# US 11,908,830 B2 · Semiconductor device and method for fabricating the same

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- Number: US 11,908,830 B2
- Document ID: US11908830B2
- Status: Granted
- Kind: B2
- Application number: 17/390,101
- Filed: 2021-07-30
- Published: 2022-02-10
- Granted: 2024-02-20
- Earliest claimed: 2020-08-10
- Assignees: Infineon Technologies AG
- Applicants: Infineon Technologies AG
- Inventors: Richard Knipper; Alexander Heinrich; Thorsten Scharf; Stefan Schwab
- Web page: https://patentgrep.com/patent/US11908830B2

## CPC

- H01L 24/85
- H01L 24/45
- H01L 24/48
- H01L 2224/45033
- H01L 2224/48472
- H01L 2224/85205
- H01L 2224/85214
- H01L 2224/85825
- H01L

## Abstract

A method for fabricating a semiconductor device includes providing a semiconductor die, arranging an electrical connector over the semiconductor die, the electrical connector including a conductive core, an absorbing feature arranged on a first side of the conductive core, and a solder layer arranged on a second side of the conductive core, opposite the first side and facing the semiconductor die, and soldering the electrical connector onto the semiconductor die by heating the solder layer with a laser, wherein the laser irradiates the absorbing feature and absorbed energy is transferred from the absorbing feature through the conductive core to the solder layer.

## Claims

### Claim 1

A method for fabricating a semiconductor device, the method comprising:
providing a semiconductor die;
arranging an electrical connector over the semiconductor die, the electrical connector comprising a conductive core, an absorbing feature arranged on a first side of the conductive core, and a solder layer arranged on a second side of the conductive core, opposite the first side and facing the semiconductor die; and
soldering the electrical connector onto the semiconductor die by heating the solder layer with a laser,
wherein the laser irradiates the absorbing feature and absorbed energy is transferred from the absorbing feature through the conductive core to the solder layer.

### Claim 2 (depends on 1)

The method of claim 1, wherein the material of the solder layer has a melting point that is lower than a melting point of the material of the conductive core, and wherein the absorbed energy is sufficient to melt the material of the solder layer but insufficient to melt the material of the conductive core.

### Claim 3 (depends on 1)

The method of claim 1, wherein an absorptance for the laser beam of the absorbing feature is higher than an absorptance for the laser beam of the conductive core.

### Claim 4 (depends on 1)

The method of claim 1, wherein the absorbing feature comprises an absorbing layer or an antireflection layer, and wherein the absorbing layer or the antireflection layer comprises a polymer, a metal or a metal oxide.

### Claim 5 (depends on 1)

The method of claim 1, wherein the soldering comprises diffusion soldering the electrical connector onto the semiconductor die.

### Claim 6 (depends on 1)

The method of claim 1, wherein the electrical connector comprises a wire, a ribbon or a sheet metal.

### Claim 7 (depends on 1)

The method of claim 1, wherein the absorbing feature and/or the solder layer is sputtered, printed, cold rolled, dip coated or galvanically deposited on the conductive core.

### Claim 8 (depends on 1)

The method of claim 1, further comprising:
using ultrasonic excitation, in addition to the laser, to heat the solder layer.

### Claim 9 (depends on 1)

The method of claim 1, wherein the electrical connector is heated to a temperature of no more than 430° C.

### Claim 10 (depends on 1)

The method of claim 1, wherein the electrical connector is arranged over the semiconductor die by a bondhead, and wherein the laser is guided through the bondhead.

### Claim 11 (depends on 1)

The method of claim 1, further comprising:
providing the electrical connector as part of a strip; and
after the soldering, singulating the electrical connector by cutting through the strip.

### Claim 12

A semiconductor device, comprising:
a semiconductor die; and
an electrical connector arranged over the semiconductor die, the electrical connector comprising a conductive core, an absorbing feature arranged on a first side of the conductive core and facing away from the semiconductor die, and a solder joint arranged on a second side of the conductive core, opposite the first side and coupling the electrical connector to the semiconductor die.

### Claim 13 (depends on 12)

The semiconductor device of claim 12, wherein the conductive core has a thickness of 150 μm or more, measured between the first and second sides.

### Claim 14 (depends on 12)

The semiconductor device of claim 12, wherein the semiconductor die comprises a metallization, wherein the electrical connector is soldered to the metallization, and wherein the metallization has a thickness of 10 μm or less.

### Claim 15 (depends on 12)

The semiconductor device of claim 12, further comprising:
an electrically conductive substrate,
wherein the semiconductor die is arranged on the substrate, and
wherein the electrical connector electrically couples the semiconductor die to the substrate.