# US 2012/0074210 A1 · Soldering preform > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2012/0074210 A1 - Document ID: US20120074210A1 - Status: Published application - Kind: A1 - Application number: 13/270,655 - Filed: 2011-10-11 - Published: 2012-03-29 - Earliest claimed: 2009-04-09 - Assignees: ABB Technology AG - Inventors: Franc DUGAL - Web page: https://patentgrep.com/patent/US20120074210A1 ## CPC - B23K 35/0244: {Powders, particles or spheres; Preforms made therefrom} - B23K 35/38: Selection of media, e.g. special atmospheres for surrounding the working area - H05K 3/3478: Application of solder preforms; Transferring prefabricated solder patterns - H05K 3/341: Surface mounted components - H05K 2201/0373: Conductors having a fine structure, e.g. providing a plurality of contact points with a structured tool - H05K 2201/09163: Slotted edge - H05K 2203/0415: Small preforms other than balls, e.g. discs, cylinders or pillars - 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 ## Abstract A soldering preform for soldering in a reducing atmosphere is substantially disc-shaped and has two soldering surfaces each for being in contact with an object to be soldered, respectively, and with at least one recess on at least one soldering surfaces for constituting a channel open to a surface of the object. ## Claims ### Claim 1 A soldering apparatus for soldering in a reducing atmosphere, comprising: a substantially disc-shaped preform having two soldering surfaces each for contacting an object to be soldered; and at least one channel formed into the soldering preform, the at least one channel being open towards at least one of the soldering surfaces and open to a reducing atmosphere when the two soldering surfaces are in contact with objects to be soldered. ### Claim 2 (depends on 1) The soldering preform according to claim 1, wherein the soldering preform has no through-hole. ### Claim 3 (depends on 1) The soldering preform according to claim 1, wherein the soldering preform is connected via a simple connector. ### Claim 4 (depends on 1) The soldering preform according to claim 1, wherein the at least one channel comprises: a geometry on at least one of the soldering surfaces with a longest distance of every point of the soldering surface to a border of the channel being smaller than a predetermined distance, which is defined by a standard depth of penetration of the reducing atmosphere. ### Claim 5 (depends on 4) The soldering preform according to claim 4, wherein the predetermined distance is less than 6 mm. ### Claim 6 (depends on 1) The soldering preform according to claim 1, wherein the at least one channel is open to an outer border of the disc-shaped soldering preform. ### Claim 7 (depends on 6) The soldering preform according to claim 6, wherein the at least one channel tapers from a maximum opening at the outer border. ### Claim 8 (depends on 7) The soldering preform according to claim 7, wherein the maximum opening at the outer border is between 1 mm and 5 mm. ### Claim 9 (depends on 1) The soldering preform according to claim 1, wherein the soldering preform comprises: a plurality of channels. ### Claim 10 (depends on 9) The soldering preform according to claim 9, wherein each channel has a longitudinal axis running through a centre point of the soldering surfaces or of the soldering preform. ### Claim 11 (depends on 9) The soldering preform according to claim 9, wherein each channel is separated from the other channels. ### Claim 12 (depends on 1) The soldering preform according to claim 1, wherein the at least one channel is a cut-out portion extending from one soldering surface to another soldering surface. ### Claim 13 (depends on 1) The soldering preform according to claim 1, wherein the soldering preform has a plurality of channels running in parallel and/or perpendicular to each other. ### Claim 14 (depends on 1) The soldering preform according to claim 1, wherein a thickness of the soldering preform is larger than a final soldering thickness. ### Claim 15 (depends on 1) The soldering preform according to claim 1, wherein a volume of the soldering preform is larger than a final soldering volume. ### Claim 16 (depends on 1) The soldering preform according to claim 1, wherein a ratio of the total volume of the at least one channel to a volume of a solder material of the soldering preform is at most 1:1. ### Claim 17 (depends on 1) The soldering preform according to claim 1, wherein the soldering preform is selected for forming a continuous soldering layer of at least 80 mm2. ### Claim 18 (depends on 7) The soldering preform according to claim 7, wherein the maximum opening at the outer border is between 2 mm and 4 mm. ### Claim 19 (depends on 7) The soldering preform according to claim 7, wherein the maximum opening at the outer border is between 2.5 mm and 3.5 mm. ### Claim 20 (depends on 1) The soldering preform according to claim 1, wherein a ratio of a total volume of the at least one channel to the volume of solder material of the soldering preform is at most 1:1.2. ### Claim 21 (depends on 1) The soldering preform according to claim 1, wherein a ratio of a total volume of the at least one channel to a volume of the solder material of the soldering preform is at most 1:1.3. ### Claim 22 A method of soldering using a substantially disc-shaped preform, having two soldering surfaces each for contacting an object to be soldered, and at least one channel formed into the soldering preform, the at least one channel being open towards at least one of the soldering surfaces and open to a reducing atmosphere when the two soldering surfaces are in contact with objects to be soldered, the method comprising: placing the preform at a soldering position between two objects to be soldered; and establishing a reducing atmosphere around a solder joint area by introducing a reducing medium into the at least one channel.