Wafer Grounding via Controlled Electrical Pulse Breakdown

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Conventional electric contact pin designs cause significant damage to the backside of semiconductor wafers during electron beam irradiation processes, either through mechanical piercing or electrical breakdown, which can become particle sources in subsequent fabrication processes.

Innovation Solution

An electric circuit is designed with an electric contact pin that applies a controlled unidirectional electric pulse to break through the insulating layer on the wafer backside, minimizing damage by using a resistor and electrostatic chuck coupled with capacitance to manage the breakdown voltage, resulting in zapping marks less than 1 micron in size.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional electric contact pins use mechanical piercing or electrical breakdown to breakthrough the insulating layer, then electrical conductivity is achieved, but significant damage is caused on the wafer backside

Engineering Contradiction:

Improveelectrical conductivityVSAvoidbackside damage

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent applies a preliminary controlled electrical pulse to the contact pin before mechanical contact with the wafer, which pre-breaks down the insulating layer. This preliminary action reduces the force needed during mechanical piercing and minimizes the damage area, achieving conductivity establishment with reduced backside damage.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent changes the electrical parameters by applying a controlled voltage pulse (e.g., 500V for 10 microseconds) to the contact pin. This parameter change enables the insulating layer to break down electrically before mechanical contact, transforming the damage mechanism from high-force mechanical piercing to controlled electrical breakdown, thereby reducing physical damage on the wafer backside.

Inventive Principle:

Principle #35Parameter changes

2Reliability

If electric contact pins apply high force for mechanical piercing, then conductivity is established, but large zapping marks are created on the wafer backside

Engineering Contradiction:

Improveelectrical conductivityVSAvoidzapping mark size

Core Design Contradiction:

ReliabilityVSManufacturing precision

Solution Approach 1:

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent replaces part of the mechanical piercing system with an electrical breakdown mechanism. By applying a controlled voltage pulse to the contact pin, the insulating layer is broken down electrically before mechanical contact, substituting high-force mechanical action with controlled electrical action, thereby reducing zapping mark size while maintaining conductivity establishment.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Reliability

If electrical pulse is used to breakthrough insulating layer, then conductivity is achieved, but significant electrical impact is applied to the substrate

Engineering Contradiction:

Improveelectrical conductivityVSAvoidelectrical energy impact

Core Design Contradiction:

ReliabilityVSUse of energy by moving object

Solution Approach 1:

The patent applies a controlled electrical pulse with specific parameters (e.g., 500V for 10 microseconds) that is sufficient to break down the insulating layer but limited in duration and magnitude to minimize excessive energy impact on the substrate. This partial action achieves the necessary conductivity establishment while avoiding excessive electrical energy application that could damage the wafer.

Inventive Principle:

Principle #16Partial or excessive action

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This approach significantly reduces backside damage on the wafer substrate during electron beam irradiation, minimizing the risk of particle formation and maintaining conductivity while reducing physical and electrical impact on the substrate.

Implementation Method 1

applies a controlled unidirectional electric pulse to break through the insulating layer on the wafer backside

Methodology Applied

Scientific EffectElectrical breakdown: Avalanche Breakdown

Implementation Method 2

The embodiments combine mechanical piercing and electrical zapping

Methodology Applied

Scientific EffectElectrostatic discharge: Electrostatic Discharge

Implementation Method 3

an electrostatic chuck coupled with capacitance to manage the breakdown voltage

Methodology Applied

Scientific EffectElectrostatic adhesion: Electrostatics

Data Source

PatentUS8094428B2Wafer grounding methodology

Publication Date: 2012.01.10 ASML NETHERLANDS BV

AI summary

An apparatus for increasing electric conductivity to a wafer substrate, when exposed to electron beam irradiation, is disclosed. More specifically, a methodology to breakdown the insulating layer on wafer backside is provided to significantly reduce the damage on the wafer backside while proceeding with the grounding process.