversion layer ink composition.

[0051] In one embodiment, the number average molecular weight of the organosilicon partial condensate is about 800 or more, or about 1600 or more, and about 4000 or less, or about 2500 or less. When the number average molecular weight of the organosilicon partial condensate is within the above range, the film-forming properties of the photothermal conversion layer ink composition can be enhanced. The number average molecular weight of the organosilicon partial condensate is determined by gel permeation chromatography (GPC), a method calibrated with polystyrene standards.

[0052] Examples of alkali metal silicates include lithium silicate, sodium silicate, and potassium silicate.

[0053] For example, alkali metal silicates can be used in an aqueous solution (water glass). In this case, the concentration of the alkali metal silicate in the aqueous solution can be more than about 10% by mass, more than about 20% by mass, or more than about 30% by mass, and less than about 90% by mass, less than about 80% by mass, or less than about 70% by mass. In this embodiment, water in the aqueous solution is also used as a solvent for the photothermal conversion layer ink composition.

[0054] Alkali metal silicates preferably include at least one of potassium silicate or lithium silicate, more preferably potassium silicate. During the preparation and storage of the photothermal conversion layer ink composition, potassium silicate and lithium silicate, especially potassium silicate, are stable in the photothermal conversion layer ink composition and possess moderate strength and cohesion, thus enabling the formation of a photothermal conversion layer with high adhesion to the light-transmitting carrier.

[0055] Alkali metal silicates preferably include a combination of potassium silicate and lithium silicate. Combining potassium silicate and lithium silicate further enhances the chemical resistance and heat resistance of the photothermal conversion layer. The mass ratio of potassium silicate to lithium silicate (potassium silicate mass / lithium silicate mass) is preferably 1 / 10 to 10 / 1, more preferably 3 / 7 to 9 / 2, and even more preferably 6 / 4 to 8 / 2.

[0056] Based on the total mass of the binder and its precursors, the total content of organosilicon partial condensates and alkali metal silicates can be more than about 50% by mass, more than about 60% by mass, or more than about 70% by mass, and less than 100% by mass, less than about 95% by mass, or less than about 90% by mass.

[0057] The binder and its precursor preferably comprise alkali metal silicates. Because alkali metal silicates do not have organic groups, they can further enhance the alkali resistance of the photothermal conversion layer. Based on the total mass of the binder and its precursor, the content of alkali metal silicates can be more than about 80% by mass, more than about 90% by mass, or more than about 95% by mass. In one embodiment, the binder and its precursor are alkali metal silicates.

[0058] Based on the volume of solids, the total content of binder and its precursors in the photothermal conversion layer ink composition can be about 30% by volume or more, about 40% by volume or more, about 45% by volume or more, about 80% by volume or less, about 70% by volume or less, or about 65% by volume or less. By setting the total content to about 30% by volume or more, the film-forming properties of the photothermal conversion layer and the adhesion between the photothermal conversion layer and adjacent layers can be ensured, and the chemical resistance of the photothermal conversion layer can be improved. When the total content is about 80% by volume or less, voids are generated more effectively in the photothermal conversion layer, and the substrate and the light-transmitting carrier can be separated from each other with low stress.

[0059] Based on the mass of the solids content, the total content of the binder and its precursors in the photothermal conversion layer ink composition can be about 35% by mass or more, about 45% by mass or more, or about 50% by mass or more, and about 80% by mass or less, about 70% by mass or less, or about 65% by mass or less. By setting the total content to about 35% by mass or more, the film formation of the photothermal conversion layer and the adhesion between the photothermal conversion layer and adjacent layers can be ensured, and the chemical resistance of the photothermal conversion layer can be improved. When the total content is about 80% by mass or less, voids are generated more effectively in the photothermal conversion layer, and the substrate and the light-transmitting carrier can be separated from each other with low stress.

[0060] One embodiment of the photothermal conversion layer ink composition further comprises lignin sulfonate or a salt thereof. Lignosulfonate is a sulfonated compound that is a portion of the lignin decomposition products. Lignin, along with cellulose, is one of the major components constituting the cell walls of wood, straw, and other woody plants. It has a phenylpropane-type carbon skeleton and is a polymer with a complex structure containing benzene rings bonded to hydroxyl, methoxy, etc. Lignosulfonate and its salts can improve the dispersibility of the light absorber while maintaining the storage stability of the photothermal conversion layer ink composition.

[0061] Based on 100 parts by weight of the light absorber, the content of lignin sulfonic acid and its salt in the photothermal conversion layer ink composition can be about 4 parts by weight or more, about 6 parts by weight or more, or about 8 parts by weight or more, and about 20 parts by weight or less, about 16 parts by weight or less, or about 12 parts by weight or less. By setting the content of lignin sulfonic acid to about 4 parts by weight or more, the light absorber can be more uniformly dispersed in the photothermal conversion layer ink composition. By setting the content of lignin sulfonic acid to about 20 parts by weight or less, the mass reduction of the photothermal conversion layer in high-temperature environments (such as above 330°C) can be suppressed.

[0062] One embodiment of the photothermal conversion layer ink composition further comprises a transparent filler. The transparent filler serves to prevent the photothermal conversion layer from separating due to voids created by the thermal decomposition of the light absorber, thus preventing re-bonding. Examples of transparent fillers include silica, talc, and barium sulfate. The transparent filler enhances the peelability between the substrate and the transparent carrier after irradiation with radiation energy without hindering the curing of the UV-curable adhesive.

[0063] The average primary particle size of the transparent filler can be above approximately 7 nm, above approximately 10 nm, or above approximately 15 nm, and below approximately 40 nm, below approximately 30 nm, or below approximately 25 nm.

[0064] In cases where a more accurate smooth surface is required for the photothermal conversion layer, such as in the case of RDL first process, it is preferable that the photothermal conversion layer does not contain transparent fillers.

[0065] Based on the volume of solids, the total content of the light absorber and the optional transparent filler is preferably about 5% by volume or more, about 20% by volume or more, or about 35% by volume or more, and about 70% by volume or less, about 60% by volume or less, or about 55% by volume or less. When the total content is about 5% by volume or more, voids are generated more effectively in the photothermal conversion layer, and the substrate and the light-transmitting carrier can be separated from each other with low stress. By setting the total content to about 70% by volume or less, the film formation of the photothermal conversion layer and the adhesion between the photothermal conversion layer and adjacent layers can be ensured, and the chemical resistance of the photothermal conversion layer can be improved.

[0066] Based on the mass of the solids content, the total content of the light absorber and the optional transparent filler is preferably about 5% by mass or more, about 20% by mass or more, or about 35% by mass or more, and about 65% by mass or less, about 55% by mass or less, or about 45% by mass or less. When the total content is about 5% by mass or more, voids are generated more effectively in the photothermal conversion layer, and the substrate and the light-transmitting carrier can be separated from each other under low stress. By setting the total content to about 65% by mass or less, the film formation of the photothermal conversion layer and the adhesion between the photothermal conversion layer and adjacent layers can be ensured, and the chemical resistance of the photothermal conversion layer can be improved.

[0067] The photothermal conversion layer ink composition may include other additives as needed. Examples of other additives include leveling agents, silane coupling agents, foaming agents, sublimation agents, thickeners, and viscosity modifiers.

[0068] The photothermal conversion layer ink composition may contain a solvent for dissolving or dispersing other components. Examples of solvents include water, alcohols such as methanol, ethanol, and isopropanol; ketones such as acetone and methyl ethyl ketone; and esters such as ethyl acetate and butyl acetate. The solvent is preferably water, an alcohol, or a mixture of water and an alcohol.

[0069] The solids content of the photothermal conversion layer ink composition can be appropriately determined based on the coatability, drying or curability of the photothermal conversion layer ink composition and the thickness of the photothermal conversion layer to be formed. In one embodiment, the solids content of the photothermal conversion layer ink composition is about 3% by mass or more, about 5% by mass or more, or about 10% by mass or more, and about 30% by mass or less, about 25% by mass or less, or about 20% by mass or less.

[0070] The viscosity of the photothermal conversion layer ink composition can be appropriately determined based on its coatability, drying or curability, and the thickness of the photothermal conversion layer to be formed. One embodiment of the photothermal conversion layer ink composition has a viscosity of about 3 mPa·s or more, about 5 mPa·s or more, or about 10 mPa·s or more, and about 200 mPa·s or less, about 100 mPa·s or less, or about 50 mPa·s or less. Photothermal conversion layer ink compositions having viscosities of about 10 mPa·s or more and about 50 mPa·s or less are suitable for spin coating. Viscosity is measured using a rheometer (RotoVisco 1, purchased from HAAKE) at 25°C and for 100 seconds. -1 The value measured at the shear rate.

[0071] The laminate (laminate A) of the first embodiment includes a light-transmitting carrier and a photothermal conversion layer comprising a thermally decomposable light absorber and a binder. The binder includes at least one of an organosilicon condensate or an alkali metal silicate. Based on the mass of the binder, the total content of the organosilicon condensate and the alkali metal silicate may be more than about 50% by mass, more than about 60% by mass, or more than about 70% by mass, and less than 100% by mass, less than about 95% by mass, or less than about 90% by mass.

[0072] Figure 1 A schematic cross-sectional view of a laminate (laminate A) according to this embodiment is shown. The laminate 10 includes a light-transmitting carrier 12 and a photothermal conversion layer 14.

[0073] The light-transmitting carrier is formed of a material capable of transmitting radiative energy (such as laser light) and optionally radiation for curing adhesives (such as ultraviolet light). Ideally, the light-transmitting carrier is a material that keeps a substrate (e.g., a semiconductor wafer) flat and does not break during processes such as back-side grinding and transport. For the target radiative energy or radiation, the transmittance of the light-transmitting carrier is ideally greater than approximately 50%.

[0074] Examples of translucent carriers include glass and acrylic resins. Translucent carriers may optionally undergo surface treatments, such as treatment with silane coupling agents, to improve adhesion to adjacent layers, such as photothermal conversion layers. Examples of shapes for translucent carriers include circular and rectangular. Translucent carriers may also be flat.

[0075] In one embodiment, the light-transmitting carrier is glass. Examples of glass include quartz glass, sapphire glass, and borosilicate glass.

[0076] The light-transmitting carrier ideally has sufficient rigidity to prevent warping of the substrate (e.g., semiconductor wafer). The light-transmitting carrier preferably has a Young's modulus of 1 MPa to 10 MPa and a thickness of 500 µm or more.

[0077] The light-transmitting carrier may be exposed to high temperatures due to heat generated in the photothermal conversion layer during irradiation and frictional heat generated during back-side grinding. Alternatively, before the semiconductor chip is stripped from the light-transmitting carrier, processes such as CMP, resin molding, etching such as wet and dry etching, vapor deposition, PVD such as sputtering, CVD, plating such as electrolytic and chemical plating, patterning by photolithography, and high-temperature processing to form an oxide film on the silicon wafer surface can be added. Depending on these steps, a light-transmitting carrier with heat resistance, chemical resistance, or a low coefficient of thermal expansion can be selected. Examples of light-transmitting carriers with heat resistance, chemical resistance, and a low coefficient of thermal expansion include glass, such as quartz glass, borosilicate glass, and sapphire glass, specifically Pyrex (trade name), Corning #1737 and #7059 (Corning Corporation), and Tempax (Schott AG).

[0078] After the back-side grinding step and before slicing, as an intermediate step, wet etching can be performed on the surface of the semiconductor wafer using a chemical solution. This step is performed to remove the damaged layer on the back surface of the semiconductor wafer caused by grinding and to improve the wafer's bending strength. Alternatively, as the final step in the semiconductor wafer thinning process, wet etching can remove a thickness of tens of µm. When the semiconductor wafer is a single crystal silicon (Si), a mixed acid containing hydrogen fluoride is typically used as the etching chemical solution. In this case, when the light-transmitting carrier is glass (excluding sapphire glass), the ends of the light-transmitting carrier are also etched by the chemical solution. Therefore, when the light-transmitting carrier is reused, the glass can be protected from corrosion caused by hydrogen fluoride by pre-applying a protective film with acid resistance (resistance to etching chemicals) on the glass. As a protective film, an acid-resistant resin can be used. Ideally, the acid-resistant resin is dissolved in an organic solvent, applied in solution form, and fixed to the glass by drying. Furthermore, it is ideal that the acid-resistant resin transmits a sufficient amount of light of the laser wavelength emitted to separate the glass from the semiconductor wafer. From this perspective, examples of suitable acid-resistant resins include amorphous polyolefins, cyclic olefin copolymers, and polyvinyl chloride (PVC) that do not contain condensation bonds in their molecules.

[0079] Ideally, the thickness of the light-transmitting carrier should be uniform. For example, to thin a silicon wafer to below 50µm and achieve a uniformity of less than ±10%, the thickness deviation of the light-transmitting carrier should ideally be less than ±2µm. When reusing the light-transmitting carrier, it is ideal for it to be scratch-resistant. When reusing the light-transmitting carrier, it is ideal to select the carrier material considering the wavelength of the radiation energy to suppress damage from radiation. For example, when using Pyrex glass as the light-transmitting carrier and irradiating it with a 3× harmonic YAG laser (355nm), the light-transmitting carrier can be separated from the semiconductor wafer or chip; however, there is a possibility that the carrier absorbs radiation energy and is thermally damaged, rendering it unusable.

[0080] The laminate includes a photothermal conversion layer comprising a thermally decomposable light absorber and a binder, wherein the binder comprises at least one of an organosilicon condensate or an alkali metal silicate. Radiant energy emitted to the photothermal conversion layer in the form of laser light or the like is absorbed by the light absorber and converted into heat energy. The generated heat energy raises the temperature of the photothermal conversion layer, and the light absorber itself thermally decomposes at this temperature. Depending on the type of light absorber and binder, gas may be generated during the thermal decomposition of the light absorber. This allows for easy separation of the carrier and substrate on both sides of the photothermal conversion layer without applying unnecessary stress.

[0081] The photothermal conversion layer can be formed on a transparent carrier using the above-described photothermal conversion layer ink composition. The photothermal conversion layer ink composition is applied to the transparent carrier by spin coating, rod coating, roller coating, casting, spraying, etc., and heated to, for example, about 100°C to about 250°C to evaporate the water or alcohol, or optionally the solvent, generated during the condensation reaction of the organosilicon partial condensate or alkali metal silicate. This allows the formation of a photothermal conversion layer containing at least one of the organosilicon condensate and alkali metal silicate as a binder.

[0082] The thickness of the photothermal conversion layer can be set to approximately 0.1µm or more, approximately 0.3µm or more, or approximately 0.5µm or more, and approximately 5µm or less, approximately 3µm or less, or approximately 2µm or less. By setting the thickness of the photothermal conversion layer to approximately 0.1µm or more, the film-forming properties and adhesion of the photothermal conversion layer can be maintained. By setting the thickness of the photothermal conversion layer to approximately 5µm or less, the required UV transmittance can be ensured when forming an adhesive layer using a UV-curable adhesive.

[0083] In one embodiment, the photothermal conversion layer has a mass retention rate of over 97% when exposed to air at 350°C for 1 hour.

[0084] In one embodiment, when the laminate is immersed in N-methyl-2-pyrrolidone at 50°C for 50 minutes, the photothermal conversion layer does not peel off from the light-transmitting carrier. In another embodiment, when the laminate is immersed in a 9.7% by mass aqueous sulfuric acid solution at 25°C for 70 minutes, the photothermal conversion layer does not peel off from the light-transmitting carrier. In yet another embodiment, when the laminate is immersed in a 10% by mass aqueous potassium hydroxide solution at 25°C for 90 seconds, the photothermal conversion layer does not peel off from the light-transmitting carrier.

[0085] The laminate (laminate B) according to the second embodiment includes a light-transmitting carrier, a photothermal conversion layer, an adhesive layer disposed on the photothermal conversion layer, and a substrate to be ground disposed on the adhesive layer, wherein the photothermal conversion layer and the substrate to be ground are bonded together by the adhesive layer. The photothermal conversion layer is decomposed and separated into two parts by irradiation with radiation energy such as laser, thereby separating the substrate from the light-transmitting carrier without damage.

[0086] Figure 2 A schematic cross-sectional view of a laminate (laminate B) according to this embodiment is shown. The laminate 20 includes a light-transmitting carrier 12, a photothermal conversion layer 14, an adhesive layer 22 disposed on the photothermal conversion layer 14, and a substrate 24 to be ground disposed on the adhesive layer 22, wherein the photothermal conversion layer 14 and the substrate 24 to be ground are bonded to each other by the adhesive layer 22.

[0087] The adhesive layer can be formed using liquid adhesives. Examples of liquid adhesives include rubber-based adhesives, in which rubber, elastomers, etc., are dissolved in a solvent; one-component thermosetting adhesives based on epoxy or urethane resins; two-component mixed reactive adhesives based on epoxy, urethane, or acrylic resins; hot-melt adhesives; ultraviolet (UV)-curable or electron beam-curable adhesives based on acrylic or epoxy resins; and water-dispersible adhesives. Among these adhesives, UV-curable adhesives are suitable.

[0088] The adhesive layer can be a double-sided adhesive tape or double-sided adhesive film, with or without a carrier. Examples of carriers include plastic films, paper, non-woven fabrics, etc. Examples of adhesives used for double-sided adhesive tapes and double-sided adhesive films include adhesives containing acrylic resins, urethane resins, or natural rubber as main components.

[0089] When the substrate is separated from the light-transmitting carrier, it is typically obtained with an adhesive layer attached. Therefore, it is ideal for the adhesive layer to be easily peeled off from the substrate. The adhesive layer has sufficient adhesive force (holding force) to hold the substrate to the light-transmitting carrier, but ideally it should have sufficiently low adhesive force to allow for peeling after heat treatment.

[0090] The thickness of the adhesive layer is preferably such that surface inhomogeneities of the substrate are absorbed, and the thickness uniformity required for processes such as back-side grinding and the tear strength required to peel off the adhesive layer are ensured. When the adhesive layer is removed using a chemical solution, the tear strength of the adhesive layer is not particularly required. In one embodiment, the thickness of the adhesive layer is greater than about 3 µm or greater than about 10 µm, and less than about 150 µm or less than about 100 µm.

[0091] Examples of substrates to be ground include substrates comprising III-V compound semiconductors (such as silicon (Si), germanium (Ge), silicon-germanium (SiGe), silicon carbide (SiC), or gallium arsenide (GaAs)) or II-VI compound semiconductors (such as zinc sulfide (ZnS)). The substrate to be ground may have the shape of a semiconductor wafer, and structures such as circuit patterns may be formed on the surface in contact with the adhesive layer. In one embodiment, the substrate to be ground is intended to be thinned by back-side grinding in a laminated state. Other examples of substrates to be ground include crystal wafers, sapphire, glass, and quartz.

[0092] When the substrate to be ground is a semiconductor wafer with a circuit pattern, the circuitry can be damaged by radiation energy (such as laser light) that penetrates the transparent carrier, photothermal conversion layer, and adhesive layer to reach the semiconductor wafer. To avoid this damage, dyes that absorb light with wavelengths of radiation energy or pigments that reflect light can be included in any layer forming the laminate, or the layer containing such dyes or pigments can be further disposed between the photothermal conversion layer and the semiconductor wafer. Examples of dyes that absorb laser light include dyes with absorption peaks near the wavelength of the laser used, such as phthalocyanine dyes and anthocyanin dyes. Examples of pigments that reflect laser light include inorganic white pigments, such as titanium dioxide.

[0093] Laminate B can be produced, for example, by applying a liquid adhesive to one or both of the surface of the photothermal conversion layer of laminate A and the surface of the substrate to be ground on the non-grinding side of the substrate. The photothermal conversion layer and the substrate are bonded together with the liquid adhesive inserted therebetween, or the liquid adhesive is cured by irradiation with ultraviolet light through a light-transmitting carrier, thereby forming an adhesive layer. Therefore, it is possible to manufacture a laminate with… Figure 2 The structure shown is laminate B. Ideally, the laminate should be formed under vacuum to prevent air from getting into the interlayer.

[0094] According to one embodiment, a method for manufacturing a thinned substrate includes preparing a laminate B; grinding the substrate to be ground until the substrate to be ground has a desired thickness; irradiating a photothermal conversion layer with radiant energy through a light-transmitting carrier to decompose the photothermal conversion layer, thereby separating the ground substrate having an adhesive layer from the light-transmitting carrier; and optionally, removing the adhesive layer from the ground substrate.

[0095] Figure 3 This is an illustrative diagram of a method for manufacturing a thinned substrate according to one embodiment. Figure 3 (a) shows laminate 20 (laminate B). Figure 3 As shown in (b), the substrate 24 to be ground is ground to thin it. Figure 3 As shown in (c), the photothermal conversion layer 14 undergoes photothermal conversion by irradiation with radiation energy such as laser light (indicated by the upward arrow) through the transparent carrier 12, thereby decomposing the photothermal conversion layer 14. Figure 3 In (c), the photothermal conversion layer 14 is divided into two parts at the position indicated by the dashed line. For example... Figure 3 As shown in (d), the milled thin substrate 25 with adhesive layer 22 and the light-transmitting carrier (not shown) are separated. Figure 3 As shown in (e), the adhesive layer 22 is removed from the thinned substrate 25 to obtain the thinned substrate 25.

[0096] Grinding of the substrate to be ground can be performed using a grinding apparatus, which includes a base capable of adsorbing and fixing the object to be ground, a mandrel, and a grinding wheel rotatably mounted on the lower end of the mandrel. The light-transmitting carrier side of the laminate B is mounted on the base of the grinding apparatus, and the laminate B is adsorbed and fixed to the base. Then, the substrate to be ground is ground by bringing the rotating grinding wheel into contact with the laminate B while simultaneously supplying water to the laminate B. Grinding can be performed until the thickness of the substrate to be ground is 150 µm or less, preferably 50 µm or less, and more preferably 25 µm or less.

[0097] Irradiation with radiant energy can be performed using lasers. Examples of lasers include YAG lasers (wavelength 1064 nm), second-harmonic YAG lasers (wavelength 532 nm), semiconductor lasers (wavelength 780–1300 nm), KrF excimer lasers (wavelength 248 nm), ArF excimer lasers (wavelength 193 nm), F2 excimer lasers (wavelength 157 nm), XeCl lasers (wavelength 308 nm), XeF lasers (wavelength 351 nm), and solid-state UV lasers (wavelength 355 nm). Irradiation with radiant energy can also be performed using ultraviolet light (wavelengths above 254 nm and below 436 nm) generated from high-pressure mercury lamps, such as gamma rays (wavelength 436 nm), h-rays (wavelength 405 nm), or i-rays (wavelength 365 nm).

[0098] Irradiation with radiation energy can be performed with the laminate to be ground adsorbed and fixed to a stage, such that the light-transmitting carrier is on the upper surface. When using a laser, it is ideal that the laser focal depth is at least approximately 30 µm to stably separate the substrate and the light-transmitting carrier. The laser output can be from 0.3 W to 100 W, the scanning speed can be from 0.1 m / sec to 40 m / sec, and the beam diameter can be from 5 µm to 300 µm. The scanning speed can be increased by increasing the laser output, thereby increasing the processing speed. When there is a margin in the laser output, the processing speed can be increased by increasing the beam diameter and reducing the number of scans. Furthermore, it is ideal that the laser scanning is preferably performed without gaps from the end portion of the laminate to be ground. For example, the laser can scan linearly back and forth along the tangent direction of the substrate from the end portion, or it can scan spirally from the end portion toward the center.

[0099] After the photothermal conversion layer is decomposed by irradiation with radiation energy, the light-transmitting carrier is separated from the grinding substrate using a vacuum pickup or the like.

[0100] After separating the light-transmitting carrier from the ground substrate, the adhesive layer is removed from the ground substrate as needed. To remove the adhesive layer, an adhesive layer removal tape can be used, which forms a stronger bond between the tape and the adhesive layer than the bond between the ground substrate and the adhesive layer. The adhesive layer removal tape is then bonded to the adhesive layer, and the adhesive layer can be peeled off from the ground substrate. Alternatively or otherwise, a solvent can be used to clean the adhesive layer. Examples of solvents include acetone, methyl ethyl ketone, N-methylpyrrolidone, N-ethylpyrrolidone, N-methylsuccinimide, dimethylfuran, toluene, N,N'-dimethylacetamide, tris(dimethylamino)phosphine oxide, dimethyl sulfoxide, and γ-butyrolactone.

[0101] Following the grinding step, steps such as chemical mechanical polishing (CMP), resin molding, etching (such as wet and dry etching), vapor deposition, physical vapor deposition (PVD) (such as sputtering), chemical vapor deposition (CVD), plating (such as electrolytic plating and chemical plating), patterning by photolithography, and oxide film formation on the silicon wafer surface can be performed as needed. After the grinding step, slicing can be performed before radiation irradiation or after the adhesive layer removal step to separate the thinned substrate into multiple wafers. When the thinned substrate is a semiconductor wafer, the wafers are semiconductor chips. The slicing step can be performed using slicing tape, die frames, or die bonding tape as needed.

[0102] The laminate (laminate C) of the third embodiment includes a light-transmitting carrier, a photothermal conversion layer, a patterned metal layer disposed on the photothermal conversion layer, a patterned insulating layer disposed on the metal layer, a semiconductor device disposed on or above the insulating layer, and a sealing material covering the semiconductor device.

[0103] Figure 4 A schematic cross-sectional view of a laminate (laminate C) according to this embodiment is shown. The laminate 30 includes a light-transmitting carrier 12, a photothermal conversion layer 14, a patterned metal layer 32 disposed on the photothermal conversion layer 14, a patterned insulating layer 34 disposed on the metal layer 32, a semiconductor device 36 disposed on or above the insulating layer 34, and a sealing material 38 covering the semiconductor device 36. Figure 4 In this process, the redistribution layer (RDL) is formed by a patterned metal layer 32 and a patterned insulating layer 34, and the semiconductor device 36 is electrically connected to the metal layer 32 via bumps 362.

[0104] The patterned metal layer can be formed using conductors used in the manufacture of semiconductor devices. Examples of conductors include metals such as aluminum, copper, titanium, nickel, gold, and silver, as well as alloys such as silver-tin alloys. In one embodiment, the patterned metal layer is wiring in a redistribution layer (RDL) for transmitting signals from a semiconductor device (semiconductor chip) to a wiring substrate, and preferably includes copper. In one embodiment, a portion of the patterned metal layer has an exposed portion electrically connected to the semiconductor device through a patterned insulating layer.

[0105] Patterned insulating layers can be formed using insulators used in the manufacture of semiconductor devices. Examples of insulators include organic materials such as polyimide resins and inorganic materials such as silicon oxide and silicon nitride. In one embodiment, the patterned insulating layer, together with a patterned metal layer, constitutes a redistribution layer (RDL). The patterned insulating layer may have regions in contact with the photothermal conversion layer.

[0106] Examples of semiconductor devices include integrated circuits such as ICs or LSIs, discrete semiconductors such as high-frequency transistors or high-frequency diodes, and optical semiconductors such as light-emitting diodes (LEDs), laser diodes, or imaging elements. Semiconductor devices can take the form of a silicon wafer or SOI substrate on which multiple semiconductor chips are formed.

[0107] Examples of sealing materials include molding compounds known in semiconductor device manufacturing, including epoxy resins, polyimide resins, and the like. In addition to resins, sealing materials may also include fillers, such as spherical silica.

[0108] Figure 5 It is used for manufacturing Figure 4 An explanatory diagram of the method for producing the laminate (laminate C) according to the third embodiment shown. Figure 5 (a) shows laminate 10 (laminate A). Figure 5As shown in (b), a patterned metal layer 32 and a patterned insulating layer 34 are formed on the photothermal conversion layer 14. The patterned metal layer 32 and the patterned insulating layer 34 can be formed using known semiconductor process techniques, such as photolithography, vapor deposition, physical vapor deposition (PVD) such as sputtering, plating such as electrolytic plating and chemical plating, and etching such as wet etching or dry etching. Figure 5 As shown in (c), the semiconductor device 36 is mounted using a top mounting bracket or the like, such that the bump 362 is in electrical contact with the exposed portion of the patterned metal layer 32. Figure 5 As shown in (d), the semiconductor device 36 is covered and sealed by a sealing material 38. The sealing material 38 is heated to, for example, 130°C to 170°C and then molded. Thus, a laminate 30 is obtained.

[0109] According to one embodiment, a method for manufacturing a semiconductor chip includes: preparing a laminate C; irradiating a photothermal conversion layer with radiation energy through a transparent carrier to decompose the photothermal conversion layer, thereby separating a metal layer and the transparent carrier from each other; and optionally, removing any residue of the photothermal conversion layer from the surface of the metal layer. This manufacturing method is part of a first process of an RDL (Real-Time Layer).

[0110] Figure 6 This is an illustrative diagram of a method for manufacturing a semiconductor chip according to one embodiment. (e.g.) Figure 6 As shown in (a), the photothermal conversion layer 14 is irradiated with radiation energy such as laser light (indicated by the upward arrow) through a light-transmitting carrier 12 of the laminate 30 (laminate C) to decompose the photothermal conversion layer 14. Figure 6 In (a), the photothermal conversion layer 14 is divided into two parts at the position indicated by the dashed line. For example... Figure 6 As shown in (b), the metal layer 32 and the transparent carrier (not shown) are separated. Figure 6 As shown in (c), the residue of the photothermal conversion layer 14 is removed from the surface of the metal layer 32 to obtain the semiconductor chip 50.

[0111] The irradiation with radiation energy and the separation of the metal layer and the light-transmitting carrier can be carried out in the same manner as the method described above for manufacturing thinned substrates.

[0112] After separating the light-transmitting carrier from the metal layer, the residue of the photothermal conversion layer is removed from the surface of the metal layer as needed, and the residue of the photothermal conversion layer is removed from the surface of the insulating layer as needed. Adhesive tape can be used to remove the residue of the photothermal conversion layer. The adhesive tape can be adhered to contact the residue of the photothermal conversion layer, and the residue can be peeled off from the surface of the metal layer. Alternatively or otherwise, the residue of the photothermal conversion layer can be washed away. Examples of cleaning agents include aqueous solutions of hydrogen fluoride, potassium hydroxide, and tetramethylammonium hydroxide. During washing, the cleaning agent can be heated to, for example, 40°C to 80°C.

[0113] The laminate (laminate D) according to the fourth embodiment includes a light-transmitting carrier, a photothermal conversion layer, an adhesive layer disposed on the photothermal conversion layer, and a semiconductor substrate disposed on the adhesive layer. The semiconductor substrate includes an insulating layer disposed on a surface of the semiconductor substrate opposite to the adhesive layer, and one or more conductive connectors electrically connected to the semiconductor substrate through the insulating layer.

[0114] Figure 7 A schematic cross-sectional view of the laminate (laminate D) according to this embodiment is shown. The laminate 40 also includes a light-transmitting carrier 12, a photothermal conversion layer 14, an adhesive layer 42 disposed on the photothermal conversion layer 14, and a semiconductor substrate 44 disposed on the adhesive layer 42. The semiconductor substrate 44 includes an insulating layer 442 disposed on a surface of the semiconductor substrate 44 opposite to the adhesive layer 42, and one or more conductive connectors 444 passing through the insulating layer 442 and electrically connected to the semiconductor substrate 44.

[0115] The adhesive layer is the same as the adhesive layer in the laminate (laminate B) of the second embodiment.

[0116] Examples of semiconductor substrates include silicon wafers and SOI substrates on which multiple semiconductor chips are formed. Semiconductor chips include, for example, integrated circuits such as ICs or LSIs, or imaging elements such as CCDs.

[0117] The insulating layer and conductive connectors can be formed using known semiconductor process techniques, such as photolithography, vapor deposition, physical vapor deposition (PVD) such as sputtering, plating such as electrolytic plating and chemical plating, and etching such as wet etching or dry etching. In one embodiment, the insulating layer comprises silicon oxide (SiO2) or polyimide resin. In one embodiment, the conductive connectors comprise copper.

[0118] Laminate D can be produced, for example, by applying a liquid adhesive to one or both of the surfaces of the photothermal conversion layer of laminate A and the semiconductor substrate on the side opposite to the side forming the insulating layer and conductive connectors. The photothermal conversion layer and the semiconductor substrate are bonded together with the liquid adhesive inserted therebetween and then heated, or cured by irradiation with ultraviolet light through a light-transmitting carrier, thereby forming an adhesive layer. Thus, it is possible to manufacture a laminate with… Figure 7 The laminate D with the structure shown is ideally formed under vacuum to prevent air from getting into the interlayer.

[0119] According to one embodiment, a method for manufacturing a semiconductor substrate laminate includes: preparing a laminate D; preparing a second semiconductor substrate, the second semiconductor substrate including a second insulating layer disposed on a surface of the second semiconductor substrate, and one or more second conductive connectors electrically connected to the second semiconductor substrate through the second insulating layer; forming the semiconductor substrate laminate, wherein the conductive connectors and the second conductive connectors are bonded together by placing the conductive connectors of the semiconductor substrate opposite to each other and thermally pressing the semiconductor substrate and the second semiconductor substrate together, and the insulating layer and the second insulating layer are bonded together; irradiating a photothermal conversion layer with radiant energy through a light-transmitting carrier to decompose the photothermal conversion layer, thereby separating the semiconductor substrate laminate including the adhesive layer from the light-transmitting carrier; and optionally, removing the adhesive layer from the surface of the semiconductor substrate laminate. This manufacturing method is a hybrid bonding process.

[0120] Figure 8 This is an illustrative diagram of a method for manufacturing a semiconductor substrate laminate according to this embodiment. Figure 8 (a) A laminate 40 (laminate D) and a second semiconductor substrate 64 are shown. The second semiconductor substrate 64 includes a second insulating layer 642 disposed on its surface, and one or more second conductive connectors 644 passing through the second insulating layer 642 and electrically connected to the second semiconductor substrate 64. The conductive connectors 444 included in the semiconductor substrate 44 within the laminate 40 face the second conductive connectors 644 of the second semiconductor substrate 64. Figure 8 In (b), the semiconductor substrate 44 and the second semiconductor substrate 64 are thermo-pressed together. Therefore, the conductive connector 444 and the second conductive connector 644 are bonded together, and the insulating layer 442 and the second insulating layer 642 are bonded together. Figure 8 As shown in (c), the photothermal conversion layer 14 is irradiated through the translucent carrier 12 with radiation energy such as laser light (indicated by the upward arrow) to decompose the photothermal conversion layer 14. Figure 8 In (c), the photothermal conversion layer 14 is divided into two parts at the position indicated by the dashed line. For example... Figure 8 As shown in (d), the semiconductor substrate laminate having the photothermal conversion layer 14 is separated from the light-transmitting carrier (not shown). Figure 8 As shown in (e), the adhesive layer 42 is removed from the surface of the semiconductor substrate laminate to obtain the semiconductor substrate laminate 70.

[0121] As the second semiconductor substrate, the same substrate as the semiconductor substrate in laminate D can be used.

[0122] The semiconductor substrate and the second semiconductor substrate can be hot-pressed together for 20 to 60 minutes at a temperature of 300°C to 450°C and a pressure of 200 MPa to 400 MPa.

[0123] In one embodiment, the insulating layer and conductive connector of the semiconductor substrate, as well as the second insulating layer and second conductive connector of the second semiconductor substrate, are formed using a CMP (Damascus process) method, employing copper as the conductive connector and the silicon oxide (SiO2) film as the insulating layer and the second insulating layer. During the CMP step, because the etching rate of copper is higher than that of silicon oxide, the copper surface is slightly recessed (disc-shaped) from the surface of the surrounding silicon oxide insulating layer after the CMP step. Furthermore, the lower copper surface than the surface of the surrounding silicon oxide insulating layer advantageously contributes to reliable adhesion between the insulating layer and the second insulating layer during the thermo-pressing bonding step. The coefficient of thermal expansion of copper is greater than that of silicon oxide. Therefore, copper expands during the thermo-pressing bonding step, the conductive connector and the second conductive connector come into contact with each other, and interdiffusion of copper occurs at the contact portion, thereby filling the gap formed by the recess on the copper surface, and the conductive connector and the second conductive connector are electrically connected to each other through the oxide film and impurities on the copper surface. Additionally, during the thermo-pressing bonding step, the insulating layer and the second insulating layer are simultaneously bonded while the condensation reaction of silicon oxide is carried out at a high temperature.

[0124] The irradiation with radiation energy and the stripping of the semiconductor substrate laminate from the light-transmitting carrier can be carried out in the same manner as the methods described above for manufacturing thinned substrates.

[0125] Removing the adhesive layer from the surface of the semiconductor substrate laminate can be done in a manner similar to the method described above for manufacturing a thinned substrate.

[0126] The photothermal conversion layer ink composition and laminate disclosed herein can be used in a variety of applications, including temporary fixing applications. Specifically, the photothermal conversion layer ink composition and laminate are suitable for manufacturing high-density mounted stacked chip-scale packages (CSPs), through-type CSPs requiring high functionality and high speed, ultra-thin compound semiconductors (such as GaAs) requiring improved thermal efficiency, electrical characteristics and stability, and semiconductor chips using large wafers (such as 16-inch silicon wafers).

[0127] Example

[0128] The following embodiments illustrate specific implementations of this disclosure, but the invention is not limited to these embodiments. Unless otherwise specified, all parts and percentages are by mass. Numerical values ​​substantially include errors due to the measuring principles and measuring equipment. Numerical values ​​are represented by significant figures that have been properly rounded.

[0129] The materials, reagents, etc. used in these embodiments are shown in Table 1.

[0130] Table 1

[0131]

[0132] 1. Preparation of UV-curable liquid adhesives

[0133] Light acrylate 1.6HX-A and Omnirad (trade name) 369 were placed in a lightfast plastic bottle and stirred until Omnirad (trade name) 369 was completely dissolved. Then, UV-3300B was added to the plastic bottle and stirred to prepare a UV-curable liquid adhesive.

[0134] The formulations of UV-curable liquid adhesives are shown in Table 2.

[0135] Table 2 UV-curable liquid adhesives

[0136]

[0137] 2. Preparation of photothermal conversion layer ink composition

[0138] The components shown in Table 3 were mixed using a sand mill (Examples 1 to 6 and Comparative Example 3) or a magnetic stirrer (Comparative Examples 1 and 2) to prepare the photothermal conversion layer ink compositions of Examples 1 to 6 and Comparative Examples 1 to 3.

[0139] Table 3. Ink Compositions for Photothermal Conversion Layer

[0140]

[0141] 1) Total amount of carbon black and pyrolysis silica

[0142] 3. Heat resistance test

[0143] The photothermal conversion layer ink compositions of Examples 1 to 6 and Comparative Example 3 were applied to a glass substrate with a width of 500 mm × a length of 700 mm × a thickness of 1 mm using a wire rod, and heated at 180°C for 1 hour to form a photothermal conversion layer. The photothermal conversion layer was then scraped off with a razor blade to obtain powder. The obtained powder was kept in ambient air at room temperature for 5 hours and weighed. After weighing, the powder was heat-treated in air at 350°C for 1 hour, and then kept in ambient air at room temperature for another 5 hours and weighed. The mass retention rate was calculated using the following formula. The results are shown in Table 4.

[0144] [Formula 1]

[0145] Mass retention rate (%) = Mass of photothermal conversion layer powder after heat treatment (g) / Mass of photothermal conversion layer powder before heat treatment (g)

[0146] Table 4 Thermal stability test

[0147]

[0148] 4. Chemical resistance test

[0149] The photothermal conversion layer ink compositions of Examples 1 to 6 and Comparative Example 3 were applied to a glass substrate with a width of 200 mm × a length of 700 mm × a thickness of 1 mm using a wire rod, and heated at 180°C for 1 hour to form a photothermal conversion layer with a thickness of 0.5 µm. The optical density of the photothermal conversion layer at a wavelength of 600 nm was adjusted to 1.5. The glass substrates coated with the photothermal conversion layer were immersed in a wide-mouth glass bottle in a mixed solvent of N-methyl-2-pyrrolidone (NMP), 9.7% by mass aqueous sulfuric acid solution, 10% by mass aqueous potassium hydroxide solution, or tetramethylammonium hydroxide (TMAH) / water / dimethyl sulfoxide (DMSO) = 5 / 15 / 80 (mass ratio), at the temperatures and times shown in Table 5. The condition of each sample was visually observed. The results are shown in Table 5.

[0150] Table 5 Chemical Resistance Tests

[0151] 1) After soaking, there is no visual change, and it falls off after wiping.

[0152] 5. Laser separation test

[0153] A disc-shaped glass substrate with a diameter of 154 mm and a thickness of 800 µm was used as a light-transmitting carrier, and a silicon wafer with a diameter of 152 mm and a thickness of 750 µm was used as a semiconductor device wafer model. The photothermal conversion layer ink compositions of Examples 1 to 6 and Comparative Examples 1 to 3 were applied to the glass substrate using a spin coater, heated at 40°C for 3 minutes, and then further heated at 250°C for 1 hour to form a photothermal conversion layer. The optical density of the photothermal conversion layer was adjusted to 1.0 at a wavelength of 600 nm. A UV-curable liquid adhesive was applied to the silicon wafer in a similar manner using a spin coater. The glass substrate and silicon wafer were bonded together using a coating and bonding apparatus WSS 8101 M (Tazmo Co., Ltd., Okayama-shi, Okayama, Japan), and then the UV-curable liquid adhesive was cured by irradiation from the glass substrate side to obtain a laminate. The laminate has a structure of glass substrate / photothermal conversion layer / adhesive layer / silicon wafer, with the photothermal conversion layer having a thickness of 0.9µm and the adhesive layer having a thickness of 50µm.

[0154] A slicing strip and slicing frame were placed on the silicon wafer of the laminate. The laminate was then transferred to the platform of a carrier stripping device (Tazmo Corporation, Okayama-shi, Okayama, Japan), and depressurized from below using a vacuum device to adsorb and fix it onto the platform. Under conditions of 6.0 W laser output, 100 µm beam diameter, 100 µm scanning spacing, and 1.0 m / sec laser scanning speed, a YAG laser (wavelength: 1064 nm) was used to irradiate the glass substrate side of the laminate. The laser was linearly traversed tangentially from the edge portion of the laminate to irradiate the entire surface of the laminate. The adsorption device was attached to the glass substrate of the laser-irradiated laminate, and the ease of separation between the glass substrate and the silicon wafer was manually confirmed. The results are shown in Table 6.

[0155] Table 6 Laser Separation Test

[0156]

[0157] It will be apparent to those skilled in the art that various modifications and variations can be made to the present invention without departing from its scope and spirit.

[0158] List of reference numerals

[0159] 10, 20, 30, 40 laminates

[0160] 12 Transparent Carrier

[0161] 14 Photothermal conversion layer

[0162] 22 adhesive layers

[0163] 24 substrates to be ground

[0164] 25Thinning substrate

[0165] 32 patterned metal layers

[0166] 34 Patterned Insulating Layer

[0167] 36 Semiconductor Devices

[0168] 362 bumps

[0169] 38 Sealing Material

[0170] 42 Adhesive Layer

[0171] 44 Semiconductor Substrate

[0172] 442 insulation layer

[0173] 444 conductive connector

[0174] 50 semiconductor chips

[0175] 64 Second Semiconductor Substrate

[0176] 642 Second Insulation Layer

[0177] 644 Second Conductive Connector

[0178] 70 Semiconductor Substrate Laminate

Claims

1. A photothermal conversion layer ink composition, the photothermal conversion layer ink composition comprising: A light absorber with thermal decomposability, said light absorber comprising hydrophilic carbon black particles; and Adhesive or its precursor, The adhesive or its precursor comprises at least one of an organosilicon partial condensate or an alkali metal silicate.

2. The photothermal conversion layer ink composition according to claim 1, wherein the organosilicon fraction comprises tetraethyl orthosilicate.

3. The photothermal conversion layer ink composition according to claim 1, wherein the alkali metal silicate comprises at least one of potassium silicate or lithium silicate.

4. The photothermal conversion layer ink composition according to claim 3, wherein the alkali metal silicate comprises potassium silicate.

5. The photothermal conversion layer ink composition according to claim 1, wherein the photothermal conversion layer ink composition further comprises lignin sulfonic acid or a salt thereof.

6. The photothermal conversion layer ink composition according to claim 1, wherein the photothermal conversion layer ink composition further comprises a transparent filler.

7. The photothermal conversion layer ink composition according to claim 1, wherein the total content of the binder and its precursor is 30% to 80% by volume, based on the volume of solids.

8. The photothermal conversion layer ink composition according to claim 1, wherein the viscosity is from 3 mPa·s to 200 mPa·s.

9. A laminate, the laminate comprising: Translucent carrier; and A photothermal conversion layer comprising a light absorber and a binder, wherein the light absorber is thermally decomposable. The binder comprises at least one of an organosilicon condensate or an alkali metal silicate.

10. The laminate according to claim 9, wherein the light-transmitting carrier is glass.

11. The laminate according to claim 9, further comprising: An adhesive layer disposed on the photothermal conversion layer; and The substrate to be ground is disposed on the adhesive layer. The photothermal conversion layer and the substrate to be ground are bonded together by the adhesive layer.

12. The laminate according to claim 9, further comprising: A patterned metal layer disposed on the photothermal conversion layer; A patterned insulating layer disposed above the metal layer; Semiconductor devices disposed on or above the insulating layer; and A sealing material covering the semiconductor device.

13. The laminate according to claim 9, further comprising: An adhesive layer disposed on the photothermal conversion layer; and Semiconductor substrate disposed on the adhesive layer. The semiconductor substrate includes an insulating layer disposed on a surface of the semiconductor substrate opposite to the adhesive layer, and one or more conductive connectors electrically connected to the semiconductor substrate through the insulating layer.

14. A method for manufacturing a thinned substrate, the method comprising: Prepare the laminate according to claim 11; Grind the substrate to be ground until the substrate has the desired thickness; The photothermal conversion layer is irradiated with radiant energy through the transparent carrier to decompose the photothermal conversion layer, thereby separating the ground substrate, including the adhesive layer, from the transparent carrier. as well as Optionally, the adhesive layer is removed from the ground substrate.

15. A method for manufacturing a semiconductor chip, the method comprising: Prepare the laminate according to claim 12; The photothermal conversion layer is decomposed by irradiating the photothermal conversion layer through the light-transmitting carrier, thereby separating the metal layer from the light-transmitting carrier; as well as Optionally, the residue of the photothermal conversion layer is removed from the surface of the metal layer.

16. A method for manufacturing a semiconductor substrate laminate, the method comprising: Prepare the laminate according to claim 13; A second semiconductor substrate is prepared, the second semiconductor substrate including a second insulating layer disposed on the surface of the second semiconductor substrate, and one or more second conductive connectors electrically connected to the second semiconductor substrate through the second insulating layer; A semiconductor substrate laminate is formed, wherein the conductive connector of the semiconductor substrate and the second conductive connector of the second semiconductor substrate are positioned opposite each other, and the semiconductor substrate and the second semiconductor substrate are thermally pressed together, thereby bonding the conductive connector and the second conductive connector together, and bonding the insulating layer and the second insulating layer together. The photothermal conversion layer is decomposed by irradiating the photothermal conversion layer through the transparent carrier, thereby separating the semiconductor substrate laminate including the adhesive layer from the transparent carrier. as well as Optionally, the adhesive layer is removed from the semiconductor substrate laminate.

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