Semiconductor Die Street Cleaning After SiC Singulation
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Solution Overview
Problem
Current methods for singulating semiconductor die from substrates are inefficient, particularly for hard materials like silicon carbide, leading to slow cutting processes, high blade wear rates, and increased sidewall damage, which reduces die strength and increases processing costs.
Innovation Solution
The method involves forming a damage layer beneath the die street in the semiconductor substrate using laser irradiation and applying sonic energy during the sawing process, which enhances the cutting efficiency by vibrating the saw blade and exposing fresh diamond grit, while also removing particulates using megasonic energy in a liquid bath.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional sawing methods are used to singulate semiconductor die from hard substrates like silicon carbide, then the cutting process can be performed, but the cutting speed is slow and blade wear rate is high
Solution Approach 1:
A damage layer is formed in the substrate material along the intended cut path before the actual sawing operation. This preliminary damage to the crystal structure weakens the material, allowing the saw blade to cut through much faster with reduced wear. The damage layer is created using laser irradiation or other methods that fracture the substrate material in advance.
Solution Approach 2:
The saw blade is subjected to ultrasonic vibration during the cutting process. This vibration causes the diamond grit particles on the blade to strike the substrate with greater impact force, significantly increasing cutting speed and reducing blade wear when cutting hard materials like silicon carbide.
2Strength
If conventional sawing methods are used, then the substrate can be cut, but sidewall damage increases and die strength decreases
Solution Approach 1:
The damage layer is precisely formed only in the die street region where the cut will occur, leaving the sidewalls of the die intact and undamaged. This selective preliminary damage allows the blade to follow a predetermined path with minimal deviation, reducing sidewall damage and preserving die strength.
Solution Approach 2:
The cutting process applies damage and cutting forces locally only to the die street region, while the die sidewalls remain unaffected. This localized approach ensures that the structural integrity and strength of the die are maintained while still achieving efficient singulation.
3Ease of manufacture
If conventional singulation methods are used, then die can be separated, but processing costs increase due to inefficiency
Solution Approach 1:
By pre-forming the damage layer and using ultrasonic vibration during cutting, the overall singulation process is dramatically accelerated. This reduces processing time and increases throughput, thereby lowering per-unit manufacturing costs despite the added complexity of the process.
Solution Approach 2:
Ultrasonic vibration of the saw blade enables much faster cutting speeds through hard substrates like silicon carbide, significantly improving productivity and reducing processing costs for singulating semiconductor die from expensive hard materials.
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 results in faster cutting processes, longer saw blade lifetimes, reduced sidewall damage, and increased die strength, with improved efficiency and reduced processing costs, especially for hard substrates like silicon carbide.
Implementation Method 1
forming a damage layer beneath a surface of a die street in a semiconductor substrate... irradiating the die street with a laser beam at a focal point within the semiconductor substrate
Implementation Method 2
sawing the semiconductor substrate... exposing fresh diamond grit
Implementation Method 3
removing one or more particulates in the die street after singulating through applying sonic energy to the plurality of semiconductor die
Implementation Method 4
removing particulates using megasonic energy in a liquid bath
Data Source
AI summary
Implementations of methods of forming a plurality of semiconductor die may include forming a damage layer beneath a surface of a die street in a semiconductor substrate, singulating the semiconductor substrate along the die street into a plurality of semiconductor die, and removing one or more particulates in the die street after singulating through applying sonic energy to the plurality of semiconductor die.