Browse Prior Art Database

Method for measuring individual structures within an array of modular dies

IP.com Disclosure Number: IPCOM000020307D
Publication Date: 2003-Nov-12
Document File: 4 page(s) / 94K

Publishing Venue

The IP.com Prior Art Database

Abstract

Disclosed is a method for measuring individual structures within an array of modular dies. Benefits include improved functionality, improved performance, and improved ease of implementation.

This text was extracted from a Microsoft Word document.
At least one non-text object (such as an image or picture) has been suppressed.
This is the abbreviated version, containing approximately 56% of the total text.

Method for measuring individual structures within an array of modular dies

Disclosed is a method for measuring individual structures within an array of modular dies. Benefits include improved functionality, improved performance, and improved ease of implementation.

Background

A lack of capability exists for measuring individual cells in the internal cells of an array of modular test dies.

Structures that reside within a single cell of an array of modular testing dies cannot conventionally be measured using 4-wire measurement techniques on wire-bonded dies. This limitation is due to the complexity of routing and the limited number of metal layers. The structures within each cell are chained together in series.

Four-wire measurements are performed at the periphery of the die for the entire chain because wire bonds only attach to the die at the periphery (see Figure 1). The measurements are averaged across the entire chain. Measurements from individual cells are not possible due to the limitations of wire-bond lengths and the locations of the wire-bond pads.

Structures based on the conventional solution are used with resistive thermal devices (RTD) for measuring the overall die temperature. The large size of the structure over the entire die results in average temperature readings. Typically, the die could have a ~10°C difference across the die but with the conventional solution it cannot be accurately detected. Additionally, the test die cannot provide the information for the accurate location of the localized defects, such as voiding and die-attach delamination.

General description

The disclosed method is a modular die design that enables the 4-wire measurement of individual structures in an array of modular cells.

         The key elements of the method include:

•         Overall die is composed of cells and is wire bonded at the periphery to enable connectivity.

•         Each cell contains the structure of interest.

•         Each cell must have at least two metal layers to accommodate the required routing.

•         Each cell is chained together in series to form a row.

•         Four-wire measurements are performed at the periphery of the die, so the disclosed method does not require modification of wire bond equipment.

•         Each row has a common current line.

•         Choosing the appropriate bond pads on the periphery of the die enables measurement of the selected structure in a cell in that particular row.

•         Measurement between cells is accomplished by using diagonal traces on a different metal layer than the actual structure.

Advantages

         The disclosed method provides advantages, including:

•         Improved function...