# US 4,394,844 A · Chip coater

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- Number: US 4,394,844 A
- Document ID: US4394844A
- Status: Granted
- Kind: A
- Application number: 06/337,953
- Filed: 1982-01-07
- Granted: 1983-07-26
- Earliest claimed: 1981-05-04
- Inventors: Laurior A. Wood; Donald N. Humphries
- Web page: https://patentgrep.com/patent/US4394844A

## CPC

- H10W 72/013: {of die-attach connectors}
- H05K 3/305: {Affixing by adhesive}
- H05K 3/3485: Application of solder paste, slurry or powder (using printing techniques to form the desired conductive pattern of the printed circuit by applying conductive material H05K3/12)
- H10W 72/0113: {Apparatus for manufacturing die-attach connectors}
- H10W 72/073: {of die-attach connectors}
- H10W 72/07337: {using a polymer adhesive, e.g. an adhesive based on silicone or epoxy}
- H10W 72/354: {comprising polymers}
- 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

## Abstract

An apparatus for applying an epoxy glue, solder paste or a similar material to the surface of a planar circuit chip, such as a silicon integrated circuit chip. Positioned just above the liquid epoxy in the bath is a fine mesh, stainless steel screen clamped at its periphery and having supported thereover a leveling paddle with a micrometer adjustment rotatable relative to the bath itself for smoothing the material over the screen surface. After this smoothing or leveling operation, the chip, usually held by a vacuum chuck, is pressed against the screen into the epoxy with the screen functioning as a resilient means enabling the chip to be withdrawn therefrom with uniform deposition of material applied to the undersurface thereof. The apparatus may also have a spongy material such as polyurethane or a sponge neoprene rubber under the screen to enhance chip removal.

## Claims

### Claim 1

Apparatus for applying an adhesive or the like to a circuit chip comprising:
a bath tray for carrying a quantity of a liquid adhesive or the like,
a mesh screen,
means securing said mesh screen to said bath tray with the screen extending at approximately the level of the liquid in the bath tray,
a leveling paddle,
and means supporting the paddle so as to sweep relative to the screen, essentially pressing the screen into the adhesive as the weeping action occurs.

### Claim 2 (depends on 1)

An apparatus as set forth in claim 1 wherein said means for supporting said leveling paddle include adjustable means for adjusting the vertical position of the leveling paddle.

### Claim 3 (depends on 2)

Apparatus as set forth in claim 2 wherein said means for adjustment provide a micrometer type of adjustment.

### Claim 4 (depends on 1)

Apparatus as set forth in claim 1 including drive means for said bath tray for rotating the bath tray to provide the sweeping action as the leveling paddle is maintained stationary.

### Claim 5 (depends on 1)

Apparatus as set forth in claim 1 wherein the means for securing the screen includes a clamp secured at the periphery of the bath tray.

### Claim 6 (depends on 1)

Apparatus as set forth in claim 1 including a sponge material disposed under the mesh screen for the storage of adhesive.