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EP0628992A2 Expired / Lapsed EP ⏱️ 0.0 years remaining

Method of making semiconductor wafers

Assignee: Shin-Etsu Handotai Co Ltd
•
Filing: 1994-06-01
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Granted: —
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Expires: 2014-06-01
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Abstract

Abstract A method for a flatter semiconductor wafer free of ORP -observed irregularity and particles generated in handling on the back side of the wafer, in which an alkaline etching is adopted to utilize its advantage and a slight polishing step is combined to a conventional method of this kind. A deficiency of alkaline etching which brings about rougher surface irregularities on the surface of a wafer is eliminated by the use of the step of slight polishing on the back surface after the etching step and the inherent advantage stands without a loss, so that particle generation from the back surface of a semiconductor wafer in handling is much reduced and what's more a flatter semiconductor wafer is realized and a yield of an electronic device fabrication grows the higher.

Inventors

  • 👤 Tadahiro 89-2 Aza-Haranaka Kato
  • 👤 Masami 150-5 Aza-Ohira Nakano
  • 👤 Sunao 150-5 Aza-Ohira Shima
  • 👤 Hisashi 89-2 Aza-Haranaka Masumura

Bibliographic Details

Application Number —
Jurisdiction EP
Data Source google_patents
Last Synchronized 2026-11-03 08:41
CPC Classifications
H; H10; H10P; H10P90/00; H10P90/12; H10P50/00; Y; Y10; Y10S; Y10S438/00; Y10S438/906; Y10S438/928; Y10S438/959; Y10S438/974; Y10S438/977

Claims Analysis

Total Claims: 6
Claim 1
Independent Claim 137 words
A method of making semiconductor wafers comprising the steps of (a) slicing a monocrystalline ingot pulled in a monocrystalline ingot puller to obtain disk-shaped wafers, (b) chamfering the wafer periphery to prevent cracks in and chipping off of the sliced wafer, (c) lapping the chamfered wafer to flatten the surface, (d) etching off the work damage retained in the wafer, (e) polishing the etched wafer across one of the surfaces, and (f) cleaning the polished wafer to remove the residual of a polishing slurry and the other foreign substances on the wafer characterized by choosing an alkaline etching in the etching step for etching off the work damage and further partly removing the surface irregularities formed on the back side during the alkaline etching before the polishing step across one of the surfaces of the wafer .
Claim 2
Dependent Claim 38 words
A method according to claim 1, wherein the alkaline etching is performed by the use of an aqueous solution of sodium hydroxide or an aqueous solution of potassium hydroxide as an etching solution in the etching step .
Claim 3
Dependent Claim 18 words
A method according to claim 2, wherein the aqueous solution of sodium hydroxide 45% by weight is adopted.
Claim 4
Dependent Claim 36 words
A method according to claim 2, wherein the surface of the back side is finished by an alkaline etching into a surface roughness of 10 to 20 µm and a peak-to-valley height of under 1.5 µm.
Claim 5
Dependent Claim 43 words
A method according to claim 1, wherein a slight polishing is applied on a back surface of the etched wafer between the etching for etching off the work damage and the front polishing step for polishing the etched wafer across a front surface.
Claim 6
Dependent Claim 24 words
A method according to claim 5, wherein the stock removal on the back surface is restricted under 3.0µm in depth in the slight polishing.

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