Thermoshock Wafer Dicing for Microelectronic Yield
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Solution Overview
Problem
The reduction in thickness of microelectronic devices and dielectric films in 3D microelectronic assemblies makes them more fragile and susceptible to cracking and damage from particulate contaminants, leading to yield losses and premature failures in semiconductor devices like HBMx and HMCs.
Innovation Solution
A method involving the formation of recessed regions on a wafer, deposition of metal material, heating, and rapid cooling to induce thermoshock, which fractures the wafer along these regions, allowing for the separation of semiconductor dice while minimizing the introduction of particles and reducing the width of streets between dice, thus reducing the risk of damage and increasing yield.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the thickness of microelectronic devices and dielectric films is reduced to shrink form factor, then the footprint and height of 3D microelectronic assemblies are reduced, but the devices become more fragile and susceptible to cracking under stress and from particulate contaminants
Solution Approach 1:
The method performs preliminary actions by forming recessed regions and depositing metal materials before the actual dicing process. This preparation creates controlled fracture paths that guide the breaking process, preventing uncontrolled cracking that would damage thin devices. The preliminary structuring of the wafer ensures that when separation occurs, it follows predetermined safe paths.
Solution Approach 2:
The invention changes physical parameters by applying rapid thermal cycling (heating to elevated temperatures followed by rapid cooling). This parameter change induces thermal stress that, combined with the recessed region geometry, creates controlled fractures along the streets between dice. The thermal parameter transformation enables clean separation without mechanical contact that could damage thin devices.
2Productivity
If conventional dicing methods are used to separate semiconductor dice, then the dice are separated from the wafer, but a significant number of particles are introduced and the width of streets between dice must be increased, leading to yield losses
Solution Approach 1:
The invention replaces conventional mechanical dicing systems (blades, saws) with a thermal-field-based system. By applying rapid thermal cycling, the method induces thermally-driven fractures that separate the dice without mechanical contact. This substitution eliminates the primary source of particulate contamination associated with mechanical cutting tools while maintaining high dicing efficiency.
Solution Approach 2:
The method utilizes phase transitions of thermal energy - rapidly heating the wafer to elevated temperatures and then rapidly cooling it. This thermal phase transition creates controlled thermal stress that propagates fractures along the streets between dice. The phase transition approach enables particle-free separation while maintaining productivity.
3Length of stationary object
If the bond line thickness is reduced to decrease assembly height, then the height of 3D microelectronic assemblies is reduced, but the ability to accommodate particulate contaminants is diminished, exacerbating susceptibility to damage
Solution Approach 1:
The method performs preliminary action by creating controlled fracture paths through recessed regions and metal deposits before dicing occurs. This preliminary structuring ensures that when dice are separated, no particulate contaminants are generated that could later compromise the reduced bond lines. The preliminary preparation prevents the introduction of harmful factors that would otherwise require thicker bond lines to accommodate.
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 effectively reduces the number of particles produced during dicing, increases the yield of microelectronic devices, and decreases the cost of production by minimizing damage and failures, enabling the use of thinner microelectronic devices with improved reliability and longevity.
Implementation Method 1
depositing a metal material on one or more sides of the recessed region in the streets; heating the metal material on the one or more sides of the recessed region in the streets
Implementation Method 2
cooling the wafer after heating the metal material; fracturing the wafer along the streets through thermoshock induced by cooling the wafer
Data Source
AI summary
Microelectronic devices may include an active surface and a side surface. The side surface may include a first portion having a reflective surface and a second portion having a non-reflective surface. The reflective surface may be formed by depositing a conductive material in trenches formed in material of the wafer along streets between the microelectronic devices on a wafer. The conductive material may be heated. The wafer may be cooled after the conductive material is heated fracturing the wafer along the streets and separating the microelectronic devices.