US 6560740

Patent Overview: US6560740

Title: Apparatus and method for programmable built-in self-test and self-repair of embedded memory

Patent number: US6560740 (US6560740B1)

Assignee: Advanced Micro Devices, Inc. (original assignee, per the supplied record)

Key dates:

• Priority/filing date: 1999-08-03 (application US09/366,444)
• Granted/published: 2003-05-06
• Anticipated expiration: 2019-08-03
• Status shown: Expired – Lifetime

Purpose and plain-language scope:
The patent describes testing and repairing memory arrays that are embedded within an integrated circuit chip. Testing circuitry—built-in self-test (BIST), and specifically array BIST (ABIST)—is placed on the chip itself, so the chip can test its own embedded memory rather than relying solely on external equipment.

In broad terms, a semiconductor device may include a memory unit plus a BIST system made up of a BIST logic unit coupled to the memory unit and a master test unit coupled to the BIST logic unit. The master test unit provides a stored memory test pattern to the BIST logic unit and generates address and control signals. The BIST logic unit produces data input signals based on the test pattern, sends them to the memory unit, receives the resulting data output signals, and compares the two to form BIST results. The BIST results may provide fault location information as well as fault detection, and that location information may be used to guide repair of the embedded memory—which typically has redundant rows and/or columns that can replace faulty ones (built-in self-repair, BISR).

The patent is characterized as addressing limitations of hardwired ABIST circuits that cannot be altered after fabrication; the text notes that programmable BIST may avoid needing external circuitry to generate/provide test patterns.

Source: https://patents.google.com/patent/US6560740/en

What the excerpt does not establish: It does not provide the full claims, detailed embodiments, drawing descriptions, examiner citations, or prior-art analysis. It states no litigation, ownership-transfer, or validity conclusions—and none is asserted here.