PTAB

IPR2016-01314

Qualcomm Inc v. DSS Technology Management Inc

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Petition
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1. Case Identification

2. Patent Overview

  • Title: Semiconductor Device Structure and Manufacturing Method
  • Brief Description: The ’552 patent relates to a method for manufacturing semiconductor transistors. The invention purports to solve the problem of electrical short-circuits caused by the erosion of sidewall spacers during the creation of contact openings, disclosing a process using an anisotropic etchant to retain the spacer’s "substantially rectangular" shape.

3. Grounds for Unpatentability

Ground 1: Claims 8-12 are Anticipated by Heath

  • Prior Art Relied Upon: Heath (Patent 4,686,000).
  • Core Argument for this Ground:
    • Prior Art Mapping: Petitioner argued that Heath, filed nearly a decade prior to the ’552 patent’s claimed priority date, discloses every element of the challenged claims and was not considered during prosecution. Heath describes an "improved process for self-aligned contact window formation" that leaves a "‘Stick’ of etch stop on vertical sidewall surfaces to be protected," addressing the same short-circuit problem as the ’552 patent. Petitioner asserted that Heath’s figures and specification explicitly teach a transistor structure comprising a source/drain region on a substrate, a gate electrode, an electrically insulative spacer with a "substantially vertical" (i.e., 90-degree) side relative to the substrate, an etch stop material of a different composition than the spacer, and a contact opening, all arranged as recited in independent claim 8 and its dependent claims.

Ground 2: Claims 8-12 are Obvious over Heath in view of Dennison

  • Prior Art Relied Upon: Heath (Patent 4,686,000) and Dennison (Patent 5,338,700).
  • Core Argument for this Ground:
    • Prior Art Mapping: Petitioner asserted this ground as an alternative, particularly if the "angle" limitation of claim 8 is narrowly construed to require a vertical side formed on a partially etched portion of the spacer. While Heath teaches a fully vertical spacer, Dennison explicitly discloses a process where etching proceeds only partially through a sidewall spacer, leaving a "substantially vertical portion at the top of the insulating spacer." Petitioner argued the combination of Heath’s fundamental structure with Dennison’s partial etching technique meets all claim limitations. The argument also addressed a scenario where Heath might be found not to disclose an etch stop material over the spacer; in that case, Dennison's teaching of leaving etch stop material over a partially etched spacer would have made this configuration obvious.
    • Motivation to Combine: A POSITA would combine Heath and Dennison as both patents are in the same field of transistor manufacturing and address the common goal of creating properly aligned contact openings. Heath recognizes that proper alignment is a desired goal to prevent short-circuits. Dennison teaches that improved alignment can result in a structure with a partially etched spacer having a vertical side. A POSITA seeking to improve alignment in Heath's process would have been motivated to apply the partial etching technique from Dennison.
    • Expectation of Success: A POSITA would have had a high expectation of success in combining the teachings. The etching processes described in both references (e.g., using CHF3 and O2 gases) were well-known and predictable. Dennison itself demonstrated that it was possible to control the etch to leave a vertical side on a partially etched spacer, confirming the feasibility of the combination.

4. Key Claim Construction Positions

  • Term: "a side of the insulating spacer has an angle relative to the substrate surface that is either a right angle or an acute angle of more than 85°" (from claim 8).
  • Petitioner's Proposed Construction: Petitioner argued the term should be construed to mean "a side of the insulating spacer has an angle relative to the horizontal substrate surface that is greater than 85° and less than or equal to 90°."
  • Rationale: Petitioner contended this construction was supported by the plain language ("a side" meaning any side), the specification (which shows the angle measured at both the top and bottom of the spacer in different figures), and the Patent Owner's own infringement contentions in co-pending litigation. The core of the position was that the claim is not limited to measuring the angle on a specific portion of the spacer (e.g., only an upper, partially etched side).

5. Relief Requested

  • Petitioner requests institution of an inter partes review and cancellation of claims 8-12 of the ’552 patent as unpatentable.