Trenched Device Wafer for Debris-Free Laser Dicing
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Solution Overview
Problem
The existing wafer-level manufacturing processes for camera modules using CMOS technologies face issues with debris generation during laser grooving, which can damage vacuum nozzles and the top surface of the device wafer, leading to inefficiencies in the dicing process.
Innovation Solution
A trenched device wafer with trenches between adjacent devices, formed by a dry-etching process, is introduced, along with a method that includes forming a trench and decreasing the wafer thickness between devices to prevent debris from accumulating on the surface, allowing for the singulation of device dies with stepped sidewalls and reduced debris-related damage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If laser grooving is used to dice the device wafer, then the dicing process can be performed, but debris is generated that accumulates on the top surface and damages the vacuum nozzle and device surface
Solution Approach 1:
The patent extracts the harmful debris from the problematic location (top surface) by providing trenches where debris can be collected instead. The trenches act as designated receptacles that remove debris from the surface area, preventing it from damaging the vacuum nozzle and device structures.
Solution Approach 2:
The patent converts the harmful debris byproducts of laser grooving into a beneficial situation by directing them into trenches. Instead of debris being a contaminant on the surface, it becomes contained material in designated areas, transforming a harmful factor into a controlled element that no longer threatens the vacuum nozzle or device integrity.
2Object-affected harmful factors
If the wafer thickness is reduced between devices, then debris accumulation on the surface is prevented, but the structural integrity of the wafer may be compromised
Solution Approach 1:
The patent segments the wafer structure by introducing trenches that create localized variations in thickness between devices. This segmentation allows different regions of the wafer to have different thickness characteristics - the trench regions are thinner to collect debris, while the device regions maintain sufficient thickness for structural integrity.
Solution Approach 2:
The patent applies local quality by creating non-uniform wafer thickness - thinner in trench regions for debris collection and thicker in device regions for structural support. This localized variation in thickness allows each region to optimize its function without compromising the overall wafer integrity.
3Object-affected harmful factors
If trenches are formed between devices, then debris is directed into trenches preventing surface accumulation, but the device wafer structure becomes more complex
Solution Approach 1:
The patent uses segmentation to divide the wafer surface into functional zones - device regions and trench regions. This segmentation creates a simpler overall structure compared to attempting to manage debris through complex surface treatments or additional protective layers, as the trenches provide an obvious and effective debris collection mechanism.
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 effectively prevents debris from accumulating on the top surface, reducing damage to the vacuum nozzle and improving the efficiency of the dicing process by ensuring debris collects in the trenches, facilitating the production of high-quality device dies.
Implementation Method 1
formed by a dry-etching process
Data Source
AI summary
A trenched device wafer includes a device substrate layer having a top surface; a plurality of devices in the device substrate layer, and a trench in the top surface. The trench extends into the device substrate layer, and is located between a pair of adjacent devices of the plurality of devices. A method for forming a device die from a device wafer includes forming a trench in a top surface of the device wafer between two adjacent devices of the device wafer. The trench has a bottom surface located (a) at a first depth beneath the top surface and (b) at a first height above a wafer bottom surface. The method also includes, after forming the trench, decreasing a thickness of the device wafer, between the two adjacent devices, to a thickness less than the first height.