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Updated 07/29/2022
0

Wafer breakage at flash heating

Cause and Effect Chain #

Wafer breakage within the flash heating system:

The flash heating with the upper lamp created the gradient of the temperature of the air. The fast-changing of temperature results in the wind (tornado) formation that leads to the movement of the wafer. The moving of the wafer may result in a mechanical hit followed by the wafer breakage.

May 29 2022 3:12:51 pm
5 Whys #
Causes Chain
Root Cause Analysis

Wafer breakage occurs at flash heating

Why?

Run additional wafers to compensate for the broken wafers

0

A mechanical hit occurs

Why?

Redesign the pedestal or add a ring having no "walls" - no parts that the wafer can hit

3

Wafer moves due to air pressure difference appearing due to flash heating

Why?

Keep the wafer static - no movements at all (vacuum keeper?)

1

The pedestal has a special configuration: the wafer moves and can get a mechanical hit

This is the fundamental reason for the problem (FRP).

Redesign the pedestal to exclude a mechanical hit

2
Jun 12 2022 1:04:05 pm
Functional Modeling #

How wafer breakage occurs while the flash heating process:

Functional rank
Problematic rank
Pedestal
10
Low lamp
7.5
Bumps
5
Upper light (flash)
5
Centering pins
5
5
Atmosphere (N2)
10

The main conclusion is that we need to exclude either movement of the wafer or vertical solid parts that the wafer can hit

Jun 12 2022 1:18:45 pm
Inventive principles #
Contradiction:
If
we exclude the wafer movement
Then
no breakage will occur due to a mechanical hit
But
The thermal stress could appear and affect the parameters of the product or even result in breakage due to thermal stress
Improving parameter
Description of what is improving:
No breakage will occur
Selected improving parameter:
Shape
Worsening parameter
Description of what is worsening:
thermal stress will occur
Selected worsening parameter:
Strength
Matching principles:
  • 10
    Preliminary action
  • 14
    Spheroidality - Curvature
  • 30
    Flexible shells and thin films
  • 40
    Composite materials
  • Jun 12 2022 1:32:07 pm

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