Soldering a conductor to an aluminum metallization

Patent metadata

Field	Value
Publication number	US-10615145-B2
Application number	US-201816036252-A
Country	US
Kind code	B2
Filing date	Jul 16, 2018
Priority date	Jul 31, 2017
Publication date	Apr 7, 2020
Grant date	Apr 7, 2020

Abstract

A method of making a semiconductor including soldering a conductor to an aluminum metallization is disclosed. In one example, the method includes substituting an aluminum oxide layer on the aluminum metallization by a substitute metal oxide layer or a substitute metal alloy oxide layer. Then, substitute metal oxides in the substitute metal oxide layer or the substitute metal alloy oxide layer are at least partly reduced. The conductor is soldered to the aluminum metallization using a solder material.

First claim

What is claimed is:

1. A method of soldering a conductor to an aluminum metallization, the method comprising:
substituting an aluminum oxide layer on the aluminum metallization by a substitute metal oxide layer or a substitute metal alloy oxide layer;
at least partly reducing a substitute metal oxide in the substitute metal oxide layer or in the substitute metal alloy oxide layer, wherein at least partly reducing comprises applying a reducing gas at elevated temperature to the substitute metal oxide layer or the substitute metal alloy oxide layer; and
soldering the conductor to the aluminum metallization using a solder material.

2. The method of claim 1 , wherein a substitute metal of the substitute metal oxide layer is one of Zn, Cr, Cu, Pb, or Sn.

3. The method of claim 2 , wherein substituting comprises depositing the substitute metal over the aluminum oxide layer by an electrochemical deposition process or by an electroless deposition process.

4. The method of claim 1 , wherein a substitute metal alloy of the substitute metal alloy oxide layer comprises at least two of the elements Zn, Cr, V, Cu, Pb, Sn and Mo.

5. The method of claim 4 , wherein substituting comprises depositing the substitute metal alloy over the aluminum oxide layer by an electrochemical deposition process or by an electroless deposition process.

6. The method of claim 1 , wherein substituting comprises applying one or more of hydrofluoric acid (HF) and methanesulfonic acid (MSA) to the aluminum oxide layer.

7. The method of claim 1 , wherein substituting comprises applying a halogenide via a plasma process to the aluminum oxide layer.

8. The method of claim 1 , wherein the reducing gas comprises one or more of H 2 , CH 2 O 2 , ethanol, propanol, acetone.

9. The method of claim 1 , wherein the elevated temperature is equal to or less than 500° C.

10. The method of claim 1 , wherein the at least partly reducing comprises applying a lowly activating flux during soldering the conductor to the aluminum metallization.

Assignees

• Infineon Technologies Ag

Inventors

• Riedl Edmund
• Li Wu Hu
• Heinrich Alexander
• Otremba Ralf
• Reiss Werner

Classifications

• B23K2101/42

  Printed circuits · CPC title

• B23K1/203

  Fluxing, i.e. applying flux onto surfaces · CPC title

• B23K2101/38

  Conductors · CPC title

• B23K35/288

  with Sn or Zn · CPC title

• B23K35/282

  Zn as the principal constituent · CPC title