# US 2008/0187267 A1 · Methods of forming printed circuit boards having optical functionality

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- Number: US 2008/0187267 A1
- Document ID: US20080187267A1
- Status: Published application
- Kind: A1
- Application number: 12/005,990
- Filed: 2007-12-28
- Published: 2008-08-07
- Earliest claimed: 2006-12-31
- Assignees: Rohm and Haas Electronic Materials LLC
- Inventors: Edgardo Anzures; Philip D. Knudsen
- Web page: https://patentgrep.com/patent/US20080187267A1

## CPC

- G02B 6/10: of the optical waveguide type (G02B6/02, G02B6/24 take precedence; devices or arrangements for the control of light by electric, magnetic, electro-magnetic or acoustic means G02F1/00; transferring the modulation of modulated light G02F2/00; optical logic elements G02F3/00; optical analogue/digital converters G02F7/00)
- G02B 6/1221: {made from organic materials}
- G02B 6/136: by etching
- G02B 6/138: by using polymerisation
- G02B 6/43: Arrangements comprising a plurality of opto-electronic elements and associated optical interconnections
- H05K 1/0274: {Optical details, e.g. printed circuits comprising integral optical means (H05K1/0269 takes precedence; coupling light guides with opto-electronic components G02B6/42)}
- G02B: OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- H05K: PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS

## Abstract

Provided are methods of forming printed circuit boards having optical functionality. The methods involve applying a dry-film to a printed circuit board substrate and forming an optical waveguide over the dry-film. The invention finds particular applicability in the electronics and optoelectronics industries.

## Claims

### Claim 1

A method of forming a printed circuit board having optical functionality, comprising:
applying a dry-film layer to a printed circuit board substrate; and
forming an optical waveguide directly on the dry-film layer, the optical waveguide comprising a core and a clad surrounding the core.

### Claim 2 (depends on 1)

The method of claim 1, wherein the dry-film layer is of a type which is useful as solder-mask or dielectric dry-film layer.

### Claim 3 (depends on 1)

The method of claim 1, wherein the waveguide core and/or clad comprises units of the formula (RSiO1.5), wherein R is a substituted or unsubstituted organic group.

### Claim 4 (depends on 1)

The method of claim 1, wherein the optical waveguide formation comprises:
forming a first clad layer directly on the dry-film layer;
forming a core layer on the first clad layer;
patterning the core layer to form the core; and
forming a second clad layer on the first clad layer and the core.

### Claim 5 (depends on 1)

The method of claim 1, further comprising forming a second optical waveguide on the optical waveguide in a stacked arrangement.

### Claim 6 (depends on 5)

The method of claim 5, further comprising applying a second dry-film layer on the waveguide and forming the second optical waveguide directly on the second dry-film layer.

### Claim 7 (depends on 1)

The method of claim 1, further comprising before formation of the clad, treating the surface of the dry-film layer to improve adhesion to the waveguide.

### Claim 8 (depends on 7)

The method of claim 7, wherein the treating comprises one or more of mechanical polishing or treatment with corona discharge, flame, ozone or plasma.

### Claim 9 (depends on 1)

The method of claim 1, further comprising forming electrical circuitry on the printed circuit board substrate.

### Claim 10 (depends on 1)

A printed circuit board formed by the method of claim 1.