Trench Gate Lead-out Structure with Partial Polysilicon Fill
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Solution Overview
Problem
Conventional trench gate lead-out structures in semiconductor manufacturing require thicker polysilicon deposition for larger trench sizes, increasing costs and limiting product capacity.
Innovation Solution
A trench gate lead-out structure where the trench is partially filled with polysilicon, forming a recess, and a second dielectric layer is filled in the recess, with a metal plug extending through the dielectric layers to connect with the polysilicon gate, reducing the thickness of deposited polysilicon and eliminating the need for complete trench filling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If the trench size is enlarged to accommodate larger end portions, then the lead-out capability is improved, but the polysilicon deposition thickness increases, resulting in increased cost
Solution Approach 1:
The patent applies partial filling by depositing polysilicon only to a controlled thickness that does not completely fill the trench. This partial action allows the trench gate structure to accommodate larger end portions while limiting the polysilicon thickness to a controlled level, thereby resolving the contradiction between improved lead-out capability and increased material consumption
Solution Approach 2:
The patent introduces a dielectric material as an intermediary substance to fill the remaining space in the trench after partial polysilicon deposition. This dielectric mediator allows the trench to be completely filled for structural integrity while preventing excessive polysilicon thickness, thus enabling larger trench sizes without proportionally increasing polysilicon consumption
2Reliability
If thicker polysilicon is deposited to fill larger trenches, then the trench gate structure is completed, but the product capacity of polysilicon deposition is reduced and cost increases
Solution Approach 1:
By performing partial filling with polysilicon instead of complete filling, the patent reduces the total polysilicon deposition thickness required. This partial action increases the deposition capacity within the same process time and reduces material costs while maintaining sufficient structural integrity through the combination of polysilicon and dielectric materials
Solution Approach 2:
The patent creates a composite structure by combining polysilicon gate material with dielectric filling material in the trench. This composite approach allows the trench to be completely filled for structural reliability while limiting the polysilicon thickness to a thinner, more cost-effective level, thereby improving deposition capacity and reducing costs
Data Source
AI summary
A trench gate lead-out structure comprises a substrate (10), a trench formed in the surface of the substrate (10) and a first dielectric layer (22) on the substrate (10), and also comprises a polysilicon gate (31) at the inner surface of the trench. The trench is partially filled by the polysilicon gate (31), so that a recess exists in the trench above the polysilicon gate (31). A second dielectric layer (41) is filled in the recess. The trench gate lead-out structure also comprises a metal plug (50). The metal plug (50) downwards penetrates through the first dielectric layer (22) and then is inserted between the second dielectric layer (41) and the polysilicon gate (31), and accordingly is connected to the polysilicon gate (31).