JP2012129327A - Base material processing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a base material processing method capable of processing a base material with excellent accuracy while maintaining a certain distance between a support base material and the base material when temporarily fixing the base material onto the support base material and processing the base material.SOLUTION: A base material processing method comprises: a step of preparing a semiconductor wafer (base material) 3, a support base material 1, and a temporarily fixing agent composed of a resin composition including a resin component; a step of supplying the temporarily fixing agent to one surface of the support base material 1 in a spin coating method and forming a sacrificial layer (thin film) 21 by drying the temporarily fixing agent and then supplying the temporarily fixing agent to one surface of the semiconductor wafer 3 in the spin coating method and forming a sacrificial layer (thin film) 22 by drying the temporarily fixing agent; a step of bonding the semiconductor wafer 3 and the support base material 1 by bringing the sacrificial layer 21 into contact with the sacrificial layer 22; a step of processing the other surface of the semiconductor wafer 3; and a step of detaching the semiconductor wafer 3 from the support base material 1 by thermally decomposing the resin component by heating the sacrificial layer 21 and the sacrificial layer 22.

Description

  The present invention relates to a base material processing method, and more particularly to a base material processing method in which a base material is temporarily fixed to a supporting base material using a temporary fixing agent.

  In order to perform processing such as polishing and etching on a semiconductor wafer, it is necessary to temporarily fix the semiconductor wafer on a base material for supporting the semiconductor wafer, and various methods have been proposed. For example, at present, a method of fixing a semiconductor wafer on a fixing film in which an adhesive layer is provided on a PET film as a base material is often used.

  In this method, when the grinding accuracy (about 1 μm) of a general back grinding machine used for grinding is combined with the thickness accuracy (about 5 μm) of a general back grinding (BG) tape for fixing a semiconductor wafer, There is a problem that the required thickness accuracy is exceeded and the thickness of the ground wafer varies.

  Also, when processing a semiconductor wafer used for through silicon vias, via holes and films are formed with a BG tape attached, and the temperature at that time reaches at least about 180 ° C., This will increase the adhesive strength of the BG tape. Further, the adhesive layer of the BG tape is eroded by the plating chemicals for film formation, and peeling may occur.

  In addition, since a fragile semiconductor wafer typified by a compound semiconductor may be damaged by mechanical grinding, it is thinned by etching. In this etching, there is no particular problem as long as the etching amount is for the purpose of removing stress. However, when etching is performed by several μm, the BG tape may be deteriorated by the etching chemical.

  On the other hand, in recent years, a method of fixing a semiconductor wafer to a support substrate having a smooth surface via a fixing material has been adopted.

  For example, in order to perform etching for the purpose of stress removal, it is necessary to heat to a high temperature, but PET film cannot withstand such a high temperature. In such a case, a method using a supporting substrate Is preferably applied.

  As a material for fixing the base material to the supporting base material, a fixing material that softens at a high temperature and facilitates the removal of the semiconductor wafer (see, for example, Patent Document 1) has been proposed.

  However, when such a fixing material is used and the semiconductor wafer is fixed on the support base, the semiconductor wafer is positioned between the support base and the semiconductor wafer when processing such as polishing or etching is performed. When the thickness of the thin film formed using the fixing material is not uniform, for example, when the semiconductor wafer is polished, there is a problem that the thickness of the semiconductor wafer varies.

  In particular, when a semiconductor wafer has irregularities on the surface that contacts the fixing material, a thin film (fixing material) cannot be sufficiently filled in the recesses of the irregularities, leaving gaps between the substrate and the thin film. There are things to do. In this case, due to the variation in the size of the gap, the semiconductor wafer is supported in an inclined state with respect to the support substrate, and when the semiconductor wafer is polished, the thickness of the semiconductor wafer varies, and the semiconductor wafer The machining accuracy is reduced.

  Such a problem is not limited to the processing of semiconductor wafers, but also occurs in various substrates that are processed in a state of being fixed to a supporting substrate via a fixing member.

Special table 2010-53385 gazette

  The purpose of the present invention is to maintain a constant distance between the supporting base material and the base material when the base material is temporarily fixed on the supporting base material to process the base material. It is providing the processing method of the base material which can process.

Such an object is achieved by the present invention described in the following (1) to (14).
(1) A base material having irregularities on one surface, a support base material that supports the base material when processing the other surface of the base material, and a resin that is melted or vaporized by thermal decomposition by heating A first step of preparing a temporary fixative composed of a resin composition containing components;
The temporary fixing agent is supplied to one surface of the supporting base material using a spin coating method and then dried to form a first thin film, and the temporary fixing agent is formed on the one surface of the base material. A second step of forming a second thin film by supplying the material using a spin coating method and then drying;
A third step of bonding the base material and the support base material by bringing the first thin film and the second thin film into contact with each other;
A fourth step of processing the other surface of the substrate;
A fifth step of heating the first and second thin films and thermally decomposing the resin component to desorb the base material from the support base material. Method.

  (2) The base material processing method according to (1), wherein the base material includes a conductive portion on the one surface, and the unevenness is formed on the one surface due to the presence of the conductive portion.

  (3) In the first step, the substrate processing method according to (1) or (2) above, wherein the viscosity (25 ° C.) of the temporary fixing agent is adjusted to 500 to 100,000 mPa · s. .

  (4) The said 2nd process WHEREIN: The base material which supplies the said temporary fixing agent, and the rotation speed of the said support base material shall be 300-4,000 rpm, Any one of said (1) thru | or (3) Substrate processing method.

  (5) The said 1st and 2nd thin film in said 2nd process WHEREIN: The sum total average thickness is formed in the thickness of 50-100 micrometers in any one of said (1) thru | or (4). Processing method of the substrate.

  (6) The substrate processing method according to any one of (1) to (5), wherein in the second step, the first and second thin films having a TMA softening point of less than 200 ° C. are formed.

  (7) In the third step, pressurization is performed at a pressure of 0.01 to 3 MPa in a direction in which the base material and the support base material approach each other in a state where the first and second thin films are in contact with each other. The processing method of the base material in any one of said (1) thru | or (5).

  (8) The substrate processing method according to any one of (1) to (7), wherein in the third step, the first and second thin films are heated at a temperature of 100 to 300 ° C.

  (9) The substrate processing method according to (8), wherein the time for heating the first and second thin films is 0.1 to 10 minutes.

  (10) The resin component is one in which the thermal decomposition temperature is lowered by irradiation of the temporary fixing agent with active energy rays. Prior to the fifth step, the active energy rays are converted into the first energy components. And the method for processing a substrate according to any one of (1) to (9), wherein the second thin film is irradiated.

  (11) The resin component is such that the thermal decomposition temperature decreases in the presence of an acid or a base, and the resin composition further comprises an activator that generates an acid or a base by irradiation with the active energy ray. The processing method of the base material as described in said (10) containing.

  (12) The substrate processing method according to (10) or (11), wherein the resin component is a polycarbonate-based resin.

  (13) The base material processing method according to any one of (1) to (9), wherein the resin component is such that a temperature at which the thermal decomposition is not reduced by irradiation of active energy rays to the temporary fixing agent.

  (14) The substrate processing method according to (13), wherein the resin component is a norbornene-based resin.

  According to the base material processing method of the present invention, the distance between the base material and the supporting base material can be kept constant using the temporary fixing agent. As a result, there is an effect that the substrate can be processed with high accuracy.

It is a longitudinal cross-sectional view for demonstrating the process process which processes the semiconductor wafer to which the processing method of the base material of this invention was applied.

  Hereinafter, the processing method of the base material of this invention is demonstrated in detail based on suitable embodiment shown to an accompanying drawing.

  First, prior to explaining the processing method of the base material of the present invention, the temporary fixing agent used in the present invention will be described.

<Temporary fixative>
The temporary fixing agent is used to temporarily fix the base material to a supporting base material in order to process the base material, and to release the base material from the supporting base material by heating after processing the base material. And a resin composition containing a resin component that is thermally decomposed by heating.

  By using such a temporary fixing agent, the first thin film and the second thin film (hereinafter sometimes collectively referred to as “thin film”) formed using the temporary fixing agent are used as a base material. The substrate can be processed while temporarily fixed to the supporting substrate, and the substrate is removed from the supporting substrate by melting or vaporizing the first thin film and the second thin film by heating after the processing. Can be separated.

  Hereinafter, each component which comprises the resin composition containing this resin component is demonstrated sequentially.

  The resin component has a function of fixing the base material to the supporting base material at the time of temporary fixing (processing the base material), and further thermally decomposes to lower the molecular weight by the heating of the temporary fixing agent. Since the bonding strength is reduced due to the melting or vaporization of the substrate, it has a function of allowing the substrate to be detached from the supporting substrate.

  The resin component is not particularly limited as long as it has the above-described function, but is not limited to polycarbonate resin, polyester resin, polyamide resin, polyimide resin, polyether resin, polyurethane resin, ( Examples thereof include a (meth) acrylate resin, a norbornene resin, and a polyolefin resin, and one or more of these can be used in combination. Among these, norbornene resins, polycarbonate resins, vinyl resins and (meth) acrylic resins are preferable, and norbornene resins or polycarbonate resins are particularly preferable. These are more suitably selected as the resin component because they exhibit the above functions more remarkably.

  Although it does not restrict | limit especially as a polycarbonate-type resin, Polypropylene carbonate resin, polyethylene carbonate resin, 1, 2- polybutylene carbonate resin, 1, 3- polybutylene carbonate resin, 1, 4- polybutylene carbonate resin, cis-2, 3-polybutylene carbonate resin, trans-2,3-polybutylene carbonate resin, α, β-polyisobutylene carbonate resin, α, γ-polyisobutylene carbonate resin, cis-1,2-polycyclobutylene carbonate resin, trans- 1,2-polycyclobutylene carbonate resin, cis-1,3-polycyclobutylene carbonate resin, trans-1,3-polycyclobutylene carbonate resin, polyhexene carbonate resin, polycyclopropyl Carbonate resin, polycyclohexene carbonate resin, 1,3-polycyclohexane carbonate resin, poly (methylcyclohexene carbonate) resin, poly (vinylcyclohexene carbonate) resin, polydihydronaphthalene carbonate resin, polyhexahydrostyrene carbonate resin, polycyclohexanepropylene Carbonate resin, polystyrene carbonate resin, poly (3-phenylpropylene carbonate) resin, poly (3-trimethylsilyloxypropylene carbonate) resin, poly (3-methacryloyloxypropylene carbonate) resin, polyperfluoropropylene carbonate resin, polynorbornene Carbonate resin, polynorbornane carbonate resin, exo-polynorbornene carbonate tree Fat, endo-polynorbornene carbonate resin, trans-polynorbornene carbonate resin, cis-polynorbornene carbonate resin can be used, and one or more of these can be used in combination.

  Examples of the polycarbonate resin include polypropylene carbonate / polycyclohexene carbonate copolymer, 1,3-polycyclohexane carbonate / polynorbornene carbonate copolymer, poly [(oxycarbonyloxy-1,1,4,4- Tetramethylbutane) -alt- (oxycarbonyloxy-5-norbornene-2-endo-3-endo-dimethane)] resin, poly [(oxycarbonyloxy-1,4-dimethylbutane) -alt- (oxycarbonyloxy -5-norbornene-2-endo-3-endo-dimethane)] resin, poly [(oxycarbonyloxy-1,1,4,4-tetramethylbutane) -alt- (oxycarbonyloxy-p-xylene)] Resin and poly [(oxycal Nyloxy-1,4-dimethylbutane) -alt- (oxycarbonyloxy-p-xylene)] resin, 1,3-polycyclohexane carbonate resin / exo-polynorbornene carbonate resin, 1,3-polycyclohexane carbonate resin / endo -Copolymers, such as polynorbornene carbonate resin, can also be used.

  Furthermore, as the polycarbonate-based resin, in addition to the above, a polycarbonate resin having at least two cyclic bodies in the carbonate constituent unit can also be used.

  The number of cyclic bodies may be two or more in the carbonate structural unit, but is preferably 2 to 5, more preferably 2 or 3, and further preferably 2. By including such a number of cyclic bodies as the carbonate constituent unit, the adhesion between the supporting base material and the base material becomes excellent. Moreover, when the temporary fixing agent is heated, the polycarbonate resin is thermally decomposed to have a low molecular weight, thereby melting.

  In addition, the plurality of cyclic bodies may have a linked polycyclic structure in which the vertices are connected to each other, but a condensed polycyclic structure in which the sides of each ring are connected to each other. It is preferable. Thereby, both heat resistance as a temporary fixing agent and shortening of the thermal decomposition time when this thing melts can be made compatible.

  Furthermore, it is preferable that each of the plurality of cyclic bodies is a 5-membered ring or a 6-membered ring. Thereby, since the planarity of a carbonate structural unit is maintained, the solubility with respect to a solvent can be stabilized more.

  Such a plurality of cyclic bodies are preferably alicyclic compounds. When each cyclic body is an alicyclic compound, the effects as described above are more remarkably exhibited.

  In consideration of these, in the polycarbonate resin, as the carbonate structural unit, for example, a structure represented by the following chemical formula (1X) is a particularly preferable structure.

  In addition, the polycarbonate-type resin which has a carbonate structural unit represented by the said Chemical formula (1X) can be obtained by the polycondensation reaction of decalin diol and carbonic acid diester like diphenyl carbonate.

  In the carbonate structural unit represented by the chemical formula (1X), those derived from the carbon atom linked to the hydroxyl group of decalin diol are each decalin (that is, two cyclic bodies forming a condensed polycyclic structure). It is preferable that three or more atoms intervene between the carbon atoms that are bonded to the carbon atoms constituting and bonded to these hydroxyl groups. Thereby, the decomposability | degradability of polycarbonate-type resin can be controlled, As a result, heat resistance as a temporary fixing agent and shortening of the thermal decomposition time when this thing fuse | melts can be made compatible. Furthermore, the solubility with respect to a solvent can be stabilized more.

  Examples of such a carbonate structural unit include those represented by the following chemical formulas (1A) and (1B).

  Further, the plurality of cyclic bodies may be alicyclic compounds or may be heteroalicyclic compounds. Even when each cyclic body is a heteroalicyclic compound, the effects as described above are more remarkably exhibited.

  In this case, in the polycarbonate resin, as the carbonate structural unit, for example, one represented by the following chemical formula (2X) is a particularly preferable structure.

  In addition, the polycarbonate-type resin which has a carbonate structural unit represented by the said Chemical formula (2X) can be obtained by the polycondensation reaction of ether diol represented by the following Chemical formula (2a), and carbonic acid diester like diphenyl carbonate.

  In the carbonate structural unit represented by the chemical formula (2X), the carbon atom derived from the hydroxyl group of the cyclic ether diol represented by the chemical formula (2a) forms the cyclic ether (that is, a condensed polycyclic structure). It is preferable that three or more atoms are interposed between these carbon atoms and bonded to the carbon atoms constituting the two cyclic bodies. Thereby, both heat resistance as a temporary fixing agent and shortening of the thermal decomposition time when this thing melts can be made compatible. Furthermore, the solubility with respect to a solvent can be stabilized more.

  Examples of such a carbonate structural unit include those of the 1,4: 3,6-dianhydro-D-sorbitol (isosorbide) type represented by the following chemical formula (2A), and those represented by the following chemical formula (2B). 4: 3,6-dianhydro-D-mannitol (isomannide) type.

  The weight-average molecular weight (Mw) of the polycarbonate-based resin is preferably 1,000 to 1,000,000, and more preferably 5,000 to 800,000. By setting the weight average molecular weight to the above lower limit or more, it is possible to obtain the effect of improving the wettability with respect to the support substrate and further improving the film formability. Moreover, by setting it as the said upper limit or less, the effect that the solubility with respect to various solvents and also the fall of the melt viscosity by the heating of a temporary fixing agent are recognized more notably can be acquired.

  In addition, the polymerization method of polycarbonate-type resin is not necessarily limited, For example, well-known polymerization methods, such as the phosgene method (solvent method) or the transesterification method (melting method), can be used.

  Although it does not specifically limit as norbornene-type resin, For example, what contains the structural unit shown by the following general formula (1Y) can be mentioned.

In the formula (1Y), R ^{1 to} R ⁴ are each hydrogen, a linear or branched alkyl group having 1 to 20 carbon atoms, an aromatic group, an alicyclic group, a glycidyl ether group, the following substituent (2Y ) Moreover, m is an integer of 0-4.

In the formula (2Y), R ⁵ is hydrogen, a methyl group, or an ethyl group, and R ⁶ , R ^7, and R ⁸ are each a linear or branched alkyl group having 1 to 20 carbon atoms, linear, or Branched alkoxy group having 1 to 20 carbon atoms, linear or branched alkylcarbonyloxy group having 1 to 20 carbon atoms, linear or branched alkyl peroxy group having 1 to 20 carbon atoms, substituted or unsubstituted It is any of aryloxy groups having 6 to 20 carbon atoms. N is an integer of 0-5.

  The linear or branched alkyl group having 1 to 20 carbon atoms is not particularly limited, but is a methyl group, ethyl group, propyl group, butyl group, pentyl group, hexyl group, heptyl group, octyl group. , Nonyl group, decyl group and the like.

  Among these, compatibility with various components constituting the temporary fixing agent (resin composition) and solubility in various solvents, and a butyl group having excellent mechanical properties when temporarily fixing the base material and the supporting base material, A decyl group is preferred.

  The aromatic group is not particularly limited, and examples thereof include a phenyl group, a phenethyl group, and a naphthyl group. Among these, the mechanical properties when the substrate and the supporting substrate are temporarily fixed are excellent. A phenethyl group and a naphthyl group are preferred.

  The alicyclic group is not particularly limited, but is a cyclohexyl group, norbornenyl group, dihydrodicyclopentadiethyl group, tetracyclododecyl group, methyltetracyclododecyl group, tetracyclododecadiethyl group, dimethyltetracyclododecyl group. And alicyclic groups such as trimer of ethyl group, ethyltetracyclododecyl group, ethylidenyltetracyclododecyl group, phenyltetracyclododecyl group, and cyclopentadiethyl group.

  Among these, a cyclohexyl group and a norbornenyl group, which are excellent in mechanical properties when the base material and the supporting base material are temporarily fixed, and further excellent in thermal decomposability when the temporary fixing agent is heated, are preferable.

R ⁵ in the substituent (2Y) is not particularly limited as long as it is hydrogen, a methyl group, or an ethyl group, but a hydrogen atom that is excellent in thermal decomposability during heating of the temporary fixing agent is preferable.

R ⁶ , R ⁷ and R ⁸ in the substituent (2Y) are each a linear or branched alkyl group having 1 to 20 carbon atoms, a linear or branched alkoxy group having 1 to 20 carbon atoms, Either a linear or branched alkylcarbonyloxy group having 1 to 20 carbon atoms, a linear or branched alkylperoxy group having 1 to 20 carbon atoms, or a substituted or unsubstituted aryloxy group having 6 to 20 carbon atoms If so, there is no particular limitation.

  Examples of such substituents include methoxy group, ethoxy group, propoxy group, butoxy group, pentyloxy group, acetoxy group, propoxy group, butoxy group, methylperoxy group, isopropylperoxy group, t-butylperoxy group, phenoxy group. , A hydroxyphenoxy group, a naphthyloxy group, a phenoxy group, a hydroxyphenoxy group, a naphthyloxy group, and the like. An ethoxy group and a propoxy group are preferable.

  M in the general formula (1Y) is an integer of 0 to 4, and is not particularly limited, but 0 or 1 is preferable. When m is 0 or 1, the structural unit represented by the general formula (1Y) can be represented by the following general formula (3Y) or (4Y).

In the formulas (3Y) and (4Y), R ^{1 to} R ⁴ are each hydrogen, a linear or branched alkyl group having 1 to 20 carbon atoms, an aromatic group, an alicyclic group, a glycidyl ether group, One of the substituents (2Y).

  N in the substituent (2Y) is an integer of 0 to 5, and is not particularly limited, but n is preferably 0. When n is 0, the silyl group is directly bonded to the polycyclic ring via a silicon-carbon bond, so that both the thermal decomposability of the temporary fixing agent and the mechanical properties during processing of the substrate can be achieved.

  The structural unit represented by the general formula (1Y) is not particularly limited, but norbornene, 5-methylnorbornene, 5-ethylnorbornene, 5-propylnorbornene, 5-butylnorbornene, 5-pentylnorbornene, 5 -Hexyl norbornene, 5-heptyl norbornene, 5-octyl norbornene, 5-nonyl norbornene, 5-decyl norbornene, 5-phenethyl norbornene, 5-triethoxysilyl norbornene, 5-trimethylsilyl norbornene, 5-trimethoxysilyl norbornene, 5 It can be obtained by polymerizing norbornene-based monomers such as methyldimethoxysisilylnorbornene, 5-dimethylmethoxynorbornene, and 5-glycidyloxymethylnorbornene.

  When the norbornene monomer is polymerized, it may be polymerized with a single norbornene monomer or a plurality of norbornene monomers. Among these norbornene-based monomers, 5-butylnorbornene, 5-decylnorbornene, 5-phenethylnorbornene, 5-triethoxysilylnorbornene, and 5-glycidyloxy are excellent in mechanical properties when the substrate and the supporting substrate are temporarily fixed. Methylnorbornene is preferred.

  The norbornene-based resin is not particularly limited, and may be formed of a single structural unit represented by the general formula (1Y) or may be formed of a plurality of structural units.

  More specifically, the norbornene-based resin is polynorbornene, polymethylnorbornene, polyethylnorbornene, polypropylnorbornene, polybutylnorbornene, polypentylnorbornene, polyhexylnorbornene, polyheptylnorbornene, polyoctylnorbornene, polynonyl. Single polymer such as norbornene, polydecyl norbornene, polyphenethyl norbornene, polytriethoxysilyl norbornene, polytrimethylsilyl norbornene, polytrimethoxysilyl norbornene, polymethyldimethoxysisilyl norbornene, polydimethylmethoxynorbornene, polyglycidyloxymethyl norbornene, norbornene -Triethoxysilyl norbornene copolymer, norbornene-glycidyloxymethyl ester Borene copolymer, butylnorbornene-triethoxysilylnorbornene copolymer, decylnorbornene-triethoxysilylnorbornene copolymer, butylnorbornene-glycidyloxymethylnorbornene copolymer, decylnorbornene-glycidyloxymethylnorbornene copolymer, decyl Examples thereof include copolymers such as norbornene-butylnorbornene-phenethylnorbornene-glycidyloxymethylnorbornene copolymer.

  Among these, polybutylnorbornene, polydecylnorbornene, polytriethoxysilylnorbornene, polyglycidyloxymethylnorbornene-butylnorbornene-triethoxysilylnorbornene copolymer having excellent mechanical properties when the substrate and the supporting substrate are temporarily fixed Polymer, decylnorbornene-triethoxysilylnorbornene copolymer, butylnorbornene-glycidyloxymethylnorbornene copolymer, decylnorbornene-glycidyloxymethylnorbornene copolymer, decylnorbornene-butylnorbornene-phenethylnorbornene-glycidyloxymethylnorbornene copolymer Coalescence is preferred.

  The norbornene-based resin having the structural unit represented by the general formula (1Y) is not particularly limited, but ring-opening metathesis polymerization (hereinafter also referred to as ROMP), a combination of ROMP and hydrogenation reaction. It can be synthesized by polymerization with radicals or cations.

  More specifically, the norbornene-based resin having the structural unit represented by the general formula (1Y) is obtained by using, for example, a catalyst containing a palladium ion source, a catalyst containing nickel and platinum, a radical initiator, or the like. Can be synthesized.

  Moreover, it is preferable to mix | blend the resin component in the ratio of 10 wt%-100 wt% of the whole quantity which comprises a resin composition (when a solvent is included, the whole quantity except a solvent). More preferably, it is blended at a ratio of 50 wt% or more, particularly 80 wt% to 100 wt%. By making it 10 wt% or more, particularly 80 wt% or more, there is an effect that the residue after thermally decomposing the temporary fixing agent can be reduced. Moreover, there exists an effect that a temporary fixing agent can be thermally decomposed in a short time by increasing the resin component in a resin composition.

  The resin components as described above are classified into those in which the temperature for thermal decomposition decreases in the presence of an acid or a base and those in which the temperature for thermal decomposition does not decrease.

  Specifically, examples of the resin component that lowers the thermal decomposition temperature in the presence of an acid or base include, for example, polycarbonate resins, polyester resins, polyamide resins, polyether resins, polyurethane resins, (meth) An acrylate resin etc. are mentioned, Among these, it can use combining 1 type (s) or 2 or more types. Among these, it is preferable to use a polycarbonate-based resin from the viewpoint that a decrease in the temperature for thermal decomposition is more remarkably recognized. In particular, polypropylene carbonate, 1,4-polybutylene carbonate, 1,3-polycyclohexane carbonate / A polynorbornene carbonate copolymer is preferred.

  In addition, examples of the resin component that does not decrease the thermal decomposition temperature in the presence of an acid or a base include norbornene-based resins and polyolefin-based resins, and one or more of these are used in combination. be able to.

  Therefore, when a resin component whose thermal decomposition temperature is reduced in the presence of an acid or a base is selected, an acid or a base is generated in the resin composition by irradiation with active energy rays on the temporary fixing agent. By setting it as the structure containing an activator, the temperature which thermally decomposes a resin component by irradiation of the active energy ray to a temporary fixing agent shall fall.

  Therefore, the temporary fixing agent (resin composition) contains a resin component whose temperature for thermal decomposition is reduced and an active agent that generates an acid or a base by irradiation of active energy rays to the temporary fixing agent. Because the temperature at which the resin component is thermally decomposed by irradiation with active energy rays decreases, the temporary fixing agent after heating with active energy rays can be more easily detached from the supporting substrate. An effect is obtained.

  When the resin component is selected so that the temperature at which pyrolysis does not decrease in the presence of an acid or base, the acid or base is added to the resin composition by irradiation with active energy rays. Even if the generated activator is added, naturally, the temperature at which the resin component is thermally decomposed does not change even when the temporary fixing agent is irradiated with active energy rays.

  Hereinafter, the activator contained in the resin composition will be described when a resin component having a reduced thermal decomposition temperature in the presence of an acid or a base is selected.

(Active agent)
As described above, the activator generates an active species such as an acid or a base when energy is applied by irradiation with an active energy ray, and the action of the active species causes thermal decomposition of the resin component. It has a function to lower the temperature.

  The activator is not particularly limited, and examples thereof include a photoacid generator that generates an acid upon irradiation with active energy rays, and a photobase generator that generates a base upon irradiation with active energy rays.

  The photoacid generator is not particularly limited, and examples thereof include tetrakis (pentafluorophenyl) borate-4-methylphenyl [4- (1-methylethyl) phenyl] iodonium (DPI-TPFPB), tris (4-t- Butylphenyl) sulfonium tetrakis- (pentafluorophenyl) borate (TTBPS-TPFPB), tris (4-t-butylphenyl) sulfonium hexafluorophosphate (TTBPS-HFP), triphenylsulfonium triflate (TPS-Tf), bis ( 4-tert-butylphenyl) iodonium triflate (DTBPI-Tf), triazine (TAZ-101), triphenylsulfonium hexafluoroantimonate (TPS-103), triphenylsulfonium bis (par Fluoromethanesulfonyl) imide (TPS-N1), di- (pt-butyl) phenyliodonium, bis (perfluoromethanesulfonyl) imide (DTBPI-N1), triphenylsulfonium, tris (perfluoromethanesulfonyl) methide ( TPS-C1), di- (pt-butylphenyl) iodonium tris (perfluoromethanesulfonyl) methide (DTBPI-C1), and the like, and one or a combination of two or more of these can be used. . Among these, tetrakis (pentafluorophenyl) borate-4-methylphenyl [4- (1-methylethyl) phenyl] iodonium (DPI-), particularly from the viewpoint that the melt viscosity of the resin component can be efficiently lowered. TPFPB) is preferred.

  The photobase generator is not particularly limited, and examples thereof include 5-benzyl-1,5-diazabicyclo (4.3.0) nonane, 1- (2-nitrobenzoylcarbamoyl) imidazole, and the like. 1 type or 2 types or more can be used in combination. Among these, 5-benzyl-1,5-diazabicyclo (4.3.0) nonane and derivatives thereof are particularly preferable from the viewpoint that the melt viscosity of the resin component can be efficiently lowered.

  The activator is preferably about 0.01 to 50% by weight, and more preferably about 0.1 to 30% by weight, based on the total amount of the resin composition (temporary fixing agent). By setting it within such a range, it becomes possible to stably lower the melt viscosity of the resin component within the target range.

  By irradiating active energy rays by adding such an activator, an active species such as an acid or a base is generated, and the action of the active species lowers the thermal decomposition temperature of the main chain of the resin component. It is inferred that a structure is formed, and as a result, the temperature at which the resin component is thermally decomposed decreases.

Here, the mechanism by which the thermal decomposition temperature is lowered when a polypropylene carbonate resin, which is a polycarbonate resin, is used as the resin component and a photoacid generator is used as the activator will be described. As shown by the following formula (1Z), first, H ⁺ derived from the photoacid generator protonates the carbonyl oxygen of the polypropylene carbonate resin, and further transitions the polar transition state to an unstable tautomeric intermediate [A ] And [B]. Next, the thermal decomposition temperature of the intermediate [A] is lowered because fragmentation as acetone and CO ₂ occurs. Further, the intermediate [B] generates propylene carbonate, and propylene carbonate forms a thermal ring-closing structure that is fragmented as CO ₂ and propylene oxide, so that the thermal decomposition temperature is lowered.

(Sensitizer)
Further, when the temporary fixing agent contains an active agent, it may contain a sensitizer that is a component having a function of expressing or increasing the reactivity of the active agent with respect to an active energy ray of a specific wavelength together with the active agent. good.

  The sensitizer is not particularly limited. For example, anthracene, phenanthrene, chrysene, benzpyrene, fluoranthene, rubrene, pyrene, xanthone, indanthrene, thioxanthen-9-one, 2-isopropyl-9H- Examples include thioxanthen-9-one, 4-isopropyl-9H-thioxanthen-9-one, 1-chloro-4-propoxythioxanthone, and mixtures thereof.

  The content of such a sensitizer is preferably 100 parts by weight or less with respect to 100 parts by weight of the total amount of the activator such as the photoacid generator and the photo radical initiator, and is 20 parts by weight or less. More preferably.

  In the resin composition as described above, the resin component may be any of those whose thermal decomposition temperature decreases in the presence of an acid or a base and those whose thermal decomposition temperature does not decrease. Other components as shown may be included.

(Antioxidant)
That is, the resin composition (temporary fixing agent) may contain an antioxidant.

  This antioxidant has a function of preventing acid generation and natural oxidation in the resin composition (temporary fixing agent).

  The antioxidant is not particularly limited. For example, “Ciba IRGANOX (registered trademark) 1076” and “Ciba IRGAFOS (registered trademark) 168” manufactured by Ciba Fine Chemicals are preferably used.

  Other antioxidants include, for example, “Ciba Irganox 129”, “Ciba Irganox 1330”, “Ciba Irganox 1010”, “Ciba Cyanox (registered trademark) 1790”, “Ciba Irganox 3114 C” Can also be used.

  The content of the antioxidant is preferably 0.1 to 10 parts by weight, and more preferably 0.5 to 5 parts by weight with respect to 100 parts by weight of the resin component described above.

(Additive)
Moreover, the resin composition (temporary fixing agent) may contain additives such as acid scavengers, acrylic, silicone, fluorine, and vinyl leveling agents, silane coupling agents, and diluents as necessary. .

  The silane coupling agent is not particularly limited. For example, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, 3-glycidoxypropyltriethoxysilane, p -Styryltrimethoxysilane, 3-methacryloxypropylmethyldimethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-methacryloxypropylmethyldiethoxysilane, 3-methacryloxypropyltriethoxysilane, 3-acryloxypropyltrimethoxy Silane, N-2- (aminoethyl) -3-aminopropylmethyldimethoxysilane, N-2- (aminoethyl) -3-aminopropyltrimethoxysilane, N-2- (aminoethyl) -3-aminopropyltri Ethoxysilane 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, N-phenyl-3-aminopropyltrimethoxysilane, 3-mercaptopropylmethyldimethoxysilane, 3-mercaptopropyltrimethoxysilane, bis (triethoxypropyl) Examples thereof include tetrasulfide and 3-isocyanatopropyltriethoxysilane, and among these, one kind or two or more kinds can be used in combination.

  By including a silane coupling agent in the resin composition (temporary fixing agent), it is possible to improve the adhesion between the base material and the support base material.

  The diluent is not particularly limited, and examples thereof include cycloether compounds such as cyclohexene oxide and α-pinene oxide, aromatic cycloethers such as [methylenebis (4,1-phenyleneoxymethylene)] bisoxirane, 1, Examples thereof include cycloaliphatic vinyl ether compounds such as 4-cyclohexanedimethanol divinyl ether, and one or more of these can be used in combination.

  When the resin composition (temporary fixing agent) contains a diluent, the fluidity of the temporary fixing agent can be improved, and the wettability of the temporary fixing agent with respect to the support base material is improved in the sacrificial layer forming step described later. It becomes possible.

(solvent)
Moreover, the resin composition (temporary fixing agent) may contain a solvent.

  By setting the resin composition to include a solvent, it is possible to easily adjust the viscosity and the like of the resin composition.

  The solvent is not particularly limited. For example, hydrocarbons such as mesitylene, decalin, and mineral spirits, aromatic hydrocarbons such as toluene, xylene, and trimethylbenzene, anisole, propylene glycol monomethyl ether, Alcohols / ethers such as propylene glycol methyl ether, diethylene glycol monoethyl ether, diglyme, ethylene carbonate, ethyl acetate, N-butyl acetate, ethyl lactate, ethyl 3-ethoxypropionate, propylene glycol monomethyl ether acetate, diethylene glycol monoethyl ether acetate , Esters / lactones such as propylene carbonate and γ-butyrolactone, keto such as cyclopentanone, cyclohexanone, methyl isobutyl ketone, 2-heptanone S, N- methyl-2-amide / lactam such as pyrrolidone, and the like, can be used singly or in combination of two or more of them. Thereby, it becomes easy to adjust the viscosity of the temporary fixing agent, and it becomes easy to form a sacrificial layer (thin film) composed of the temporary fixing agent on the support base material.

  Although content of the said solvent is not specifically limited, It is preferable that it is 5-98 weight% with respect to the whole quantity of a resin composition (temporary fixing agent), and it is more preferable that it is 10-95 weight%.

<Method for Manufacturing Semiconductor Device>
The temporary fixing agent as described above is applied to a method for manufacturing a semiconductor device, for example.

  That is, the substrate processing method of the present invention using a temporary fixing agent is applied to the processing of a semiconductor wafer in the method for manufacturing a semiconductor device.

Hereinafter, an example of the embodiment of the processing method of the substrate of the present invention will be described.
The processing method of this semiconductor wafer (base material) includes a semiconductor wafer having irregularities on one surface, a support base material that supports the semiconductor wafer when processing the other surface of the semiconductor wafer, and the above-described temporary fixing agent. And a first fixing layer (first thin film) is formed on one surface of the support substrate by supplying a temporary fixing agent using a spin coating method and then drying. A second step of forming a second sacrificial layer (second thin film) by supplying a temporary fixing agent to one surface of the semiconductor wafer by spin coating and then drying the first sacrificial layer; And the second sacrificial layer are brought into contact with each other, a third step of bonding the semiconductor wafer and the support base, a fourth step of processing the other surface of the semiconductor wafer, and the first and second steps The sacrificial layer is heated to thermally decompose the resin component, thereby supporting the semiconductor wafer. And a fifth step of detaching from the substrate.

  FIG. 1 is a longitudinal sectional view for explaining a processing step of processing a semiconductor wafer to which the substrate processing method of the present invention is applied. In the following description, in FIG. 1, the upper side is “upper” and the lower side is “lower”.

Hereinafter, each of these steps will be described sequentially.
(Preparation process)
First, a support base material 1, a semiconductor wafer (base material) 3, and a temporary fixing agent are prepared (first step).

  Although it will not specifically limit as the support base material 1 if it has the intensity | strength which can support the base material 3, It is preferable that it has a light transmittance. As a result, when a resin component whose thermal decomposition temperature is lowered by irradiation with active energy rays is used as the resin component, the active energy rays are transmitted from the support base material 1 side, and the first sacrificial layer 21 and the first sacrificial layer 21 The active energy rays can be reliably irradiated to the two sacrificial layers 22.

  As the support substrate 1 having optical transparency, for example, glass materials such as quartz glass and soda glass, and resin materials such as polyethylene terephthalate, polyethylene naphthalate, polypropylene, cycloolefin polymer, polyamide, and polycarbonate are mainly used. The board | substrate comprised as a material is mentioned.

  In addition, on the lower surface (one surface) of the semiconductor wafer 3, conductive portions such as wirings, terminals, and bumps made of a conductive material are formed. That is, the lower surface of the semiconductor wafer 3 constitutes a functional surface 31. Due to the presence of the conductive portion, the semiconductor wafer 3 has irregularities on the lower surface side.

  As the temporary fixing agent, in this step, the viscosity (25 ° C.) is preferably adjusted to be about 500 to 100,000 mPa · s, and adjusted to be about 1,000 to 50,000 mPa · s. More preferably, it is more preferable to adjust so that it may become about 2,000-40,000 mPa * s. Since such a temporary fixing agent has an appropriate viscosity, it is easy to handle and has excellent coating properties. Therefore, the first sacrificial layer 21 and the second sacrificial layer 22 can be easily and reliably formed.

  The viscosity (25 ° C.) can be measured by using an E-type viscometer (manufactured by Toki Sangyo Co., Ltd., viscometer TVE-22 type) at a cone temperature of 25 ° C. after 3 minutes.

(Sacrificial layer formation process)
Next, as shown in FIG. 1 (a), the temporary fixing agent is supplied to the upper surface (one surface) of the support substrate 1 by using a spin coating method, and then dried by heating to be a first sacrifice. The layer 21 is formed, and the functional surface (lower surface) 31 of the semiconductor wafer 3 is supplied with a temporary fixing agent using a spin coat method and then heated to be dried to form the second sacrificial layer 22 (first). Step 2; see FIG.

  Here, the rotation speed of the support base 1 and the semiconductor wafer 3 for supplying the temporary fixing agent is preferably set to about 300 to 4,000 rpm, more preferably about 500 to 3,500 rpm, More preferably, it is set to about 600 to 3,000 rpm. By setting the number of rotations of the support substrate 1 and the semiconductor wafer 3, the first sacrificial layer 21 and the second sacrificial layer 22 having a uniform thickness can be formed relatively easily. In particular, if the temporary fixing agent is adjusted to the above-described viscosity, the thickness uniformity (flatness) of the first sacrificial layer 21 and the second sacrificial layer 22 can be improved.

  Further, when the viscosity (25 ° C.) of the temporary fixing agent is A [mPa · s] and the rotation speed of the support base 1 and the semiconductor wafer 3 is B [rpm], A / B is 0.13 to 330. It is preferable that it is, and it is more preferable that it is 0.5-100. Thereby, the first sacrificial layer 21 and the second sacrificial layer 22 can be formed with a particularly uniform thickness.

  Further, the TMA (Thermal Mechanical Analysis) softening point of the formed first sacrificial layer 21 and second sacrificial layer 22 is not particularly limited, but is preferably less than 200 ° C., and is about 50 to 180 ° C. Is more preferable. Thereby, in the next process (bonding process), when heated, at least the surface can be brought into a molten state.

  The TMA softening point is measured by a thermomechanical measurement device (TMA), and the temperature of the measurement object is increased while applying a constant load at a constant temperature increase rate, and the phase of the measurement object is determined. It is obtained by observation. In this specification, the temperature at which the phase of the first sacrificial layer 21 and the second sacrificial layer 22 starts to change is defined as the TMA softening point. Specifically, the TMA softening point is, for example, a thermomechanical measurement. Quartz glass with a load of 10 g and 1 mmφ when the measurement temperature range is 25 to 250 ° C. and the rate of temperature rise is 5 ° C./min using a device (manufactured by T.A. Instruments, “Q400EM”). It can be determined by measuring the temperature at which the phase begins to change when applied to a pin (needle).

  The first sacrificial layer 21 and the second sacrificial layer 22 are preferably formed so that the total average thickness is about 50 to 100 μm, and about 70 to 90 μm. More preferably, it is formed. If the first sacrificial layer 21 and the second sacrificial layer 22 are formed with such a thickness, the first sacrificial layer 21 and the second sacrificial layer 22 function as a buffer material in a later processing step. It can prevent more reliably that the electroconductive part of the functional surface 31 is damaged.

(Lamination process)
Next, as shown in FIG. 1C, the semiconductor wafer 3 is placed on the support base 1 so that the first sacrificial layer 21 and the second sacrificial layer 22 are in contact with each other. Then, the semiconductor wafer 3 is bonded to the support substrate 1 via the first sacrificial layer 21 and the second sacrificial layer 22 by thermocompression bonding (third step).

  Bonding by thermocompression bonding can be easily performed using, for example, an apparatus such as a vacuum press machine or a wafer bonder.

  Here, if a sacrificial layer is formed only on the support base material 1 side and the semiconductor wafer 3 is bonded to the support base material 1 through this sacrificial layer, wirings and terminals existing on the functional surface 31 of the semiconductor wafer 3 will be described. In some cases, the distance between the support substrate 1 and the semiconductor wafer 3 cannot be kept constant due to variations in the height of the conductive portions such as bumps. In this case, the entire upper surface of the semiconductor wafer 3 cannot be processed uniformly in the next step. That is, the processing accuracy of the semiconductor wafer 3 decreases.

  In this case, a gap remains in the portion corresponding to the gap between the convex portions of the conductive portion between the semiconductor wafer 3 and the sacrificial layer, and the semiconductor wafer 3 is heated during the next process. The air (void) in the gap expands, and the semiconductor wafer 3 is tilted with respect to the support base 1, so that the processing accuracy of the semiconductor wafer 3 is further reduced.

  In order to avoid such a problem, the sacrificial layer may be filled in the gap between the convex portions of the conductive portion (concave concave portion), but the depth of the concave portion, the hardness of the sacrificial layer (flexibility) In some cases, the sacrificial layer cannot be sufficiently filled in the gap. In this case, when the semiconductor wafer 3 is heated at the time of the next process, the air in the gap expands, and the processing accuracy of the semiconductor wafer 3 is also lowered.

  Further, in order to reliably fill the sacrificial layer in the gap, in this step, it is conceivable to heat the sacrificial layer until it melts, but depending on the melting point of the resin component in the sacrificial layer, the sacrificial layer may be heated to a high temperature. It is necessary to heat with. In this case, the conductive portion formed on the functional surface 31 of the semiconductor wafer 3 is also exposed to a high temperature, and the function may be deteriorated.

  On the other hand, when the sacrificial layer is formed only on the semiconductor wafer 3, if the height of the convex portion of the conductive portion (depth of the concave portion) is large, the gap between the convex portions of the conductive portion (concave concave portion), The sacrificial layer cannot be sufficiently filled, resulting in the same problem as described above.

  In contrast, in the present invention, the first sacrificial layer 21 and the second sacrificial layer 22 are formed on the support base material 1 and the semiconductor wafer 3, respectively, and the semiconductor wafer 3 is bonded to the support base material 1. The above-described problems can be avoided.

  For example, when the height of the convex portion of the conductive portion (depth of the concave portion) is large, a part of the wiring of the conductive portion may be exposed from the second sacrificial layer 22. The depth of the gap is small enough to be sufficiently filled with the first sacrificial layer 21.

  In addition, from the viewpoint of reliably filling the gap with the first sacrificial layer 21, the first sacrificial layer 21 may be heated. However, since the depth of the gap is extremely small, Heating to such an extent that it softens. That is, it is sufficient to heat the first sacrificial layer 21 at a low temperature. For this reason, the conductive part formed on the functional surface 31 of the semiconductor wafer 3 is not exposed to a high temperature and the function thereof is not deteriorated.

  Since the first sacrificial layer 21 and the second sacrificial layer 22 formed by the spin coating method have high thickness uniformity (flatness), the support substrate 1, the semiconductor wafer 3, The distance can be kept constant. Thereby, in the next step, the entire upper surface of the semiconductor wafer 3 can be processed uniformly. That is, the semiconductor wafer 3 can be processed with high processing accuracy.

  Further, when a sacrificial layer is formed only on one of the support base 1 and the semiconductor wafer 3 and the support base 1 and the semiconductor wafer 3 are bonded together, the resin component in the sacrificial layer and the sacrificial layer are bonded. Since the supporting base material 1 or the constituent material of the semiconductor wafer 3 to be made is a different material, strong bonding cannot be expected between them.

  In contrast, in the present invention, the first sacrificial layer 21 and the second sacrificial layer are formed by forming the first sacrificial layer 21 on the support substrate 1 and the second sacrificial layer 22 on the semiconductor wafer 3, respectively. 22 is joined. Since the resin component in the first sacrificial layer 21 and the resin component in the second sacrificial layer 22 are the same or the same material, the bonding between them becomes extremely strong. From this point of view, the semiconductor wafer 3 can be processed with high processing accuracy.

  Here, in the state where the first sacrificial layer 21 and the second sacrificial layer 22 are interposed, the pressure when the semiconductor wafer 3 and the support base 1 are pressed in a direction approaching each other is not particularly limited. The pressure is preferably about 0.01 to 3 MPa, and more preferably about 0.05 to 2 MPa.

  At this time, the temperature for heating the first sacrificial layer 21 and the second sacrificial layer 22 is not particularly limited, but is preferably about 100 to 300 ° C., more preferably about 120 to 250 ° C. preferable. According to the present invention, this step can be performed at such a relatively low temperature, and the deterioration of the conductive portion formed on the functional surface 31 of the semiconductor wafer 3 due to heat, that is, the deterioration of the function is prevented or suppressed. be able to.

  Furthermore, although the time to pressurize and heat is not specifically limited, It is preferable that it is about 0.1 to 10 minutes, and it is more preferable that it is about 0.5 to 5 minutes.

  In the case where the TMA softening points of the first sacrificial layer 21 and the second sacrificial layer 22 are within the range described in the sacrificial layer forming step, the first sacrificial layer is subjected to the first sacrificial condition and the pressure condition and the temperature condition described above. By thermocompression bonding the layer 21 and the second sacrificial layer 22, the bonding between the semiconductor wafer 3 and the support base 1 through the first sacrificial layer 21 and the second sacrificial layer 22 can be performed with higher accuracy. Can be done.

(Processing process)
Next, the surface (back surface) opposite to the functional surface 31 of the semiconductor wafer 3 fixed on the support substrate 1 through the sacrificial layer 2 is processed (fourth step).

  The processing of the semiconductor wafer 3 is not particularly limited. For example, in addition to grinding and polishing the back surface of the semiconductor wafer 3 as shown in FIG. 1D, for forming a via hole in the semiconductor wafer 3 and for stress release. Examples include etching of the upper surface (back surface) of the semiconductor wafer 3, lithography, and coating and vapor deposition of a thin film on the back surface of the semiconductor wafer 3.

  Here, in the present invention, as described in the sacrificial layer forming step and the bonding step, the first sacrificial layer 21 and the second sacrificial layer 22 are formed with a uniform film thickness. The semiconductor wafer 3 is bonded to the support base material 1 via the first sacrificial layer 21 and the second sacrificial layer 22 in a state in which the distance 3 and the support base material 1 are maintained at a constant interval. Therefore, grinding and polishing of the upper surface (back surface) of the semiconductor wafer 3 can be performed without causing variations in the thickness.

(Desorption process)
Next, as shown in FIG. 1E, the first sacrificial layer 21 and the first sacrificial layer 21 and After the second sacrificial layer 22 is melted or vaporized, the semiconductor wafer 3 is detached from the support substrate 1 (fifth step).

  The temperature at which the sacrificial layer 2 is heated is set to a temperature at which the resin component is thermally decomposed, and a temperature at which the deterioration / deterioration of the semiconductor wafer 3 is prevented. Specifically, the temperature is preferably about 100 to 500 ° C. Preferably, it is set to about 120 to 450 ° C.

  Here, in this specification, desorption means an operation of peeling the semiconductor wafer 3 from the support substrate 1, and the case where the first sacrificial layer 21 and the second sacrificial layer 22 are in a molten state. Regardless of vaporization, for example, this operation may be performed by detaching the semiconductor wafer 3 in a direction perpendicular to the surface of the support substrate 1 or by sliding the semiconductor wafer 3 in the horizontal direction relative to the surface of the support substrate 1. Examples include a method of detaching the semiconductor wafer 3 and a method of detaching the semiconductor wafer 3 by lifting it from the support base 1 from one end side of the semiconductor wafer 3 as shown in FIG.

  When the first sacrificial layer 21 and the second sacrificial layer 22 are vaporized through the heating step, the first sacrificial layer 21 is interposed between the semiconductor wafer 3 and the support base 1. Further, since the second sacrificial layer 22 is removed, the semiconductor wafer 3 can be detached from the support base 1 more easily.

(Washing process)
Next, in the desorption step, the first sacrificial layer 21 and the second sacrificial layer 22 are heated by being heated, and the first sacrificial layer 21 and the second sacrificial layer 22 are melted or vaporized. If part of the first sacrificial layer 21 and the second sacrificial layer 22 remains, the first sacrificial layer 21 and the second sacrificial layer 21 remaining on the functional surface 31 of the semiconductor wafer 3 as necessary. The sacrificial layer 22 is cleaned.

  That is, the residues of the first sacrificial layer 21 and the second sacrificial layer 22 remaining on the functional surface 31 are removed.

  A method for removing this residue is not particularly limited, and examples thereof include plasma treatment, chemical immersion treatment, polishing treatment, and heat treatment.

As described above, the upper surface (back surface) of the semiconductor wafer 3 is processed.
In addition, when the resin components contained in the first and second sacrificial layers (resin compositions) 21 and 22 are those whose thermal decomposition temperature is lowered by irradiation with active energy rays, the desorption is performed. Prior to heating the first sacrificial layer 21 and the second sacrificial layer 22 in the process, the following active energy ray irradiation process may be performed.

(Active energy ray irradiation process)
In this step, the first sacrificial layer 21 and the second sacrificial layer 22 are irradiated with active energy rays.

  Here, in the case where the resin component has a temperature at which thermal decomposition occurs due to irradiation with active energy rays, the temperature at which thermal decomposition occurs in the presence of an acid or a base in the resin composition decreases. The resin component and an activator that generates an acid or a base upon irradiation with an active energy ray on the temporary fixing agent are included. Therefore, when energy is imparted to the active agent contained in the temporary fixing agent (resin composition), active species such as acid or base are generated from the active agent. The temperature for thermal decomposition decreases.

  Therefore, before the first sacrificial layer 21 and the second sacrificial layer 22 are heated, the first sacrificial layer 21 and the second sacrificial layer 22 are irradiated with active energy rays, so that the first sacrificial layer 21 and the second sacrificial layer 22 are irradiated. Since the heating temperature and the heating time for heating the sacrificial layer 21 and the second sacrificial layer 22 can be reduced or shortened, this heating can be performed under more relaxed conditions. As a result, alteration / deterioration due to heating of the semiconductor wafer 3 can be suppressed or prevented more accurately.

  Moreover, it is although it does not specifically limit as an active energy ray, For example, it is preferable that it is a light ray with a wavelength of about 200-800 nm, and it is more preferable that it is a light ray with a wavelength of about 300-500 nm.

Further, the irradiation amount of the active energy ray is not particularly ^limited, but is preferably ^{10mj / cm 2 ~20000mj / cm 2} , and more preferably ^{20mj / cm 2 ~10000mj / cm 2} .

  In the above embodiment, the case where the first sacrificial layer 21 and the second sacrificial layer 22 are formed using the same temporary fixing agent has been described. However, different temporary fixing agents may be used.

  In this case, for example, if a material having a lower viscosity is used as the temporary fixing agent for forming the second sacrificial layer 22, the second sacrificial layer 22 is formed in the gaps between the wirings of the conductive parts (uneven recesses). More reliable filling is possible.

  In this embodiment, the case where the semiconductor wafer 3 is used as the base material has been described as an example. However, the present invention is not limited to this, and for example, a wiring board, a circuit board, or the like can be used.

  As mentioned above, although the processing method of the base material of this invention was demonstrated based on embodiment of illustration, this invention is not limited to these.

For example, each constituent material contained in the temporary fixing agent can be replaced with an arbitrary material that can exhibit the same function, or an arbitrary material can be added.
Moreover, the arbitrary process may be added to the processing method of the base material of this invention as needed.

Next, specific examples of the present invention will be described.
1. Preparation of temporary fixing agents First, temporary fixing agents A and B as shown below were prepared.

[Temporary fixative A]
<Synthesis of 1,3-polycyclohexane carbonate resin / endo-polynorbornene carbonate resin>
1,3-cyclohexanediol 30.43 g (0.262 mol), 2,3-norbornanedimethanol 23.02 g (0.147 mol), diphenyl carbonate 84.63 g (0.395 mol), lithium carbonate 0.0163 g (0.0021 mol) was placed in a reaction vessel. As the first step of the reaction, the reaction vessel was immersed in a heating tank heated to 120 ° C. under a nitrogen atmosphere, stirred, the raw materials were dissolved, and stirring was continued for 2 hours. As the second step of the reaction, the pressure inside the reaction vessel was reduced to 10 kPa, and stirring was continued at 120 ° C. for 1 hour. As the third step of the reaction, the pressure inside the reaction vessel was reduced to 0.5 kPa or less, and stirring was continued at 120 ° C. for 1.5 hours. As a fourth step of the reaction, the temperature of the heating tank was raised to 180 ° C. over about 30 minutes while the pressure in the reaction vessel was reduced to 0.5 kPa or less, and stirring was continued at 180 ° C. for 1 hour. The phenol produced in the second to fourth steps of the reaction was distilled out of the reaction vessel.

  After returning the pressure in the reaction vessel to normal pressure, 600 ml of tetrahydrofuran was added to dissolve the product. In a state where 6.0 L of a mixed solution of isopropanol / water = 9/1 (v / v) was stirred, a solution in which the product was dissolved was dropped. The deposited precipitate was collected by suction filtration, and the collected precipitate was washed with 3.0 L of a mixed solution of isopropanol / water = 9/1 (v / v), and then collected by suction filtration.

  The recovered precipitate was dried with a vacuum dryer at 60 ° C. for 18 hours to obtain 49.27 g of polycarbonate powder.

  When the weight average molecular weight of the synthesized 1,3-polycyclohexane carbonate resin / endo-polynorbornene carbonate resin was measured by GPC, it was 48,600.

<Preparation of temporary fixative>
100 g of the obtained 1,3-polycyclohexane carbonate resin / endo-polynorbornene carbonate resin, 5 g of Rhodorsil Photoinitiator 2074 (FABA) (Rhodiasil Photoinitiator 2074) manufactured by Rhodia Japan Co., Ltd., and 1-chloro-4 as a sensitizer -1.5 g of propoxythioxanthone (SPEEDCURE CPTX (trade name) manufactured by Lambson UK) was dissolved in 200 g of γ-butyrolactone (solvent) to prepare a temporary fixing agent having a resin concentration of 33%.

  The boiling point X of γ-butyrolactone is 204 ° C., the SP value is 12.6, and the temperature at which 1,3-polycyclohexane carbonate resin / endo-polynorbornene carbonate resin is thermally decomposed is 293 ° C.

[Temporary fixative B]
<Synthesis of 5-decylnorbornene polymer>
Ethyl acetate (430 g), cyclohexane (890 g) and 5-decylnorbornene (223 g, 0.95 mol) were introduced into the reaction vessel, and dry nitrogen was passed through the system at 40 ° C. for 30 minutes to remove dissolved oxygen. A solution prepared by dissolving 1.33 g (0.275 mmol) of bis (toluene) bis (perfluorophenyl) nickel in 12 g of ethyl acetate was added to the reaction system, and the above system was added at 20 ° C. to 35 ° C. over 15 minutes. Then, the system was stirred for 3 hours while maintaining the temperature.

  After cooling the system to room temperature, 26 g of glacial acetic acid was dissolved in about 1500 g of pure water to which 49 g of 30% hydrogen peroxide was added, and this was added to the reaction system, and the reaction system was stirred at 50 ° C. for 5 hours. After that, stirring was stopped and the separated aqueous layer was removed. The remaining organic layer was washed by adding, stirring, and removing a mixture of 220 g of methanol and 220 g of isopropyl alcohol. Furthermore, after adding 510 g of cyclohexane and 290 g of ethyl acetate to the system and dissolving uniformly, another 156 g of methanol and 167 g of isopropyl alcohol are mixed and washed by adding to stirring to removing, Repeated twice.

  180 mL of cyclohexane was added to the washed organic layer to uniformly dissolve the system, and 670 g of mesitylene was further added. Then, the cyclohexane was removed by evaporation under reduced pressure using a rotary evaporator to obtain a resin composition C having a yield of 543 g (35% mesitylene solution).

  When the weight average molecular weight of the synthesized 5-decylnorbornene polymer was measured by GPC, it was 177,000.

<Preparation of temporary fixative>
100 g of the obtained 5-decylnorbornene polymer was dissolved in 200 g of trimethylbenzene (solvent) to prepare a temporary fixing agent having a resin concentration of 30%.

  The boiling point X of trimethylbenzene is 165 ° C., the SP value is 18.0, and the temperature at which decylnorbornene is thermally decomposed is 425 ° C.

2. Backside processing of semiconductor wafer (Example 1)
<1> First, using a spin coater, the temporary fixing agent A was applied to 8-inch transparent glass (rotation speed: 800 rpm, time: 60 seconds), and then on a hot plate at 120 ° C. for 5 minutes. Pre-baking was performed to form a thin film made of temporary fixing agent A having a thickness of 50 μm.

  Also, using a spin coater, the temporary fixing agent A was applied to the functional surface of an 8 inch silicon wafer (725 μm thick) (rotation speed: 1000 rpm, time: 60 seconds), and then on a hot plate at 120 ° C. for 5 minutes. Pre-baking was performed under the conditions described above to form a thin film made of the temporary fixing agent A having a thickness of 30 μm.

<2> Next, an 8-inch silicon wafer (725 μm thickness) was temporarily fixed to 8-inch transparent glass via two thin films using a substrate bonder (model number SB-8e, manufactured by SUSS MICROTECH) ( (Atmosphere: 10 ⁻² mbar, temperature: 210 ° C., load: 10 kN, time: 5 minutes).

<3> Next, with respect to the silicon wafer temporarily fixed to the transparent glass, the upper surface (back surface) of the semiconductor wafer is ground using a grinding apparatus (“DFG8540” manufactured by DISCO), and the thickness of the semiconductor wafer is determined. It processed so that it might become 145 micrometers.

<4> Next, the temperature at which the temporary fixing agent A was thermally decomposed was lowered by irradiating the ^two thin films with ultraviolet rays (active energy rays) having a wavelength of 365 nm for 1,000 mj / cm ² .

<5> Next, a sample in which an 8-inch silicon wafer was temporarily fixed on an 8-inch transparent glass was put into an oven, heat treatment was performed at a predetermined temperature and time, and the temporary fixing agent A was thermally decomposed. This thermal decomposition was performed by heat treatment at 320 ° C. for 30 minutes.

<6> Next, the pyrolyzed sample was taken out of the oven, tweezers were put in the gap between the 8-inch transparent glass and the 8-inch silicon wafer, and the 8-inch silicon wafer was detached.

(Example 2)
Example 1 except that the temporary fixing agent B was used, the step <4> was omitted, and the thermal decomposition was performed at 450 ° C. for 120 minutes in the step <5>. Similarly, the back surface processing of the semiconductor wafer was performed.

(Comparative Example 1)
The back surface of the semiconductor wafer was processed in the same manner as in Example 1 except that the temporary fixing agent A was applied only to the transparent glass side to form a thin film.

(Comparative Example 2)
The back surface of the semiconductor wafer was processed in the same manner as in Example 1 except that the temporary fixing agent A was applied only to the silicon wafer side to form a thin film.

(Comparative Example 3)
The back surface processing of the semiconductor wafer was performed in the same manner as in Example 2 except that the temporary fixing agent B was applied only to the transparent glass side to form a thin film.

(Comparative Example 4)
The back surface of the semiconductor wafer was processed in the same manner as in Example 2 except that the temporary fixing agent B was applied only to the silicon wafer side to form a thin film.

3. Result It turned out that Example 1 and 2 have few variations in the thickness of a semiconductor wafer compared with Comparative Examples 1-4, and are excellent in the processing precision of back surface processing.

DESCRIPTION OF SYMBOLS 1 Support base material 21 1st sacrificial layer 22 2nd sacrificial layer 2 Sacrificial layer 3 Semiconductor wafer 31 Functional surface

Claims (14)

A base material having irregularities on one surface, a support base material that supports the base material when processing the other surface of the base material, and a resin component that melts or vaporizes by being thermally decomposed by heating A first step of preparing a temporary fixing agent composed of a resin composition;
The temporary fixing agent is supplied to one surface of the supporting base material using a spin coating method and then dried to form a first thin film, and the temporary fixing agent is formed on the one surface of the base material. A second step of forming a second thin film by supplying the material using a spin coating method and then drying;
A third step of bonding the base material and the support base material by bringing the first thin film and the second thin film into contact with each other;
A fourth step of processing the other surface of the substrate;
A fifth step of heating the first and second thin films and thermally decomposing the resin component to desorb the base material from the support base material. Method.   The base material processing method according to claim 1, wherein the base material includes a conductive portion on the one surface, and the unevenness is formed on the one surface due to the presence of the conductive portion.   The substrate processing method according to claim 1 or 2, wherein in the first step, the viscosity (25 ° C) of the temporary fixing agent is adjusted to 500 to 100,000 mPa · s.   The base material processing method according to any one of claims 1 to 3, wherein in the second step, the number of revolutions of the base material to which the temporary fixing agent is supplied and the support base material is set to 300 to 4,000 rpm.   5. The substrate processing method according to claim 1, wherein, in the second step, the first and second thin films are formed to have a total average thickness of 50 to 100 μm. .   The substrate processing method according to claim 1, wherein, in the second step, the first and second thin films having a TMA softening point of less than 200 ° C. are formed.   2. In the third step, pressurization is performed at a pressure of 0.01 to 3 MPa in a direction in which the base material and the support base material approach each other in a state where the first and second thin films are in contact with each other. The processing method of the base material in any one of 5 thru | or 5.   The substrate processing method according to any one of claims 1 to 7, wherein in the third step, the first and second thin films are heated at a temperature of 100 to 300 ° C.   The substrate processing method according to claim 8, wherein the time for heating the first and second thin films is 0.1 to 10 minutes.   The resin component is one in which the thermal decomposition temperature is lowered by irradiation of the temporary fixing agent with active energy rays. Prior to the fifth step, the active energy rays are converted into the first and second active energy rays. The method for processing a substrate according to claim 1, wherein the thin film is irradiated.   The resin component is such that the temperature at which the thermal decomposition occurs in the presence of an acid or a base decreases, and the resin composition further contains an activator that generates an acid or a base upon irradiation with the active energy ray. Item 11. A method for processing a substrate according to Item 10.   The substrate processing method according to claim 10, wherein the resin component is a polycarbonate-based resin.   The method for processing a substrate according to any one of claims 1 to 9, wherein the resin component does not lower the temperature at which the thermal decomposition is caused by irradiation of the temporary fixing agent with active energy rays.   The substrate processing method according to claim 13, wherein the resin component is a norbornene-based resin.

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