Semiconductor Device With Integrated Passive Circuit Using Sacrificial Substrate
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Solution Overview
Problem
The high manufacturing costs and form factor limitations of using highly resistive silicon wafers for integrated passive devices (IPDs) in semiconductor devices hinder the development of smaller, higher-density, and cost-effective integrated circuits.
Innovation Solution
A method involving a sacrificial substrate is used to form integrated passive devices, where a sacrificial substrate is provided, followed by the formation of insulating and passivation layers, an integrated passive device, a wafer support structure, and an interconnect structure, with the sacrificial substrate being removed to expose the underlying layers for electrical contact, allowing for the creation of semiconductor devices with reduced costs and enhanced design flexibility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If highly resistive silicon wafers are used for forming integrated passive devices, then device performance and reliability are improved, but manufacturing cost increases and form factor is limited
Solution Approach 1:
The patent employs a disposable sacrificial substrate (glass or silicon wafer) that is used temporarily during manufacturing and then removed. This allows IPDs to be formed on cost-effective substrates without the need for expensive highly resistive silicon wafers in the final product, resolving the contradiction between manufacturing cost and device performance
Solution Approach 2:
The sacrificial substrate is extracted/removed from the final device structure after serving its purpose during manufacturing. This extraction allows the IPDs to be formed on inexpensive substrates while maintaining the performance characteristics that would require expensive substrates, thus reducing manufacturing cost without sacrificing reliability
2Reliability
If highly resistive silicon wafers are used for forming integrated passive devices, then device performance is improved, but device size and design flexibility are limited
Solution Approach 1:
The disposable sacrificial substrate enables designers to choose from various inexpensive substrate materials (glass, silicon, ceramic, polymer) without being constrained by the requirements of highly resistive silicon wafers. This provides greater design flexibility and adaptability while maintaining IPD performance through the sacrificial substrate process
Solution Approach 2:
The sacrificial substrate process is universally applicable to multiple substrate types (glass, silicon, ceramic, polymer), allowing the same IPD formation process to work across different materials and applications. This multi-functionality enhances design flexibility and adaptability without compromising device performance
3Ease of manufacture
If traditional substrate materials are used for IPDs, then manufacturing process is simpler, but device density and integration level are reduced
Solution Approach 1:
The sacrificial substrate acts as an intermediary that enables complex high-density IPD structures to be formed through a relatively simple process. It provides a temporary support structure that allows for precise positioning and formation of multiple IPDs in close proximity, achieving high device density without complicating the manufacturing process
Solution Approach 2:
The sacrificial substrate is prepared in advance with appropriate properties (thickness, material, surface characteristics) to facilitate subsequent IPD formation. This preliminary preparation enables high-density integration to be achieved through standard manufacturing processes, maintaining process simplicity while increasing device density
Data Source
AI summary
A semiconductor device is made by providing a sacrificial substrate, forming a first insulating layer over the sacrificial substrate, forming a first passivation layer over the first insulating layer, forming a second insulating layer over the first passivation layer, forming an integrated passive device over the second insulating layer, forming a wafer support structure over the integrated passive device, removing the sacrificial substrate to expose the first insulating layer after forming the wafer support structure, and forming an interconnect structure over the first insulating layer in electrical contact with the integrated passive device. The integrated passive device includes an inductor, capacitor, or resistor. The sacrificial substrate is removed by mechanical grinding and wet etching. The wafer support structure can be glass, ceramic, silicon, or molding compound. The interconnect structure can include a solder bump, wire bond, and intermediate conduction layer formed on a backside of the semiconductor device.