JP2014150201A - Bonding method of substrate and semiconductor substrate, and balloon experimental substrate depressing device used therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To manufacture a bonding substrate which does not cause displacement between substrates when performing a grinding process on a laminated substrate obtained by bonding two substrates with a water film.SOLUTION: A bonding method of a substrate wand a substrate wcomprises: depressing a top face of a bonded substrate w in which two substrates w, wwhich are fixed to ceramic chucks are bonded by water, with a flexible rubber film 19 of a balloon experimental substrate depressing device 1 which is provided above the bonded substrate and had a flexible rubber film 19 as a substrate holding surface and which can move upward and downward in a vertical direction thereby discharging excess water from between the substrates and adjusting a surface tension of a water film wto be a value which does not cause displacement between the substrates.

Description

  In the present invention, two substrates are bonded and bonded together with a water film, the back surface of the bonded substrate is ground (including polishing) to reduce the thickness of the substrate, and then the bonded substrate is separated from the bonded surface. In addition, the present invention relates to a method for bonding two substrates used for recovery as two substrates, and a balloon inflatable substrate pressing device used for carrying out the method.

  After bonding the two substrates and grinding the back and front and back surfaces of the bonded substrate (including polishing) to reduce the thickness of the substrate, the bonded substrate is separated from the bonded surface and recovered as two substrates. How to do is known. For example, Japanese Patent Laid-Open No. 6-762 (Patent Document 1) discloses that two substrates such as a semiconductor substrate, a dielectric substrate, and a glass substrate are brought into parallel contact with each other in water in a water tank, and are further pressed to provide an extra bonding surface. After removing moisture and strengthening the bonding of both substrates with the surface tension of water, this bonded substrate is taken out of the water tank and inserted into the carrier of the double-side polishing apparatus, and then the front and back surfaces of the bonded substrate are polished. After polishing, a method is disclosed in which the bonded substrate for polishing is again put into the water in the water tank to reduce the surface tension, and the two substrates are shifted in parallel and separated into two polishing substrates.

  In addition, the wiring printed surface of a semiconductor substrate with a printed wiring surface on the surface of a silicon substrate is applied to a template substrate (bare silicon substrate, glass substrate, sapphire substrate, engineer plastic substrate, etc.) as a water-soluble adhesive layer or a heating foam adhesive. After laminating through the layers, this bonded substrate is fixed on the vacuum chuck, and then the silicon substrate of the semiconductor substrate using a tool (cup wheel type grindstone, polishing pad) of a single wafer grinder (including a grinder) After flattening processing to reduce the thickness of the surface, the flattened bonded substrate is poured into water, and the water-soluble adhesive is dissolved in water to separate the thinned semiconductor substrate and dummy substrate Or a thinned semiconductor substrate by heating or flattening the bonded substrate to heat or irradiate the electron beam to thermally decompose the foamed adhesive. Being implemented in a semiconductor substrate processing manufacturers also be separated in the template substrate and.

On the other hand, a balloon-expandable substrate carrier or a transport pad for holding a substrate that can be moved up and down using a flexible rubber film as a substrate holding surface has been put into practical use. For example, as for the former, Japanese Patent Laid-Open No. 2001-105305 (Patent Document 2) discloses that a substrate held by a carrier is placed on a polishing cloth surface affixed to a surface plate supported by a rotating drive shaft. A substrate carrier head structure of a polishing apparatus that polishes the surface of a substrate by further pressing and rubbing the substrate and a polishing cloth, wherein the carrier head structure is a bowl-shaped main body supported by a hollow spindle shaft, A diaphragm made of a flexible material fixed in the horizontal direction at the lower end of the main body, a gas passage in the vertical direction is provided in the center fixed to the diaphragm, and formed through the gas passage on the lower surface. A rigid support plate having a recess, means for supplying and discharging the gas in the gas passage, means for supplying gas to a pressurizing chamber formed by the inside of the bowl-shaped main body and the upper surface side of the diaphragm, the rigid body A flexible membrane was attached to the lower surface of the holding plate so that a highly confidential space with a clearance of 0.1 to 0.3 mm was formed between the rigid support plate and the flexible membrane. A substrate carrier part, an annular holding ring that protrudes from the lower surface of the flexible film and is attached to the lower outer periphery of the rigid support plate; and a side wall of the annular holding ring and the lower surface of the flexible film. There is disclosed a head structure of a substrate carrier in a polishing apparatus, comprising a formed substrate storage pocket portion. In addition, Japanese Patent Application No. 2012-263594 (Patent Document 3) discloses an elastic resin foam sheet intermediate layer (192) on the back surface of a polyorganosiloxane-based silicone resin adhesive layer (191), and an elastic resin foam sheet intermediate. A disc-shaped flexible laminate (19) having a flexible rubber film substrate layer (193) bonded to the back surface of the layer is used, and a polyorganosiloxane-based silicone resin adhesion layer (191) of the disc-shaped flexible laminate is used. The annular groove (191c) having a groove width of 0.5 to 2 mm which is divided into a circular area (191a) for holding the substrate and an annular polyorganosiloxane silicone resin adhesion layer area (191b) for adhering the annular holding ring. Of the disc-shaped flexible laminate (19) provided with the polyorganosiloxane-based silicone resin adhesion layer (191) and the elastic resin foam sheet intermediate layer (192). A backing material in which an annular retaining ring (22) is bonded to a cyclic polyorganosiloxane-based silicone resin adhesion layer region (191b), wherein the polyorganosiloxane-based silicone resin circular adhesion layer (191a) has a substrate carrier region portion (4). A backing material in which a substrate storage pocket portion (4a) is formed in a space formed by the inner side wall of the annular retaining ring (22) and the lower surface of the polyorganosiloxane-based silicone resin circular adhesion layer (191a). The disc-shaped flexible laminate (19) has a polyorganosiloxane-based silicone resin adhesion layer (191a, 191b) adhered to the polyorganosiloxane-based silicone resin circular adhesion layer (191a) and a poly surface. Peel strength with organosiloxane silicone resin adhesion layer (JIS K-6854 Compliant) is 10mN / 12.7
It is a polyorganosiloxane silicone resin adhesion layer (191) having a width of mm or less and a shear force of 1.0 N / cm ² or more for shifting the substrate in parallel from the surface of the polyorganosiloxane silicone resin circular adhesion layer (191a). A backing material (BM) for a carrier head structure of a polishing apparatus and a carrier head structure of a substrate using the same are disclosed (see FIG. 2).

For the latter, Japanese Patent Application Laid-Open No. 2012-204709 (Patent Document 4) discloses that the lower surface of the rigid arm 3 made of a non-breathable material having a fluid passage 3b in the longitudinal direction portion of the handle has a circular arc-shaped recess. A pad holding substrate 2 having a rigid waffle slab structure made of a non-breathable material having a fluid passage hole is supported, and an adhesive layer 19b is formed on the surface of the flexible rubber film 19a via an adhesive S on an annular lower surface of the pad holding substrate. A substrate holding pad 19 having a laminated structure in which the surface of the flexible rubber film is attached so that the surface of the flexible rubber film is on the adhesive side, and a cross-sectional arc-shaped recess 2c on the lower surface of the pad holding substrate is formed in the fluid chamber. A fluid passage 3b provided in the handle 3 of the rigid arm communicates with a fluid passage hole of the pad holding substrate facing the fluid chamber, and a base of the laminated structure is provided by pressurized fluid supplied from the fluid chamber. The holding pad 19 expands and discharges fluid from the fluid chamber, so that the substrate holding pad can be restored to its original shape. The arm structure includes a substrate holding pad for transporting a semiconductor substrate. The adhesion layer 19b formed on the surface of the flexible rubber film of the pad is formed of an adhesion layer selected from a polyorganosiloxane silicone resin layer, an acrylic resin adhesive layer, and a synthetic rubber adhesive layer. The shearing force that the peeling force (conforming to JIS K-6854) between the adhesion layer and the semiconductor substrate is 10 mN / 12.7 mm width or less, and the substrate holding pad holding the semiconductor substrate is shifted in parallel with the semiconductor substrate from the processing stage. Disclosed is an arm structure 1 having a substrate holding pad, wherein the force is 1.0 N / cm ² or more (see FIG. 1).

JP-A-6-762 JP 2001-105305 A Japanese Patent Application No. 2012-263594 JP 2012-204709 A

The method for bonding substrates described in Patent Document 1 has an environmentally friendly advantage of using inexpensive pure water as an adhesive, but since the operation of bonding substrates together is a manual operation, the thickness of the water film to be formed (Water surface tension) is difficult to set, and depending on the type of semiconductor substrate, it becomes a discontinuous water film in which bubbles are mixed in the water film, or the surface tension of the water film between the substrates is large because the continuous water film is thick. It has been found that there is a problem that the upper semiconductor substrate is displaced during the grinding (polishing) processing of the bonded substrate in the next process.

  The latter method of bonding a dummy wafer through a water-soluble adhesive layer or a heat-foaming adhesive layer has the disadvantage that the adhesive is more expensive than pure water, and the adhesive residue remains on the semiconductor substrate surface, resulting in thinning processing. After separating into two substrates, a step of cleaning the semiconductor substrate and removing the residue from the semiconductor substrate surface is required.

  In order to set the strength of the surface tension of the water film between the substrates, the present inventors use the method described in Patent Document 1 that utilizes the surface tension of water for bonding the substrates together. When the excessive water is pressed and the surface tension of the water film is set to a strength at which the two substrates are firmly bonded together, the flexible rubber film described in Patent Document 2 and Patent Document 3 is used as the substrate holding surface. A balloon inflatable substrate carrier that can be moved up and down or a substrate holding transfer pad described in Patent Document 4 is used as a bonding substrate pressing device, and the air pressure supplied to the pressing device is a parameter for setting the surface tension of the water film. As a precondition, the air pressure applied to the upper substrate of the bonded substrate is changed in various ways to check the air pressure threshold at which the substrates do not shift when grinding the bonded substrate, and the substrate bonded with the water film is checked. By supplying the compressed air within the threshold to the pressing device in pressure time, single wafer grinding (polishing) of the bonded substrate in the next step displacement of the substrate during processing it is conceived to be able to prevent.

According to the first aspect of the present invention, the upper surface of the bonded substrate in which the substrate fixed on the work table and the semiconductor substrate are bonded together by the water film is held on the flexible rubber film provided above the bonded substrate. Pressing with a flexible rubber film of a balloon inflatable substrate pressing device that can move up and down in the vertical direction, excess water is discharged from between the substrates, causing the surface tension of the water film between the substrates to shift between the substrates A method for bonding a substrate and a semiconductor substrate to be adjusted to a value not to
The flexible rubber film of the balloon inflatable substrate pressing device is pre-expanded with pressurized air and then lowered to contact the upper surface of the bonded substrate, and the flexible rubber film is further lowered to be flexible. When the entire surface of the adhesive rubber film comes into contact with the entire upper surface of the bonded substrate, the pressurized air having a pressure within a preset threshold is supplied to the balloon inflatable substrate pressing device to finish discharging excess water from between the substrates. The present invention provides a method for bonding a substrate and a semiconductor substrate.

According to a second aspect of the present invention, in the balloon inflatable substrate pressing device according to the first aspect, a polyorganosiloxane-based silicone resin layer, an acrylic resin pressure-sensitive adhesive layer, and a synthetic material are formed on the surface of the flexible rubber film of the substrate holding pad. An adhesion layer selected from the rubber-based adhesive layer is formed, and the peeling force between the adhesion layer and the bonded substrate (conforming to JIS K-6854) is 10 mN / 12.7 mm or less, and the bonded substrate is held. The present invention provides a balloon inflatable substrate pressing device, wherein a shearing force for shifting the substrate holding pad in parallel with the bonded substrate from the substrate bonding processing stage is 1.0 N / cm ² or more.

  Since the surface tension of the continuous water film between the substrates is adjusted by adjusting the air pressure supplied to the balloon inflatable substrate pressing device, the surface tension of the water film between the substrates can be reduced during grinding even if the type of substrate changes. The surface tension can be set so as not to deviate. In addition, when excessive water is discharged from the water film between the substrates to make the thickness of the water film 0.5 to 2.5 mm, the flexible rubber film of the balloon inflatable substrate pressing device is previously pressurized with pressurized air. Threshold value that is set in advance when the lower surface of the bonded substrate is brought into contact with the upper surface of the bonded substrate, and the lower surface of the flexible rubber film is further lowered so that the entire surface of the flexible rubber film contacts the entire upper surface of the bonded substrate. Since the pressurized air at the internal pressure is supplied to the balloon inflatable substrate pressing device and excess water is discharged from between the substrates, no air bubbles remain in the water film.

  The adhesion layer formed on the surface of the flexible rubber film of the balloon inflatable substrate pressing device is in a solid state at room temperature and has a very low adhesive force (peeling force is 10 mN / 12.7 mm width or less). The adhesive layer residue does not remain on the upper surface of the laminated substrate. Further, when the bonded substrate with the surface tension of the water film adjusted is transported to the grinding process stage of the next process, the bonded substrate does not fall off from the adhesion layer. The bonded substrate transported to the work chuck table of the grinding stage is held on the substrate by inflating the flexible rubber film by supplying pressurized air while raising the flexible rubber film of the substrate holding pad. The balloon inflatable substrate pressing device can also be used as a substrate transfer device because it is away from the pad.

FIG. 1 is a process diagram for adjusting the surface tension of a water film between substrates using a balloon inflatable substrate pressing device. FIG. 2 is a front sectional view of a balloon inflatable substrate carrier structure described in Japanese Patent Application No. 2012-263594.

  As shown in FIG. 1, a balloon inflatable substrate pressing apparatus 1 having a substrate holding pad has a lower surface on a rigid arm 3 made of a non-breathable material having a fluid passage 3b in a longitudinal direction portion of a handle 3a. A pad holding substrate 2 having a rigid waffle slab structure made of a non-breathable material having a circular arc-shaped recess 2a and having a fluid passage hole 2b is supported, and an adhesive S is attached to the annular lower surface of the pad holding substrate. A substrate holding pad 19 having a laminated structure in which an adhesive layer 19b is formed on the surface of the flexible rubber film 19a is attached with an adhesive S so that the surface of the flexible rubber film is on the bonding side, and the lower surface of the pad holding substrate Is formed in the fluid chamber 2c, and the fluid passage 3b provided in the handle 3a of the rigid arm communicates with the fluid passage hole 2b of the pad holding substrate facing the fluid chamber 2c.

The bonded substrate w is placed on the first processing stage (porous ceramic chuck table) by the water film. The water film w _m between the bonded substrates is
(I). After the two substrates are brought into parallel contact with each other in the water in the water tank as described in Patent Document 1 and further pressed to eliminate excess moisture on the bonding surface, the bonding between the two substrates is strengthened by the surface tension of the water. The bonded substrate may be formed by removing it from the water tank. (Ii). Upper surface roll coater or die coater first substrate w _b placed on the first processing stage or, Supureko - coater coating pure water using, then this coated surface in a second substrate w _a The water film w _m may be formed by overlapping a certain semiconductor substrate. Or (iii). A water film w _m is formed by bringing the first substrate w _b into contact with a sponge roll coater provided in the middle of transporting the first substrate w _b stored in the substrate storage cassette onto the first processing stage, This may be bonded to a semiconductor substrate. Further, after the first substrate w _b and the second substrate w _a are stored in _a constant temperature and high humidity chamber (absolute humidity is 80% or more) and moisture is attached to the surfaces of both substrates, the two substrates are overlapped. A water film may be formed between the substrates by carrying it out of the constant temperature and humidity chamber and exposing it to cold air.

  Supply pressurized fluid (preferably air) to the fluid chamber 2c on the back side of the substrate holding pad 19 made of a flexible rubber film 19a formed on the surface of the adhesion layer 19b of the balloon inflatable substrate pressing device 1. Then, while the substrate holding pad 19 is expanded, the substrate holding pad 19 is lowered (see FIG. 1b) and brought into contact with the upper surface of the bonded substrate w.

Further, when the substrate holding pad 19 continues to descend and the entire surface of the adhesion layer 19b formed on the surface of the flexible rubber film 19a comes into contact with the entire upper surface of the bonded substrate w, the pressure within a preset threshold value is reached. The pressurized air is supplied to the fluid chamber 2c of the balloon inflatable substrate pressing device 1 to finish discharging excess water in the water film from between the substrates (see FIG. 1c).

  The fluid pressure for supplying the pressurized fluid (preferably air) to the fluid chamber 2c on the back side of the substrate holding pad 19 to expand the substrate holding pad 19 is a pressurized air having a pressure within the threshold value of the latter stage. The pressure may be the same as or less than the fluid pressure. The fluid may be any of air, nitrogen gas, carbon dioxide gas, argon gas, and helium gas, but air is inexpensive and environmentally friendly.

The pressure threshold value of the pressurized fluid supplied to the fluid chamber 2c is an experiment for removing excess water in the water film between the substrates by variously changing the pressure of the pressurized fluid supplied to the fluid chamber 2c in advance, as in the examples described later. Then, the bonded substrate is ground (polished) and selected from the pressure threshold value of the pressurized fluid at the time of manufacturing the bonded substrate w that does not cause a shift between the substrates w _a and w _b . The pressure threshold varies depending on the type and weight of the substrate, but is usually a pressure of 10 to 40 Pa.

  Examples of the film material of the flexible rubber 19a for the substrate holding pad include a rubber substance, a mixture of the rubber substance and a thermoplastic elastomer or an adhesive thermoplastic resin.

  Rubber materials include butyl rubber, chloroprene rubber, silicone rubber, ethylene / propylene / ethylidene norbornene copolymer rubber, ethylene / propylene / butadiene copolymer rubber, ethylene / propylene copolymer rubber, brominated styrene / butadiene / styrene block. Copolymer rubber, Chlorinated styrene / butadiene / styrene block copolymer rubber, Hydrogenated bromostyrene / butadiene / styrene block copolymer rubber, Hydrogenated butadiene / acrylonitrile copolymer rubber, Chlorinated styrene -Hydrogenated butadiene / styrene block copolymer rubber, brominated styrene / isoprene / styrene block copolymer rubber, chlorinated styrene / isoprene / styrene block copolymer rubber, brominated styrene / isopre · Styrene block copolymer hydrogenated product of the rubber, chlorinated styrene-isoprene-styrene block copolymer hydrogenation product of rubber, vinylidene fluoride-ethylene copolymer rubber. These may be cross-linked.

  Examples of thermoplastic elastomers or adhesive thermoplastic resins include ethylene / vinyl acetate copolymer, soft polyvinyl chloride, chlorinated polyethylene, chloro / sulfonated polyethylene, ethylene / acrylic acid copolymer, and ethylene / methyl acrylate. Examples include copolymers, ethylene / ethyl acrylate copolymers, ethylene / methyl acrylate / 2-ethylhexyl acrylate copolymers, and the like.

  In the case of a mixture, the rubber substance is used in a proportion of 10 to 97% by weight, preferably 30 to 85% by weight, and the thermoplastic elastomer or thermoplastic resin in a proportion of 90 to 3% by weight, preferably 70 to 15% by weight. . The rubber material is used for the purpose of spreading the flexible rubber film and returning to the elongation, and the thermoplastic elastomer or the thermoplastic resin is used for the purpose of improving the strength, hardness and heat resistance of the flexible rubber film. When the matrix component of the film containing the rubber substance, elastomer, and resin does not show adhesiveness to the substrate at room temperature (10 to 30 ° C.), process oil, petroleum resin, hydrogenated castor oil, epoxidized soybean oil, 1 to 10 weights of a tackifier such as rosin abietic acid, myrcene / maleinized product, terpene / phenol copolymer, etc. with respect to 100 parts by weight of the total amount of rubber material, thermoplastic elastomer, and thermoplastic resin of the matrix component of the film Part.

As the physical properties of the flexible rubber film 19a, the hardness (JIS K-6301) is 10 to 100,
Preferably 35 to 85, tensile strength (JIS K-6301) is 30 to 200 kgf / cm ² , preferably 50 to 150 kgf / cm ² , tensile elongation (JIS K-6301) is 50 to 1000%, 200 to 800% , Thickness 0.03 to 3 mm, preferably 0.05 to 1.5 m
m.

The adhesion layer 19b in direct contact with the semiconductor substrate is formed of an adhesion layer selected from a polyorganosiloxane-based silicone resin layer, an acrylic resin adhesive layer, and a synthetic rubber-based adhesive layer. The peeling force between the substrates (conforming to JIS K-6854) is 10 mN / 12.7 mm or less, and the shearing force for shifting the substrate holding pad holding the semiconductor substrate in parallel with the semiconductor substrate from the processing stage is 1.0 N / cm ² or more.

  The thickness of the adhesion layer 19b is 5 to 100 μm, preferably 5 to 30 μm. When the adhesive force with the flexible rubber film 19a is lower than 50 gf / 25 mm width or less, a 0.5 to 10 μm layer of adhesive, pressure-sensitive adhesive, or primer is provided on the flexible rubber film 19a. An adhesion layer forming liquid coating agent is applied and dried to form the adhesion layer 19b.

The adhesive layer 19b is a double-sided fixed sheet made of a release paper / adhesive layer / base film / adhesive layer 19b / release paper laminate sold on the market, for example, STD1 of FIXFILM (trade name) series from Fujikopian Corporation. , STD2, HG1, HG2 (adhesion layer single side) grade name, HGW1, HGW2 (adhesion layer both sides), or “Q-Chuck” series (trade name) release paper / polyorgano sold by Maruishi Sangyo Co., Ltd. Siloxane silicone resin adhesive layer, synthetic rubber adhesive layer or acrylic adhesive layer / base film / adhesion layer 19b / release paper laminate or release paper / polyorganosiloxane silicone resin adhesive layer, synthetic rubber adhesive Purchase the adhesive layer or acrylic adhesive layer / adhesion layer 19b / release paper laminate and peel the release paper It may be used after that.

  As the material for the adhesion layer 19b, in addition to the materials such as the rubber materials, thermoplastic elastomers, and thermoplastic resins described above, a polyorganosiloxane-based silicone resin layer, a polymerized rosin ester-containing acrylic resin pressure-sensitive adhesive layer, and a liquid epoxy resin Petroleum resin, terpene / phenol copolymer, alloocimene / terpene / phenol copolymer, hydrogenated maleic acid modified alloocimene, maleic acid modified myrcene hydrogenated product, liquid rubber such as rubber, liquid butadiene rubber and silicone rubber Adhesives such as adhesives such as ethylene / vinyl acetate copolymer and lubricants such as poly (tetrafluoroethylene), melamine, isocyanuric acid, melamine isocyanurate double salt, talc, and fillers such as calcium carbonate and kaolin clay Adhesion selected from a synthetic rubber adhesive layer with reduced strength There can be used. By adjusting the blending amount of the lubricant or filler, the type of acrylate monomer to be used, and the copolymerization molar ratio, the value of the peeling force from the held material (semiconductor substrate) can be adjusted.

  The polyorganosiloxane-based silicone resin material for the adhesion layer is composed of a silicone composed of linear polyorganosiloxane having vinyl groups only at both ends and a linear polyorganosiloxane having vinyl groups at both ends and side chains. Copolymerizing at least one silicone selected from silicone, a silicone composed of a branched polyorganosiloxane having a vinyl group only at the terminal, and a silicone composed of a branched polyorganosiloxane having a vinyl group at the terminal and side chains; A polyorganosiloxane-based silicone resin obtained by crosslinking can be used.

  As the cross-linking agent, organohydropolyene polysiloxane is preferred.

  As the crosslinking accelerator, 3-methyl-1-buten-3-ol is preferable.

Examples of platinum-based catalysts used for the crosslinking reaction include chloroplatinic acid such as chloroplatinic acid and chloroplatinic acid, alcohol compounds of chloroplatinic acid, aldehyde compounds, and chain salts of chloroplatinic acid and various olefins. It is done. The polyorganosiloxane-based silicone resin obtained by the crosslinking reaction has a flexibility such as a silicone gel, and this flexibility makes it easy to adhere to the bonded substrate w as the adherend.

  The adhesion layer formed from this polyorganosiloxane-based silicone resin has an Asker FP hardness of 25 or more and an Asker CSC2 hardness of 80 or less.

  As the material for the rigid arm 3 and the handle 3a, aluminum, polyacetal resin, glass fiber reinforced epoxy resin, PEEK and the like are suitable because they are lightweight.

The substrate w _a is the holding material, the template substrate (bare silicon substrate, a glass substrate, silicon nitride substrate, silicon carbide substrate, a sapphire substrate, a ceramic chuck substrate, brass chuck substrate, polycarbonate resin substrate, etc.), wiring on the surface Examples thereof include a semiconductor substrate on which printing has been performed. As the semiconductor substrate w _b, a semiconductor substrate, TSV substrate, SOI substrate, the sensor substrate, the inkjet electronic wiring substrate, solar cell substrates, and the like

Example 1
A glass substrate (w _a ) having _a diameter of 320 mm and a thickness of 2 mm, and two semiconductor substrates (w _b ) having a diameter of 775 μm and a silicon substrate surface with a printed wiring provided on a surface of 300 mm in diameter are brought into contact in parallel in water in a water bath, and A bonded substrate (w) bonded with a water film (w _m ) by pressing was obtained.

  Next, the bonded substrate w was placed on the first processing stage (a porous ceramic chuck table as a work table) shown in FIG. 1a.

  The pressure shown in Table 1 is applied to the fluid chamber 2c on the back side of the substrate holding pad 19 made of a flexible rubber film 19a formed on the surface of the adhesion layer 19b of the balloon inflatable substrate pressing apparatus 1 shown in FIG. 1a. While the compressed air is supplied to expand the substrate holding pad 19, the substrate holding pad 19 is lowered (see FIG. 1 b) and brought into contact with the upper surface of the bonded substrate w, and further, the substrate holding pad 19 When the entire surface of the adhesion layer 19b formed on the surface of the flexible rubber film 19a comes into contact with the entire upper surface of the bonded substrate w, pressurized air with a pressure within a preset threshold value is applied to the balloon inflatable substrate. Supplying the fluid chamber 2c of the pressing device 1 to discharge excess water from between the substrates was completed (see FIG. 1c).

Table 1 shows values of the surface tension (shearing force) and the thickness of the water film (w _m ) present between the substrates of the obtained bonded substrate w.

Next, after raising the arm 3 to which the substrate holding pad 19 is attached, the arm 3 is pendant-rotated in the horizontal direction, and the single wafer backside grinding apparatus “GNX312B” (trade name) manufactured by Okamoto Machine Tool Co., Ltd. The bonded substrate w is transported to the upper side of the second processing stage (adsorption chuck table), and the substrate holding pad 19 is lowered and expanded at that position to separate the bonded substrate w from the surface of the substrate holding pad 19. Fixed on the aforementioned suction chuck table (FIG. 1d).
reference).

Using the above-described single wafer back surface grinding apparatus, a diamond vitrified cup type grinding wheel with a diameter of 420 mm is used to perform grinding processing for reducing the thickness of the silicon substrate surface of the semiconductor substrate w _b of the bonded substrate w on the suction chuck table by 700 μm. This was carried out while supplying a grinding liquid (pure water) to the silicon substrate surface under the conditions of 150 rpm and 1800 rpm of the cup-type grinding wheel. When the substrate was displaced during the grinding process, the grinding process was stopped at that time.

  Table 1 shows whether or not the substrate has been displaced during grinding.

The bonded substrate w after finishing grinding is put into a water tank, the glass substrate w _a and the semiconductor substrate w _b are naturally separated, the semiconductor substrate w _b is taken out of the water, and the silicon substrate surface of the semiconductor substrate w _b is ground. The machining allowance and surface roughness (Ra) were measured. The results are listed in Table 1.

The threshold value of the pressure of the pressurized air supplied to the fluid chamber 2c of the balloon inflatable substrate pressing device when discharging the excess water w _m between the substrates of the bonded substrate w is 10 to 40 Pa from the values described in Table 1. It can be read as pressure range.

  Since the threshold value varies depending on the type, thickness, and weight of the substrate, an appropriate threshold value is obtained in advance by performing an experiment for determining the threshold value each time the substrate type changes.

  The bonding method using a water film between a substrate and a semiconductor substrate according to the present invention is a water film in which the bonded substrate w is pushed with a substrate holding pad to remove excess moisture from the water film and the substrate does not shift between the substrates It is possible to adjust the pressure of the compressed air supplied to the fluid chamber 2c of the balloon inflatable substrate pressing device used to obtain the shearing force. It is also possible to form a water film on a ceramic chuck (assumed to be a template substrate) stage such as a grinding machine and use this ceramic chuck stage and a semiconductor substrate together, without using a vacuum chuck or the like. Thus, the semiconductor substrate can be ground on the ceramic chuck as the template.

DESCRIPTION OF SYMBOLS 1 Balloon inflatable board | substrate pressing apparatus provided with the board | substrate holding pad 2 Pad holding board | substrate 2a Cross-section circular arc-shaped recessed part 2b Fluid passage hole 2c Fluid chamber 3 Rigid arm 3a Handle 3b Fluid path 19 Substrate holding pad 19a Flexible rubber film 19b adhesion layer S adhesive w bonded substrate _{w a} first substrate _{w b} second substrate (semiconductor substrate)
w _m water film

Claims (2)

The upper surface of the bonded substrate in which the substrate fixed on the work table and the semiconductor substrate are bonded with a water film is moved up and down in the vertical direction using the flexible rubber film provided above the bonded substrate as the substrate holding surface. A substrate that is pressed by a flexible rubber film of a balloon-expandable substrate pressing device capable of discharging excess water from between the substrates and adjusting the surface tension of the water film between the substrates to a value that does not cause a shift between the substrates; A method of bonding with a semiconductor substrate,
The flexible rubber film of the balloon inflatable substrate pressing device is pre-expanded with pressurized air and then lowered to contact the upper surface of the bonded substrate, and the flexible rubber film is further lowered to be flexible. When the entire surface of the adhesive rubber film comes into contact with the entire upper surface of the bonded substrate, the pressurized air having a pressure within a preset threshold is supplied to the balloon inflatable substrate pressing device to finish discharging excess water from between the substrates. A method for bonding a substrate and a semiconductor substrate. 2. The balloon inflatable substrate pressing apparatus according to claim 1, wherein the flexible rubber film surface of the substrate holding pad is selected from a polyorganosiloxane silicone resin layer, an acrylic resin adhesive layer, and a synthetic rubber adhesive layer. The substrate holding pad for holding the bonded substrate is formed with a peeling force (conforming to JIS K-6854) between the adhesive layer and the bonded substrate being 10 mN / 12.7 mm or less. A balloon inflatable substrate pressing apparatus, wherein a shearing force shifted in parallel with a bonded substrate from a bonding stage is 1.0 N / cm ² or more.

Images