Protective Tape Detection of Laser Dicing Damage in Wafers
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Solution Overview
Problem
Microelectronic devices face yield and reliability issues due to irregularities at the edges during separation, caused by low mechanical strength of polymeric low-k dielectrics and residual energy from laser dicing processes, which are difficult to detect.
Innovation Solution
A protective tape with nano-particles or dyes that react visibly to infrared or heat exposure is used to detect and indicate residual energy, allowing for early identification and removal of damaged devices.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If polymeric low-k dielectrics are used to reduce parasitic capacitance and eliminate crosstalk, then electrical performance is improved, but mechanical strength and thermal stability deteriorate
Solution Approach 1:
The patent uses composite materials by combining polymeric low-k dielectric layers with supporting structures such as trenches filled with different materials (e.g., oxide, nitride, or air gaps). This composite approach maintains the electrical benefits of low-k materials while providing mechanical support through the additional layers, thereby resolving the contradiction between electrical performance and mechanical strength.
2Productivity
If low-k dielectric materials are used to enable scaling of integrated circuitry, then circuit density is improved, but yield and reliability deteriorate due to edge irregularities
Solution Approach 1:
The patent applies preliminary protective actions by depositing protective layers (such as oxide or nitride) over the low-k dielectric structures before subsequent processing steps. These protective layers are applied in advance to prevent edge damage during dicing and handling, thereby maintaining high yield while enabling continued scaling and high circuit density.
Solution Approach 2:
The patent implements beforehand cushioning by creating buffer structures such as trenches and protective overhangs that absorb mechanical stress and prevent edge damage during separation. These cushioning structures are built prior to dicing, protecting the fragile low-k dielectric edges and maintaining high yield despite increased circuit density.
3Strength
If conventional insulating dielectrics are used, then mechanical strength is maintained, but charge buildup and crosstalk increase
Solution Approach 1:
The patent employs composite material structures where conventional dielectric layers (providing mechanical strength) are combined with low-k dielectric layers (reducing charge buildup and crosstalk). The composite structure allows both materials to contribute their beneficial properties, achieving both mechanical strength and reduced electrical interference simultaneously.
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
Enhances the detection of laser-induced defects, increasing the yield and reliability of microelectronic devices by identifying and removing potentially faulty components before final assembly.
Implementation Method 1
A protective tape with nano-particles or dyes that react visibly to infrared or heat exposure is used to detect and indicate residual energy
Implementation Method 2
forming a modified layer along a separation region extending between adjacent microelectronic devices by focusing a laser beam into an interior portion of the wafer
Data Source
AI summary
Methods of identifying damaged microelectronic devices are described. A method includes applying a detection material to an active surface of a wafer. The detection material includes an additive configured to yield a visible reaction to heat or infrared or near-infrared light. The method may further include focusing a laser beam into an interior portion of the wafer through a second surface of the wafer opposite the active surface to form a modified layer along a separation region extending between adjacent microelectronic devices. The method may also include inspecting the detection material for visible reactions. The method may further include identifying reactions that indicate exposure to heat or infrared or near-infrared light over a pre-determined threshold. Protective tape, backgrind tapes, and methods of manufacturing a microelectronic device are also described.