UV Light Source for Wafer Defect Inspection
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Solution Overview
Problem
In semiconductor manufacturing, the increasing demand for thin wafers leads to higher chances of physical defects such as cracks during processes like back lap and grind after laser, which existing inspection techniques struggle to detect effectively.
Innovation Solution
A semiconductor manufacturing apparatus that uses an ultraviolet light source to weaken the adhesive strength of a die attach film with an ultraviolet sensitive layer on a wafer, allowing for defect inspection by capturing images through the wafer with a camera and processing them to determine defects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If thin wafers are used to meet product development demands, then productivity and adaptability are improved, but the likelihood of physical defects such as cracks increases during processing
Solution Approach 1:
The patent applies preliminary action by performing defect inspection using transmitted ultraviolet light before the wafer undergoes processes that may cause cracks (back lap, GAL). The ultraviolet sensitive layer is attached in advance, and defects are detected while the wafer is still in a relatively intact state, allowing preventive measures to be taken before physical processing induces cracks.
Solution Approach 2:
The patent introduces an intermediary substance - the ultraviolet sensitive layer - that mediates between the inspection system and the wafer. This layer enhances the visibility of defects by reacting to ultraviolet light transmission, allowing indirect detection of cracks and defects that would be difficult to observe directly in thin wafers.
2Device complexity
If existing inspection techniques are used on thin wafers, then device complexity is maintained, but measurement precision and defect detection capability deteriorate
Solution Approach 1:
The patent changes the parameter of light wavelength to ultraviolet range, which has different transmission and absorption characteristics compared to visible light. This parameter change enables the detection of defects in thin wafers that are invisible under conventional inspection methods, significantly improving measurement precision without requiring complex equipment modifications.
Solution Approach 2:
The patent utilizes color/opacity changes in the ultraviolet sensitive layer when exposed to ultraviolet light. The layer's optical properties change based on the presence of defects, allowing visual or automated detection of cracks and imperfections that would otherwise be imperceptible, thereby enhancing defect detection accuracy.
3Ease of operation
If ultraviolet light is used to weaken adhesive strength for defect inspection, then ease of operation is improved, but the wafer may be damaged or the adhesive layer compromised
Solution Approach 1:
The patent applies partial action by using controlled ultraviolet light exposure that is sufficient to enable defect detection through the ultraviolet sensitive layer but limited in intensity and duration to avoid excessive weakening of the adhesive. The inspection process uses just enough ultraviolet energy to create detectable optical contrast without compromising the structural integrity of the adhesive bond.
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 method improves the detection of defects on wafers, enhancing the semiconductor manufacturing process by enabling effective inspection and separation of semiconductor devices while maintaining wafer integrity, thus increasing throughput and productivity.
Implementation Method 1
an ultraviolet light source configured to irradiate ultraviolet light onto the first surface of the wafer attached to the die attach film to weaken adhesive strength of the ultraviolet sensitive layer
Implementation Method 2
a camera configured to generate a wafer image by capturing ultraviolet light transmitted through a second surface of the wafer opposite to the first surface of the wafer
Data Source
AI summary
A semiconductor manufacturing apparatus and a method of manufacturing semiconductor device are provided. The semiconductor manufacturing apparatus includes a loading unit configured to load a wafer having a first surface to which a die attach film is attached through an ultraviolet sensitive layer, an ultraviolet light source configured to irradiate ultraviolet light onto the first surface of the wafer attached to the die attach film to weaken adhesive strength of the ultraviolet sensitive layer, and a camera configured to generate a wafer image by capturing ultraviolet light transmitted through a second surface of the wafer opposite to the first surface of the wafer.