JP2023098471A - Photothermal conversion layer ink composition and laminate - Google Patents

Abstract

To provide an ink composition capable of forming a photothermal conversion layer having high heat resistance and chemical resistance.SOLUTION: A photothermal conversion layer ink composition according to one embodiment includes a light absorber having thermal decomposability, and a binder or a precursor thereof, where the binder or precursor thereof contains at least one of an organic silicate partial condensate and an alkali metal silicate.SELECTED DRAWING: Figure 1

Description

The present disclosure relates to photothermal conversion layer ink compositions and laminates including photothermal conversion layers. The present disclosure also relates to a method for manufacturing a thin base material, a method for manufacturing a semiconductor chip, and a method for manufacturing a semiconductor substrate laminate using the laminate.

In the semiconductor industry, in order to meet the demand for thinner packages and higher density due to chip stacking technology, thinning of semiconductor wafers by grinding the surface opposite to the surface on which the pattern is formed, so-called back grinding, has been promoted. ing. The prior art, in which the wafer is supported only by protective tape during the backgrinding and transport steps, is inadequate to meet the demands of the new and diverse manufacturing processes. Therefore, during backgrinding and, if necessary, subsequent steps, the semiconductor wafer is glued onto a rigid transparent support such as a glass substrate having a Light-To-Heat-Conversion (LTHC) layer. Techniques have been proposed for separating a semiconductor wafer or a semiconductor chip obtained by dicing a semiconductor wafer from a support without stress by supporting and finally destroying the photothermal conversion layer by laser scanning.

Patent Document 1 (Japanese Patent Application Laid-Open No. 2004-064040) discloses that "a base material to be ground, a bonding layer in contact with the base material to be ground, a photothermal conversion layer containing a light absorber and a thermally decomposable resin, and a light and a transparent support, wherein the photothermal conversion layer is decomposed and ground when irradiated with radiant energy after the surface of the substrate to be ground opposite to the bonding layer is ground. Laminate, which separates the subsequent substrate and said light-transmitting support.

Patent Document 2 (Japanese National Publication of International Patent Application No. 2013-534721) describes "a laminate comprising a substrate, a bonding layer positioned adjacent to the substrate, and a metal absorption layer positioned adjacent to the bonding layer. and a light-transmitting support positioned adjacent to said light-to-heat conversion layer.

Patent Document 3 (Japanese Patent Application Laid-Open No. 2019-189868) describes "a bonding step of forming a bonding layer on the surface of at least one substrate and/or at least one workpiece, and bonding the substrate and the workpiece. a bonding step of bonding and bonding by layers; a processing step of processing the workpiece; and a peeling step of irradiating the bonding layer with a laser to separate the workpiece from the substrate, wherein the bonding layer is composed of an adhesive containing a polymer and a light-absorbing substance, wherein the solid content of the adhesive includes 50% to 98% by weight of the polymer, and the solid content of the adhesive is 2% to 50% by weight. a light-absorbing material, wherein the polymer is a polyimide or (amic acid/imide) copolymer, the backbone of the polymer comprises from 5% to 45% by weight of hydroxyl-containing units, and from 5% to 40% by weight of an aliphatic A method for temporarily bonding workpieces further comprising an ether-containing unit or a siloxane-containing unit, and wherein the polymer has a cyclization rate of 90% or more.

Patent Document 4 (Japanese Patent Application Laid-Open No. 2015-199794) discloses that "a laminate comprising a light-transmitting support and an adherend fixed to the support via an adhesive is applied from the support side to the laminate. a step of irradiating an energy ray to separate the support and the adherend, the pressure-sensitive adhesive includes a condensation resin and carbon particles containing boron, and the adherend is A stripping method containing at least one of an inorganic material and an organic material".

Patent Document 5 (Japanese Unexamined Patent Application Publication No. 2012-052031) describes "(1) an adhesive layer containing a polymer (A) and a photoradical generator (B) on a support, wherein the adhesive layer (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 the support side; and (5) peeling off the processed layer from the support, in this order. described.

Japanese Patent Application Laid-Open No. 2004-064040 Japanese Patent Publication No. 2013-534721 JP 2019-189868 A JP 2015-199794 A JP 2012-052031 A

The techniques described in Patent Documents 1 to 5 have problems such as non-uniformity of the substrate thickness during back grinding, warpage of the wafer thinned after back grinding, and wafer breakage due to stress applied during back grinding. can be resolved.

Rapid advances in the fields of power semiconductors and high-density packaging place additional demands on heat and/or chemical resistance for adhesive materials that allow temporary adhesion and subsequent detachment. The heat and chemical resistance required depends entirely on what processing steps the adhesive material is subjected to. Examples of treatment processes include chemical mechanical polishing (CMP), resin molding, etching such as wet etching and dry etching, vapor deposition, physical vapor deposition (PVD) such as sputtering, chemical vapor deposition (CVD), electrolytic plating, Examples include plating such as electroless plating, pattern formation by photolithography, and formation of an oxide film on the surface of a silicon wafer. In process steps such as sputtering where process temperatures reach above 350° C., the adhesive material needs to be stable for several hours at the process temperature. When plating and/or wet etching processes are performed, the adhesive material should be stable in various chemicals such as acids, alkaline solutions, organic solvents, inorganic solvents, and the like. In particular, in some semiconductor processes, such as the RDL (redistribution layer) first process, the entire surface of a layer that constitutes an adhesive material, such as a photothermal conversion layer, is exposed to a high-temperature atmosphere or chemical substances.

The present disclosure provides an ink composition capable of forming a photothermal conversion layer having high heat resistance and chemical resistance.

According to one embodiment of the present disclosure, a light-to-heat conversion layer ink composition comprising a thermally decomposable light absorber and a binder or a precursor thereof, wherein the binder or a precursor thereof comprises at least an organic silicate portion A photothermal conversion layer ink composition is provided comprising any one of a condensate and an alkali metal silicate.

According to another embodiment of the present disclosure, there is provided a laminate comprising a light-transmitting support, a heat-decomposable light-absorbing agent, and a light-to-heat conversion layer containing a binder, wherein the binder is at least an organic silicate A laminate is provided that includes any one of a condensate and an alkali metal silicate.

According to still another embodiment of the present disclosure, further comprising a bonding layer disposed on the photothermal conversion layer, and a base material to be ground disposed on the bonding layer, The laminate (laminate B) is provided, in which the base material to be ground is bonded by the bonding layer.

According to still another embodiment of the present disclosure, preparing the laminate B, grinding the substrate to be ground until the substrate to be ground has a desired thickness, and the light transmissive support. irradiating the photothermal conversion layer with radiant energy through the photothermal conversion layer to decompose the photothermal conversion layer, thereby separating the ground substrate having the bonding layer and the light transmissive support; Accordingly, there is provided a method of manufacturing a thinned substrate, comprising removing the bonding layer from the ground substrate.

According to yet another embodiment of the present disclosure, a patterned metal layer disposed over the photothermal conversion layer; a patterned insulating layer disposed over the metal layer; and the insulating layer. and a sealing material covering the semiconductor device (laminate C).

According to still another embodiment of the present disclosure, preparing the laminate C, irradiating the photothermal conversion layer with radiant energy through the light-transmitting support to decompose the photothermal conversion layer, thereby , separating the metal layer and the light-transmitting support, and optionally removing the residue of the photothermal conversion layer from the surface of the metal layer. be.

According to yet another embodiment of the present disclosure, the laminate (laminate D) further including a bonding layer disposed on the photothermal conversion layer and a semiconductor substrate disposed on the bonding layer The semiconductor substrate includes an insulating layer disposed on a surface of the semiconductor substrate opposite to the bonding layer, and one or more insulating layers penetrating the insulating layer and electrically connected to the semiconductor substrate. A laminate is provided having a conductive connection of .

According to yet another embodiment of the present disclosure, providing the laminate D, a second semiconductor substrate, a second insulating layer disposed on a surface of the second semiconductor substrate, and the second insulating layer providing a second semiconductor substrate having one or more second conductive connections through a layer and electrically connected to the second semiconductor substrate; the conductive connections of the semiconductor substrate; The conductive connection portion and the second conductive connection portion are formed by heat-pressing the semiconductor substrate and the second semiconductor substrate with the second conductive connection portion of the second semiconductor substrate facing each other. are bonded together, and the insulating layer and the second insulating layer are bonded together to form a semiconductor substrate laminate; decomposing a layer, thereby separating the semiconductor substrate stack having the bonding layer and the light-transmitting support, and optionally removing the bonding layer from the surface of the semiconductor substrate stack; A method of manufacturing a semiconductor substrate stack is provided, comprising:

According to the present disclosure, it is possible to provide a photothermal conversion layer ink composition capable of forming a photothermal conversion layer having high heat resistance and chemical resistance. A laminate including a light-to-heat conversion layer formed using the light-to-heat conversion layer ink composition can be used in various processes in the manufacture of semiconductor devices, particularly processes involving high-temperature treatment steps or chemical treatment steps.

The above description should not be considered to disclose all embodiments of the invention or all advantages associated with the invention.

1 is a schematic cross-sectional view of a laminate of a first embodiment; FIG. It is a schematic sectional drawing of the laminated body of 2nd embodiment. It is explanatory drawing of the manufacturing method of the thinned base material of one embodiment. It is a schematic sectional drawing of the laminated body of 3rd embodiment. It is explanatory drawing of the manufacturing method of the laminated body of 3rd embodiment. It is explanatory drawing of the manufacturing method of the semiconductor chip of one embodiment. It is a schematic sectional drawing of the laminated body of 4th embodiment. It is explanatory drawing of the manufacturing method of the semiconductor substrate laminated body of one embodiment.

Hereinafter, for the purpose of illustrating representative embodiments of the present invention, the present invention will be described in more detail with reference to the drawings as necessary, but the present invention is not limited to these embodiments.

The photothermal conversion layer ink composition of one embodiment contains a thermally decomposable light absorbent and a binder or a precursor thereof. The binder or its precursor contains at least one of an organic silicate partial condensate and an alkali metal silicate.

Since the photothermal conversion layer formed using the photothermal conversion layer ink composition contains an inorganic binder, it has high heat resistance and small mass loss at high temperatures. Therefore, the photothermal conversion layer can be used in high-temperature processing steps in the manufacture of semiconductor devices, for example, high-temperature processing steps in the temperature range of 350.degree. C. to 400.degree. In addition, since the photothermal conversion layer contains an inorganic binder, it has high chemical resistance and is stable against organic solvents, acids, and most alkaline solutions.

Another layer such as a redistribution layer (RDL) can be directly formed on the photothermal conversion layer formed using the photothermal conversion layer ink composition without arranging the bonding layer. In the RDL first process, the photothermal conversion layer is directly exposed to a high-temperature atmosphere or various chemical substances, but as described above, the photothermal conversion layer has high heat resistance and chemical resistance, so it is also suitable for the RDL first process. can do.

A thermally decomposable light absorber (hereinafter also simply referred to as “light absorber”) is a substance that absorbs radiation energy such as laser irradiation and converts it into heat, and thermally decomposes itself. For example, in the case of carbon black particles, which are one of the thermally decomposable light absorbers, when the temperature rises due to light absorption, combustion (in the presence of oxygen) or graphitization occurs, and decomposition occurs while generating gas. Particles lose their shape. As a result, voids are generated in the photothermal conversion layer, and the photothermal conversion layer is decomposed and separated into two layers. As a result, the support and the substrate on both sides of the photothermal conversion layer can be easily separated without applying unnecessary stress.

As the light absorber, one can be selected that absorbs the radiant energy of the wavelength used. As the radiant energy, laser light with a wavelength of usually 150 to 2000 nm, preferably 300 to 1100 nm can be used. wave YAG laser, and semiconductor laser with a wavelength of 780 to 1300 nm, KrF excimer laser (wavelength 248 nm), ArF excimer laser (wavelength 193 nm), _F2 excimer laser (wavelength 157 nm), XeCl laser (wavelength 308 nm), XeF laser (wavelength 351 nm), and solid-state UV lasers (wavelength 355 nm). As radiant energy, ultraviolet rays generated from a high-pressure mercury lamp (wavelength 254 nm or more and 436 nm or less), such as g-line (wavelength 436 nm), h-line (wavelength 405 nm), or i-line (wavelength 365 nm) can also be used.

Examples of light absorbers include carbon black, graphite powder, black pigments such as black titanium oxide, inorganic materials that specifically absorb laser wavelengths such as cesium-doped tungsten oxide (CWO); aromatic diamine-based metal complexes; Aliphatic diamine-based metal complexes, aromatic dithiol-based metal complexes, mercaptophenol-based metal complexes, squarylium-based compounds, cyanine-based dyes, methine-based dyes, naphthoquinone-based dyes, black dyes such as anthraquinone-based dyes, red dyes, or purple dyes; UV absorbers such as octyl methoxycinnamate, octyl dimethoxybenzylidenedioxoimidazolidine propionate, hexyl diethylaminohydroxybenzoylbenzoate, t-butylmethoxydibenzoylmethane, octyltriazone, 2-ethylhexyl paramethoxycinnamate, dihydroxybenzophenone, etc. compound.

The light absorbent is preferably particulate in the light-to-heat conversion layer ink composition. In other words, the particulate light absorbing agent has low compatibility with the binder and its precursor, or the solvent of the photothermal conversion layer ink composition, and may be dispersed without being dissolved in the photothermal conversion layer ink composition. preferable. Even when the temperature of the particulate light absorber reaches a high temperature during the process of absorbing light and converting it into heat, changes such as oxidation, decomposition, and phase change gradually progress from the particle surface to the interior of the particle. , the inside of the particle can retain the light absorption capacity for some time. Therefore, when the particulate light-absorbing agent is viewed on a particle-by-particle basis, light-to-heat conversion occurs continuously for a longer time at the position where the particulate light-absorbing agent exists inside the light-to-heat conversion layer, and voids are formed inside the light-to-heat conversion layer. can be effectively generated. From this point of view, the particulate light absorber is preferably a black pigment.

Preferably, the average primary particle size of the particulate light absorber is about 10 nm or more, or about 20 nm or more, about 400 nm or less, or about 300 nm or less. When the photothermal conversion layer is required to have a smooth surface with higher precision, for example, when the photothermal conversion layer is used in the RDL first process, the average primary particle size of the particulate light absorbent is about 10 nm or more. , preferably less than or equal to about 30 nm. In the present disclosure, the average primary particle size of a particulate substance means that the aggregate is made into primary particles using an ultrasonic disperser in a solvent in which the substance is insoluble, and then a transmission electron microscope is used at a magnification of 50,000. It is the average value obtained by randomly measuring the particle diameters (equivalent circular diameters) of 1,000 or more primary particles in an image taken at a magnification of 200,000 to 200,000 times.

In one embodiment, the light absorber comprises carbon black particles. Carbon black particles include, for example, 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 support after irradiation with radiant energy.

The content of carbon black particles in the light absorber can be about 40 wt% or more, about 50 wt% or more, or about 60 wt% or more based on the weight of the light absorber. In one embodiment, the light absorbers are carbon black particles.

Preferably, the carbon black particles have an average primary particle size of about 10 nm or more and about 400 nm or less. When the photothermal conversion layer is required to have a smooth surface with higher precision, for example, when used in the RDL (redistribution layer) first process, the average primary particle size of the carbon black particles is about 10 nm or more, about It is preferably 30 nm or less.

The carbon black particles preferably include hydrophilic carbon black particles. Hydrophilic carbon black particles have hydrophilic functional groups, such as carboxy groups, on their surfaces. Therefore, the hydrophilic carbon black particles exhibit self-dispersibility in the photothermal conversion layer ink composition and can be highly dispersed. The use of hydrophilic carbon black particles avoids the use of a dispersant that may gel the binder or its precursor in the ink composition for the light-to-heat conversion layer, thereby enhancing the storage stability of the ink composition for the light-to-heat conversion layer. can also

A dye that selectively absorbs wavelengths of radiant energy and transmits other wavelengths may be used in conjunction with the carbon black particles. This is useful when forming a photothermal conversion layer that selectively transmits alignment light in a dicing process.

The content of the light absorbing agent in the ink composition for the light-to-heat conversion layer varies depending on the type, particle form, and dispersibility of the light absorbing agent. , or greater than or equal to about 35 vol.%, less than or equal to about 70 vol.%, less than or equal to about 60 vol.%, or less than or equal to about 55 vol.%. By setting the content of the light-absorbing agent to about 20% by volume or more, voids can be more effectively generated inside the light-to-heat conversion layer, and the substrate and the light-transmitting support can be separated with low stress. . By setting the content of the light-absorbing agent to about 70% by volume or less, it is possible to ensure the film-forming properties of the photothermal conversion layer and the adhesiveness to adjacent layers. In order to make the UV transmittance of the photothermal conversion layer sufficient for curing the adhesive when the adhesive used to form the bonding layer is a UV curable adhesive and the photothermal conversion layer is irradiated with UV rays. , the content of the light absorbing agent is preferably 60% by volume or less.

The content of the light absorbing agent in the ink composition for the light-to-heat conversion layer varies depending on the type, particle form and dispersibility of the light absorbing agent. , or about 35 wt % or more, about 65 wt % or less, about 55 wt % or less, or about 50 wt % or less. By setting the content of the light-absorbing agent to about 20% by mass or more, voids can be more effectively generated inside the light-to-heat conversion layer, and the substrate and the light-transmitting support can be separated with low stress. . By setting the content of the light-absorbing agent to about 65% by mass or less, it is possible to ensure the film-forming properties of the photothermal conversion layer and the adhesiveness to adjacent layers. In order to make the UV transmittance of the photothermal conversion layer sufficient for curing the adhesive when the adhesive used to form the bonding layer is a UV curable adhesive and the photothermal conversion layer is irradiated with UV rays. , the content of the light absorbing agent is preferably 65% by mass or less.

The binder or its precursor contains at least one of an organic silicate partial condensate and an alkali metal silicate. At least part of the organic silicate partial condensate can be condensed to form an organic silicate condensate during formation of the light-to-heat conversion layer. Alkali metal silicates may also be condensed during the formation of the light-to-heat conversion layer to form a more highly crosslinked structure. The organic silicate condensate and the alkali metal silicate form the matrix of the light-to-heat conversion layer and function as a binder for the thermally decomposable light absorber. The organic silicate condensate and alkali metal silicate in the photothermal conversion layer lose their structure or integrity as a matrix when the light absorbent is thermally decomposed by laser irradiation or the like. During thermal decomposition of the light absorber, alcohol may be generated and volatilized due to the decomposition of the organic group of the organic silicate partial condensate or the organic silicate condensate. As a result, the interior of the photothermal conversion layer is decomposed to separate the substrate and the support. The organic silicate partial condensate and the alkali metal silicate also function as a dispersant for an optional transparent filler, particularly silica, which will be described later.

Partial condensates of organic silicates include, for example, partial condensates of alkyl silicates such as methyl silicate, ethyl silicate, n-propyl silicate, isopropyl silicate and n-butyl silicate. A partial condensate of an alkyl silicate is obtained by adding water and, if necessary, an alcohol such as methanol, ethanol, or isopropanol to the alkyl silicate, and reacting the alkyl silicate in the presence of an acidic catalyst such as sulfuric acid, hydrochloric acid, nitric acid, phosphoric acid, or an organic acid. By allowing the hydrolysis and condensation reactions to proceed, it can be obtained as a solution of a mixed solvent of water, by-produced alcohol, and optionally used alcohol.

The organic silicate partial condensate preferably contains tetraethylorthosilicate. Tetraethyl orthosilicate can improve the film formability while maintaining the storage stability of the ink composition for the light-to-heat conversion layer.

In one embodiment, the number average molecular weight of the organosilicate partial condensate is about 800 or greater, or about 1600 or greater, about 4000 or less, or about 2500 or less. When the number average molecular weight of the organic silicate partial condensate is within the above range, the film formability of the ink composition for the photothermal conversion layer can be enhanced. The number average molecular weight of the organosilicate partial condensate is determined using standard polystyrene in a gel permeation chromatography (GPC) method.

Alkali metal silicates include, for example, lithium silicate, sodium silicate, and potassium silicate.

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

The alkali metal silicate preferably contains at least one of potassium silicate and lithium silicate, and more preferably contains potassium silicate. Potassium silicate and lithium silicate, especially potassium silicate, are stable in the light-to-heat conversion layer ink composition during preparation and storage of the light-to-heat conversion layer ink composition, and have appropriate strength and cohesion. It is possible to form a light-to-heat conversion layer having high adhesion to a flexible support.

The alkali metal silicate preferably comprises a combination of potassium silicate and lithium silicate. By combining potassium silicate and lithium silicate, the chemical resistance and heat resistance of the photothermal conversion layer can be further enhanced. The mass ratio of potassium silicate and lithium silicate (mass of potassium silicate/mass of lithium silicate) is preferably 1/10 to 10/1, more preferably 3/7 to 9/2, and still more preferably 6/4 to 8. /2.

The total content of the organic silicate partial condensate and the alkali metal silicate is about 50% by mass or more, about 60% by mass or more, or about 70% by mass or more and 100% by mass or less, based on the total mass of the binder and its precursor. , about 95% by weight or less, or about 90% by weight or less.

The binder and its precursor preferably comprise an alkali metal silicate. Since alkali metal silicate does not have an organic group, the alkali resistance of the photothermal conversion layer can be further enhanced. The alkali metal silicate content can be about 80% or more, about 90% or more, or about 95% or more by weight, based on the total weight of the binder and its precursor. In one embodiment, the binder and its precursors are alkali metal silicates.

The total content of the binder and its precursor in the light-to-heat conversion layer ink composition is about 30% by volume or more, about 40% by volume or more, or about 45% by volume or more, about 80% by volume, based on the solid content volume. Below, 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 light-to-heat conversion layer and the adhesion to adjacent layers can be ensured, and the chemical resistance of the light-to-heat conversion layer can be enhanced. By setting the total content to about 80% by volume or less, voids can be effectively generated inside the light-to-heat conversion layer, and the substrate and the light-transmitting support can be separated with low stress.

The total content of the binder and its precursor in the light-to-heat conversion layer ink composition is about 35% by mass or more, about 45% by mass or more, or about 50% by mass or more, about 80% by mass, based on the mass of the solid content. Below, it can be about 70 mass % or less, or about 65 mass % or less. By setting the above total content to about 35% by mass or more, it is possible to ensure the film-forming properties of the photothermal conversion layer and the adhesiveness to adjacent layers, and to enhance the chemical resistance of the photothermal conversion layer. By setting the total content to about 80% by mass or less, voids can be more effectively generated inside the light-to-heat conversion layer, and the substrate and the light-transmitting support can be separated with low stress.

The light-to-heat conversion layer ink composition of one embodiment further comprises ligninsulfonic acid or a salt thereof. Lignin sulfonic acid is a compound obtained by partially sulfonating a lignin degradation product. Lignin, along with cellulose, is one of the main components that make up the cell walls of lignified plants such as wood and straw. It is a polymer with a similar structure. Ligninsulfonic acid and salts thereof can improve the dispersibility of the light absorber while maintaining the storage stability of the ink composition for the photothermal conversion layer.

The content of ligninsulfonic acid and its salt in the photothermal conversion layer ink composition is about 4 parts by mass or more, about 6 parts by mass or more, or about 8 parts by mass or more, or about 20 parts by mass, based on 100 parts by mass of the light absorbing agent. It can be 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 ligninsulfonic acid to about 4 parts by mass or more, the light absorbing agent can be more uniformly dispersed in the ink composition for the photothermal conversion layer. By setting the content of the lignosulfonic acid to about 20 parts by mass or less, it is possible to suppress the weight loss of the photothermal conversion layer in a high temperature environment of 330° C. or higher.

The photothermal conversion layer ink composition of one embodiment further comprises a transparent filler. The transparent filler acts to prevent re-adhesion of the light-to-heat conversion layer separated due to the formation of voids due to thermal decomposition of the light absorbing agent. Transparent fillers include, for example, silica, talc, and barium sulfate. The transparent filler can enhance the releasability between the substrate and the light-transmitting support after irradiation with radiant energy without interfering with the curing of the UV-curable adhesive.

The average primary particle size of the transparent filler can be about 7 nm or more, about 10 nm or more, or about 15 nm or more, about 40 nm or less, about 30 nm or less, or about 25 nm or less.

When the light-to-heat conversion layer is required to have a smooth surface with higher precision, for example, when used in the RDL fast process, the light-to-heat conversion layer preferably does not contain a transparent filler.

The total content of the light absorber and the optional transparent filler is about 5% by volume or more and about 20% by volume or more, or about 35% by volume or more and about 70% by volume or less, based on the volume of the solid content. Preferably no more than about 60% by volume, or no more than about 55% by volume. By setting the total content to about 5% by volume or more, voids can be more effectively generated inside the light-to-heat conversion layer, and the substrate and the light-transmitting support can be separated with low stress. By setting the total content to about 70% by volume or less, the film-forming properties of the light-to-heat conversion layer and the adhesion to adjacent layers can be ensured, and the chemical resistance of the light-to-heat conversion layer can be enhanced.

The total content of the light absorber and the optional transparent filler is about 5% by mass or more and about 20% by mass or more, or about 35% by mass or more and about 65% by mass or less, based on the mass of the solid content. It is preferably about 55% by weight or less, or about 45% by weight or less. When the total content is about 5% by mass or more, voids can be more effectively generated inside the light-to-heat conversion layer, and the substrate and the light-transmitting support can be separated with low stress. By setting the total content to about 65% by mass or less, the film-forming properties of the light-to-heat conversion layer and the adhesiveness to adjacent layers can be ensured, and the chemical resistance of the light-to-heat conversion layer can be enhanced.

The photothermal conversion layer ink composition may contain other additives as needed. Other additives include, for example, leveling agents, silane coupling agents, blowing agents, sublimation agents, thickeners, and viscosity modifiers.

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 ethyl methyl ketone; and esters such as ethyl acetate and butyl acetate. The solvent is preferably water, alcohol, or a mixed solvent of water and alcohol.

The solid content of the ink composition for the light-to-heat conversion layer can be appropriately determined in consideration of the coatability, drying property or curability of the ink composition for the light-to-heat conversion layer, and the thickness of the light-to-heat conversion layer to be formed. The solids content of the photothermal conversion layer ink composition of one embodiment is about 3% by weight or more, about 5% by weight or more, or about 10% by weight or more, about 30% by weight or less, about 25% by weight or less, or about 20% by weight. % or less.

The viscosity of the light-to-heat conversion layer ink composition can be appropriately determined in consideration of the coatability, drying or curability of the light-to-heat conversion layer ink composition, and the thickness of the light-to-heat conversion layer to be formed. The viscosity of the photothermal conversion layer ink composition of one embodiment is about 3 mPa·s or more, about 5 mPa·s or more, or about 10 mPa·s or more, about 200 mPa·s or less, about 100 mPa·s or less, or about 50 mPa·s. It is below. A light-to-heat conversion layer ink composition having a viscosity of about 10 mPa·s or more and about 50 mPa·s or less can be suitably used for spin coating. The viscosity is a value measured at a temperature of 25° C. and a shear rate of 100 sec ⁻¹ using a rheometer (RotoVisco 1 manufactured by HAAKE).

The laminate (laminate A) of the first embodiment includes a light-transmitting support, a heat-decomposable light absorber, and a photothermal conversion layer containing a binder. The binder contains at least one of an organic silicate condensate and an alkali metal silicate. The total content of the organic silicate condensate and the alkali metal silicate is about 50% by weight or more, about 60% by weight or more, or about 70% by weight or more, 100% by weight or less, and about 95% by weight or less, based on the weight of the binder. , or about 90% by weight or less.

FIG. 1 shows a schematic cross-sectional view of the laminate (laminate A) of this embodiment. The laminate 10 includes a light transmissive support 12 and a photothermal conversion layer 14 .

The light-transmitting support is made of a material that can transmit radiant energy such as laser light and, if necessary, radiation (for example, ultraviolet rays) for curing the adhesive. The light-transmissive support is desirably made of a material that maintains the substrate (eg, semiconductor wafer) in a flat state and does not damage it during processes such as back-grinding and transportation. Desirably, the transmittance of the light-transmissive support is, for example, about 50% or greater for the radiant energy or radiation of interest.

Examples of light-transmitting supports include glass and acrylic resins. The light-transmitting support may be surface-treated with a silane coupling agent or the like, if necessary, in order to increase the adhesive strength with an adjacent layer such as a photothermal conversion layer. The shape of the light-transmissive support includes, for example, circular and rectangular. The light-transmissive support may be plate-shaped.

In one embodiment, the light transmissive support is glass. Examples of glass include quartz glass, sapphire glass, and borosilicate glass.

The light-transmissive support desirably has sufficient rigidity to prevent the substrate (eg, semiconductor wafer) from warping. The light-transmitting support preferably has a Young's modulus of 1-10 MPa and a thickness of 500 μm or more.

The light-transmissive support may be exposed to high temperatures due to heat generated in the photothermal conversion layer during irradiation of radiant energy, frictional heat during back-grinding, and the like. Alternatively, before peeling off the semiconductor chip from the light-transmitting support, CMP, resin molding, etching such as wet etching and dry etching, deposition, PVD such as sputtering, CVD, plating such as electrolytic plating and electroless plating, and photolithography. Processes such as pattern formation by lithography and high-temperature processing for forming an oxide film on the silicon wafer surface may be added. A light-transmitting support having heat resistance, chemical resistance, or a low expansion coefficient can be selected according to these steps. Examples of light-transmitting supports having heat resistance, chemical resistance, and low expansion coefficient include glass such as quartz glass, borosilicate glass, and sapphire glass; 1737 and #7059 (Corning), and Tempax (Schott).

After the back surface grinding process and before dicing, wet etching of the surface of the semiconductor wafer using a chemical solution may be performed as an intermediate process. This step is performed to remove the damaged layer on the back surface of the semiconductor wafer caused by grinding and to increase the bending strength of the wafer. Alternatively, a thickness of several tens of micrometers may be removed by wet etching as the final step of the semiconductor wafer thinning process. When the semiconductor wafer is a silicon (Si) single crystal, a mixed acid containing hydrogen fluoride is generally used as the etching chemical. At this time, when the light-transmitting support is made of glass (other than sapphire glass), the edge of the light-transmitting support is also etched by the chemical solution. Therefore, when the light-transmitting support is reused, the glass can be protected from corrosion by hydrogen fluoride by previously providing an acid-resistant (etching chemical-resistant) protective film on the glass. An acid-resistant resin can be used as the protective film. It is desirable that the acid-resistant resin can be fixed on the glass by dissolving it in an organic solvent, applying it in the form of a solution, and drying it. Moreover, it is desirable that the acid-resistant resin transmits a sufficient amount of light having a laser wavelength that is irradiated to separate the glass from the semiconductor wafer. From this point of view, suitable acid-resistant resins include, for example, amorphous polyolefins, cyclic olefin copolymers, and polyvinyl chlorides that do not contain condensed bonds in their molecules.

It is desirable that the thickness of the light-transmitting support is uniform. For example, in order to reduce the thickness of the silicon wafer to 50 μm or less and achieve a uniformity of ±10% or less, it is desirable that the thickness variation of the light-transmissive support is ±2 μm or less. When the light-transmitting support is used repeatedly, it is desirable that the light-transmitting support has scratch resistance. When the light-transmitting support is used repeatedly, it is desirable to select the material for the light-transmitting support in consideration of the wavelength of the radiant energy so as to suppress damage to the light-transmitting support due to the radiant energy. For example, when using Pyrex (registered trademark) glass as a light-transmitting support and irradiating with a triple harmonic YAG laser (355 nm), it is possible to separate the light-transmitting support from the semiconductor wafer or semiconductor chip. However, the light-transmitting support may absorb the radiant energy and suffer thermal damage, rendering it unusable.

The laminate includes a photothermal conversion layer containing a thermally decomposable light absorber and a binder, and the binder contains at least one of an organic silicate condensate and an alkali metal silicate. Radiant energy applied to the photothermal conversion layer in the form of laser light or the like is absorbed by the light absorbent and converted into thermal energy. The generated heat energy rapidly raises the temperature of the photothermal conversion layer, and the light absorbent itself is thermally decomposed at that temperature. Depending on the type of light absorbent and binder, gas may be generated during thermal decomposition of the light absorbent. As a result, voids are generated in the photothermal conversion layer, and the photothermal conversion layer is decomposed and separated into two layers. As a result, the support and the substrate on both sides of the photothermal conversion layer can be easily separated without applying unnecessary stress.

A photothermal conversion layer can be formed on a light-transmitting support using the photothermal conversion layer ink composition described above. The photothermal conversion layer ink composition is applied onto a light transmissive support by spin coating, bar coating, roll coating, cast coating, spraying, or the like, and heated to, for example, about 100° C. to about 250° C. to partially condense the organic silicate. By volatilizing water, alcohol, or an arbitrary solvent generated in the condensation reaction of a substance or an alkali metal silicate, a light-to-heat conversion layer containing at least one of an organic silicate condensate and an alkali metal silicate as a binder is formed. can do.

The thickness of the photothermal conversion layer can be greater than or equal to about 0.1 μm, greater than or equal to about 0.3 μm, or greater than or equal to about 0.5 μm, less than or equal to about 5 μm, less than or equal to about 3 μm, or less than or equal to about 2 μm. By setting the thickness of the photothermal conversion layer to about 0.1 μm or more, the film formability and adhesiveness of the photothermal conversion layer can be maintained. By setting the thickness of the photothermal conversion layer to about 5 μm or less, it is possible to secure the necessary ultraviolet transmittance when forming the bonding layer using a UV-curable adhesive.

In one embodiment, the light-to-heat conversion layer has a mass retention rate of about 97% or more when exposed to air at 350° C. for 1 hour.

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

The laminate (laminate B) of the second embodiment comprises a light-transmitting support, a photothermal conversion layer, a bonding layer disposed on the photothermal conversion layer, and a substrate to be ground disposed on the bonding layer. The photothermal conversion layer and the base material to be ground are joined by a joining layer. The photothermal conversion layer is decomposed and separated into two by irradiation with radiant energy such as laser light, and can be separated from the light-transmitting support without damaging the substrate.

FIG. 2 shows a schematic cross-sectional view of the laminate (laminate B) of this embodiment. The laminate 20 includes a light-transmitting support 12, a photothermal conversion layer 14, a bonding layer 22 disposed on the photothermal conversion layer 14, and a substrate to be ground 24 disposed on the bonding layer 22. Including, the photothermal conversion layer 14 and the base material 24 to be ground are bonded by the bonding layer 22 .

The bonding layer can be formed using a liquid adhesive. Liquid adhesives include, for example, rubber-based adhesives in which rubber, elastomer, etc. are dissolved in a solvent; one-liquid thermosetting adhesives based on epoxy resins, urethane resins, etc.; epoxy resins, urethane resins, acrylic resins, etc. Two-liquid mixed reactive adhesives as bases; hot melt adhesives; ultraviolet (UV) curable or electron beam curable adhesives based on acrylic resins, epoxy resins, etc.; and water dispersion adhesives. . Among these, UV curing adhesives are preferably used.

The bonding layer may be a double-sided adhesive tape or a double-sided adhesive film with or without a support inside. Supports include, for example, plastic films, paper, and nonwoven fabrics. Examples of adhesives for double-sided adhesive tapes and double-sided adhesive films include adhesives containing acrylic resins, urethane resins, natural rubbers, and the like as main components.

Separating the substrate from the light-transmissive support generally provides the substrate with the bonding layer attached. Therefore, it is desirable that the bonding layer can be easily peeled off from the substrate. The bonding layer has sufficient adhesive strength (holding power) to fix the substrate to the light-transmitting support, but desirably has low adhesive strength to the extent that it can be peeled off after heat treatment.

The thickness of the bonding layer should be such that it absorbs unevenness on the surface of the base material and ensures the uniformity of thickness necessary for processes such as back grinding and the tearing strength necessary when peeling off the bonding layer. is preferred. When the bonding layer is removed using a chemical solution, the bonding layer does not need to have a particular tear strength. In one embodiment, the thickness of the bonding layer is about 3 μm or more, or about 10 μm or more, about 150 μm or less, or about 100 μm or less.

Substrates to be ground include, for example, silicon (Si), germanium (Ge), silicon germanium (SiGe), silicon carbide (SiC), III-V compound semiconductors such as gallium arsenide (GaAs), or zinc sulfide (ZnS). including II-VI compound semiconductors such as The substrate to be ground may be in the shape of a semiconductor wafer, and may have a structure such as a circuit pattern formed on the surface in contact with the bonding layer. In one embodiment, it is contemplated that the substrate to be ground is thinned by back-grinding in the state of a laminate. Other ground substrates include, for example, quartz wafers, sapphire, glass, and quartz.

When the substrate to be ground is a semiconductor wafer having a circuit pattern, the circuit may be damaged by radiant energy such as laser light that reaches the semiconductor wafer through the light-transmitting support, the photothermal conversion layer and the bonding layer. be. To avoid such damage, a dye that absorbs or reflects light at the wavelength of the radiant energy is included in one of the layers forming the laminate, or between the photothermal conversion layer and the semiconductor wafer. A further layer containing such dyes or pigments may be provided. Examples of dyes that absorb laser light include dyes such as phthalocyanine dyes and cyanine dyes that have an absorption peak near the wavelength of the laser light used. Pigments that reflect laser light include inorganic white pigments such as titanium oxide.

Laminate B can be manufactured, for example, by the following method. A liquid adhesive is applied to either the surface of the photothermal conversion layer of the laminate A or the surface of the substrate to be ground which is not ground, or both. The light-to-heat conversion layer and the substrate are adhered via a liquid adhesive and heated, or the liquid adhesive is cured by irradiating ultraviolet rays through the light-transmitting support to form a bonding layer. Thereby, the laminate B having the structure shown in FIG. 2 can be manufactured. Formation of the laminate is desirably performed under vacuum in order to prevent air from entering between layers.

One embodiment of the method for producing a thinned substrate comprises: preparing a laminate B; grinding the substrate to be ground until the substrate to be ground reaches a desired thickness; irradiating the photothermal conversion layer with radiant energy to decompose the photothermal conversion layer, thereby separating the ground substrate having the bonding layer and the light-transmitting support, and, if necessary, grinding including removing the bonding layer from the subsequent substrate.

FIG. 3 shows an explanatory diagram of a method for manufacturing a thinned base material according to one embodiment. FIG. 3(a) shows the laminate 20 (laminate B). As shown in (b), the substrate 24 to be ground is ground to be thinned. As shown in (c), the photothermal conversion layer 14 is decomposed by irradiating the photothermal conversion layer 14 with radiant energy (indicated by upward arrows) such as laser light through the light-transmitting support 12 . In (c), the photothermal conversion layer 14 is separated into two at the position of the dotted line. As shown in (d), the ground thinned substrate 25 having the bonding layer 22 is separated from the light transmissive support (not shown). As shown in (e), the bonding layer 22 is removed from the thinned base material 25 after grinding to obtain the thinned base material 25 .

Grinding of the base material to be ground can be performed using a grinding device comprising a pedestal to which the object to be ground can be fixed by suction, a spindle, and a grinding wheel rotatably attached to the lower end of the spindle. . The light-transmitting support side of the laminate B is placed on the pedestal of the grinding machine, and the laminate B is fixed to the pedestal by suction. After that, while supplying the water flow to the laminate B, the rotating grinding wheel is brought into contact with the substrate to grind the substrate to be ground. Grinding can be performed until the thickness of the substrate to be ground is about 150 μm or less, preferably about 50 μm or less, more preferably about 25 μm or less.

Irradiation of radiant energy can be performed using laser light. Examples of laser light include YAG laser (wavelength 1064 nm), double harmonic YAG laser (wavelength 532 nm), semiconductor laser (wavelength 780 to 1300 nm), KrF excimer laser (wavelength 248 nm), ArF excimer laser (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 is performed using ultraviolet rays generated from a high-pressure mercury lamp (wavelength 254 nm or more and 436 nm or less), such as g-line (wavelength 436 nm), h-line (wavelength 405 nm), or i-line (wavelength 365 nm). can also

Irradiation of radiant energy can be performed in a state in which the laminated body after grinding is fixed by suction to a fixing table so that the light-transmitting support faces the upper surface. When laser light is used, the focal depth of the laser light is desirably as deep as about 30 μm or more in order to stably separate the substrate and the light-transmissive support. The laser power can be 0.3-100 W, the scanning speed can be 0.1-40 m/sec, and the beam diameter can be 5 μm-300 μm. Processing speed may be increased by increasing laser power and increasing scan speed. If there is sufficient laser output, the processing speed may be increased by increasing the beam diameter and reducing the number of scans. It is desirable that the scanning of the laser beam is performed from the edge of the laminated body after grinding without gaps. For example, the laser beam may be linearly reciprocatingly scanned from the end in the tangential direction of the substrate, or may be scanned spirally from the end toward the center.

After the photothermal conversion layer is decomposed by irradiation with radiant energy, the light-transmitting support is separated from the ground substrate using a vacuum pickup or the like.

After separating the light-transmissive support from the ground substrate, if necessary, the bonding layer is removed from the ground substrate. For removing the bonding layer, an adhesive tape for removing the bonding layer can be used, which can form an adhesive force with the bonding layer that is higher than the adhesive force between the base material and the bonding layer after grinding. The adhesive tape for removing the bonding layer can be adhered onto the bonding layer, and the bonding layer can be peeled off from the substrate after grinding. Alternatively or additionally, a solvent may be used to wash off the bonding layer. Examples of solvents include acetone, methyl ethyl ketone, N-methylpyrrolidone, N-ethylpyrrolidone, N-methylsuccinimide, dimethylfuran, toluene, N,N'-dimethylacetamide, tris(dimethylamino)phosphine oxide, dimethylsulfoxide, and γ-butyrolactone can be mentioned.

After the grinding process, if necessary, chemical mechanical polishing (CMP), etching such as resin molding, wet etching, dry etching, vapor deposition, physical vapor deposition (PVD) such as sputtering, chemical vapor deposition (CVD), Processes such as plating such as electrolytic plating and electroless plating, pattern formation by photolithography, and formation of an oxide film on the surface of a silicon wafer may be performed. After the grinding step, before applying the radiant energy, or after the bonding layer removing step, dicing may be performed to separate the thinned substrate into a plurality of pieces. If the thinned substrate is a semiconductor wafer, the piece is a semiconductor chip. The dicing process can be performed using a dicing tape, a die frame, and, if necessary, a die bonding tape.

The laminate of the third embodiment (laminate C) comprises a light-transmitting support, a photothermal conversion layer, a patterned metal layer disposed on the photothermal conversion layer, and a patterned metal layer disposed on the metal layer. a patterned insulating layer; a semiconductor device disposed on or over the insulating layer; and an encapsulant covering the semiconductor device.

FIG. 4 shows a schematic cross-sectional view of the laminate (laminate C) of this embodiment. The laminate 30 comprises a light transmissive support 12, a photothermal conversion layer 14, a patterned metal layer 32 disposed on the photothermal conversion layer 14, and a patterned insulating layer disposed on the metal layer 32. 34 , a semiconductor device 36 disposed on or over the insulating layer 34 , and an encapsulant 38 covering the semiconductor device 36 . In FIG. 4 , the patterned metal layer 32 and the patterned insulating layer 34 form a redistribution layer (RDL), and the semiconductor device 36 is electrically connected to the metal layer 32 via bumps 362 . Connected.

The patterned metal layer can be formed using conductors used in semiconductor device manufacturing. Examples of conductors include metals such as aluminum, copper, titanium, nickel, gold, and silver, and alloys such as silver-tin alloys. In one embodiment, the patterned metal layer is wiring in a redistribution layer (RDL) for sending signals of a semiconductor device (semiconductor chip) to a wiring substrate, and preferably comprises copper. In one embodiment, a portion of the patterned metal layer has exposed portions that extend through the patterned insulating layer to electrically connect with the semiconductor device.

The patterned insulating layer can be formed using insulators used in semiconductor device manufacturing. 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 the patterned metal layer constitute a redistribution layer (RDL). The patterned insulating layer may have areas in contact with the photothermal conversion layer.

Examples of semiconductor devices include integrated circuits such as ICs and LSIs, discrete semiconductors such as high-frequency transistors and high-frequency diodes, and optical semiconductors such as light-emitting diodes (LEDs), laser diodes, and imaging devices. The semiconductor device may be in the form of a silicon wafer or SOI substrate with a plurality of semiconductor chips formed thereon.

Examples of the encapsulating material include molding compounds known in the manufacture of semiconductor devices, including epoxy resins, polyimide resins, and the like. The sealing material may contain a filler such as spherical silica in addition to the resin.

FIG. 5 shows an explanatory diagram of a method for manufacturing the laminate (laminate C) of the third embodiment shown in FIG. FIG. 5(a) shows the laminate 10 (laminate A). As 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 are formed by known semiconductor processing techniques such as photolithography, vapor deposition, physical vapor deposition (PVD) such as sputtering, electroplating, electroless plating and other plating. , and etching such as wet etching and dry etching. As shown in (c), the semiconductor device 36 is placed using a chip mounter or the like so that the bumps 362 are in electrical contact with the exposed portions of the patterned metal layer 32 . As shown in (d), the semiconductor device 36 is covered with a sealing material 38 for sealing. The sealing material 38 is heated to, for example, 130.degree. C. to 170.degree. C. and compression-molded. Thus, the laminate 30 is obtained.

One embodiment of the method for manufacturing a semiconductor chip includes preparing a laminate C, irradiating the photothermal conversion layer with radiant energy through a light-transmitting support to decompose the photothermal conversion layer, thereby forming a metal layer and a photothermal conversion layer. separating from the transparent support and, if necessary, removing the residue of the photothermal conversion layer from the surface of the metal layer. This manufacturing method is part of the RDL First process.

FIG. 6 shows an explanatory diagram of a method for manufacturing a semiconductor chip according to one embodiment. As shown in FIG. 6A, the photothermal conversion layer 14 is irradiated with radiant energy (indicated by upward arrows) such as laser light through the light-transmitting support 12 of the laminate 30 (laminate C), The photothermal conversion layer 14 is decomposed. In (a), the photothermal conversion layer 14 is separated into two at the position of the dotted line. As shown in (b), the metal layer 32 and the light transmissive support (not shown) are separated. As shown in (c), the semiconductor chip 50 is obtained by removing the residue of the photothermal conversion layer 14 from the surface of the metal layer 32 .

Irradiation of radiant energy and separation of the metal layer and the light-transmitting support can be carried out in the same manner as in the method for producing a thinned substrate.

After separating the light-transmitting support from the metal layer, if necessary, the residue of the photothermal conversion layer is removed from the surface of the metal layer and, if necessary, the surface of the insulating layer. An adhesive tape can be used to remove the residue of the photothermal conversion layer. An adhesive tape can be adhered so as 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 additionally, residues of the photothermal conversion layer may be washed off. Examples of cleaning agents include hydrogen fluoride aqueous solution, potassium hydroxide aqueous solution, and tetramethylammonium hydroxide aqueous solution. During washing off, the washing agent may be heated to, for example, 40°C to 80°C.

The laminate (laminate D) of the fourth embodiment comprises a light-transmitting support, a photothermal conversion layer, a bonding layer disposed on the photothermal conversion layer, and a semiconductor substrate disposed on the bonding layer. further includes The semiconductor substrate has an insulating layer disposed on a surface of the semiconductor substrate opposite the bonding layer, and one or more conductive connections penetrating the insulating layer and electrically connected to the semiconductor substrate.

FIG. 7 shows a schematic cross-sectional view of the laminate (laminate D) of this embodiment. The laminate 40 further includes a light transmissive support 12, a photothermal conversion layer 14, a bonding layer 42 disposed on the photothermal conversion layer 14, and a semiconductor substrate 44 disposed on the bonding layer 42. . The semiconductor substrate 44 includes an insulating layer 442 disposed on the surface of the semiconductor substrate 44 opposite the bonding layer 42 and one or more conductive layers 442 extending through the insulating layer 442 and electrically connected to the semiconductor substrate 44 . and a connecting portion 444 .

The bonding layer is as described for the laminate (laminate B) of the second embodiment.

Examples of semiconductor substrates include silicon wafers and SOI substrates on which a plurality of semiconductor chips are formed. Semiconductor chips include, for example, integrated circuits such as ICs and LSIs, or imaging devices such as CCDs.

The insulating layer and the conductive connection are formed by known semiconductor processing techniques, such as photolithography, vapor deposition, physical vapor deposition (PVD) such as sputtering, plating such as electrolytic plating and electroless plating, wet etching, dry etching, etc. can be formed using etching. In one embodiment, the insulating layer comprises silicon oxide ( _SiO2 ) or polyimide. In one embodiment, the electrically conductive connection comprises copper.

The laminate D can be produced, for example, by the following method. A liquid adhesive is applied to one or both of the surface of the light-to-heat conversion layer of the laminate A or the surface of the semiconductor substrate opposite to the side on which the insulating layer and the conductive connection are formed. The photothermal conversion layer and the semiconductor substrate are adhered via a liquid adhesive and heated, or the liquid adhesive is cured by irradiating ultraviolet rays through the light-transmissive support to form a bonding layer. Thus, a laminate D having the structure shown in FIG. 7 can be manufactured. Formation of the laminate is desirably performed under vacuum in order to prevent air from entering between layers.

A method for manufacturing a semiconductor substrate laminate according to one embodiment includes preparing a laminate D, a second semiconductor substrate having a second insulating layer disposed on a surface of the second semiconductor substrate, and a second insulating layer. providing a second semiconductor substrate having one or more second conductive connections extending therethrough and electrically connected to the second semiconductor substrate; The semiconductor substrate and the second semiconductor substrate are thermo-compression bonded with the second conductive connecting portion facing each other, so that the conductive connecting portion and the second conductive connecting portion are joined together, and the insulating layer and the second insulating layer are bonded together. forming a semiconductor substrate laminate having layers bonded thereto, irradiating the photothermal conversion layer with radiant energy through the light-transmissive support to decompose the photothermal conversion layer, thereby forming a semiconductor substrate laminate having a bonding layer; and the light-transmissive support, and, if necessary, removing the bonding layer from the surface of the semiconductor substrate laminate. This manufacturing method is a kind of hybrid bonding.

FIG. 8 shows an explanatory view of the manufacturing method of the semiconductor substrate laminate of this embodiment. FIG. 8A shows the laminate 40 (laminate D) and the second semiconductor substrate 64 . The second semiconductor substrate 64 has a second insulating layer 642 disposed on its surface and one or more second conductive connections passing through the second insulating layer 642 and electrically connected to the second semiconductor substrate 64 . 644. The conductive connection portion 444 of the semiconductor substrate 44 included in the laminate 40 faces the second conductive connection portion 644 of the second semiconductor substrate 64 . In (b), the semiconductor substrate 44 and the second semiconductor substrate 64 are thermocompression bonded. Thereby, the conductive connecting portion 444 and the second conductive connecting portion 644 are joined together, and the insulating layer 442 and the second insulating layer 642 are joined together. As shown in (c), the photothermal conversion layer 14 is decomposed by irradiating the photothermal conversion layer 14 with radiant energy (indicated by upward arrows) such as laser light through the light-transmitting support 12 . In (c), the photothermal conversion layer 14 is separated into two at the position of the dotted line. As shown in (d), the semiconductor substrate laminate having the bonding layer 14 is separated from the light transmissive support (not shown). As shown in (e), the semiconductor substrate laminate 70 is obtained by removing the bonding layer 22 from the surface of the semiconductor substrate laminate.

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

The thermocompression bonding between the semiconductor substrate and the second semiconductor substrate can be performed for 20 minutes to 60 minutes under conditions of a temperature of 300° C. to 450° C. and a pressure of 200 to 400 MPa.

In one embodiment, the insulating layer and the conductive connection of the semiconductor substrate and the second insulating layer and the second conductive connection of the second semiconductor substrate use copper for the conductive connection and the second conductive connection. , the insulating layer and the second insulating layer are formed by the CMP method (damascene method) using silicon oxide (SiO ₂ ) films. In the CMP process, the etching rate of copper is higher than the etching rate of silicon oxide, so the copper surface after the CMP process is slightly recessed (dishing) from the surface of the surrounding silicon oxide insulating layer. In addition, the fact that the copper surface is lower than the surface of the surrounding silicon oxide insulating layer works advantageously for reliable bonding between the insulating layer and the second insulating layer in the thermocompression bonding process. The coefficient of thermal expansion of copper is greater than that of silicon oxide. Therefore, copper expands during the thermocompression bonding process, and the conductive connecting portion and the second conductive connecting portion come into contact with each other, and interdiffusion of copper occurs at the contact portion, resulting in depressions on the copper surface. The gap is filled, and the conductive connecting portion and the second conductive connecting portion are electrically connected through the oxide film and impurities on the copper surface. In addition, bonding between the insulating layer and the second insulating layer occurs at the same time as the condensation reaction of silicon oxide proceeds in the high temperature environment of the thermocompression bonding process.

Irradiation of radiant energy and separation of the semiconductor substrate laminate and the light-transmitting support can be carried out in the same manner as in the method for producing a thinned base material.

Removal of the bonding layer from the surface of the semiconductor substrate laminate can be performed in the same manner as in the method for manufacturing the thinned base material.

The photothermal conversion layer ink compositions and laminates of the present disclosure can be used in various applications including temporary fixing applications. Specifically, the ink composition for the photothermal conversion layer and the laminate include a laminated CSP (Chip Size Package) that is mounted at high density, a through-type CSP that requires high performance and high speed, heat dissipation efficiency, electrical properties and It can be suitably used for manufacturing semiconductor chips using ultra-thin compound semiconductors (such as GaAs) requiring improved stability and large wafers such as 16-inch silicon wafers.

The following examples illustrate specific embodiments of the present disclosure, but the invention is not limited thereto. All parts and percentages are by weight unless otherwise specified. Numerical values inherently contain errors resulting from measurement principles and measurement equipment. Numbers are shown to significant digits with normal rounding applied.

Table 1 shows the materials, reagents, etc. used in Examples and Comparative Examples.

1. Preparation of UV Curable Liquid Adhesive Light acrylate 1.6HX-A and Omnirad™ 369 were placed in a light resistant plastic bottle and stirred until Omnirad™ 369 was completely dissolved. After that, UV-3300B was placed in a plastic bottle and stirred to prepare a UV curable liquid adhesive.

Table 2 shows the formulation of the UV curable liquid adhesive.

2. Preparation of ink composition for light-to-heat conversion layer 6 and the light-to-heat conversion layer ink compositions of Comparative Examples 1 to 3 were prepared.

3. Heat Resistance Test The photothermal conversion layer ink compositions of Examples 1 to 6 and Comparative Example 3 were applied onto a glass substrate having a width of 500 mm, a length of 700 mm, and a thickness of 1 mm using a wire bar, and heated at 180° C. for 1 hour. Then, a photothermal conversion layer was formed. The photothermal conversion layer was then scraped off with a razor blade to obtain a powder. The resulting powder was kept in ambient atmosphere for 5 hours and weighed. After weighing, the powder was heat treated in air at 350° C. for 1 hour, after which the powder was again held in ambient atmosphere for 5 hours and weighed. The mass retention rate was calculated from the following formula. Table 4 shows the results.

4. Chemical Resistance Test The photothermal conversion layer ink compositions of Examples 1 to 6 and Comparative Example 3 were applied to a glass substrate having a width of 200 mm, a length of 700 mm, and a thickness of 1 mm using a wire bar, and the temperature was maintained at 180° C. for 1 hour. A photothermal conversion layer having a thickness of 0.5 μm was formed by heating. The optical density of the photothermal conversion layer was adjusted to 1.5 at a wavelength of 600 nm. The glass substrate coated with the photothermal conversion layer was placed in a glass jar with N-methyl-2-pyrrolidone (NMP), 9.7% by mass sulfuric acid aqueous solution, 10% by mass potassium hydroxide aqueous solution, or tetramethylammonium hydroxide ( TMAH)/water/dimethyl sulfoxide (DMSO)=5/15/80 (mass ratio) at the temperature and time shown in Table 5. The state of each sample was visually observed. Table 5 shows the results.

5. Laser Separation Test A disk-shaped glass substrate with a diameter of 154 mm and a thickness of 800 μm was used as a light-transmissive support, 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 light-to-heat conversion layer ink compositions of Examples 1 to 6 and Comparative Examples 1 to 3 were applied onto a glass substrate using a spin coater, heated at 40° C. for 3 minutes, and 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 similarly applied onto the silicon wafer using a spin coater. After bonding the glass substrate and the silicon wafer using a coating and bonding apparatus WSS8101M (Tatsumo Co., Ltd., Okayama City, Okayama Prefecture, Japan), the UV curable liquid adhesive is cured by irradiating ultraviolet rays from the glass substrate side. to obtain a laminate. The laminate had a structure of glass substrate/photothermal conversion layer/bonding layer/silicon wafer, the thickness of the photothermal conversion layer was 0.9 μm, and the thickness of the bonding layer was 50 μm.

A dicing tape and a dicing frame are placed on the silicon wafer of the laminate, the laminate is transferred to the stage of the support peeling device TWS (Tatsumo Co., Ltd., Okayama City, Okayama Prefecture, Japan), and the pressure is reduced from the bottom by a vacuum device. Then, the laminate was adsorbed and fixed on the stage. Laser irradiation was performed from the glass substrate side of the laminate using a YAG laser (wavelength: 1064 nm) under the conditions of a laser output of 6.0 W, a beam diameter of 100 μm, a scanning pitch of 100 μm, and a laser scanning speed of 1.0 m/sec. The laser beam was linearly reciprocated in the tangential direction from the edge portion of the laminate to irradiate the entire surface of the laminate. A suction device was attached to the glass substrate of the laminate irradiated with the laser, and it was manually checked whether the glass substrate and the silicon wafer could be easily separated. Table 6 shows the results.

Various modifications and alterations of this invention will become apparent to those skilled in the art without departing from the scope and spirit of this invention.

REFERENCE SIGNS LIST 10, 20, 30, 40 laminate 12 light-transmitting support 14 photothermal conversion layer 22 bonding layer 24 base material to be ground 25 thinned base material 32 patterned metal layer 34 patterned insulating layer 36 semiconductor Device 362 Bump 38 Sealing material 42 Bonding layer 44 Semiconductor substrate 442 Insulating layer 444 Conductive connection 50 Semiconductor chip 64 Second semiconductor substrate 642 Second insulation layer 644 Second conductive connection 70 Semiconductor substrate laminate

Claims (19)

A light-to-heat conversion layer ink composition comprising a thermally decomposable light absorber and a binder or its precursor, wherein the binder or its precursor is at least one of an organic silicate partial condensate and an alkali metal silicate. A light-to-heat conversion layer ink composition comprising a seed. 2. The photothermal conversion layer ink composition of claim 1, wherein the organic silicate partial condensate comprises tetraethylorthosilicate. 2. The photothermal conversion layer ink composition according to claim 1, wherein the alkali metal silicate contains at least one of potassium silicate and lithium silicate. 4. The photothermal conversion layer ink composition of claim 3, wherein the alkali metal silicate comprises potassium silicate. The light-to-heat conversion layer ink composition according to any one of claims 1 to 4, wherein the light absorbing agent comprises carbon black particles. 6. The photothermal conversion layer ink composition according to claim 5, wherein the carbon black particles have an average primary particle size of 10 nm to 400 nm. 7. The photothermal conversion layer ink composition according to claim 5 or 6, wherein the carbon black particles comprise hydrophilic carbon black particles. The light-to-heat conversion layer ink composition according to any one of claims 1 to 7, further comprising ligninsulfonic acid or a salt thereof. The light-to-heat conversion layer ink composition according to any one of claims 1 to 8, further comprising a transparent filler. The light-to-heat conversion layer ink composition according to any one of claims 1 to 9, wherein the total content of the binder and its precursor is 30% by volume to 80% by volume based on the solid content volume. The light-to-heat conversion layer ink composition according to any one of claims 1 to 10, which has a viscosity of 3 mPa·s to 200 mPa·s. a light-transmitting support;
A laminate comprising a thermally decomposable light absorbent and a photothermal conversion layer containing a binder,
A laminate, wherein the binder contains at least one of an organic silicate condensate and an alkali metal silicate. 13. The laminate of Claim 12, wherein the light-transmitting support is glass. a bonding layer disposed on the photothermal conversion layer;
14. The laminate according to claim 12, further comprising a substrate to be ground disposed on said bonding layer, wherein said photothermal conversion layer and said substrate to be ground are bonded by said bonding layer. Preparing the laminate according to claim 14,
Grinding the substrate to be ground until the substrate to be ground has a desired thickness;
The photothermal conversion layer is irradiated with radiant energy through the light-transmitting support to decompose the photothermal conversion layer, thereby separating the ground substrate having the bonding layer and the light-transmitting support. A method for producing a thinned substrate, comprising: separating; and optionally removing the bonding layer from the ground substrate. a patterned metal layer disposed over the photothermal conversion layer;
a patterned insulating layer disposed over the metal layer;
a semiconductor device disposed on or above the insulating layer;
14. The laminate according to claim 12, further comprising a sealing material covering said semiconductor device. Preparing the laminate according to claim 16,
irradiating the light-to-heat conversion layer with radiant energy through the light-transmitting support to decompose the light-to-heat conversion layer, thereby separating the metal layer and the light-transmitting support; and removing the residue of the photothermal conversion layer from the surface of the metal layer. a bonding layer disposed on the photothermal conversion layer;
14. The laminate according to claim 12 or 13, further comprising a semiconductor substrate arranged on the bonding layer,
The semiconductor substrate comprises an insulating layer disposed on a surface of the semiconductor substrate opposite the bonding layer, and one or more conductive connections passing through the insulating layer and electrically connected to the semiconductor substrate. and a laminate. Preparing the laminate according to claim 18,
a second semiconductor substrate, a second insulating layer disposed on the surface of the second semiconductor substrate; and one or more insulating layers penetrating the second insulating layer and electrically connected to the second semiconductor substrate providing a second semiconductor substrate having a second conductive connection;
The conductive connection portion of the semiconductor substrate and the second conductive connection portion of the second semiconductor substrate are opposed to each other, and the semiconductor substrate and the second semiconductor substrate are thermally and pressure-bonded to each other, thereby increasing the conductivity. forming a semiconductor substrate laminate in which the connecting portion and the second conductive connecting portion are bonded together and the insulating layer and the second insulating layer are bonded together;
Radiant energy is applied to the light-to-heat conversion layer through the light-transmitting support to decompose the light-to-heat conversion layer, thereby separating the semiconductor substrate laminate having the bonding layer from the light-transmitting support. and optionally removing the bonding layer from the surface of the semiconductor substrate laminate.

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