Laser welding method

• US 10,442,035 B2
• Filed: 06/14/2016
• Issued: 10/15/2019
• Est. Priority Date: 12/19/2013
• Status: Active Grant

• Current Assignee: Fuji Electric Company Limited (Fuji Electric Systems Company Limited)
• Original Assignee: Fuji Electric Company Limited (Fuji Electric Systems Company Limited)
• Inventors: Tamai, Yuta
• Primary Examiner(s): Ross, Dana
• Assistant Examiner(s): Iskra, Joseph W
• Application Number:
  US15/181,988
• Publication Number:
  US 20160288259A1
• Time in Patent Office: 1,218 Days
• Field of Search: 21912164
• CPC Class Codes: B23K 2101/34 Coated articles , e.g. plated or painted; Surface treated articles
• CPC Class Codes: B23K 2101/35 Surface treated articles
• CPC Class Codes: B23K 2101/42 Printed circuits
• CPC Class Codes: B23K 2103/08 Non-ferrous metals or alloys
• CPC Class Codes: B23K 2103/10 Aluminium or alloys thereof
• CPC Class Codes: B23K 2103/12 Copper or alloys thereof
• CPC Class Codes: B23K 2103/16 Composite materials , e.g. fibre reinforced
• CPC Class Codes: B23K 2103/172 wherein at least one of the layers is non-metallic
• CPC Class Codes: B23K 2103/50 Inorganic material, e.g. metals, not provided for in B23K2103/02 – B23K2103/26
• CPC Class Codes: B23K 26/0006 taking account of the properties of the material involved B23K26/32, B23K26/40 take precedence
• CPC Class Codes: B23K 26/037 by pressing on the workpiece, e.g. pressing roller foot
• CPC Class Codes: B23K 26/0622 by shaping pulses
• CPC Class Codes: B23K 26/206 Laser sealing
• CPC Class Codes: B23K 26/211 with interposition of special material to facilitate connection of the parts
• CPC Class Codes: B23K 26/22 Spot welding
• CPC Class Codes: B23K 26/32 taking account of the properties of the material involved
• CPC Class Codes: H01L 21/4846 Leads on or in insulating or insulated substrates, e.g. metallisation H01L21/4821 takes precedence; metallisation of ceramics in general C04B41/51; printed circuits H05K3/00
• CPC Class Codes: H01L 2224/291 with a principal constituent of the material being a metal or a metalloid, e.g. boron [B], silicon [Si], germanium [Ge], arsenic [As], antimony [Sb], tellurium [Te] and polonium [Po], and alloys thereof
• CPC Class Codes: H01L 2224/29101 the principal constituent melting at a temperature of less than 400°C
• CPC Class Codes: H01L 2224/32225 the item being non-metallic, e.g. insulating substrate with or without metallisation
• CPC Class Codes: H01L 2224/32245 : the item being metallic
• CPC Class Codes: H01L 2224/33181 : On opposite sides of the body
• CPC Class Codes: H01L 2224/37124 : Aluminium [Al] as principal constituent
• CPC Class Codes: H01L 2224/37138 : the principal constituent melting at a temperature of greater than or equal to 950°C and less than 1550°C
• CPC Class Codes: H01L 2224/37147 : Copper [Cu] as principal constituent
• CPC Class Codes: H01L 2224/3718 : Molybdenum [Mo] as principal constituent
• CPC Class Codes: H01L 2224/37184 : Tungsten [W] as principal constituent
• CPC Class Codes: H01L 2224/37187 : Ceramics, e.g. crystalline carbides, nitrides or oxides
• CPC Class Codes: H01L 2224/3754 : Coating
• CPC Class Codes: H01L 2224/37638 : the principal constituent melting at a temperature of greater than or equal to 950°C and less than 1550°C
• CPC Class Codes: H01L 2224/37655 : Nickel [Ni] as principal constituent
• CPC Class Codes: H01L 2224/37663 : the principal constituent melting at a temperature of greater than 1550°C
• CPC Class Codes: H01L 2224/40137 : the bodies being arranged next to each other, e.g. on a common substrate
• CPC Class Codes: H01L 2224/40499 : Material of the auxiliary connecting means
• CPC Class Codes: H01L 2224/48227 : connecting the wire to a bond pad of the item
• CPC Class Codes: H01L 2224/73265 : Layer and wire connectors
• CPC Class Codes: H01L 2224/75261 : Laser
• CPC Class Codes: H01L 2224/7555 : Mechanical means, e.g. for planarising, pressing, stamping
• CPC Class Codes: H01L 2224/83224 : using a laser
• CPC Class Codes: H01L 2224/834 : with a principal constituent of the material being a metal or a metalloid, e.g. boron [B], silicon [Si], germanium [Ge], arsenic [As], antimony [Sb], tellurium [Te] and polonium [Po], and alloys thereof
• CPC Class Codes: H01L 2224/83801 : Soldering or alloying
• CPC Class Codes: H01L 2224/83895 : between electrically conductive surfaces, e.g. copper-copper direct bonding, surface activated bonding
• CPC Class Codes: H01L 23/049 : the other leads being perpendicular to the base
• CPC Class Codes: H01L 23/3735 : Laminates or multilayers, e.g. direct bond copper ceramic substrates
• CPC Class Codes: H01L 24/00 : Arrangements for connecting or disconnecting semiconductor or solid-state bodies; Methods or apparatus related thereto
• CPC Class Codes: H01L 24/29 : of an individual layer connector
• CPC Class Codes: H01L 24/32 : of an individual layer connector
• CPC Class Codes: H01L 24/33 : of a plurality of layer connectors
• CPC Class Codes: H01L 24/37 : of an individual strap connector
• CPC Class Codes: H01L 24/40 : of an individual strap connector
• CPC Class Codes: H01L 24/75 : Apparatus for connecting with bump connectors or layer connectors
• CPC Class Codes: H01L 24/83 : using a layer connector
• CPC Class Codes: H01L 24/84 : using a strap connector
• CPC Class Codes: H01L 24/92 : Specific sequence of method steps
• CPC Class Codes: H01L 2924/00 : Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
• CPC Class Codes: H01L 2924/00012 : Relevant to the scope of the group, the symbol of which is combined with the symbol of this group
• CPC Class Codes: H01L 2924/00014 : the subject-matter covered by the group, the symbol of which is combined with the symbol of this group, being disclosed without further technical details
• CPC Class Codes: H01L 2924/01005 : Boron [B]
• CPC Class Codes: H01L 2924/01013 : Aluminum [Al]
• CPC Class Codes: H01L 2924/01014 : Silicon [Si]
• CPC Class Codes: H01L 2924/01015 : Phosphorus [P]
• CPC Class Codes: H01L 2924/01028 : Nickel [Ni]
• CPC Class Codes: H01L 2924/01029 : Copper [Cu]
• CPC Class Codes: H01L 2924/01042 : Molybdenum [Mo]
• CPC Class Codes: H01L 2924/01046 : Palladium [Pd]
• CPC Class Codes: H01L 2924/01074 : Tungsten [W]
• CPC Class Codes: H01L 2924/01079 : Gold [Au]
• CPC Class Codes: H01L 2924/013 : Alloys
• CPC Class Codes: H01L 2924/014 : Solder alloys
• CPC Class Codes: H01L 2924/04642 : SiC
• CPC Class Codes: H01L 2924/1203 : Rectifying Diode
• CPC Class Codes: H01L 2924/12042 : LASER
• CPC Class Codes: H01L 2924/13055 : Insulated gate bipolar transistor [IGBT]
• CPC Class Codes: H01L 2924/181 : Encapsulation
• CPC Class Codes: H01L 2924/19107 : off-chip wires
• CPC Class Codes: H01L 2924/40102 : being pulsed

Abstract

A laser welding method using a laser welding jig having a plurality of pressing parts, includes a step of placing a second member on a first member; a step of pressing the second member with the plurality of pressing parts in a direction toward the first member to thereby form a gap between the first member and the second member at most 300 μm; and a first welding step of laser-welding the first member and the second member by irradiating on a surface of the second member at a location between the pressing parts with laser light while conducting the step of pressing.

Claims

1. A laser welding method using a laser welding jig having a plurality of pressing parts, comprising:

a step of placing a second member on a first member;

a step of pressing the second member with the plurality of pressing parts in a direction toward the first member to thereby form a gap between the first member and the second member at most 300 μ

m, the plurality of pressing parts being a pair of claws with an interval therebetween;

a first welding step of laser-welding the first member and the second member by irradiating on a surface of the second member through the interval between the pair of claws with laser light while conducting the step of pressing; and

a second welding step of laser-welding the first member and the second member by irradiating on the surface of the second member with the laser light while the pair of claws does not press the second member toward the first member.

2. The laser welding method according to claim 1, further comprising:

a step of preparing a semiconductor device that comprises a ceramic insulated substrate, a front surface conductor pattern fixed on a front surface of the ceramic insulated substrate, a semiconductor chip electrically connected to the front surface conductor pattern, the first member electrically connected to the semiconductor chip, and the second member laser-welded to the first member at at least one portion to electrically connect thereto, and

a step of sealing the ceramic insulated substrate, the front surface conductor pattern, the semiconductor chip, and a part of the first member with a sealing material before the step of placing the second member on the first member.

3. A laser welding method using a laser welding jig having a plurality of pressing parts, comprising

a step of placing a second member on a first member;

a step of inserting a spacer between the first and second members so that a gap between the first and second members is more than 0 μ

m and at most 300 μ

m,

a step of pressing the second member with the plurality of pressing parts in a direction toward the first member to thereby form the gap between the first member and the second member at most 300 μ

m, the plurality of pressing parts being a pair of claws with an interval therebetween; and

a first welding step of laser-welding the first member and the second member by irradiating on a surface of the second member through the interval between the pair of claws with laser light while conducting the step of pressing,

wherein in the first welding step, the laser is irradiated on the surface of the second member above the gap where the spacer is not inserted, to melt the first and second members and form a welded part, and a melted part of the first and second members enters into the gap to expand the welded part in a direction perpendicular to the direction toward the first member for increasing a shear strength of the welded part.

4. The laser welding method according to claim 3, further comprising a second welding step of laser-welding the first member and the second member at a region with a gap between the first member and the second member of at most 300 μ

m after the first welding step.

5. The laser welding method according to claim 4, wherein a distance between centers of welding portions at the first and second welding steps is at most 4 mm.

6. The laser welding method according to claim 4, further comprising a step of forming engaging parts on the first member and the second member, for positioning the first member and the second member,

wherein a portion of laser welding is different from the engaging parts.