Wafer Resistivity Marking for Faster Laser Processing Setup
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Solution Overview
Problem
The existing methods for manufacturing semiconductor wafers and device chips are inefficient due to the need to measure the transmittance of the laser beam for determining processing conditions, which decreases productivity and leads to laser oscillator degradation.
Innovation Solution
A method where a character, number, or mark representing resistivity information is formed on or inside the wafer, allowing for quick determination of processing conditions without measuring transmittance, thereby optimizing laser processing conditions based on pre-measured resistivity values.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If transmittance measurement is performed for each wafer to determine laser processing conditions, then processing precision is improved, but productivity deteriorates due to time-consuming measurements and laser oscillator degradation
Solution Approach 1:
The invention applies preliminary action by pre-measuring the resistivity of the ingot before wafer fabrication and marking this information on the wafer. This allows the resistivity (and thus laser transmittance characteristics) to be known in advance, eliminating the need for time-consuming transmittance measurements on each individual wafer during processing, thereby resolving the contradiction between precision and productivity
Solution Approach 2:
The invention uses copying by transferring the resistivity information from the ingot to the wafer through marking. Instead of measuring each wafer individually, the resistivity characteristic is copied from the source material (ingot) to the product (wafer), allowing rapid retrieval of processing parameters without repeated measurements
2Measurement precision
If laser oscillator remains in operational state during transmittance measurement, then measurement accuracy is maintained, but energy consumption increases and device degradation accelerates
Solution Approach 1:
The resistivity measurement is performed preliminarily on the ingot before wafer fabrication, allowing the laser oscillator to be turned off between wafer processing operations. This maintains measurement accuracy when needed while reducing energy consumption and device degradation by eliminating continuous operational state requirements
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 enables faster and more efficient determination of processing conditions for wafer and device chip manufacturing, reducing the need for repeated transmittance measurements and minimizing laser oscillator degradation.
Implementation Method 1
a laser beam of a wavelength transmissible through a material constituting the ingot (wavelength passing through the ingot) is condensed at a predetermined depth position from the top surface of the ingot and is scanned along a predetermined separation plane
Implementation Method 2
Irradiation conditions such as the energy of the laser beam at a time of forming the modified layers within the wafer may be adjusted in consideration of transmittance of the wavelength of the laser beam in the wafer
Implementation Method 3
modified layers are formed along planned dividing lines set on the top surface of the wafer so as to demarcate the plurality of devices by condensing a laser beam of a wavelength passing through the wafer within the wafer along the planned dividing lines
Data Source
AI summary
A wafer manufacturing method for manufacturing a wafer from an ingot includes forming a peeling layer within the ingot by positioning a condensing point at a depth corresponding to the thickness of the wafer to be produced, and irradiating the ingot with a first laser beam, forming a character, a number, or a mark representing information regarding resistivity in or on the ingot by positioning a condensing point in a region in which devices are not to be formed and irradiating the ingot with a second laser beam, and dividing the ingot with the peeling layer as a starting point.