JP5511932B2 - Semiconductor wafer processing method - Google Patents

Description

The present invention relates to a processing method for performing processing such as conveyance of a semiconductor wafer and back surface grinding.

   With the recent widespread use of IC cards, semiconductor wafers for manufacturing IC chips, which are constituent members, are being made thinner. It has been demanded to reduce the thickness of a conventional wafer having a thickness of about 350 μm to 50 to 100 μm or less.

   As the wafer that is a brittle member becomes thinner, the risk of breakage increases during processing and transportation. For this reason, when grinding a wafer to an extremely thin thickness or transporting an extremely thin wafer, the wafer is fixed and protected on a hard plate such as a glass plate or an acrylic plate with a double-sided adhesive sheet. It is desirable to proceed.

   However, in the method of laminating the wafer and the hard plate with the double-sided pressure-sensitive adhesive sheet, the wafer may be broken when the both are peeled after the series of steps is finished. When peeling a laminate formed by bonding two thin-layer products, it is necessary to bend one or both of the thin-layer products and to peel them off. However, since it is impossible or difficult to curve the hard plate, the wafer side must be curved. For this reason, a fragile wafer is distorted and cracked.

   As a means for solving such a problem, a method of performing separation while reducing deformation of the wafer as much as possible, a method of performing separation after reinforcing the wafer by laminating a protective film on the wafer, and the like As a means of fixing the wafer to the hard plate, there is a method of using a pressure-sensitive adhesive or double-sided pressure-sensitive adhesive tape whose adhesive force can be controlled, and performing peeling after reducing the adhesive force by an appropriate means such as foaming of the adhesive at the time of peeling. Various proposals have been made (Patent Documents 1 to 5).

   Patent Document 6 discloses a method for protecting a brittle member using a relatively rigid resin film without using a hard plate.

Patent Document 7 discloses a support plate for a semiconductor wafer made of a synthetic resin having a thickness of 0.5 to 3 mm and a thickness variation of 2 μm or less. Examples of the fixing means for the semiconductor wafer include an adhesive tape that generates gas when irradiated with ultraviolet rays.
JP 2004-153227 A JP 2005-116678 A JP 2003-324142 A JP 2005-277037 A International Patent Publication WO2003 / 049164 JP 2004-63678 A JP 2005-333100 A

   When the wafer is held on a hard plate, the wafer side is deformed when the wafer is peeled off. For this reason, it is difficult to completely prevent the wafer from being damaged. In addition, when a special pressure-sensitive adhesive or double-sided pressure-sensitive adhesive tape designed to reduce the adhesive force by foaming or the like is used, the adhesive may remain on the wafer and contaminate the wafer. In the methods proposed in Patent Document 6 and Patent Document 7, the rigid resin film or resin plate side is deformed and peeled from the wafer, so that the problem of wafer breakage in the peeling process can be solved. However, since the support is made of resin, the shape retention is not always sufficient, and the wafer may be damaged when the wafer is transferred. In addition, the resin film or the resin plate has low heat resistance and is likely to be thermally deformed, and cannot be repeatedly used because it plastically deforms even at room temperature. Furthermore, it is difficult to reduce the thickness error, and the thickness error may affect the thickness accuracy of the processed wafer.

   The present invention seeks to solve the problems associated with the prior art as described above. In other words, the present invention can stably hold a semiconductor wafer when performing a predetermined process such as transfer of the semiconductor wafer or processing such as back grinding, and breaks the semiconductor wafer after the required process is completed. It is an object of the present invention to provide a method for processing a semiconductor wafer with high thickness accuracy that can be peeled without any problems.

   The gist of the present invention aimed at solving such problems is as follows.

(1) It has a thickness of 300 to 1000 μm, a compressive stress layer chemically strengthened by ion exchange treatment with one or more ions selected from Na ions and K ions, and a maximum bending angle of 30 degrees or more. A step of removably fixing a semiconductor wafer on a flexible glass substrate;
Processing the semiconductor wafer;
A method for processing a semiconductor wafer, comprising: a step of fixing the semiconductor wafer side by a supporting means; and a step of bending the flexible glass substrate and peeling it from the semiconductor wafer.
(2) The processing method according to (1), wherein the compressive stress layer of the flexible glass substrate is formed by a chemical strengthening process by ion exchange with at least K ions.
(3) The processing method according to (1) or (2), wherein the thickness of the compressive stress layer of the flexible glass substrate is about 100 μm.
(4) The processing method according to any one of (1) to (3), wherein an outer diameter of the flexible glass substrate is equal to or larger than an outer diameter of the semiconductor wafer.
(5) In the peeling step, the end portion of the flexible glass substrate is gripped, and the end portion is lifted from the semiconductor wafer and moved in the folding direction of the flexible glass substrate to be peeled off (1) to (4) The processing method in any one of.
(6) The processing method according to any one of (1) to (5), wherein the processing applied to the semiconductor wafer is backside grinding of the semiconductor wafer.
(7) The processing method according to any one of (1) to (6), wherein the flexible glass substrate contains Na ₂ O or Li ₂ O.
(8) The processing method according to (1), wherein the compressive stress layer of the flexible glass substrate is formed by ion exchange treatment with Na ions and K ions.

  In the present invention, since the semiconductor wafer is fixed and protected on the flexible glass substrate, the brittle member can be held without being deformed during the transportation, storage and processing of the semiconductor wafer, and the semiconductor wafer has high thickness accuracy. Can be applied. In addition, unlike the conventional hard glass plate, the flexible glass substrate used in the present invention can be bent, so that the semiconductor wafer is deformed when the flexible glass substrate is peeled from the semiconductor wafer. Since the flexible glass substrate side can be deformed and peeled, the semiconductor wafer is prevented from being damaged.

1 shows one step of a semiconductor wafer processing method of the present invention. One mode of a peeling means is shown. The process of peeling a flexible glass substrate using a peeling means is shown. The process of peeling a flexible glass substrate using the peeling means which concerns on another aspect is shown. FIG. 5 is a cross-sectional view taken along line AA in FIG. 4. FIG. 5 shows a side view of FIG. 4. The process of peeling a flexible glass substrate using the peeling means which concerns on another aspect is shown. The measuring method of the bending angle of a flexible glass substrate is shown.

  Hereinafter, the present invention will be described more specifically with reference to the drawings. In the following description, the term “brittle member” may be used instead of the term semiconductor wafer, but the brittle member is interpreted to indicate a semiconductor wafer.

  In the processing method of the present invention, as shown in FIG. 1, a structure in which a brittle member 3 is removably fixed on a flexible glass substrate 1 via a temporary attachment means 2 to protect the brittle member 3. Form body 10.

  Examples of the brittle member 3 to be protected include workpieces made of fragile materials such as silicon wafers, various semiconductor wafers such as gallium / arsenic wafers, optical glass, ceramic plates, and the like that require precise machining. However, it is not limited to these. Among these, it is particularly suitable for a semiconductor wafer, and specifically, it is particularly preferred to be applied to a semiconductor wafer having a circuit formed on the surface. Furthermore, the processing method of the present invention can be preferably applied to a semiconductor wafer that has been subjected to backside grinding to have a very thin thickness and extremely low strength.

  The flexible glass substrate 1 functions to support and protect the brittle member 3 during transportation, storage, and processing. Moreover, when peeling the flexible glass substrate 1 from the brittle member 3, the flexible glass substrate 1 side is deformed and curved to perform peeling. For this reason, it is particularly preferable that the flexible glass substrate 1 has an appropriate bending property.

  Specifically, it is preferable that the flexible glass substrate 1 bends 30 degrees or more, preferably 40 degrees or more, and more preferably 50 degrees or more when it is curved. That is, the maximum bending angle of the flexible glass substrate 1 used in the present invention is 30 degrees or more. The maximum bending angle is defined as the tangential angle of the maximum bending immediately before the breakage when holding one end of the flexible glass substrate 1 and bending the other end in the folding direction of the substrate. When the maximum bending angle is too small, the flexible glass substrate 1 reaches a yield point during the bending, and there is a possibility that the flexible glass substrate 1 is damaged or the brittle member 3 is damaged.

The material of the flexible glass substrate 1 is not particularly limited, but as a material that can satisfy the preferable bending physical properties, for example, chemically strengthened glass described in JP-A-5-32431 can be mentioned. Specifically, such chemically tempered glass is composed of 62 to 75 wt% SiO ₂ , 5 to 15 wt% Al ₂ O ₃ , 4 to 10 wt% Li ₂ O, and 4 to 12 wt% Na. ₂ O and 5.5 to 15% by weight of ZrO ₂ , the Na ₂ O / ZrO ₂ weight ratio is 0.5 to 2.0, and the Al ₂ O ₃ / ZrO ₂ weight ratio is 0.00. Glass obtained from 4 to 2.5 (hereinafter referred to as “raw glass”) is obtained by chemical strengthening by ion exchange treatment in a treatment bath containing Na ions and / or K ions.

  As the treatment bath containing Na ions and / or K ions, it is preferable to use a treatment bath containing sodium nitrate and / or potassium nitrate, but the treatment bath is not limited to nitrate, and sulfate, bisulfate, carbonate Salts, bicarbonates and halides may be used. When the treatment bath contains Na ions, the Na ions exchange with Li ions in the glass, and when the treatment bath contains K ions, the K ions exchange with Na ions in the glass. When the treatment bath further contains Na ions and K ions, these Na ions and K ions exchange with Li ions and Na ions in the glass, respectively. By this ion exchange, alkali metal ions in the glass surface layer portion are replaced with alkali metal ions having a larger ion radius, and a compressive stress layer is formed in the glass surface layer portion to chemically strengthen the glass. Since the raw glass has excellent ion exchange performance, the compressive stress layer formed by ion exchange is deep and the bending strength is high, so that the chemically strengthened glass obtained has excellent fracture resistance. The depth of the compressive stress layer is such that an appropriate bending strength can be obtained, and the depth of the compressive stress layer is measured, for example, by a method such as observation with a polarizing microscope of a glass cross section.

  Such chemically strengthened glass has the above-described bending physical properties and exhibits flexibility that is not broken even when bent. When the stress is removed after bending, the shape is quickly restored.

  Although the thickness of the flexible glass substrate 1 is not specifically limited, about 300-1500 micrometers is suitable. If the thickness of the flexible glass substrate 1 is too thin, sufficient strength to support the brittle member may not be obtained. If it is too thick, the flexible glass substrate is bent in the peeling step. There are cases where it is not possible.

  Moreover, the diameter of the flexible glass substrate 1 is the same as or slightly larger than the diameter of the brittle member 3 to be protected. More specifically, the flexible glass substrate 1 has an outer diameter that is preferably about 0.1 to 5 mm, more preferably about 0.5 to 2 mm larger than the outer diameter of the brittle member 3 to be protected. . Furthermore, as will be described later, when the temporary attachment means 2 is configured using an ultraviolet curable adhesive, the flexible glass substrate 1 preferably has ultraviolet transparency.

  The maximum bending angle of the flexible glass substrate 1 is larger as the thickness is smaller if the same material is used.

  In the structure 10, the brittle member 3 is fixed on the flexible glass substrate 1 through the temporary attachment means 2 so as to be removable. The temporary attachment means 2 has a function that can stably hold the brittle member 3 on the flexible glass substrate 1 and can be easily peeled off. The temporary attachment means 2 is not particularly limited as long as it has such a function, and may be a single-layer adhesive film, or may be a double-sided adhesive tape as shown in FIG. For example, the temporary attachment means 2 may be a single-layer adhesive film made of a weak adhesive. Moreover, the single layer film which consists of an ultraviolet curable adhesive may be sufficient. UV curable adhesives lose or drastically decrease adhesive strength when irradiated with ultraviolet light, so that the brittle member 3 is stably held on the flexible glass substrate 1 before ultraviolet light irradiation and easily peeled off after ultraviolet light irradiation. it can. Unlike the resin plate, the flexible glass substrate 1 used in the present invention is transparent and has ultraviolet transparency, so there is no problem even if an ultraviolet curable adhesive is used.

  Further, from the viewpoint of ease of handling and the like, the temporary attachment means 2 is particularly preferably made of a double-sided adhesive tape as shown in FIG.

  As shown in FIG. 1, the double-sided pressure-sensitive adhesive tape 2 has a structure in which a base material 21 is provided at the center and pressure-sensitive adhesive layers 22 and 23 are provided on both sides thereof. In this case, the base material 21 disposed in the center is not particularly limited, and is made of a film such as polyethylene terephthalate. In addition, as the pressure-sensitive adhesive layers 22 and 23 provided on both sides of the base material 21, conventionally known pressure-sensitive adhesives can be used as long as they can be removed again. For example, it may be a normal weak pressure-sensitive adhesive, or an ultraviolet curable pressure-sensitive adhesive whose peeling force can be controlled by ultraviolet irradiation.

  The pressure-sensitive adhesive layers 22 and 23 provided on both sides of the base material 21 may be the same, or may be made of different materials on both sides. For example, one of the pressure-sensitive adhesive layers 22 and 23 may be configured with an ultraviolet curable pressure-sensitive adhesive, and the other may be configured with a non-ultraviolet curable pressure-sensitive adhesive. A configuration in which the pressure-sensitive adhesive layer 22 attached to the brittle member 3 is selected so that the peeling force is smaller than that of the pressure-sensitive adhesive layer 23 provided on the flexible glass substrate 1 side at the time of peeling. Then, when peeling the flexible glass substrate 1 from the brittle member 3, the double-sided pressure-sensitive adhesive tape 2 remains on the flexible glass substrate 1 side and is peeled off without remaining on the brittle member 3 side. Therefore, the process of peeling the double-sided adhesive tape 2 from the brittle member 3 again becomes unnecessary. On the other hand, the pressure-sensitive adhesive layer 22 on the side adhered to the flexible glass substrate 1 is selected so that the peeling force is smaller than that of the pressure-sensitive adhesive layer 23 provided on the brittle member 3 side. If it exists, when peeling the flexible glass substrate 1 from the brittle member 3, the double-sided adhesive tape 2 will remain on the surface of the brittle member 3, and will not peel on the flexible glass substrate 1 side. Therefore, it can be used as a protective film for the brittle member 3.

  In the structure 10, the brittle member 3 may be reinforced by further bonding a protective tape or the like on the brittle member 3.

  The means for realizing the structure 10 is not particularly limited, and the brittle member 3 may be attached to the flexible glass substrate 1 to which the temporary attachment means 2 has been attached in advance, or vice versa. When the brittle member 3 is a semiconductor wafer having a circuit formed on the surface, the circuit surface side is bonded to the temporary attachment means 2 to protect the circuit surface.

  Next, an arbitrary treatment is performed on the brittle member 3. This process varies depending on the use of the brittle member 3, and includes various processing processes, conveyance, storage, and the like. For example, when the brittle member 3 is a semiconductor wafer having a circuit formed on the surface, the processing includes etching, polishing, sputtering, vapor deposition, and grinding on the wafer back surface. If the processing applied to the brittle member 3 is storage or transportation, a protective tape or the like is further bonded on the brittle member 3 to reinforce the brittle member 3 prior to such processing. Also good.

  Thereafter, the flexible glass substrate 1 is peeled from the brittle member 3. Prior to the peeling step, as shown in FIG. 1, the brittle member 3 side is fixed by the support means 11 in order to prevent deformation of the brittle member 3. The support means 11 is not particularly limited as long as it can hold the brittle member 3 without being deformed. For example, the support means 11 is an adsorption table, an adhesive tape, or a magnetic material such as an electromagnet depending on the material of the brittle member. It may be.

  While fixing the brittle member 3 with such a support means 11, as shown in FIG. 3, FIG. 7, the flexible glass substrate 1 side is peeled. As a result, since the deformation of the brittle member 3 is prevented, the breakage of the brittle member 3 is reduced.

  In the present invention, since the flexible glass substrate 1 is used to support the brittle member 3, when the brittle member 3 is peeled from the flexible glass substrate 1, the flexible glass substrate 1 is used. Can be peeled off.

  In order to bend and peel the flexible glass substrate 1, for example, the end of the flexible glass substrate 1 is gripped, and the end is pulled up from the brittle member 3 while the flexible glass substrate 1 is folded in the folding direction. Moving. Any means for gripping the end of the flexible glass substrate 1 may be used. For example, as shown in a perspective view in FIG. 2A and a side view in FIG. A peeling jig 30 including an upper movable plate 32, a lower insertion plate 33, and a shaft 34 that supports them is preferably used. When this peeling jig 30 is used, as shown in FIG. 3, the lower insertion plate 33 is inserted between the brittle member 3 and the temporary attachment means 2 and the upper movable plate 32 is lowered to The insertion plate 33 and the upper movable plate 32 hold the end portion of the flexible glass substrate 1. Thereafter, as shown in FIG. 3, the end portion is pulled up from the brittle member 3, moved in the folding direction of the flexible glass substrate 1, and peeled while curving the flexible glass substrate 1. According to this method, since the temporary attachment means 2 is peeled off together with the flexible glass substrate 1, a step of peeling the temporary attachment means 2 from the brittle member 3 again becomes unnecessary. Further, the flexible glass substrate 1 may be peeled by inserting a lower insertion plate between the flexible glass substrate 1 and the temporary attachment means 2. In this case, the temporary attachment means 2 remains on the brittle member 3, but since the temporary attachment means is flexible, the temporary attachment means 2 is easily peeled off.

  After the flexible glass substrate 1 is peeled off, the brittle member free from breakage and contamination is recovered by releasing the holding force of the support means 11. In order to release the holding force of the support means 11, for example, when the support means is a suction table, the suction force may be released, and when the support means is an adhesive tape, it may be peeled off. In the case of a magnetic material, the holding force of the support means is released by using an electromagnet or the like and stopping energization after the required process is completed.

  Further, when the brittle member 3 is a semiconductor wafer, a dicing sheet may be used as the support means 11. The semiconductor wafer is transferred onto the dicing sheet by peeling the flexible glass substrate 1 while fixing the semiconductor wafer on the dicing sheet. Therefore, the transition to the dicing process following the back grinding process is easily performed.

  In particular, when a semiconductor wafer is transferred onto a dicing sheet, it is preferable to employ the following method using two sets of ring frames, two adhesive sheets for peeling, and a transferring device 40 as a peeling means. .

  First, two sets of fixing jigs made of an adhesive sheet (AS) stretched on the ring frame (RF) are prepared. Next, the laminate of the flexible glass substrate 1 and the semiconductor wafer 3 is sandwiched between the two sets of fixing jigs. Hereinafter, the fixing jig on the semiconductor wafer 3 side is referred to as a first fixing jig, the ring frame constituting the jig is referred to as a first ring frame RF1, and the adhesive sheet is referred to as a first adhesive sheet AS1. Similarly, the fixing jig on the flexible glass substrate 1 side is called a second fixing jig, the ring frame constituting the jig is the second ring frame RF2, and the adhesive sheet is the second adhesive sheet AS2. Call it.

  As shown in FIG. 4, the transfer device 40 includes a rotation shaft 41, a pair of thin plate arms 42 attached to the rotation shaft, and a suction table 43 as a support means for temporarily fixing an object to be processed. . The laminated body of the flexible glass substrate 1 and the semiconductor wafer 3 sandwiched between the two sets of fixing jigs is mounted on the transfer device 40. At this time, the first fixing jig side is fixed on the suction table 43. Next, the thin plate arm 42 is inserted between the ring frames RF1 and RF2. A sectional view taken along line AA in FIG. 4 is shown in FIG. 5, and a side view of FIG. 4 is shown in FIG.

  Thereafter, the rotating shaft 41 to which the thin plate-like arm 42 is connected is rotated, and the interval between the ring frame RF1 and the ring frame RF2 is separated (FIG. 7). As a result, the flexible glass substrate 1 is deformed as the second fixing jig is moved, and is peeled off from the surface of the semiconductor wafer 3 while being curved.

  Thereafter, if the temporary attachment means 2 remains on the surface of the semiconductor wafer 3, it is peeled off and the semiconductor wafer 3 is transferred onto the first adhesive sheet AS1.

  The semiconductor wafer 3 transferred onto the adhesive sheet AS1 stretched on the ring frame RF1 is stored in a wafer cassette (not shown) and transferred to the next process such as a dicing process. In this case, the adhesive sheet AS1 can be used as it is as a dicing sheet. On the other hand, the flexible glass substrate 1 held by the second fixing jig is peeled off from the pressure-sensitive adhesive sheet AS2, and is used again after washing and distortion removal processing as necessary.

  In addition, although the example applied to the semiconductor wafer was mainly demonstrated about the processing method of the brittle member which concerns on this invention, the structure and method of this invention are not only a semiconductor wafer but various brittle members, such as glass and ceramics. Applicable to.

  In the present invention, since the brittle member is fixed and protected on the flexible glass substrate, the brittle member can be held without being deformed during transportation, storage, and processing of the brittle member. Further, unlike the conventional hard glass, the flexible glass substrate used in the present invention can be bent, so when peeling the flexible glass substrate from the brittle member, without deforming the brittle member, Since the flexible glass substrate side can be deformed and peeled, the brittle member is prevented from being damaged.

(Example)
EXAMPLES Hereinafter, although an Example demonstrates this invention, this invention is not limited to these Examples.

  The maximum bending angle of the flexible glass substrate 1 was measured as follows.

  FIG. 8 is a diagram showing a method for measuring the bending angle of the flexible glass substrate. In FIG. 8A, a soft sheet 62A such as a rubber sheet or a vinyl sheet having a thickness of 3 mm × width of 200 mm × depth of 250 mm is pasted on a hard plate 61A such as a wooden plate or an iron plate having a thickness of 25 mm × width of 200 mm × depth of 250 mm. It was. A hard plate 61B having the same size and a soft sheet 62B having the same size was prepared, and the surfaces of 28 mm × 250 mm were combined. A hinge is attached in the vicinity of the point A so that the upper end of the abutting surface is a point A and the bending can be performed with the point A as the base point. The hard plate 61A with the soft sheet 62A is fixed so as not to move, and the hard plate 61B with the soft sheet 62B can be bent at the point A.

  The semi-cylindrical hard plate 65 having a thickness of 25 mm, a width of 150 mm, and a depth of 250 mm is finished into a semi-cylinder having a depth of 250 mm and a radius of 12.5 mm. A second soft sheet 66 having a thickness of 3 mm × width of 290 mm × depth of 250 mm is attached to the semi-cylindrical hard plate 65 as shown in FIG.

  When measuring the bending angle of the flexible glass substrate, the point A is arranged so as to coincide with the circle center line of the flexible glass substrate. Then, the semi-cylindrical hard plate 65 with the second adhesive sheet 66 is pressed onto the flexible glass substrate so that the flexible glass substrate does not move. The position where the semi-cylindrical hard plate 65 presses the flexible glass substrate is a position where the outermost half-column of the second soft sheet 66 coincides with the circle center line of the flexible glass substrate.

  Next, as shown in FIG. 8B, the hard plate 61B with the soft sheet 62B rotates slowly in the direction of the arrow 67, with the point A as a fulcrum. The flexible glass substrate bends along the arc of the lower half cylinder of the half cylinder hard plate 65 with the second soft sheet 66. The angle of rotation in the direction of arrow 67 is a bending angle of about 1 ° / second. The bending angle is represented by an angle 69 between the upper surface of the soft 62A and the upper surface of the soft sheet 62B. The maximum bending angle was defined as the angle at which the flexible glass substrate was pushed up in the direction of the arrow 67 and the flexible glass substrate was broken. An angle 69 between the upper surface of the soft sheet 62A and the upper surface of the soft sheet 62B was measured in units of 1 ° using a protractor.

  Moreover, evaluation of supportability and peelability was performed as follows.

(1) Supportability A predetermined flexible glass substrate and an 8-inch silicon wafer (thickness: 720 μm) as a brittle member were laminated via a double-sided adhesive tape. Then, it grinded until the thickness of the silicon wafer became 50 micrometers using the wafer back surface grinding machine (DFG-840 by DISCO Corporation), and it was set as the structure. Place a columnar table with a height of 50 mm and a diameter of 50 mm on a smooth plate, and then place the ground silicon wafer on the table with the flexible glass substrate side down, so that the center of the wafer matches the center of the table. Placed to do. The distance from the smooth plate to the edge portion of the flexible glass substrate was measured with a ruler.

(2) Peelability The flexible glass substrate was peeled using the peeling means shown in FIG. 3 or FIG. A semiconductor wafer that could be peeled off without being damaged or contaminated was regarded as good. A semiconductor wafer that could not be peeled off or was damaged or contaminated was regarded as defective.

Example 1
(Manufacture of double-sided adhesive tape)
The following adhesives were prepared as adhesives A and B.

Adhesive A: comprising 85 parts by weight of 2-ethylhexyl acrylate, 100 parts by weight of a copolymer having a weight average molecular weight of 400,000 comprising 15 parts by weight of 2-hydroxyethyl acrylate, and an adduct of tolylene diisocyanate and trimethylolpropane. A pressure-sensitive adhesive containing 9.4 parts by weight of a crosslinking agent.
Adhesive B: Addition of 80 parts by weight of butyl acrylate, 10 parts by weight of methyl methacrylate, 100 parts by weight of a copolymer having a weight average molecular weight of 500,000 consisting of 5 parts by weight of 2-hydroxyethyl acrylate, tolylene diisocyanate and trimethylolpropane A pressure-sensitive adhesive containing 0.9 parts by weight of a cross-linking agent.

  A pressure-sensitive adhesive A was applied to a polyethylene terephthalate (PET) film having a thickness of 50 μm using a roll coater so as to have a dry thickness of 20 μm, and was laminated with a release film. Subsequently, the pressure-sensitive adhesive B was applied and dried on another release film so as to have a dry thickness of 20 μm, and laminated on the surface opposite to the surface where the pressure-sensitive adhesive A of PET was applied to obtain a double-sided pressure-sensitive adhesive sheet.

(Manufacture of flexible glass substrate)
A raw glass mixture comprising a composition ratio of 63 wt% SiO ₂ , 14 wt% Al ₂ O ₃ , 6 wt% Li ₂ O, 10 wt% Na ₂ O, 7 wt% ZrO ₂ is 1500-1600. After being melted by heating at 5 ° C. for 5 hours, it was poured onto an iron plate and pressed to obtain a glass plate. Next, it was processed and polished to a desired size to obtain a circular glass plate having an outer diameter of 201 mm and a thickness of 0.5 mm. Subsequently, the glass plate was immersed in a 360 ° C. KNO ₃ : 60%, NaNO ₃ : 40% mixed salt melt for 3 hours to perform ion exchange on the surface of the glass plate, and the compressive stress layer was chemically strengthened to 100 μm. A flexible glass substrate A was obtained. The maximum bending angle of this glass was about 40 degrees.

(Formation of structure)
A flexible glass substrate A and an 8-inch silicon wafer having a thickness of 720 μm were laminated under vacuum through a double-sided adhesive sheet from which the release films on both sides were peeled off. Then, it grinds until the thickness of a silicon wafer will be 50 micrometers using a wafer back surface grinding machine (DFG-840 by DISCO Corporation), and peeling of the flexible glass substrate A using the peeling means shown in FIG. went. The support and peelability of this structure were evaluated. Both supportability and peelability were good.

(Example 2)
The same operation as in Example 1 was performed except that the flexible glass substrate was peeled off using the peeling means shown in FIG. Both supportability and peelability were good.

(Example 3)
(Manufacture of flexible glass substrate)
A raw material glass mixture having the same composition ratio as in Example 1 was heated and melted at 1500 to 1600 ° C. for 5 hours, then poured onto an iron plate and pressed to obtain a glass plate. Next, it was processed and polished to a desired size to obtain a circular glass plate having an outer diameter of 201 mm and a thickness of 1 mm. Subsequently, the glass plate was immersed in a 360 ° C. KNO ₃ : 60%, NaNO ₃ : 40% mixed salt melt for 3 hours to perform ion exchange on the surface of the glass plate, and the compressive stress layer was chemically strengthened to 100 μm. A flexible glass substrate B was obtained. The maximum bending angle of this glass was about 32 degrees. The same operation as in Example 2 was performed except that the flexible glass substrate B was peeled off using the peeling means shown in FIG. Both supportability and peelability were good.

DESCRIPTION OF SYMBOLS 1 ... Flexible glass substrate 2 ... Double-sided adhesive tape (temporary attachment means)
21 ... base material 22, 23 ... adhesive layer 3 ... brittle member 10 ... structure 11 ... support means 30 ... peeling means 31 ... air cylinder 32 ... Upper movable plate 33 ... lower insertion plate 34 ... shaft 40 ... transfer device (other peeling means)
41 ... rotating shaft 42 ... thin plate arm 43 ... suction table 61A, 61B ... hard plate 62A, 62B ... soft sheet 65 ... semi-cylindrical hard plate 66 ... second soft Sheet 69 ... Angle

Claims (8)

Flexibility having a compressive stress layer having a thickness of 300-1000 μm, chemically strengthened by ion exchange treatment with one or more ions selected from Na ions and K ions, and a maximum bending angle of 30 degrees or more Fixing the semiconductor wafer on the glass substrate so as to be re-peelable;
Processing the semiconductor wafer;
A method for processing a semiconductor wafer, comprising: a step of fixing the semiconductor wafer side by a supporting means; and a step of bending the flexible glass substrate and peeling it from the semiconductor wafer.   The processing method according to claim 1, wherein the compressive stress layer of the flexible glass substrate is formed by a chemical strengthening process by ion exchange with at least K ions.   The processing method according to claim 1, wherein a thickness of the compressive stress layer of the flexible glass substrate is about 100 μm.   The processing method according to claim 1, wherein an outer diameter of the flexible glass substrate is the same as or larger than an outer diameter of the semiconductor wafer.   The said peeling process hold | grips the edge part of a flexible glass substrate, moves to the folding | turning direction of a flexible glass substrate, pulling up an edge part from a semiconductor wafer, and peels. Processing method.   The processing method according to claim 1, wherein the processing performed on the semiconductor wafer is backside grinding of the semiconductor wafer. The processing method according to claim 1, wherein the flexible glass substrate contains Na ₂ O or Li ₂ O. The processing method according to claim 1, wherein the compressive stress layer of the flexible glass substrate is formed by ion exchange treatment with Na ions and K ions.

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