Recessed Bond Pads with Protective Layer for MEMS
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Solution Overview
Problem
Traditional MEMS device assembly processes face challenges in maintaining quality and reliability due to damage from debris during capping structure singulation, which can result in defects on the substrate.
Innovation Solution
A method involving the formation of recessed connective elements, such as bond pads, on the substrate with a protective layer to shield them from debris during capping substrate singulation, followed by bonding and subsequent removal of the protective layer for electrical connection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional assembly processes are used for bonding and formation of the capping structure, then the manufacturing process is simple, but the quality and reliability of the product deteriorates due to damage from debris during singulation
Solution Approach 1:
The patent applies preliminary action by forming a protective layer over the connective elements (bond pads) before the singulation process occurs. This protective layer is deposited in advance to prevent debris from landing on and damaging the connective elements during the subsequent singulation step, thereby maintaining product quality without significantly complicating the overall assembly process
Solution Approach 2:
The protective layer serves as an intermediary between the connective elements and the debris generated during singulation. This intermediate layer physically separates the vulnerable connective elements from the harmful debris, allowing the singulation process to proceed while protecting the critical bonding surfaces from contamination and damage
2Productivity
If the capping structure is singulated without protective measures, then the manufacturing process is fast, but debris lands on the substrate causing defects
Solution Approach 1:
The protective layer is deposited over the connective elements before singulation occurs, enabling the fast singulation process to proceed without compromising manufacturing precision. This preliminary protective measure allows debris to be generated during rapid singulation while preventing it from contaminating the substrate, thus maintaining both productivity and low defect rates
3Ease of manufacture
If connective elements are exposed during assembly, then the bonding process is simple, but the connective elements suffer damage from debris
Solution Approach 1:
The protective layer is formed over the connective elements before the bonding process, maintaining the simplicity of the bonding operation while preventing debris from damaging the connective elements. The bonding process proceeds as before, but the protective layer ensures that the connective elements maintain their structural integrity throughout the assembly process
Solution Approach 2:
The protective layer acts as an intermediary shield between the connective elements and the debris environment during bonding and singulation. This intermediate protection layer allows the bonding process to remain simple and straightforward while ensuring that the connective elements are not exposed to damaging debris that would compromise their strength and integrity
Data Source
AI summary
The present disclosure provides a method including providing a first substrate; and forming a microelectromechanical system (MEMS) device on a first surface of the first substrate. A bond pad is formed on at least one bonding site on the first surface of the first substrate. The bonding site is recessed from the first surface. Thus, a top surface of the bond pad may lie below the plane of the top surface of the substrate. A device with recessed connective element(s) (e.g., bond pad) is also described. In further embodiments, a protective layer is formed on the recessed connective element during dicing of a substrate.