US20120028555A1 - Grinding Tool For Trapezoid Grinding Of A Wafer - Google Patents
Grinding Tool For Trapezoid Grinding Of A Wafer Download PDFInfo
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- US20120028555A1 US20120028555A1 US12/847,015 US84701510A US2012028555A1 US 20120028555 A1 US20120028555 A1 US 20120028555A1 US 84701510 A US84701510 A US 84701510A US 2012028555 A1 US2012028555 A1 US 2012028555A1
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- wafer
- grinding
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- grooves
- wheel
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B24—GRINDING; POLISHING
- B24B—MACHINES, DEVICES, OR PROCESSES FOR GRINDING OR POLISHING; DRESSING OR CONDITIONING OF ABRADING SURFACES; FEEDING OF GRINDING, POLISHING, OR LAPPING AGENTS
- B24B9/00—Machines or devices designed for grinding edges or bevels on work or for removing burrs; Accessories therefor
- B24B9/02—Machines or devices designed for grinding edges or bevels on work or for removing burrs; Accessories therefor characterised by a special design with respect to properties of materials specific to articles to be ground
- B24B9/06—Machines or devices designed for grinding edges or bevels on work or for removing burrs; Accessories therefor characterised by a special design with respect to properties of materials specific to articles to be ground of non-metallic inorganic material, e.g. stone, ceramics, porcelain
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B24—GRINDING; POLISHING
- B24B—MACHINES, DEVICES, OR PROCESSES FOR GRINDING OR POLISHING; DRESSING OR CONDITIONING OF ABRADING SURFACES; FEEDING OF GRINDING, POLISHING, OR LAPPING AGENTS
- B24B9/00—Machines or devices designed for grinding edges or bevels on work or for removing burrs; Accessories therefor
- B24B9/02—Machines or devices designed for grinding edges or bevels on work or for removing burrs; Accessories therefor characterised by a special design with respect to properties of materials specific to articles to be ground
- B24B9/06—Machines or devices designed for grinding edges or bevels on work or for removing burrs; Accessories therefor characterised by a special design with respect to properties of materials specific to articles to be ground of non-metallic inorganic material, e.g. stone, ceramics, porcelain
- B24B9/065—Machines or devices designed for grinding edges or bevels on work or for removing burrs; Accessories therefor characterised by a special design with respect to properties of materials specific to articles to be ground of non-metallic inorganic material, e.g. stone, ceramics, porcelain of thin, brittle parts, e.g. semiconductors, wafers
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B24—GRINDING; POLISHING
- B24D—TOOLS FOR GRINDING, BUFFING OR SHARPENING
- B24D5/00—Bonded abrasive wheels, or wheels with inserted abrasive blocks, designed for acting only by their periphery; Bushings or mountings therefor
- B24D5/14—Zonally-graded wheels; Composite wheels comprising different abrasives
Definitions
- This disclosure relates to semiconductor and solar wafers such as silicon on insulator (SOI) bonded structures, and more particularly to a grinding tool for grinding a bonded SOI wafer.
- SOI silicon on insulator
- SOI wafers are generally prepared from a single crystal ingot (e.g., a silicon ingot) which is sliced into individual wafers. While reference will be made herein to semiconductor wafers constructed from silicon, other materials may be used as well, such as germanium, gallium arsenide or other materials described below.
- One type of wafer is a silicon-on-insulator (SOI) wafer.
- An SOI wafer includes a thin layer of silicon (an active layer) atop an insulating layer (i.e., an oxide layer) which is in turn disposed on a silicon substrate.
- a bonded SOI semiconductor wafer is a type of SOI structure.
- SOI silicon on insulator
- outer peripheral portions of the two wafers to be bonded are subjected to R or T chamfering, or edge profiling (as further described below), in order to prevent wafer breakage, cracks and/or particle generation.
- outer peripheral portions of a bonded substrate have uneven thickness due to wafering steps. Because of this uneven thickness, during the bonding process, the outer peripheral portion is either not bonded at all and/or weakly bonded.
- an active wafer thickness is reduced with processes such as grinding, etching, polishing, etc.
- this unbonded portion is partially delaminated from the bonded substrate during the film thickness reducing processes.
- the delaminated parts cause problems for film thickness reduction, cleaning, and measurement processes.
- the remaining unbonded portions are delaminated, which causes particle generation and severely impacts device yields.
- FIGS. 1A-1D show a progression of steps for bonding a substrate wafer S and an active layer wafer A to each other and then chamfering the edge peripheral portion of the bonded wafer W.
- FIG. 1A shows the substrate below the active layer wafer
- FIG. 1B shows the bonded wafers.
- FIG. 1C shows a grinder G grinding the outer peripheral edges of the wafers
- FIG. 1D shows the complete SOI wafer W (note that the complete wafer is further processed).
- This method is believed to be substantively similar to that shown in Japanese Patent Application No. 1986-256621.
- the diameter of the wafer W is smaller than the standard wafer diameter, which causes problems for the downstream handling facilities and jigs.
- a bonded SOI wafer W is formed as described above from an active layer wafer A and a substrate wafer S.
- the wafer edges are ground as shown in FIGS. 2B-2C such that the entire outer edge of the active wafer A is ground off, but only a portion of substrate is ground off.
- This method is believed to be substantively similar to that shown in Japanese Patent Application No. 1989-227441. This method suffers from poor efficiency.
- the active wafer A is ground at its edges to form a ledge L (wafer A is thus a pre-ground wafer).
- the wafer A is bonded to substrate wafer S in FIG. 3B .
- FIG. 3C the top surface of the bonded SOI wafer W is ground to remove the ledge L, and the complete wafer is shown in FIG. 3D .
- the unbonded portion of the active layer wafer can thereafter be ground down. This method is believed to be substantively similar to that shown in Japanese Patent Application No. 1992-85827.
- a bonded SOI wafer W is formed as described above from an active layer wafer A and a substrate wafer S.
- the active wafer A is ground at its upper peripheral edge E to form the ledge L shown in FIG. 4C .
- selective etching, polishing and/or PAC plasma assisted chemical etching processes are used to remove the unbonded parts from the outer peripheral edge of the active layer wafer A.
- This method is believed to be substantively similar to that shown in U.S. Pat. No. 6,534,384 B2, which is incorporated herein by reference. As can be seen, many steps are required to form the complete wafer.
- the active layer wafer A includes a groove R formed in its lower surface prior to bonding.
- the active wafer A is bonded to the substrate wafer S in FIG. 5B .
- This method is believed to be substantively similar to that shown in US Patent Application 2009/0203167 A1, which is incorporated herein by reference.
- grinding is performed on wafer A on the opposite side from the groove R.
- the unbonded portion of the outer peripheral portion of the wafer A can be removed after grinding the wafer to predetermined thickness, as shown in the complete wafer W of FIG. 5D .
- a grinding tool for trapezoid grinding of a wafer on a profiling machine comprises an annular wheel including a central hole adapted for mounting the wheel on a spindle.
- the wheel includes at least two grooves disposed at an outer edge of the wheel and the grooves are sized for receiving an outer edge of the wafer. At least one of the grooves is adapted for rough grinding of the wafer. At least one other of the grooves is adapted for fine grinding of the wafer.
- the wheel of the grinding tool includes three or more grooves disposed at an outer edge of the wheel and the grooves and sized for receiving an outer edge of the wafer. At least one of the grooves is adapted for rough grinding of the wafer and at least one other of the grooves is adapted for fine grinding of the wafer. Each groove is sized and shaped so that only the upper peripheral edge of the wafer is ground.
- a grinding tool for grinding of a wafer on a profiling machine comprises an annular wheel including a central hole adapted for mounting the wheel on a spindle.
- the wheel includes three or more grooves disposed at an outer edge of the wheel and the grooves are sized for receiving an outer edge of the wafer.
- One groove is for rough grinding of the wafer and at least two grooves are for fine grinding of the wafer.
- Each groove has a V-shape in cross-section and is sized relative to the wafer so that only the upper peripheral edge of the wafer is ground.
- FIGS. 1A-5D are side views showing prior art methods of making an SOI wafer.
- FIG. 6 is a flowchart showing a method of manufacturing an SOI wafer according to one embodiment.
- FIGS. 7A-7E are a progression of side views showing aspects of the method of manufacturing of FIG. 6 .
- FIG. 8 is a flowchart showing a method of manufacturing an SOI wafer according to another embodiment.
- FIGS. 9A-9D are a progression of side views showing aspects of the method of manufacturing of FIG. 8 .
- FIGS. 10 and 11 show a grinding wheel of one embodiment for performing a trapezoid grinding step.
- FIG. 12 is a side view of an SOI wafer aligned with a groove of the grinding wheel of FIG. 10 .
- FIG. 13 is an enlarged view of an SOI wafer after trapezoid grinding.
- FIGS. 6 and to 7 A- 7 E a method 100 of manufacturing or processing a bonded wafer (alternatively, a silicon-on-insulator structure or SOI wafer) is shown.
- An active wafer 101 and a substrate wafer 103 are conventional wafers. Both have mirror-polished front surfaces 101 F, 103 F and are relatively defect-free.
- Active wafer 101 and substrate wafer 103 may be any single crystal semiconductor material suitable for use in an SOI structure.
- the wafers may be composed of a material selected from the group consisting of silicon, germanium, gallium arsenide, silicon germanium, gallium nitride, aluminum nitride, phosphorous, sapphire and combinations thereof.
- the wafers 101 , 103 are made of silicon.
- a layer of oxide is deposited 102 on the front surface of the active wafer.
- Oxidation is typically performed in a vertical furnace, e.g. commercially available AMS400.
- the front surface of the wafer is then bonded 104 to the front surface of the substrate wafer to form a bonded wafer 105 as shown in FIG. 7B .
- Bonding can be performed in a conventional hydrophilic bonding process using a tool such as Model EVG® 850 from EV Group of Austria.
- Heat treatment 106 is suitably performed in an electric oven (such as model Blue M from TPS of Pennsylvania) to strengthen the bond.
- trapezoid grinding 108 is further described below with reference to FIG. 7C .
- Surface grinding 110 shown in FIG.
- the surface grinding 110 suitably includes a rough grinding step and a fine grinding step.
- Rough grinding is suitably performed using a 600 mesh with 20-30 microns grit size, and fine grinding is 3000 mesh and grit size of 2-6 microns.
- etching 112 is next performed on the bonded wafer 105 , and is suitably performed in a conventional etching apparatus using an alkali etchant, though an acid etchant may also be used.
- Polishing 114 is then performed and is suitably a single-side polishing on front surface 105 F using a Strasbaugh Mark 9-K. Alternatively, the polishing 114 may be a double-side polishing of both the front surface 105 F and back surface 105 B.
- Finishing 116 of the bonded wafer 105 includes inspecting the wafer for all required parameters, such as flatness and particle count, and then packaging the wafer for shipment to customers.
- the finished or bonded wafer 105 has an upper portion having a trapezoid shape. More specifically, the upper portion including the remainder of the active layer wafer 101 and a relatively small portion of the substrate wafer is angled at the outer peripheral edge portion so that the wafer is said to have a trapezoid shape or a trapezoid shape in cross-section.
- the lower portion of the bonded wafer 105 (which corresponds substantially to the substrate wafer 103 in this embodiment) has a conventional bevel or rounded shape (broadly, a curved shape) at its outer peripheral edge and thus does not have a trapezoid shape.
- the upper portion of the bonded wafer 105 is substantially coincident with the active wafer 101 in this embodiment.
- an outer peripheral edge of the active wafer 101 is brought into contact with the grinding wheel and is ground at an angle relative to the front surface 105 F of the bonded wafer 105 .
- the angle is suitably between about 3° and 10°, and in this embodiment the angle is about 7°.
- the edge grinding is performed until the entire outer peripheral edge is ground as shown in FIG. 7D .
- the grinding eliminates any notch in the outer peripheral edge.
- the grinding may suitably be done such that the length of the angled or sloped portion is between about 1 mm and 1.5 mm, e.g. about 1.25 mm. Note that the angle and depth of grind is such that a small portion of the top bevel 119 of the substrate wafer 103 is removed during the trapezoid grinding.
- the surface of the active wafer 101 is ground until it has a thickness of 40-50 microns, as shown in FIG. 7D .
- the edge grind is performed such that a portion of the substrate wafer 103 is ground.
- the grinding steps are reversed as compared to that of FIGS. 6 and 7 A- 7 D.
- the surface of the active wafer 101 is ground first, before the trapezoid grinding.
- the surface grinding step may include a rough grinding step and a fine grinding step. Rough grinding is suitably performed using a 600 mesh and grit size of 20 to 30 microns, and fine grinding is 3000 mesh and grit size of 2 to 6 microns.
- the surface is ground as shown in FIG. 9B , and then the edge of the active wafer 101 is next ground in FIG. 9C until the edges have the trapezoid shape shown in FIG. 9D .
- a grinding wheel 151 (broadly, a trapezoid grinding tool) of one embodiment is designed for the performance of the trapezoid grinding 108 .
- the wheel 151 is adapted to be mounted on a conventional edge profiling machine 152 that performs the trapezoid grinding.
- the profiling machine is an STC EP-5800RHO machine adapted for 200 mm diameter wafers.
- the wheel 151 is mounted on a spindle 153 of the profiling machine 152 .
- the wheel 151 of this embodiment is ring-shaped or annular and has a central hole 154 adapted for mounting the wheel on the on the spindle 151 of the profiling machine 152 .
- the wheel 151 has a diameter D of 202 mm with a central hole diameter HD of 30 mm and thickness of 20 mm.
- the wheel 151 of this embodiment has an upper groove 155 , a central groove 157 and a lower groove 159 disposed at an outer edge of the wheel.
- the grooves 155 , 157 , 159 are generally V-shaped in this embodiment. Note that the wheel 151 may alternatively have just one groove, or practically any other number of grooves, within the scope of this disclosure.
- the upper and central grooves 155 , 157 are adapted for fine grinding, and the lower groove 159 is adapted for rough grinding.
- Each groove suitably includes diamond grits.
- diamond grit size 2000 or 3000 mesh is suitable.
- 600 mesh or 800 mesh is suitable.
- the wheel 151 is suitably made of metal alloy, aluminum alloy, or stainless steel, though other materials are contemplated.
- Each groove wall of this embodiment slopes from a bottom of the groove to a top of the groove and has a flat bottom. In this embodiment, the slope is at about a 7° angle.
- the width of the bottom of the groove is about 1.8 mm for use with a bonded wafer having a total thickness of about 200 mm, so that the substrate wafer or back surface of the wafer is not in contact with the groove during trapezoid grinding.
- the width of each groove at its widest portion (the top of the groove) is about 3.5 mm.
- the wall of the groove curves into the bottom of the groove at a radius of about 0.2 mm.
- the groove depth GD is about 6.0 mm and the groove root depth RD is about 8.0 mm.
- the wheel 151 is installed on the edge profiling machine 152 , such as on a spindle of the STC EP-5800 RHO. After wheel installation, spindle height (vertical direction) and distance (horizontal direction) are fine adjusted, so that groove 155 of the wheel 151 and the bonded wafer 105 are aligned as shown in FIG. 12 . Note that the outermost portion of substrate wafer edge and the bottom surface are not in contact with the grinding groove 155 . Then, trapezoid grinding is performed as described above. Trapezoid grinding can be performed with either rough grit groove or fine grit groove or both grit grooves (first rough grit groove, then fine grit groove). The grinding may be performed as a single pass or multiple pass process, depending, for example, on edge quality requirements.
- the above example methods are applied to remove the unbonded outer peripheral parts of an active layer wafer bonded on a substrate wafer. This results in a bonded wafer having a more securely bonded outer peripheral portion.
- trapezoid grinding is applied to remove the unbonded outer peripheral portion of the active layer wafer.
- An edge grinding wheel such as wheel 151 may be used to perform the trapezoid grinding step.
- the bonded wafer according to embodiments of this disclosure is less likely to suffer delamination. Additionally, the bonded wafer inhibits or prevents particle contamination that might otherwise occur due to delaminated unbonded portions on the process/device lines of the wafer.
Abstract
Description
- This disclosure relates to semiconductor and solar wafers such as silicon on insulator (SOI) bonded structures, and more particularly to a grinding tool for grinding a bonded SOI wafer.
- Semiconductor wafers are generally prepared from a single crystal ingot (e.g., a silicon ingot) which is sliced into individual wafers. While reference will be made herein to semiconductor wafers constructed from silicon, other materials may be used as well, such as germanium, gallium arsenide or other materials described below. One type of wafer is a silicon-on-insulator (SOI) wafer. An SOI wafer includes a thin layer of silicon (an active layer) atop an insulating layer (i.e., an oxide layer) which is in turn disposed on a silicon substrate. A bonded SOI semiconductor wafer is a type of SOI structure.
- Due to device width shrink, power conservation, super-high speed performance, and/or special applications in electronic industry, the demands on SOI (silicon on insulator) wafers are increasing. One challenge is to effectively remove the unbonded outer peripheral portion of an active layer wafer bonded to the support substrate in order to avoid delamination. Delamination can result in particle contamination in the process and/or device lines of the wafer.
- When manufacturing an SOI wafer, outer peripheral portions of the two wafers to be bonded are subjected to R or T chamfering, or edge profiling (as further described below), in order to prevent wafer breakage, cracks and/or particle generation. Also, outer peripheral portions of a bonded substrate have uneven thickness due to wafering steps. Because of this uneven thickness, during the bonding process, the outer peripheral portion is either not bonded at all and/or weakly bonded. When an active wafer thickness is reduced with processes such as grinding, etching, polishing, etc., this unbonded portion is partially delaminated from the bonded substrate during the film thickness reducing processes. The delaminated parts cause problems for film thickness reduction, cleaning, and measurement processes. Furthermore, in device processes, the remaining unbonded portions are delaminated, which causes particle generation and severely impacts device yields.
- There have been several prior art attempts to solve delamination. For example,
FIGS. 1A-1D show a progression of steps for bonding a substrate wafer S and an active layer wafer A to each other and then chamfering the edge peripheral portion of the bonded wafer W.FIG. 1A shows the substrate below the active layer wafer, andFIG. 1B shows the bonded wafers.FIG. 1C shows a grinder G grinding the outer peripheral edges of the wafers, andFIG. 1D shows the complete SOI wafer W (note that the complete wafer is further processed). This method is believed to be substantively similar to that shown in Japanese Patent Application No. 1986-256621. Among other drawbacks of this example, the diameter of the wafer W is smaller than the standard wafer diameter, which causes problems for the downstream handling facilities and jigs. - In another prior art example shown in
FIGS. 2A-2D , a bonded SOI wafer W is formed as described above from an active layer wafer A and a substrate wafer S. The wafer edges are ground as shown inFIGS. 2B-2C such that the entire outer edge of the active wafer A is ground off, but only a portion of substrate is ground off. This method is believed to be substantively similar to that shown in Japanese Patent Application No. 1989-227441. This method suffers from poor efficiency. - In the prior art example shown in
FIG. 3A , the active wafer A is ground at its edges to form a ledge L (wafer A is thus a pre-ground wafer). The wafer A is bonded to substrate wafer S inFIG. 3B . InFIG. 3C , the top surface of the bonded SOI wafer W is ground to remove the ledge L, and the complete wafer is shown inFIG. 3D . The unbonded portion of the active layer wafer can thereafter be ground down. This method is believed to be substantively similar to that shown in Japanese Patent Application No. 1992-85827. - In prior art
FIG. 4A , a bonded SOI wafer W is formed as described above from an active layer wafer A and a substrate wafer S. InFIG. 4B , the active wafer A is ground at its upper peripheral edge E to form the ledge L shown inFIG. 4C . To complete the wafer processing ofFIG. 4D , selective etching, polishing and/or PAC (plasma assisted chemical etching) processes are used to remove the unbonded parts from the outer peripheral edge of the active layer wafer A. This method is believed to be substantively similar to that shown in U.S. Pat. No. 6,534,384 B2, which is incorporated herein by reference. As can be seen, many steps are required to form the complete wafer. - In prior art
FIG. 5A , the active layer wafer A includes a groove R formed in its lower surface prior to bonding. The active wafer A is bonded to the substrate wafer S inFIG. 5B . This method is believed to be substantively similar to that shown in US Patent Application 2009/0203167 A1, which is incorporated herein by reference. InFIG. 5C , grinding is performed on wafer A on the opposite side from the groove R. The unbonded portion of the outer peripheral portion of the wafer A can be removed after grinding the wafer to predetermined thickness, as shown in the complete wafer W ofFIG. 5D . - There remains an unfulfilled need for a wafer surface treatment method and a wafer that addresses the disadvantages of current methods of preventing delamination of the outer peripheral portion of an active layer of a bonded structure.
- In one aspect, a grinding tool for trapezoid grinding of a wafer on a profiling machine comprises an annular wheel including a central hole adapted for mounting the wheel on a spindle. The wheel includes at least two grooves disposed at an outer edge of the wheel and the grooves are sized for receiving an outer edge of the wafer. At least one of the grooves is adapted for rough grinding of the wafer. At least one other of the grooves is adapted for fine grinding of the wafer.
- In another aspect, the wheel of the grinding tool includes three or more grooves disposed at an outer edge of the wheel and the grooves and sized for receiving an outer edge of the wafer. At least one of the grooves is adapted for rough grinding of the wafer and at least one other of the grooves is adapted for fine grinding of the wafer. Each groove is sized and shaped so that only the upper peripheral edge of the wafer is ground.
- In still another aspect, a grinding tool for grinding of a wafer on a profiling machine comprises an annular wheel including a central hole adapted for mounting the wheel on a spindle. The wheel includes three or more grooves disposed at an outer edge of the wheel and the grooves are sized for receiving an outer edge of the wafer. One groove is for rough grinding of the wafer and at least two grooves are for fine grinding of the wafer. Each groove has a V-shape in cross-section and is sized relative to the wafer so that only the upper peripheral edge of the wafer is ground.
- Various refinements exist of the features noted in relation to the above-mentioned aspects. Further features may also be incorporated in the above-mentioned aspects as well. These refinements and additional features may exist individually or in any combination. For instance, various features discussed below in relation to any of the illustrated embodiments may be incorporated into any of the above-described aspects, alone or in any combination.
-
FIGS. 1A-5D are side views showing prior art methods of making an SOI wafer. -
FIG. 6 is a flowchart showing a method of manufacturing an SOI wafer according to one embodiment. -
FIGS. 7A-7E are a progression of side views showing aspects of the method of manufacturing ofFIG. 6 . -
FIG. 8 is a flowchart showing a method of manufacturing an SOI wafer according to another embodiment. -
FIGS. 9A-9D are a progression of side views showing aspects of the method of manufacturing ofFIG. 8 . -
FIGS. 10 and 11 show a grinding wheel of one embodiment for performing a trapezoid grinding step. -
FIG. 12 is a side view of an SOI wafer aligned with a groove of the grinding wheel ofFIG. 10 . -
FIG. 13 is an enlarged view of an SOI wafer after trapezoid grinding. - The figures are not to scale, and portions are enlarged for illustrative purposes. Corresponding reference characters indicate corresponding parts throughout the figures.
- Referring now to
FIGS. 6 and to 7A-7E, amethod 100 of manufacturing or processing a bonded wafer (alternatively, a silicon-on-insulator structure or SOI wafer) is shown. Anactive wafer 101 and asubstrate wafer 103, such as those shown inFIG. 7A , are conventional wafers. Both have mirror-polished front surfaces 101F, 103F and are relatively defect-free. -
Active wafer 101 andsubstrate wafer 103 may be any single crystal semiconductor material suitable for use in an SOI structure. In general, the wafers may be composed of a material selected from the group consisting of silicon, germanium, gallium arsenide, silicon germanium, gallium nitride, aluminum nitride, phosphorous, sapphire and combinations thereof. In one embodiment, thewafers - A layer of oxide is deposited 102 on the front surface of the active wafer. Oxidation is typically performed in a vertical furnace, e.g. commercially available AMS400. The front surface of the wafer is then bonded 104 to the front surface of the substrate wafer to form a bonded
wafer 105 as shown inFIG. 7B . Bonding can be performed in a conventional hydrophilic bonding process using a tool such as Model EVG® 850 from EV Group of Austria.Heat treatment 106 is suitably performed in an electric oven (such as model Blue M from TPS of Pennsylvania) to strengthen the bond. The next step, trapezoid grinding 108 is further described below with reference toFIG. 7C . Surface grinding 110, shown inFIG. 7D is suitably performed using a single side grinder, such as in model DFG-830 from Disco Corporation of Japan. The surface grinding 110 suitably includes a rough grinding step and a fine grinding step. Rough grinding is suitably performed using a 600 mesh with 20-30 microns grit size, and fine grinding is 3000 mesh and grit size of 2-6 microns. - Referring again to
FIG. 6 , etching 112 is next performed on the bondedwafer 105, and is suitably performed in a conventional etching apparatus using an alkali etchant, though an acid etchant may also be used. Polishing 114 is then performed and is suitably a single-side polishing onfront surface 105F using a Strasbaugh Mark 9-K. Alternatively, the polishing 114 may be a double-side polishing of both thefront surface 105F and backsurface 105B. Finishing 116 of the bondedwafer 105 includes inspecting the wafer for all required parameters, such as flatness and particle count, and then packaging the wafer for shipment to customers. - As can be seen from
FIGS. 7E and 13 , the finished or bondedwafer 105 has an upper portion having a trapezoid shape. More specifically, the upper portion including the remainder of theactive layer wafer 101 and a relatively small portion of the substrate wafer is angled at the outer peripheral edge portion so that the wafer is said to have a trapezoid shape or a trapezoid shape in cross-section. Note the lower portion of the bonded wafer 105 (which corresponds substantially to thesubstrate wafer 103 in this embodiment) has a conventional bevel or rounded shape (broadly, a curved shape) at its outer peripheral edge and thus does not have a trapezoid shape. The upper portion of the bondedwafer 105 is substantially coincident with theactive wafer 101 in this embodiment. - Referring again to
FIG. 7C , an outer peripheral edge of theactive wafer 101 is brought into contact with the grinding wheel and is ground at an angle relative to thefront surface 105F of the bondedwafer 105. The angle is suitably between about 3° and 10°, and in this embodiment the angle is about 7°. The edge grinding is performed until the entire outer peripheral edge is ground as shown inFIG. 7D . The grinding eliminates any notch in the outer peripheral edge. The grinding may suitably be done such that the length of the angled or sloped portion is between about 1 mm and 1.5 mm, e.g. about 1.25 mm. Note that the angle and depth of grind is such that a small portion of thetop bevel 119 of thesubstrate wafer 103 is removed during the trapezoid grinding. - In
FIG. 7C , the surface of theactive wafer 101 is ground until it has a thickness of 40-50 microns, as shown inFIG. 7D . Note the trapezoid shape of theactive wafer 101 inFIG. 7D . Also, the edge grind is performed such that a portion of thesubstrate wafer 103 is ground. - Referring to FIGS. 8 and 9A-9D, the grinding steps are reversed as compared to that of FIGS. 6 and 7A-7D. In other words, the surface of the
active wafer 101 is ground first, before the trapezoid grinding. This order of steps is shown inFIG. 8 . Again, the surface grinding step may include a rough grinding step and a fine grinding step. Rough grinding is suitably performed using a 600 mesh and grit size of 20 to 30 microns, and fine grinding is 3000 mesh and grit size of 2 to 6 microns. The surface is ground as shown inFIG. 9B , and then the edge of theactive wafer 101 is next ground inFIG. 9C until the edges have the trapezoid shape shown inFIG. 9D . - Referring to
FIGS. 10 and 11 , a grinding wheel 151 (broadly, a trapezoid grinding tool) of one embodiment is designed for the performance of the trapezoid grinding 108. Thewheel 151 is adapted to be mounted on a conventionaledge profiling machine 152 that performs the trapezoid grinding. In this embodiment, the profiling machine is an STC EP-5800RHO machine adapted for 200 mm diameter wafers. Thewheel 151 is mounted on aspindle 153 of theprofiling machine 152. - The
wheel 151 of this embodiment is ring-shaped or annular and has acentral hole 154 adapted for mounting the wheel on the on thespindle 151 of theprofiling machine 152. Thewheel 151 has a diameter D of 202 mm with a central hole diameter HD of 30 mm and thickness of 20 mm. Thewheel 151 of this embodiment has anupper groove 155, acentral groove 157 and alower groove 159 disposed at an outer edge of the wheel. Thegrooves wheel 151 may alternatively have just one groove, or practically any other number of grooves, within the scope of this disclosure. - In this embodiment, the upper and
central grooves lower groove 159 is adapted for rough grinding. Each groove suitably includes diamond grits. For fine grinding, diamond grit size of 2000 or 3000 mesh is suitable. For rough grinding, 600 mesh or 800 mesh is suitable. Thewheel 151 is suitably made of metal alloy, aluminum alloy, or stainless steel, though other materials are contemplated. - Each groove wall of this embodiment slopes from a bottom of the groove to a top of the groove and has a flat bottom. In this embodiment, the slope is at about a 7° angle. The width of the bottom of the groove is about 1.8 mm for use with a bonded wafer having a total thickness of about 200 mm, so that the substrate wafer or back surface of the wafer is not in contact with the groove during trapezoid grinding. The width of each groove at its widest portion (the top of the groove) is about 3.5 mm. The wall of the groove curves into the bottom of the groove at a radius of about 0.2 mm. The groove depth GD is about 6.0 mm and the groove root depth RD is about 8.0 mm.
- The
wheel 151 is installed on theedge profiling machine 152, such as on a spindle of the STC EP-5800 RHO. After wheel installation, spindle height (vertical direction) and distance (horizontal direction) are fine adjusted, so thatgroove 155 of thewheel 151 and the bondedwafer 105 are aligned as shown inFIG. 12 . Note that the outermost portion of substrate wafer edge and the bottom surface are not in contact with the grindinggroove 155. Then, trapezoid grinding is performed as described above. Trapezoid grinding can be performed with either rough grit groove or fine grit groove or both grit grooves (first rough grit groove, then fine grit groove). The grinding may be performed as a single pass or multiple pass process, depending, for example, on edge quality requirements. - The above example methods are applied to remove the unbonded outer peripheral parts of an active layer wafer bonded on a substrate wafer. This results in a bonded wafer having a more securely bonded outer peripheral portion. In a suitable method, after bonding of an active layer wafer onto a support substrate and post-bond heat treat of the bonded pairs, trapezoid grinding is applied to remove the unbonded outer peripheral portion of the active layer wafer. An edge grinding wheel such as
wheel 151 may be used to perform the trapezoid grinding step. Among other advantages, the bonded wafer according to embodiments of this disclosure is less likely to suffer delamination. Additionally, the bonded wafer inhibits or prevents particle contamination that might otherwise occur due to delaminated unbonded portions on the process/device lines of the wafer. - When introducing elements of the present invention or the embodiment(s) thereof, the articles “a”, “an”, “the” and “said” are intended to mean that there are one or more of the elements. The terms “comprising”, “including” and “having” are intended to be inclusive and mean that there may be additional elements other than the listed elements.
- As various changes could be made in the above constructions without departing from the scope of the invention, it is intended that all matter contained in the above description and shown in the accompanying drawing[s] shall be interpreted as illustrative and not in a limiting sense.
Claims (18)
Priority Applications (8)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US12/847,015 US20120028555A1 (en) | 2010-07-30 | 2010-07-30 | Grinding Tool For Trapezoid Grinding Of A Wafer |
SG2013002647A SG187057A1 (en) | 2010-07-30 | 2011-07-22 | Grinding tool for trapezoid grinding of a wafer |
CN2011800376052A CN103180098A (en) | 2010-07-30 | 2011-07-22 | Grinding tool for trapezoid grinding of a wafer |
KR1020137002424A KR20130132388A (en) | 2010-07-30 | 2011-07-22 | Grinding tool for trapezoid grinding of a wafer |
EP11760557.6A EP2598286A2 (en) | 2010-07-30 | 2011-07-22 | Grinding tool for trapezoid grinding of a wafer |
JP2013521270A JP2013532587A (en) | 2010-07-30 | 2011-07-22 | Grinding tool for trapezoidal grinding of wafers |
PCT/IB2011/053282 WO2012014137A2 (en) | 2010-07-30 | 2011-07-22 | Grinding tool for trapezoid grinding of a wafer |
TW100126843A TW201212116A (en) | 2010-07-30 | 2011-07-28 | A grinding tool for trapezoid grinding of a wafer |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US12/847,015 US20120028555A1 (en) | 2010-07-30 | 2010-07-30 | Grinding Tool For Trapezoid Grinding Of A Wafer |
Publications (1)
Publication Number | Publication Date |
---|---|
US20120028555A1 true US20120028555A1 (en) | 2012-02-02 |
Family
ID=44674831
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US12/847,015 Abandoned US20120028555A1 (en) | 2010-07-30 | 2010-07-30 | Grinding Tool For Trapezoid Grinding Of A Wafer |
Country Status (8)
Country | Link |
---|---|
US (1) | US20120028555A1 (en) |
EP (1) | EP2598286A2 (en) |
JP (1) | JP2013532587A (en) |
KR (1) | KR20130132388A (en) |
CN (1) | CN103180098A (en) |
SG (1) | SG187057A1 (en) |
TW (1) | TW201212116A (en) |
WO (1) | WO2012014137A2 (en) |
Cited By (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US20140235032A1 (en) * | 2011-10-17 | 2014-08-21 | Shin-Etsu Chemical Co., Ltd. | Method for producing transparent soi wafer |
CN111390713A (en) * | 2020-04-09 | 2020-07-10 | 张侠 | Electric insulator machining and forming process |
US11450578B2 (en) * | 2018-04-27 | 2022-09-20 | Tokyo Electron Limited | Substrate processing system and substrate processing method |
Families Citing this family (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
KR101871854B1 (en) * | 2016-05-31 | 2018-06-28 | 주식회사 케이엔제이 | Substrate treatment apparatus |
CN106239306B (en) * | 2016-08-01 | 2018-07-31 | 中国电子科技集团公司第四十六研究所 | A kind of change R value Waffer edge chamfering methods |
CN109571183B (en) * | 2018-11-30 | 2024-02-20 | 温州市华晖汽摩配件厂(普通合伙) | Self-water-outlet multi-radian lens glass chamfering grinding head for lens edging machine |
KR102195461B1 (en) * | 2019-03-28 | 2020-12-29 | 주식회사 케이엔제이 | Substrate grinding apparatus |
KR102199074B1 (en) * | 2019-05-28 | 2021-01-06 | 주식회사 케이엔제이 | Substrate grinding apparatus |
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JP3635200B2 (en) * | 1998-06-04 | 2005-04-06 | 信越半導体株式会社 | Manufacturing method of SOI wafer |
JP2001246536A (en) * | 1999-12-27 | 2001-09-11 | Three M Innovative Properties Co | Method of mirror-finishing edge of recording medium disc original plate |
WO2001048752A1 (en) * | 1999-12-27 | 2001-07-05 | 3M Innovative Properties Company | Process for mirror-finishing the edge of a recording disk raw plate |
JP4839818B2 (en) | 2005-12-16 | 2011-12-21 | 信越半導体株式会社 | Manufacturing method of bonded substrate |
CN201350598Y (en) * | 2008-12-30 | 2009-11-25 | 浙江水晶光电科技股份有限公司 | Processing abrasive wheel for rounding wafer |
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- 2010-07-30 US US12/847,015 patent/US20120028555A1/en not_active Abandoned
-
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- 2011-07-22 KR KR1020137002424A patent/KR20130132388A/en not_active Application Discontinuation
- 2011-07-22 EP EP11760557.6A patent/EP2598286A2/en not_active Withdrawn
- 2011-07-22 SG SG2013002647A patent/SG187057A1/en unknown
- 2011-07-22 CN CN2011800376052A patent/CN103180098A/en active Pending
- 2011-07-22 WO PCT/IB2011/053282 patent/WO2012014137A2/en active Application Filing
- 2011-07-22 JP JP2013521270A patent/JP2013532587A/en not_active Withdrawn
- 2011-07-28 TW TW100126843A patent/TW201212116A/en unknown
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US6431961B1 (en) * | 1998-05-18 | 2002-08-13 | Tokyo Seimitsu Co., Ltd. | Apparatus and method for chamfering wafer |
US6482749B1 (en) * | 2000-08-10 | 2002-11-19 | Seh America, Inc. | Method for etching a wafer edge using a potassium-based chemical oxidizer in the presence of hydrofluoric acid |
US6900522B2 (en) * | 2002-01-11 | 2005-05-31 | Nikko Materials Co., Ltd. | Chamfered semiconductor wafer and method of manufacturing the same |
US20050112999A1 (en) * | 2003-11-26 | 2005-05-26 | Tokyo Seimitsu Co. | Method of truing chamfering grindstone and chamfering device |
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US20140235032A1 (en) * | 2011-10-17 | 2014-08-21 | Shin-Etsu Chemical Co., Ltd. | Method for producing transparent soi wafer |
US11450578B2 (en) * | 2018-04-27 | 2022-09-20 | Tokyo Electron Limited | Substrate processing system and substrate processing method |
CN111390713A (en) * | 2020-04-09 | 2020-07-10 | 张侠 | Electric insulator machining and forming process |
Also Published As
Publication number | Publication date |
---|---|
TW201212116A (en) | 2012-03-16 |
KR20130132388A (en) | 2013-12-04 |
SG187057A1 (en) | 2013-02-28 |
JP2013532587A (en) | 2013-08-19 |
CN103180098A (en) | 2013-06-26 |
WO2012014137A2 (en) | 2012-02-02 |
EP2598286A2 (en) | 2013-06-05 |
WO2012014137A3 (en) | 2012-03-22 |
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