Measuring and testing – Specimen stress or strain – or testing by stress or strain... – By loading of specimen
Reexamination Certificate
1999-06-14
2001-01-23
Noori, Max (Department: 2855)
Measuring and testing
Specimen stress or strain, or testing by stress or strain...
By loading of specimen
C073S15000R
Reexamination Certificate
active
06176141
ABSTRACT:
FIELD OF THE INVENTION
This invention relates generally to testing the adhesion of a film to its underlying structure in a semiconductor wafer, and more specifically it relates to an improved test sample and method for preparing the test sample.
1. Introduction
Semiconductor chips are commonly formed of multiple layers of conductors and dielectrics, for example a film of a dielectric material formed on an underlying structure. It is desirable to test the adhesion of such a film to the underlying structure. This test can be performed on an actual semiconductor device or on a sample that is made to adequately represents the film and underlying structure of the semiconductor device.
2. The Prior Art
U.S. Pat. No. 4,876,896 teaches testing the adhesion of a grouting to an underlying pier. A circular groove is cut through the grouting to isolate a circular test region. A part 42, 42a is attached to the outer surface of the test region. A screw mechanism applies a pulling force to the attached part, and a bridge applies a corresponding force to the structure outside the circular groove. The screw is calibrated to show the force.
U.S. Pat. No. 4,895,028 teaches apparatus for pulling on a wire that is bonded at each end to bonding pads of an integrated circuit device. The force is measured with a strain gauge and a computer calculates the force on the bonds.
U.S. Pat. No. 5,337,614 teaches an apparatus for grasping a circuit module and a heat sink attached to the module for an adhesion test.
In the manufacturing art to which this invention is particularly intended, tests for adhesion have been made after the wafer has been completed and formed into modules.
In another example of an adhesion test in this art, a stud has been attached to a film formed on a test sample and then the stud has been pulled from the sample until the film breaks loose from its underlying structure. Unfortunately, the stud may break from the film before the film separates from its underlying structure and before the test has reached a pull force of interest.
SUMMARY OF THE INVENTION
One object of this invention is to provide an adhesion test that can be performed on a wafer or a test sample representing a wafer and to avoid making this test at a later stage in the manufacture of the semiconductor structure.
Another object of this invention is to provide a stud pull test for a semiconductor layer in which the stud remains adhered to the layer for a greater test pull.
According to this invention a test sample is formed with an underlying structure and a film. This test sample is prepared for the attachment of a pull stud by process steps that include boiling the sample in a salt water solution for a suitable time. The stud is attached to the film with epoxy and this assembly is clamped and baked for a suitable time to form a bond. The stud pull test is then performed with significantly less likelihood that the stud will break from the film before the film breaks from the underlying structure.
REFERENCES:
patent: 4856326 (1989-08-01), Tsukamoto
patent: 4876896 (1989-10-01), Snow et al.
patent: 4895028 (1990-01-01), Mayer
patent: 4899581 (1990-02-01), Allen et al.
patent: 5337614 (1994-08-01), Jiang et al.
patent: 5673586 (1997-10-01), Mann
Chang Chung-Long
Chao Ying-Chen
Chuang Lung-Hsiang
Jang Syun-Ming
Ackerman Stephen B.
Noori Max
Robertson William
Saile George O.
Taiwan Semiconductor Manufacturing Company
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