Stacked Deep Trench Capacitor Layout With TSV for Lower ESR
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Solution Overview
Problem
The existing deep trench capacitor (DTC) manufacturing methods are complex and costly, requiring two separate wafers and resulting in a large equivalent series resistance due to the distance between the DTC structure and the die, which affects the voltage stability of integrated circuits.
Innovation Solution
A new method forms a layer of upper and lower trenches within a single wafer, using a through-substrate via (TSV) to connect the die to the DTC structure, reducing the distance and embedding the DTC within the die, thereby simplifying the process and reducing equivalent series resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If two separate wafers are used to form DTC structure, then the DTC structure can be formed with sufficient capacitance, but the equivalent series resistance increases due to the large distance between DTC structure and die
Solution Approach 1:
The patent merges the DTC structure formation process into a single wafer, integrating the capacitor formation with the die fabrication. This eliminates the need for separate wafer bonding and reduces the physical distance between the DTC structure and the die, thereby reducing equivalent series resistance and improving voltage stability.
Solution Approach 2:
The patent utilizes the vertical dimension by forming trenches that extend through or near the die substrate, allowing the DTC structure to be positioned much closer to the die in the vertical direction rather than requiring lateral proximity, thus reducing the effective distance and associated resistance.
2Reliability
If two separate wafers are used for DTC structure, then capacitance can be achieved, but the manufacturing process becomes complex and costly with multiple thin-down processes
Solution Approach 1:
The patent combines the DTC structure formation with the die fabrication process by forming trenches and depositing capacitor structures within the same wafer that contains the die. This integration eliminates multiple separate processing steps including wafer bonding and multiple thin-down processes, thereby reducing manufacturing complexity and cost while maintaining the required capacitance.
Solution Approach 2:
The single wafer serves multiple functions: it contains both the die and the DTC structure, eliminating the need for separate carrier wafers. This multi-functional approach simplifies the overall manufacturing process by reducing the number of components and processing steps required.
3Shape
If two separate wafers are bonded together, then stacked DTC structure can be formed, but the process requires multiple thin-down processes which are costly
Solution Approach 1:
The patent merges the formation of stacked DTC structures with the die substrate itself, eliminating the need for separate carrier wafers and the associated bonding and thin-down processes. The trenches are formed directly in the die substrate, and the capacitor structures are deposited in place, reducing manufacturing steps and costs.
Solution Approach 2:
The patent extracts the carrier wafer from the process entirely by forming the DTC structure directly in the die substrate. This eliminates the need for wafer bonding and the subsequent thin-down processes required when using separate carrier wafers, thereby reducing manufacturing complexity and cost.
Data Source
AI summary
In some embodiments, the present disclosure relates to an integrated circuit (IC), including a first insulating layer which includes a first metal interconnect structure stacked above a bottom die. Including a substrate disposed above the first insulating layer, a second metal interconnect structure disposed above the substrate, a through-substrate via (TSV) directly connecting the first metal interconnect structure to the second metal interconnect structure, and a stacked deep trench capacitor (DTC) structure disposed in the substrate. The DTC structure includes a first plurality of trenches extending from a first side of the substrate and a second plurality of trenches extending from a second side of the substrate.