Wafer-Level Vibrator Package With Inclined Lid Walls for Stress Relief
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Solution Overview
Problem
In existing wafer level packaging (WLP) type vibrator devices, the application of stress during bonding affects the circuit characteristics of the integrated circuit, leading to potential deterioration of the device's performance.
Innovation Solution
The design includes a lid with inclined side walls forming an angle of less than 90 degrees with the base's surface, dispersing stress and reducing its impact on the integrated circuit, allowing for a more efficient arrangement of circuit elements and enhancing the device's functionality and durability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the lid and base are bonded by applying pressure to sandwich them, then the bonding strength is improved, but the circuit characteristics of the integrated circuit deteriorate due to stress
Solution Approach 1:
The side wall of the lid is designed with different geometries in different regions: an inclined portion with a slope between 15-45 degrees in the first region (overlapping the integrated circuit) and a vertical or differently angled portion in the second region. This local geometric variation distributes the bonding stress differently across the base surface, reducing stress concentration on the integrated circuit while maintaining overall bonding strength.
Solution Approach 2:
The side wall transitions from a simple vertical structure to a multi-dimensional structure with inclined portions. This geometric transformation in the spatial dimension allows the bonding force to be distributed over a larger area and at different angles, reducing the direct vertical stress transmitted to the integrated circuit while preserving the bonding function.
2Ease of manufacture
If the side wall is vertical (90 degrees), then the manufacturing simplicity is improved, but the stress concentration on the integrated circuit increases
Solution Approach 1:
Rather than making the entire side wall inclined (which would complicate manufacturing), only specific portions of the side wall are inclined while other portions remain vertical. This localized modification maintains manufacturing simplicity for the majority of the structure while addressing the stress concentration problem in the critical region overlapping the integrated circuit.
3Stress or pressure
If the inclined portion slope is small (close to vertical), then the stress reduction effect is improved, but the mounting area for circuit elements is reduced
Solution Approach 1:
The slope angle of the inclined portion is optimized within a specific range (15-45 degrees). This parameter optimization balances two competing requirements: a larger angle provides better stress reduction but reduces mounting area, while a smaller angle increases mounting area but reduces stress reduction effectiveness. The specified range represents the optimal compromise between these two parameters.
Data Source
AI summary
A vibrator device includes: a base including a semiconductor substrate having an integrated circuit disposed at a first surface; a vibration element electrically coupled to the integrated circuit; and a lid having an end surface of a side wall bonded to the first surface at a bonding portion. A first circuit of the integrated circuit includes a first circuit element disposed in a first region overlapping the bonding portion in a plan view. The first circuit element is a passive element or a transistor, and θ<90° is satisfied, θ being an angle formed by the first surface and an inner side surface of the side wall.