Processor Die Surface Contouring for Flat Backside Cooling
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Solution Overview
Problem
Conventional methods for testing computer processors using image-based fault localization tools like laser scanning microscopes and photon emission microscopes face challenges with inadequate cooling due to the need for an optically clear path, which prevents the use of common heat removal methods like thermal interface materials and heat spreaders, and complicates cooling when a solid immersion lens is used for ultra-high-resolution imaging.
Innovation Solution
A method of preparing a computer processor die by determining its warpage shape at a testing temperature and selectively contouring its thickness by physically removing material to ensure the surface is substantially flat at that temperature, allowing for improved contact with a cooling plate and enhanced heat transfer during testing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If an optically clear path is maintained between the DUT and microscope lens, then imaging quality is improved, but heat removal capability deteriorates
Solution Approach 1:
The patent divides the testing system into two separate paths: an optical path for imaging through the optically clear window, and a thermal path for heat removal through the same window. This segmentation allows both functions to operate simultaneously without interfering with each other, resolving the contradiction between maintaining optical clarity and enabling effective cooling.
2Measurement precision
If a solid immersion lens is used for ultra-high-resolution imaging, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The optically clear window serves multiple functions simultaneously: it acts as an optical window for the solid immersion lens to achieve ultra-high-resolution imaging, and also serves as a thermal conduction path for heat removal. This multi-functionality reduces device complexity by eliminating the need for separate cooling structures that would interfere with the optical path.
3Productivity
If the DUT is operated at maximum frequency and power, then productivity is improved, but temperature increases leading to thermal runaway
Solution Approach 1:
The patent introduces an intermediary cooling system that operates through the optically clear window, using a coolant flowing through channels adjacent to the DUT. This intermediary cooling mechanism allows the DUT to be operated at maximum power for high-speed testing while continuously removing heat, preventing thermal runaway.
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 enables effective cooling and heat transfer during processor testing, preventing thermal runaway and allowing for accurate observation and energization of the processor, even under high-power conditions, by maintaining a flat backside at operating temperatures.
Implementation Method 1
a cooling plate in contact with the backside of the computer processor die
Implementation Method 2
determining a warpage shape of the computer processor die at a testing temperature
Data Source
AI summary
A method of preparing a computer processor die includes determining a warpage shape of the computer processor die at a testing temperature. The method also includes selectively contouring a thickness of the computer processor die at a contouring temperature by physically removing material from a surface of the computer processor die such that the surface will be substantially flat at the testing temperature.