Semiconductor Dicing via Two-Step Trenching for Yield and Thermal Management
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Solution Overview
Problem
Conventional semiconductor substrate dicing techniques face challenges with increased substrate dimensions and complex metallization systems, leading to yield losses due to metal debris contamination and inferior heat dissipation, particularly when using low-k dielectric materials and back side metallization.
Innovation Solution
A two-step separation process is employed, where trenches are formed from the rear side with a thicker saw blade and then connected by forming reduced-width trenches from the front side, reducing the width of scribe lines and minimizing metal contamination, allowing for efficient separation of semiconductor chips with improved yield and heat dissipation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If substrate dimensions are increased to produce more semiconductor devices per substrate, then production yield and area utilization are improved, but the complexity of metallization systems increases and heat dissipation becomes more difficult
Solution Approach 1:
The substrate is divided into multiple individual semiconductor devices through dicing, allowing each device to be processed and packaged independently. This segmentation enables efficient utilization of large substrate areas while managing the complexity of metallization systems on a per-device basis.
Solution Approach 2:
The patent introduces a new dimension by forming trenches that extend through the substrate thickness, creating a three-dimensional separation approach. This vertical dimension complements the traditional planar dicing method, enabling better management of metallization systems and heat dissipation paths in the depth direction.
2Reliability
If low-k dielectric materials and ULK materials are used to reduce parasitic capacitance, then electrical performance is improved, but thermal conductivity is significantly reduced and heat dissipation capability deteriorates
Solution Approach 1:
The patent introduces thermal management structures as intermediary elements between the low-k dielectric materials and the substrate. These structures serve as thermal conduits that bridge the thermal gap created by the low-k materials, allowing heat to be efficiently transferred from the device region to the substrate without compromising the electrical performance benefits of the low-k dielectrics.
Solution Approach 2:
The patent employs composite material structures combining low-k dielectric materials with thermally conductive materials in specific configurations. This composite approach allows the system to simultaneously achieve low parasitic capacitance from the low-k dielectrics and effective heat dissipation through the thermally conductive components.
3Ease of manufacture
If conventional dicing techniques are used with thick saw blades, then substrate separation is achieved, but metal debris contamination occurs and yield is reduced
Solution Approach 1:
The dicing process is segmented into multiple sequential steps: first forming trenches with a initial cut, then forming additional trenches to complete the separation. This multi-stage segmentation allows for better control of the cutting process and reduced metal debris generation compared to single-pass thick blade dicing.
Solution Approach 2:
The patent adds a vertical dimension to the dicing process by forming trenches that extend through the substrate thickness in a controlled sequence. This three-dimensional approach to separation allows for more precise control over debris generation and removal compared to traditional planar dicing methods.
Data Source
AI summary
The width of scribe lines may be reduced in semiconductor devices by applying a process technique in which trenches may be formed first from the rear side on the basis of a required width of the corresponding trenches, while subsequently it may be cut into the substrate from the front side on the basis of a reduced thickness of the corresponding saw blades, thereby also enabling a reduction of the scribe line width. Furthermore, contamination of the front side, i.e., of the metallization system, may be reduced, for instance, by performing an optional intermediate cleaning process.