JP2013140826A - Peeling method and peeling solution - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce residue of an adhesive when a support plate stuck to a substrate with the adhesive is peeled.SOLUTION: A peeling method for peeling a support plate from a laminate comprising the support plate and a substrate which are stuck with an adhesive comprises: a dissolution step of bringing a peeling solution into contact with an adhesive to dissolve the adhesive, the peeling solution being obtained by adding a surfactant in a solvent for the peeling solution; a peeling step of peeling the support plate from the laminate; and a cleaning step of cleaning the substrate after the peeling step using water or lower alcohol.

Description

  The present invention relates to a peeling method for peeling a support plate from a laminate in which a support plate and a substrate are bonded with an adhesive, and a stripping solution used for the peeling method.

  In recent years, with the enhancement of functions of mobile phones, digital AV devices, IC cards, and the like, there is an increasing demand for miniaturization, thinning, and high integration of semiconductor silicon chips. For example, system-in-package (SiP), in which multiple semiconductor chips are mounted in a single semiconductor package, makes the mounted chip smaller, thinner and more integrated, and electronic devices have higher performance and smaller size. In addition, it has become a very important technology for realizing weight reduction. In order to meet such demands for thinning and high integration, not only conventional wire bonding technology but also through electrode technology that stacks chips with through electrodes and forms bumps on the back of the chip I need it.

  By the way, in the manufacture of semiconductor chips, the semiconductor wafer itself is thin and fragile, and the circuit pattern has irregularities, so that it is easily damaged when an external force is applied during conveyance to the grinding process or dicing process. Therefore, a wafer handling system has been developed that maintains the strength of the wafer and prevents the occurrence of cracks and warping of the wafer by bonding a plate made of glass, hard plastic, or the like, to the wafer to be ground. . Since the wafer strength can be maintained by the wafer handling system, the transport of the thinned semiconductor wafer can be automated.

  The wafer and the support plate are bonded together using an adhesive tape, a thermoplastic resin, an adhesive, or the like. After thinning the wafer to which the support plate is attached, the support plate is peeled off before dicing the wafer, and the support plate is removed from the wafer. For example, when the wafer and the support plate are bonded together using a dissolution type adhesive, the adhesive was dissolved using propylene glycol monomethyl ether acetate (hereinafter referred to as “PGMEA”) as a stripping solution. Thereafter, the support plate is peeled off and removed from the wafer (Patent Document 1).

JP 2007-119646 A (published May 17, 2007)

  However, the conventional peeling method using a peeling solution has a problem that the solubility of the peeling solution in the adhesive is not sufficient. In the case where a stripping solution having insufficient solubility is used for the adhesive formed to temporarily fix the wafer and the support plate in the wafer handling system, an adhesive residue is generated on the wafer. Residues after peeling cause problems such as deterioration of electrical characteristics and yield of manufactured chips.

  Then, this invention is made | formed in view of said problem, The objective is to provide the peeling method of the support plate which reduced the residue of the adhesive agent.

  In order to solve the above-described problem, the peeling method according to the present invention comprises a support plate provided with a support plate provided with a through-hole penetrating in the thickness direction and a substrate, and the support plate. In the peeling method for removing the adhesive, a peeling solution in which a surfactant is added to the solvent for the peeling solution is brought into contact with the adhesive via the through-hole to dissolve the adhesive, and the dissolution It is the structure including the peeling process which peels the said support plate from the said laminated body after a process, and the washing | cleaning process which wash | cleans the said board | substrate after the said peeling process using water or a lower alcohol.

  The stripping solution according to the present invention is a stripping solution that dissolves an adhesive that adheres a support plate to a substrate, and has a configuration in which a nonionic surfactant is added to a hydrocarbon solvent.

  As described above, in the peeling method according to the present invention, the adhesive is dissolved using the peeling liquid to which the surfactant is added, and the substrate is cleaned using water or lower alcohol. Thereby, the residue of the adhesive agent after a support plate peeling can be reduced.

  An embodiment of the present invention will be described as follows.

  If the peeling method of this invention is used for the use which peels the said support plate from the laminated body by which a support plate and a board | substrate are stuck by the adhesive agent, the specific use will not be specifically limited. . In the present embodiment, a case where the support plate (support plate) temporarily attached to the wafer (substrate) with an adhesive is removed from the wafer will be described as an example for the wafer support system.

  In this specification, the “support plate” is used to temporarily protect a semiconductor wafer thinned by grinding so as not to be cracked or warped by being bonded to the semiconductor wafer when the semiconductor wafer is ground. It is a support plate used in general.

  The stripping method according to the present invention comprises a stripping solution in which a surfactant is added to a stripping solution solvent, contacting the adhesive through the through holes of the support plate, and dissolving the adhesive. After the process, a peeling process for peeling the support plate from the laminated body and a cleaning process for cleaning the wafer after the peeling process with water or lower alcohol are included.

[Dissolution process]
In the melting step, the peeling liquid is injected from the through hole of the support plate, and the peeling liquid is brought into contact with the adhesive to dissolve the adhesive. The stripping solution used in the dissolving step is obtained by adding a surfactant to a stripping solution solvent.

(Peeling solvent)
Examples of the solvent for the stripping solution include hydrocarbon solvents and the like, and may be appropriately determined according to the composition of the adhesive to be dissolved. For example, when the support plate is attached to the wafer using an adhesive having a hydrocarbon resin as an adhesive component, a hydrocarbon solvent is suitably used as the solvent for the stripping solution.

  Examples of the hydrocarbon constituting the hydrocarbon solvent include terpene hydrocarbon, naphthene hydrocarbon, aliphatic hydrocarbon, and isoparaffin hydrocarbon. Alternatively, examples of the hydrocarbon constituting the hydrocarbon solvent include linear, branched or cyclic hydrocarbons, and condensed polycyclic hydrocarbons.

  Examples of the linear, branched, or cyclic hydrocarbon include linear hydrocarbons such as hexane, heptane, octane, nonane, methyloctane, decane, undecane, dodecane, and tridecane, and branched chains having 3 to 15 carbon atoms. Hydrocarbon, cyclohexane, p-menthane, o-menthane, m-menthane, d-limonene, diphenylmentane, α-terpinene, β-terpinene, γ-terpinene, 1,4-terpine, 1,8-terpine, Examples thereof include cyclic hydrocarbons such as bornane, norbornane, pinane, α-pinene, β-pinene, tujang, α-tujon, β-tujon, caran and longifolene.

  In addition, the condensed polycyclic hydrocarbon is a condensed ring hydrocarbon in which two or more monocycles supply only one side of each ring to each other, and is a carbon that is formed by condensing two monocycles. It is preferable to use hydrogen. Such hydrocarbons include combinations of 5-membered and 6-membered rings, or combinations of two 6-membered rings. Examples of the hydrocarbon in which a 5-membered ring and a 6-membered ring are combined include indene, pentalene, indane, tetrahydroindene and the like. Examples of the hydrocarbon in which two 6-membered rings are combined include naphthalene, tetrahydronaphthalene (tetralin), decahydronaphthalene (decalin), and the like.

  These hydrocarbons may be used alone or in combination of two or more.

(Surfactant)
The surfactant is not particularly limited as long as it is soluble in the stripping solution solvent, and any of nonionic surfactants, cationic surfactants, anionic surfactants, and amphoteric surfactants are used. It can be determined appropriately depending on the type of the solvent for the stripping solution to be used. For example, when a hydrocarbon solvent is used as the solvent for the stripping solution, a nonionic surfactant is preferably used.

  Examples of nonionic surfactants include acetylene glycol surfactants, polyoxyethylene alkyl ethers, polyoxyethylene alkyl phenyl ethers, polyoxyethylene alkyl esters, polyoxyethylene sorbitan fatty acid esters, and the like. Of these, acetylene glycol surfactants and polyoxyethylene alkyl ethers are preferred.

  The acetylene glycol surfactant is available as a commercial product, and examples thereof include Surfinol series manufactured by Air Products and Chemicals (USA). Specifically, Surfinol 104E, Surfinol 420, Surfinol 440, Surfinol 465, Surfinol 485, etc. are mentioned.

  Polyoxyethylene alkyl ethers are available as commercial products, such as Neugen series manufactured by Daiichi Kogyo Seiyaku, Softal series manufactured by Nippon Shokubai Co., Ltd., and Fine Surf Series manufactured by Aoki Yushi Kogyo Co., Ltd. It is done. Specifically, Neugen XL-40, Neugen XL-80, Neugen TDS-50, Neugen TDS-70, Softanol 30, Softanol 50, Softanol 70, Softanol 90, Fine Surf TD-70, Fine Surf TD-75, Fine Surf TD-80 etc. are mentioned.

  Although the surfactant can be used as a stripping solution even if it is not completely dissolved in the stripping solution solvent, the surfactant is preferably completely dissolved in the stripping solution solvent. From such a viewpoint, when a hydrocarbon solvent is used as the solvent for the stripping solution, the HLB (Hydrophile-Lyophile-balance) of the surfactant is preferably 20 or less, and more preferably 15 or less. preferable. In addition, in this specification, HLB is a numerical value obtained by ((molecular weight of hydrophilic portion / total molecular weight) × 100) / 5, and a smaller numerical value indicates lipophilicity.

  The content of the surfactant in the stripping solution is preferably added at a rate of 0.01 to 10% by weight, preferably 0.1 to 5% by weight, based on the solvent for the stripping solution. It is more preferable that it is added at a ratio of 0.5 to 1% by weight. By making the addition amount of the surfactant within the above range, the adhesive residue reducing effect is improved.

  The stripping solution may contain other components as long as the effects of the present invention are not impaired.

  A conventionally known technique can be used as a specific means for injecting the stripping solution from the through hole of the support plate and bringing the stripping solution into contact with the adhesive.

[Peeling process]
In the peeling step, the support plate is peeled off from the laminate in which the adhesive is dissolved in the melting step, and the support plate is removed from the wafer. The method for peeling the support plate from the laminate in which the adhesive is dissolved is not particularly limited, and can be performed by a conventionally known method.

[Washing process]
In the cleaning process, the surface of the wafer from which the support plate has been removed in the peeling process is cleaned using water or lower alcohol. In the present specification, the lower alcohol is intended to be a chain alcohol having 1 to 5 carbon atoms. Specific examples include methanol, ethanol, propanol, isopropanol, n-butanol, isobutanol, and t-butanol. Among them, it is preferable to use water or isopropanol, and it is particularly preferable to use water. These may be used alone or in combination of two or more.

  In the cleaning step, prior to cleaning with water or lower alcohol, the surface of the wafer from which the support plate has been removed in the peeling step is preferably cleaned with a stripping solution. Thereby, dissolution of the adhesive can be made more reliable, and the generated residue can be reduced. The stripping solution used for cleaning is preferably a stripping solution having the same composition as the stripping solution used in the above-described dissolution step, but is not limited thereto.

  The specific method of cleaning using water or lower alcohol and the specific method of cleaning using stripping solution are not particularly limited. For example, the cleaning solution (water, lower alcohol, or stripping solution) is rotated on the semiconductor wafer. Thus, a spin cleaning method in which the surface is coated on the surface, or an immersion cleaning method in which the semiconductor wafer is immersed in the cleaning liquid as it is can be used.

  In addition, when washing is performed using water, in order to efficiently dry after washing, washing with water may be further performed after washing with water.

  As described above, in the peeling method according to the present invention, the adhesive is dissolved using the peeling liquid to which the surfactant is added, and the substrate is cleaned using water or lower alcohol. Thereby, the residue of the adhesive after support plate peeling can be reduced.

  Moreover, as shown in the Example mentioned later, the peeling liquid formed by adding a nonionic surfactant to the hydrocarbon solvent is suitably used in the peeling method according to the present invention. Accordingly, a stripping solution obtained by adding a nonionic surfactant to a hydrocarbon solvent is also included in the scope of the present invention.

  Examples will be shown below, and the embodiments of the present invention will be described in more detail. Of course, the present invention is not limited to the following examples, and it goes without saying that various aspects are possible in detail. Further, the present invention is not limited to the above-described embodiments, and various modifications can be made within the scope shown in the claims, and the present invention is also applied to the embodiments obtained by appropriately combining the disclosed technical means. It is included in the technical scope of the invention. Moreover, all the literatures described in this specification are used as reference.

(Preparation of adhesive composition)
A cycloolefin copolymer obtained by copolymerizing norbornene and ethylene (“TOPAS (trade name) 8007” manufactured by Polyplastics Co., Ltd.), norbornene: ethylene = 65: 35 (weight ratio), weight average molecular weight: 98,200, Mw / Mn : 1.69) was dissolved in p-menthane to a concentration of 25% by weight. 5 parts by weight of “IRGANOX (trade name) 1010” manufactured by BASF as an antioxidant was added to 100 parts by weight of this solution to obtain an adhesive composition.

(Production of laminate)
An adhesive layer was formed on a semiconductor wafer by spin-coating the above-mentioned adhesive composition in an amount of 15 μm after baking and baking at 100 ° C., 160 ° C. and 220 ° C. for 3 minutes each. Next, a porous glass support was bonded to the adhesive layer at 215 ° C. to prepare a laminate.

(Preparation of stripping solution)
p-Mentane (manufactured by Yasuhara Chemical Co., Ltd.), Neugen XL-40 (trade name, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.), Neugen XL-80 (trade name, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.), Softanol 30 (trade name, manufactured by Nippon Shokubai Co., Ltd.) or Surfynol 420 (trade name, manufactured by Air Products and Chemicals Co., Ltd.) was added at a ratio of 1% by weight to prepare a stripping solution.

(Removal of support)
The prepared laminate was subjected to predetermined processes such as wafer thinning and a photolithography process, and then the above-described peeling solution was injected from the holes of the hole glass support to dissolve the adhesive layer. After dissolution of the adhesive layer, the perforated glass support was peeled off and removed from the semiconductor wafer.

(Washing the substrate)
After peeling the porous glass support, the surface of the semiconductor wafer from which the porous glass support was removed was spin-washed with the above-described peeling liquid, and then spin-washed (rinsed) with pure water (Examples 1 to 1). 4). As a comparative example, after removing the hole glass support and removing it from the semiconductor wafer, the surface of the semiconductor wafer from which the hole glass support was removed was only subjected to spin cleaning using the above-described release liquid. Spin cleaning (rinsing) using pure water was not performed.

(Evaluation of detergency)
The presence or absence of residues on the cleaned semiconductor wafer surface was confirmed by a microscope. If there is a residue, the residue portion is irregularly reflected by high-intensity light emitted from the microscope and appears white. When a residue was found, the detergency was evaluated as “x”, and when no residue was found, the detergency was evaluated as “◯”. The results are shown in Table 1.

  As shown in Table 1, the adhesive residue was eliminated by rinsing the surface of the wafer with pure water after dissolving the adhesive using a peeling solution in which a surfactant was added to p-menthane. I was able to.

  The present invention can be used to separate temporarily bonded laminates used in the manufacture of various products. In particular, it can be suitably used in a manufacturing process in which a semiconductor wafer or chip is temporarily fixed to various supports and processed.

Claims (8)

In a peeling method for peeling the support plate from a laminate in which a support plate and a substrate provided with through-holes penetrating in the thickness direction are adhered by an adhesive,
A dissolving step of dissolving the adhesive by bringing a release solution in which a surfactant is added to the solvent for the peeling solution into contact with the adhesive through the through-hole;
After the melting step, a peeling step for peeling the support plate from the laminate,
And a washing step of washing the substrate after the peeling step with water or lower alcohol.   2. The peeling method according to claim 1, wherein the surfactant is added at a ratio of 0.01 to 10 wt% with respect to the solvent for the stripping solution.   In the said washing | cleaning process, it wash | cleans using water, The peeling method of Claim 1 or 2 characterized by the above-mentioned.   4. The peeling method according to claim 1, wherein, in the cleaning step, the substrate is cleaned with the stripping solution prior to cleaning with water or a lower alcohol.   The stripping method according to any one of claims 1 to 4, wherein the stripping solution solvent is a hydrocarbon solvent.   The peeling method according to claim 1, wherein the surfactant is a nonionic surfactant. A stripping solution for dissolving an adhesive that adheres a support plate to a substrate,
A stripping solution obtained by adding a nonionic surfactant to a hydrocarbon solvent.   The stripping solution according to claim 7, wherein the nonionic surfactant is added at a ratio of 0.01 to 10% by weight with respect to the hydrocarbon solvent.