# US 6,723,927 B1 · High-reliability interposer for low cost and high reliability applications

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- Number: US 6,723,927 B1
- Document ID: US6723927B1
- Status: Granted
- Kind: B1
- Application number: 09/866,434
- Filed: 2001-05-29
- Granted: 2004-04-20
- Earliest claimed: 2000-08-24
- Assignees: High Connection Density, Inc.
- Inventors: Zhineng Fan; Ai D. Le; Che-Yu Li
- Web page: https://patentgrep.com/patent/US6723927B1

## CPC

- H10W 70/635: {Through-vias}
- H05K 1/112: {directly combined with via connections}
- H05K 7/1061: {co-operating by abutting}
- H01R 12/7082: {Coupling device supported only by cooperation with PCB}
- H05K 3/325: by abutting or pinching; Mechanical auxiliary parts therefor
- H05K 3/3436: {having an array of bottom contacts, e.g. pad grid array or ball grid array components}
- H05K 2201/0314: Elastomeric connector or conductor, e.g. rubber with metallic filler
- H05K 2201/0394: Conductor crossing over a hole in the substrate or a gap between two separate substrate parts
- H05K 2201/09845: Stepped hole, via, edge, bump or conductor
- H05K 2201/10378: Interposers
- H10W: GENERIC PACKAGES, INTERCONNECTIONS, CONNECTORS OR OTHER CONSTRUCTIONAL DETAILS OF DEVICES COVERED BY CLASS H10
- H05K: PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
- H01R: ELECTRICALLY-CONDUCTIVE CONNECTIONS; STRUCTURAL ASSOCIATIONS OF A PLURALITY OF MUTUALLY-INSULATED ELECTRICAL CONNECTING ELEMENTS; COUPLING DEVICES; CURRENT COLLECTORS

## Abstract

An interposer provides a high reliability interface between an LGA connector and a motherboard. The interposer includes a stepped spacer for each solder interconnection which prevents the relaxation of mechanical contact force while ensuring the integrity of each solder interconnection. The interposer provides noble metal plated contact pads on a first surface to receive the contact members of an LGA connector, and contact pads for BGA solder connections for attachment to a motherboard. A description of the processes to manufacture the interposer is also disclosed.

## Claims

### Claim 1

A low cost, high reliability interposer for use in electronic packages, comprising:
a) at least one dielectric layer having one major surface and at least one edge;
b) a plurality of conductive pads, each having a first and second surface, spaced apart on said major surface of said at least one dielectric layer, said first surface of said conductive pads being plated with at least one layer of metal, and at least a portion of said second surface of said conductive pads being readily adaptable for connection to a conductive member;
c) a plurality of openings disposed in the interposer, said openings having a stepped cross section, each opening corresponding to and aligned with one of said conductive pads; and
d) a plurality of reformable conductive members, each one located within one of said openings of said interposer and in electrical contact with said portion of said second surface of said conductive pads.

### Claim 2 (depends on 1)

The interposer as recited in claim 1, wherein said at least one dielectric layer comprises an insulative material.

### Claim 3 (depends on 2)

The interposer as recited in claim 2, wherein said insulative material is polyimide.

### Claim 4 (depends on 2)

The interposer as recited in claim 2, wherein said insulative material is a liquid crystal polymer.

### Claim 5 (depends on 2)

The interposer as recited in claim 2, wherein said insulative material is epoxy-glass-based.

### Claim 6 (depends on 2)

The interposer as recited in claim 2, wherein said insulative material has a coefficient of thermal expansion (CTE) that substantially matches the CTE of the material to which it is to be attached.

### Claim 7 (depends on 1)

The interposer as recited in claim 1, wherein said conductive pads comprise copper.

### Claim 8 (depends on 1)

The interposer as recited in claim 1, wherein said first surface of said conductive pads being plated with at least one layer of metal is plated with nickel.

### Claim 9 (depends on 8)

The interposer as recited in claim 8, wherein said first surface of said conductive pads being plated with at least one layer of metal is also plated with gold.

### Claim 10 (depends on 1)

The interposer as recited in claim 1, wherein said conductive members comprise solder.

### Claim 11 (depends on 1)

The interposer as recited in claim 1, wherein said conductive members are comprised of conductive paste.

### Claim 12 (depends on 11)

The interposer as recited in claim 11, wherein said conductive paste comprises solder paste.

### Claim 13 (depends on 1)

The interposer as recited in claim 1, further comprises alignment means to align said carrier to a structure adapted to mate therewith.

### Claim 14 (depends on 1)

The interposer as recited in claim 1, wherein said interposer may be attached to a structure adapted to mate therewith by a reflow process.

### Claim 15 (depends on 14)

The interposer as recited in claim 14, wherein said reflow process of said interposer to said structure is performed under uniform pressure.