PTAB

IPR2018-00524

Xilinx Inc v. Anza Technology Inc

Key Events

Petition

petition

Title: Flip Chip Bonding Tool Tip
Brief Description: The ’905 patent is directed to a flip chip bonding tool tip formed from a dissipative material to avoid electrostatic discharge (ESD) during microelectronic assembly. The invention claims a method of using a tool tip with specific electrical resistance properties to prevent charge buildup and current flow that could damage the sensitive electronic device being bonded.

Prior Art Relied Upon: Onitsuka (Patent 5,839,645) and Reiber (TW 486400).
Core Argument for this Ground:
- Prior Art Mapping: Petitioner argued that Onitsuka disclosed a method for using a flip chip bonding tool in microelectronic assembly, including the steps of providing a bonding machine, equipping it with a tool, and bonding a component. However, Onitsuka did not explicitly teach making the tool tip from a dissipative material. Reiber, which relates to a "dissipative ceramic bonding tip," was argued to teach this missing element. Reiber disclosed a tool tip material with a resistance "low enough to prevent electrostatic discharge from the device being bonded, but high enough to prevent a high current from damaging the device," directly mapping onto the functional language of claim 53.
- Motivation to Combine: A person of ordinary skill in the art (POSITA) would have been motivated to combine Reiber's dissipative tip with Onitsuka's flip chip tool to achieve Reiber's stated goal of "avoid[ing] damaging delicate electronic devices by any electrostatic discharge." The combination represented the application of a known solution to a known problem.
- Expectation of Success: A POSITA would have had a reasonable expectation of success in making this combination, as it involved incorporating a known ESD-prevention material into a standard bonding tool to achieve the predictable result of a safer bonding process.

Prior Art Relied Upon: Onitsuka (Patent 5,839,645), Reiber (TW 486400), and Tan (a 1995 IEEE Symposium paper).
Core Argument for this Ground:
- Prior Art Mapping: This ground built on the combination of Onitsuka and Reiber to teach a dissipative flip chip bonding tool. Reiber further disclosed a resistance range of 10⁵ to 10¹² ohms, which overlaps with the 10² to 10¹² ohm range recited in claim 55. The argument introduced Tan to teach the final limitation of claim 55: "grounding leads on the device being bonded." Tan explicitly taught that grounding conductors is the "best method of preventing damage" from static charge in automated production tools and disclosed using grounding cables.
- Motivation to Combine: A POSITA would combine Tan’s grounding technique with the dissipative tool of Onitsuka/Reiber to provide a complete and effective discharge pathway to ground. This was described as an advantageous and well-understood method for preventing charge accumulation and device damage in ESD-sensitive environments.

Prior Art Relied Upon: Onitsuka (Patent 5,839,645) and Shinji (WO 98/49121).
Core Argument for this Ground:
- Prior Art Mapping: This ground provided an alternative combination for claim 53, substituting Shinji for Reiber. As in Ground 1, Onitsuka taught the flip chip bonding tool and method. Shinji taught a dissipative bonding tip made from a semiconductive "zirconia sinter" material, which it described as "ideally suited for applications requiring destaticizing" in device manufacturing. Shinji disclosed a material with a surface resistivity (10⁶ to 10⁹ Ω·cm) that would result in a tool having the functional resistance properties required by claim 53.
- Motivation to Combine: A POSITA would have been motivated to employ Shinji's dissipative material in Onitsuka's flip chip tool to achieve Shinji's express benefit of destaticizing and preventing ESD damage. The combination would have been a simple substitution of one known dissipative material for another to achieve a predictable function.

Prior Art Relied Upon: Onitsuka (Patent 5,839,645), Shinji (WO 98/49121), and Tan (1995 IEEE paper).
Core Argument for this Ground:
- Prior Art Mapping: This ground paralleled Ground 2, using the Onitsuka/Shinji combination as the base. The combination of Onitsuka and Shinji provided a dissipative flip chip bonding tool with a resistance within the claimed range. Tan was again relied upon to teach the "grounding leads on the device being bonded" limitation.
- Motivation to Combine: The motivation was identical to that in Ground 2: a POSITA would add Tan's known grounding technique to the dissipative tool taught by Onitsuka and Shinji to create a robust and reliable ESD protection system.

Petitioner argued that no special claim construction was necessary to find the challenged claims invalid. However, for the purposes of the petition, it adopted the Patent Owner's own proposed construction for the term "dissipative" from a related litigation: "[a material] having an electrical resistance in the range between completely insulative and completely conductive, excluding both endpoints." Petitioner contended this broad definition clearly encompassed the resistance range of 10² to 10¹² ohms and was readily met by the prior art.

A central contention of the petition was that challenged claims 53 and 55 were not entitled to the 1999 priority date of the patent's earliest parent applications. Petitioner argued that the key claimed subject matter—specifically a "flip chip bonding tool" and its required resistance range of 10² to 10¹² ohms—constituted new matter first introduced in a 2003 provisional application ('267 provisional).
The argument asserted that the patent’s ancestors focused on wire bonding and disclosed higher resistance ranges (e.g., starting at 10⁵ ohms). The absence of any disclosure related to flip chip bonding or the lower resistance range in the earlier applications was presented as dispositive evidence of a lack of written description support. This contention was critical for establishing that references like Reiber (2002) and Shinji (1998) were valid prior art against the challenged claims.

Petitioner requested that the Board institute an inter partes review of claims 53 and 55 of Patent 7,389,905 and find them unpatentable.