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KR-20260065222-A - Dresser for wafer lapping apparatus

KR20260065222AKR 20260065222 AKR20260065222 AKR 20260065222AKR-20260065222-A

Abstract

The embodiment relates to a dressing device of a wafer wrapping device capable of automatically dressing the edges of a plate worn by a wrapping process to maintain a reference curvature. According to one aspect of an embodiment, a dressing device for a wafer lapping device is provided, comprising: an upper platen installed to be vertically and rotatable; a lower platen rotatably installed below the upper platen and engaging with the upper platen to lap a wafer; an inner gear rotatably provided on the inner circumference of the lower platen; an outer gear rotatably provided on the outer circumference of the lower platen; and an edge dresser installed across the inner and outer circumferences of the upper and lower platens and engaging with the inner and outer gears, and which moves along the upper and lower platens as the inner gear and the outer gear rotate to polish the inner and outer circumference edges of the lower surface of the upper platen and the inner and outer circumference edges of the upper surface of the lower platen to have an initial curvature.

Inventors

  • 허유신

Assignees

  • 에스케이실트론 주식회사

Dates

Publication Date
20260508
Application Date
20241101

Claims (8)

  1. Upper plate installed to be able to move and rotate; A lower platen rotatably installed below the upper platen and engaging with the upper platen to wrap a wafer; An inner gear rotatably provided in the inner circumference of the lower platen above; An outer gear rotatably provided on the outer circumference of the lower platen; and A dressing device for a wafer lapping device comprising: an edge dresser installed to cross the inner and outer portions of the upper and lower platens and to mesh with the inner and outer gears, and which polishes the inner and outer edge portions of the lower surface of the upper platen and the inner and outer edge portions of the upper surface of the lower platen to have an initial curvature as it moves along the upper and lower platens as the inner gear and the outer gear rotate.
  2. In paragraph 1, The above-mentioned counter dresser is, A bar-shaped main body that crosses the inner and outer peripheries of the upper and lower plates, and An inner gear connecting part provided on one side of the main body to mesh with the inner gear, and An outer gear connecting part provided on the other side of the main body to mesh with the outer gear, and An upper/lower inner edge processing part formed between the main body part and the inner gear connection part and dressing the inner edge of the upper/lower platen, and A dressing device for a wafer lapping device comprising upper/lower outer edge processing portions formed between the main body portion and the outer gear connection portion and dressing the outer edge portions of the upper/lower platen.
  3. In paragraph 2, The upper/lower inner edge processing parts mentioned above are, A dressing device for a wafer lapping device configured to have a curvature (R1) in the vertical direction of the upper/lower platen that is the same as the curvature of the inner corner reference of the upper/lower platen.
  4. In paragraph 2, The above upper/lower outer edge processing parts are, A dressing device for a wafer wrapping device configured to have a curvature (R2) in the vertical direction of the upper/lower platen that is the same as the curvature of the outer edge reference of the upper/lower platen.
  5. In paragraph 2, The upper/lower inner edge processing parts mentioned above are, A dressing device for a wafer lapping device configured to have a radius of curvature (R3) equal to the inner circumference reference radius of the upper/lower plate in the circumferential direction of the upper/lower plate.
  6. In paragraph 2, The above upper/lower outer edge processing parts are, A dressing device for a wafer lapping device configured to have a radius of curvature (R4) equal to the outer circumference reference radius of the upper/lower plate before the upper/lower plate is worn in the circumferential direction.
  7. In any one of paragraphs 1 through 6, The above edge dresser is, A dressing device for a wafer wrapping device composed of the same material as the upper and lower plates above.
  8. In any one of paragraphs 1 through 6, The above inner/outer gears are, A dressing device for a wafer wrapping device that operates at the same rotational speed while wrapping the upper and lower plates to maintain a rotational and orbital ratio of the edge dresser at 1:1.

Description

Dresser for wafer lapping apparatus The embodiment relates to a dressing device of a wafer wrapping device capable of automatically dressing the edges of a plate worn by a wrapping process to maintain a reference curvature. A wafer, which is widely used as a material for manufacturing semiconductor devices, refers to a thin sheet of single-crystal silicon made from polycrystalline silicon as a raw material. These wafers are manufactured by growing polycrystalline silicon into a single-crystal silicon ingot, followed by a slicing process that cuts the silicon ingot into the shape of a wafer, a lapping process that flattens the thickness of the wafer, an etching process that removes or mitigates damage caused by mechanical polishing, a polishing process that mirrors the wafer surface, and a cleaning process that cleans the wafer. According to the lapping process, a wafer mounted on a disc-shaped lapping carrier equipped with multiple holes is brought into close contact between an upper platen and a lower platen, and then a slurry is injected between the wafer and the upper/lower platens, and when the upper/lower platens are rotated, the wafer rotates and revolves, and the surface of the wafer is polished by the slurry. FIG. 1 is a side cross-sectional view schematically showing a part of a wafer wrapping device according to the prior art, and FIG. 2 is a drawing showing the change in the corner of the lower platen as the wrapping process proceeds in FIG. 1. A wafer wrapping device according to the prior art positions a carrier (3) with a plurality of wafers (W) mounted between an upper plate (1) and a lower plate (2) as shown in FIG. 1, and the outer end of the carrier (3) is engaged with an inner gear (4) and an outer gear (5). By bringing the upper platen (1) and the lower platen (2) into contact with the upper and lower surfaces of the wafers (W), and rotating the upper platen (1) and the lower platen (2) in opposite directions while simultaneously supplying a slurry to the surface of the wafers (W) through holes (not shown) provided in the upper platen (1), the surface of the wafers (W) can be polished. As the lapping process is repeated, wear occurs on the lapping plate, and due to the decrease in the R value of the outer edge of the plate, a wafer overhang may occur in which a part of the wafer (W) moves out of the upper plate (1) and the lower plate (2) during the lapping process, and since the corner of the upper plate (1) or the corner of the lower plate (2) concentrates stress on the wafer (W), an edge ring pattern may occur on the wafer (W). When observing the changes in the lower platen (2) due to overhang as the lapping process is repeated, as shown in FIG. 2 (a) to (b), the corner (2a) of the lower platen wears down, and the curvature at the corner (2a) of the lower platen decreases, thereby causing damage to the contact area of the wafer that comes into contact with the corner (2a) of the lower platen. Therefore, as shown in FIG. 2 (c) to (d), the operator uses a grinding stone (10) to dress the corner (2a) of the lower platen, thereby maintaining the curvature at the corner (2a) of the lower platen as it was initially, and preventing damage to the wafer. However, according to conventional technology, since the worker directly dresses the edges of the plate using a grinding stone, the workload is high, and it is difficult to maintain a constant curvature on the edges of the plate, which leads to a problem of a high wafer defect rate. FIG. 1 is a side cross-sectional view schematically showing a part of a wafer wrapping device according to the prior art. FIG. 2 is a drawing showing the change in the edge of the lower platen as the wrapping process proceeds in FIG. 1. FIG. 3 is a side cross-sectional view schematically showing a part of a wafer wrapping device according to an embodiment. FIG. 4 is a plan view schematically showing a part of a wafer wrapping device according to an embodiment. Hereinafter, the present embodiment will be examined in detail with reference to the attached drawings. FIG. 3 is a side cross-sectional view schematically showing a part of a wafer wrapping device according to an embodiment, and FIG. 4 is a plan view schematically showing a part of a wafer wrapping device according to an embodiment. A wafer lapping device according to an embodiment may include an upper plate (110) and a lower plate (120) for polishing a wafer as shown in FIGS. 3 and 4, an inner gear (140) and an outer gear (150) for orbiting and rotating a carrier (not shown) on which a wafer is placed between the upper plate (110) and the lower plate (120), and an edge dresser (200) that polishes the lower edge of the upper plate (110) and the upper edge of the lower plate (120) while moving in engagement with the inner gear (140) and the outer gear (150) to maintain an initial curvature. The upper plate (110) is installed in the shape of a ring plate so as to be able to move up and down and rotate, and the