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A method for Improving Wireless Capacitive Probing of pads

IP.com Disclosure Number: IPCOM000245351D
Publication Date: 2016-Mar-02
Document File: 4 page(s) / 150K

Publishing Venue

The IP.com Prior Art Database

Abstract

Disclosed is a method to improve the signal transfer from the probed pad on the wafer/die to the probing pad on the tester during die testing.

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Page 01 of 4

Title

A method for Improving Wireless Capacitive Probing of pads

Abstract

Disclosed is a method to improve the signal transfer from the probed pad on the wafer/die to the probing pad on the tester during die testing.

Problem

Probing the wafers is an essential process during the testing of dies. Contact probing using mechanical probes has limitations because of the probes' relatively large size and inherent parasitic effects. The said probes can also damage the pads during the mechanical contact procedure, which renders the die/wafer redundant.

Capacitive wireless probing is an efficient method to probe the pads based on the voltage capacitance partition principle; however, a method is needed to improve the wireless probing of pads.

Figure 1: Model of a wireless bidirectional capacitive interconnection between needle and pad

Figure 2: Probe card configuration after a 50um overtravel

Solution/Novel Contribution

Because the wireless probing method is dependent on capacitive coupling, the proposed method improves the signal coupling from the wireless pad to the probe needle with the deposition of a temporary layer of high K (permittivity) dielectric material.


Page 02 of 4

Figure 3: Architecture of components

The novel contribution is a method to improve the coupling of the signal in the wireless capacitive probing method comprising:

1. Depositing a thin film of high K dielectric on the wireless pads

2. Depositing a photoresist on the said deposited film

3. Using a mask and lithography to pattern selective regions between the pads

4. Etching out the photoresist and subsequently the thin film between the wireless pads


5. Removing the photoresist

6. Performing the wireless capacitive probing of the said pads


7. Removing the thin film of high K diele...