Prior art

Analysis of Prior Art for U.S. Patent 7,288,822

Washington D.C. – May 13, 2026 – An analysis of the prior art cited against U.S. Patent No. 7,288,822, titled "Semiconductor structure and fabricating method thereof," reveals several key patents and patent applications that were considered by the United States Patent and Trademark Office (USPTO) during its examination. This review assesses the potential for these references to anticipate the claims of the '822 patent under 35 U.S.C. § 102, which pertains to novelty.

The '822 patent, granted on October 30, 2007, with a priority date of April 7, 2006, is assigned to Marlin Semiconductor Ltd. The invention focuses on a semiconductor structure that includes a doped, strained layer for the source/drain regions of a MOS transistor. A key feature is the creation of a non-uniform lattice parameter distribution within this strained layer to reduce defects at the interface with the substrate.

Below is a summary of the most relevant prior art and an analysis of their potential impact on the claims of US 7,288,822.

Prior Art Analysis:

1. US Patent No. 5,977,592 A

• Full Citation: US Patent 5,977,592 A, "Semiconductor device having an improved structure and capable of greatly reducing its occupied area"
• Publication Date: November 2, 1999
• Filing Date: January 31, 1997
• Brief Description: This patent, assigned to Oki Electric Industry Co., Ltd., describes a semiconductor device with a structure designed to reduce its overall size. It discloses various configurations of transistors and other components to achieve higher packing density.
• Potential Anticipation of Claims: While this patent addresses semiconductor device structure, its focus is primarily on layout and size reduction rather than the specific material properties of strained source/drain regions with a graded lattice parameter, as claimed in the '822 patent. Therefore, it is unlikely to anticipate the core claims of US 7,288,822, particularly those detailing the gradient distribution of the lattice parameter in the strained layer (Claims 1, 2, 12, and 13).

2. US Patent No. 6,914,307 B2

• Full Citation: US Patent 6,914,307 B2, "Semiconductor device and method of manufacturing the same"
• Publication Date: July 5, 2005
• Filing Date: November 21, 2000
• Brief Description: Assigned to Mitsubishi Denki Kabushiki Kaisha, this patent details a semiconductor device and its manufacturing method, with an emphasis on improving device performance. It discusses the use of different materials and structures within the transistor.
• Potential Anticipation of Claims: This reference is more pertinent as it discusses methods to enhance semiconductor device performance. However, a detailed review would be necessary to determine if it discloses a strained source/drain layer with a lattice parameter that is intentionally varied to be smaller at the bottom of an opening, as specified in claim 1 and its dependent claims in the '822 patent. Without a specific disclosure of this gradient, it would not anticipate these claims.

3. US Patent Application Publication No. 2003/0122199 A1

• Full Citation: US Patent Application Publication No. 2003/0122199 A1, "Semiconductor device and fabricating method for the same"
• Publication Date: July 3, 2003
• Filing Date: December 18, 2001
• Brief Description: This application from Kabushiki Kaisha Toshiba describes a semiconductor device and a method for its fabrication. It addresses improving the characteristics of semiconductor devices.
• Potential Anticipation of Claims: This document could be relevant if it teaches the formation of a strained layer in the source/drain regions. The key to an anticipation argument would be whether it explicitly or inherently discloses the gradient in the lattice parameter to reduce defects, which is a central inventive concept of the '822 patent. A thorough examination of the application's detailed description and figures is required.

4. US Patent Application Publication No. 2005/0266631 A1

• Full Citation: US Patent Application Publication No. 2005/0266631 A1, "Semiconductor device fabricating method"
• Publication Date: December 1, 2005
• Filing Date: May 26, 2004
• Brief Description: This application, assigned to Fujitsu Limited, outlines a method for fabricating a semiconductor device. It likely discusses techniques to improve device performance and reliability during the manufacturing process.
• Potential Anticipation of Claims: As this publication predates the priority date of the '822 patent, its teachings are relevant prior art. The analysis would hinge on whether the disclosed fabrication method results in a semiconductor structure with a first MOS transistor having a strained layer in a first opening with a graded lattice parameter as recited in claim 1. If the method described in this application inherently produces such a structure, it could be considered to anticipate the claim.

5. US Patent Application Publication No. 2006/0202278 A1

• Full Citation: US Patent Application Publication No. 2006/0202278 A1, "Semiconductor integrated circuit and cmos transistor"
• Publication Date: September 14, 2006
• Filing Date: March 9, 2005
• Brief Description: Another application from Fujitsu Limited, this document describes a semiconductor integrated circuit and a CMOS transistor, likely focusing on performance enhancements.
• Potential Anticipation of Claims: While published after the priority date of the '822 patent, its filing date is before, making it relevant prior art. The core of the analysis would be to determine if this application discloses a first MOS transistor on a second well with a strained layer having the specific lattice parameter difference characteristic as claimed in claim 1 of the '822 patent.

6. US Patent No. 7,226,820 B2

• Full Citation: US Patent 7,226,820 B2, "Transistor fabrication using double etch/refill process"
• Publication Date: June 5, 2007
• Filing Date: April 7, 2005
• Brief Description: This patent from Freescale Semiconductor, Inc., describes a method of transistor fabrication that involves a double etch and refill process. This is often used to create specialized structures in the source/drain regions.
• Potential Anticipation of Claims: This reference is highly relevant as it details a process for forming source/drain regions. The "double etch/refill" could potentially be used to create a graded strained layer. The key question for anticipation would be whether the patent explicitly teaches varying the material composition during the refill process to achieve the lattice parameter gradient claimed in the '822 patent.

7. US Patent Application Publication No. 2007/0018328 A1

• Full Citation: US Patent Application Publication No. 2007/0018328 A1, "Piezoelectric stress liner for bulk and SOI"
• Publication Date: January 25, 2007
• Filing Date: July 7, 2005
• Brief Description: This application describes the use of a piezoelectric stress liner to induce strain in a transistor channel.
• Potential Anticipation of Claims: This reference focuses on a different mechanism for inducing strain (a stress liner) compared to the '822 patent's approach of a graded strained layer in the source/drain regions. Therefore, it is less likely to anticipate the specific structural claims of US 7,288,822 that require the strained layer to be within an opening in the well.

In conclusion, while all cited references are within the field of semiconductor devices and fabrication, the most significant for a novelty challenge under 35 U.S.C. § 102 against US Patent 7,288,822 would be those that disclose the formation of strained source/drain regions. A definitive determination of anticipation would require a meticulous comparison of the specific teachings within each of these prior art documents against the precise language of the claims in the '822 patent. The core of the invention in US 7,288,822 appears to be the intentional grading of the lattice parameter in the epitaxially grown strained layer to mitigate defects, and a prior art reference would need to disclose this specific feature to be considered anticipatory.