IC Chip Backside Trench Formation for Unobstructed Signal Debugging
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Solution Overview
Problem
As IC chips progress to more advanced technology nodes, the presence of metallization components on both sides of the substrate interferes with the debugging process, making it difficult to detect signals emitted by the IC chip due to obstruction by metal lines and vias.
Innovation Solution
A novel packaging and testing process flow is implemented, which involves partially removing the printed circuit board (PCB) and some metallization components on the back side of the IC chip to form a trench, allowing signals to emit without obstruction. This is achieved through a multi-step approach of trench formation and refill material deposition to protect the metallization components from damage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Difficulty of detecting and measuring
If a single deep trench formation process is used to remove metallization components, then signal detection capability is improved, but the risk of damaging remaining metallization components and causing electrical shorting increases
Solution Approach 1:
The single deep trench formation process is segmented into multiple sequential trench formation processes. Each process removes a portion of the metallization components rather than attempting to remove all at once. This segmentation allows for controlled removal while minimizing the risk of damaging remaining components or causing electrical shorting between conductive layers.
Solution Approach 2:
Protective layers are formed in advance before each trench formation process. These preliminary protective layers serve as barriers that prevent the etching process from damaging underlying metallization components. The protective layers are strategically deposited to shield specific areas that should not be removed or damaged during the trench formation process.
2Object-affected harmful factors
If multiple trench formation processes are used to safely remove metallization components, then protection of metallization components is improved, but the manufacturing process complexity increases
Solution Approach 1:
The protective layers serve multiple functions: they protect underlying metallization components from etching damage, act as etch stop layers to control trench depth, and provide a foundation for subsequent processing steps. This multi-functionality reduces the need for separate dedicated protective measures for each trench formation process, thereby managing complexity.
Solution Approach 2:
The manufacturing process is structured as nested sequential steps where each trench formation process is nested within a broader multi-process flow. Each iteration follows the same pattern of forming protective layers, performing trench formation, and removing portions of metallization components. This nested structure, while sequential, uses repetitive modular steps that can be standardized and automated, managing overall process complexity.
Data Source
AI summary
An integrated circuit (IC) chip assembly includes an integrated circuit (IC) die that includes a first substrate in which plurality of transistors is formed, a first structure that contains a plurality of first metallization components, and a second structure that contains a plurality of second metallization components. The first structure is disposed over a first side of the first substrate. The second structure is disposed over a second side of the first substrate opposite the first side. The chip assembly includes a second substrate bonded to the IC die through the second side. The chip assembly includes a trench that extends through the second substrate and through the second structure of the IC die. Sidewalls of the trench are defined at least in part by one or more protective layers.