US 2003/0169633 A1 · Method of checking electrical connections between a memory module and a semiconductor memory chip

Abstract

A description is given of two methods of checking the functional capability of electrical connections between address lines of a printed circuit board of a memory module and address line contacts of an integrated semiconductor memory chip mounted on the printed circuit board. Ruptured solder contacts are conventionally examined optically or investigated by electrical resistance measurements; however, the latter do not work in the case of memory modules with a number of semiconductor chips, the pin contacts of which are connected in parallel by the address lines. The methods make it possible to locate interrupted contacts on individual address lines by the indirect use of a write-read access to the semiconductor memory chip, specifically utilizing the misrouting of writing and reading commands produced by defective contact connections.

Claims20

Dependent claims

A method for checking a functional capability of electrical connections between address lines of a printed circuit board of a memory module and address line contacts of an integrated semiconductor memory chip mounted on the printed circuit board, memory cells of the integrated semiconductor memory chip being selected by the address lines being electrically biased in a specific manner, which comprises the steps of:

checking the functional capability of the electrical connections by accessing the integrated semiconductor memory chip through writing and reading operations, the accessing step includes the steps of:
a) writing a first item of information to a first memory cell selected by none of the address lines being electrically biased;
b) writing a second item of information differing from the first item of information to a second memory cell selected by electrically biasing only a single address line;
c) reading from the integrated semiconductor memory chip with the first memory cell being selected by none of the address lines being electrically biased;
and
d) checking whether the first item of information or the second item of information was read out;
and
repeating a sequence of the steps a) to d) a number of times and, with each repetition of the sequence of the steps a) to d), a different one of the address lines being electrically biased as the single address line during step b).

5 more elements

A method for checking a functional capability of electrical connections between address lines of a printed circuit board of a memory module and address line contacts of an integrated semiconductor memory chip mounted on the printed circuit board, memory cells of the integrated semiconductor memory chip selected by the address lines being electrically biased in a specific manner, which comprises the steps of:

checking the functional capability of the electrical connections by accessing the integrated semiconductor memory chip through writing and reading operations, the accessing step includes:
a) writing a first item of information to a first memory cell selected by only a single address line being electrically biased;
b) writing a second item of information, differing from the first item of information, to a second memory cell selected by none of the address lines being electrically biased;
c) executing a read command, a same address line as in step a) being electrically biased as the single address line;
and
d) checking whether the first item of information or the second item of information was read out;
and
repeating a sequence of the steps a) to d) a number of times and, with each repetition of the sequence of the steps a) to d), a different address line being electrically biased as the single address line during step a).

5 more elements

Dependencies are inferred from the claim text.

Method of checking electrical connections between a memory module and a semiconductor memory chip

Life of this patent

Method of checking electrical connections between a memory module and a semiconductor memory chip

Life of this patent

Abstract

Claims20