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Pillar BUMPs UBM Etch Chemical Reclaim Process Optimization on AMAT Raider

IP.com Disclosure Number: IPCOM000245122D
Publication Date: 2016-Feb-10
Document File: 2 page(s) / 35K

Publishing Venue

The IP.com Prior Art Database

Abstract

Disclosed is a method to minimize both the loss and dilution of the Titanium (Ti) etch chemical in the reclaim process after wafer processing in Copper (Cu) pillar bumping technology. The solution is to add two steps to the typical process: Nitrogen Gas (N2) dry steps and N2 manifold purge.

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Page 01 of 2

Title

Pillar BUMPs UBM Etch Chemical Reclaim Process Optimization on AMAT Raider

Abstract

Disclosed is a method to minimize both the loss and dilution of the Titanium (Ti) etch chemical in the reclaim process after wafer processing in Copper (Cu) pillar bumping technology. The solution is to add two steps to the typical process: Nitrogen Gas (N2) dry steps and N2 manifold purge.

Problem

New copper (Cu) pillar bumping technology requires the use of an expensive Titanium (Ti) etch chemical. After each wafer is processed, another process needs to reclaim this chemical. Current processes do not minimize chemical loss or dilution, which puts the manufacturability of the process, would at risk due to high chemical loss. Moreover, in this particular process, the chemical is expensive; loss of the chemical adds to manufacturing costs.

A method is needed to minimize both the chemical loss in this reclaim process and any dilution effect that can limit the lifetime of the chemical itself the AMAT Raider* tool.

Solution/Novel Contribution

The novel solution is to add two steps to the typical process:


• Nitrogen Gas (N2) dry steps to address the chemical dilution issue
• N2 manifold purge to address the chemical loss issue

Method/Process

With the new steps added the under-bump metallurgy (UBM) etch process steps are as follows


1. Cu etch

2. DW Rinse1

3. N2 Dry (new)

4. Ti etch (reclaimed in tank)
5. N2 manifold purge (new)
6. DIW Rinse2

7. Dry N2


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Figure: Compo...