# US 8,740,043 B2 · Selective solder stop

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- Number: US 8,740,043 B2
- Document ID: US8740043B2
- Status: Granted
- Kind: B2
- Application number: 12/573,181
- Filed: 2009-10-05
- Published: 2010-04-15
- Granted: 2014-06-03
- Earliest claimed: 2008-10-13
- Assignees: Robert Bosch GmbH
- Applicants: Hans-Martin Irslinger
- Inventors: Hans-Martin Irslinger
- Web page: https://patentgrep.com/patent/US8740043B2

## CPC

- B23K 1/20: Preliminary treatment of work or areas to be soldered, e.g. in respect of a galvanic coating
- B23K 1/0016: {Soldering of electronic components}
- B23K 1/19: taking account of the properties of the materials to be soldered
- B23K 26/364: for making a groove or trench, e.g. for scribing a break initiation groove
- H05K 3/3452: Solder masks
- H05K 3/027: {the conductive material being removed by irradiation, e.g. by photons, alpha or beta particles}
- H05K 2201/2081: Compound repelling a metal, e.g. solder
- H05K 2203/0315: Oxidising metal
- H05K 2203/0361: Stripping a part of an upper metal layer to expose a lower metal layer, e.g. by etching or using a laser
- H10W 72/07336: {Soldering or alloying}
- H10W 72/07355: {changes in materials}
- H10W 72/352: {comprising metals or metalloids, e.g. solders}
- H10W 72/3528: {Intermetallic compounds}
- H10W 72/387: {Flow barriers}
- B23K: SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
- H05K: PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
- H10W: GENERIC PACKAGES, INTERCONNECTIONS, CONNECTORS OR OTHER CONSTRUCTIONAL DETAILS OF DEVICES COVERED BY CLASS H10

## Abstract

A method for producing a surface on a component, which has regions having different wettabilities with respect to a solder. The method includes forming a first metallic layer on the component and forming a second metallic layer on the first metallic layer, the second metallic layer preventing oxidation of the first metallic layer. The method furthermore includes removing the second metallic layer with the aid of a laser in a predefined surface region for exposing the first metallic layer, and oxidizing the exposed first metallic layer on the surface, which results in a wettability with respect to a solder in the predefined surface region that is less than in a surface region adjacent to the predefined surface region.

## Claims

### Claim 1

A method for producing a surface on a component, the surface having regions of different wettabilities with respect to a solder, the method comprising:
forming a first metallic layer on the component;
forming a second metallic layer on the first metallic layer, the second metallic layer preventing oxidation of the first metallic layer;
removing the second metallic layer using a laser in a predefined surface region to expose the first metallic layer; and
oxidizing the exposed first metallic layer on the surface, resulting in a wettability with respect to a solder in the predefined surface region that is less than in a surface region adjacent to the predefined surface region.

### Claim 2 (depends on 1)

The method as recited in claim 1, wherein the first metallic layer contains nickel.

### Claim 3 (depends on 1)

The method as recited in claim 1, wherein the second metallic layer contains gold.

### Claim 4 (depends on 1)

The method as recited in claim 1, wherein the second metallic layer has a thickness of less than one micrometer.

### Claim 5 (depends on 1)

The method as recited in claim 1, wherein the predefined surface region in which the second metallic layer is removed has the shape of a line.

### Claim 6 (depends on 1)

The method as recited in claim 1, wherein the first metallic layer is formed using one of the following processes:
electrolytic deposition;
deposition without external current; and
cathode sputtering.

### Claim 7 (depends on 1)

The method as recited in claim 1, wherein the second metallic layer is formed using one of the following processes:
electrolytic deposition;
deposition without external current; and
cathode sputtering.

### Claim 8 (depends on 1)

The method as recited in claim 1, wherein the oxidation of the exposed first metallic layer is caused by an energy input of the laser into the first layer.

### Claim 9

A method for bonding a first component to a second component, comprising:
producing a surface on the first component by forming a first metallic layer on the component, forming a second metallic layer on the first metallic layer, the second metallic layer preventing oxidation of the first metallic layer, removing the second metallic layer using a laser in a predefined surface region to expose the first metallic layer, and oxidizing the exposed first metallic layer on the surface, resulting in a wettability with respect to a solder in the predefined surface region that is less than in a surface region adjacent to the predefined surface region, the surface having a soldering region to be wetted using a solder, the soldering region being adjacent to a predefined surface region having a lesser wettability;
applying a solder to the soldering region;
melting the solder; and
bringing the first and second components close together in order to bond the first and second components via the solder.