Wafer-Level Vibrator Lid Structure for Bonding Stress Control
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Solution Overview
Problem
In wafer level packaging (WLP) type vibrator devices, stress applied during the bonding process affects the circuit characteristics of the integrated circuit, leading to deteriorated performance due to residual stress, which restricts the arrangement of circuit elements and compromises device functionality and size reduction.
Innovation Solution
The vibrator device design incorporates a semiconductor substrate base with an integrated circuit and a lid with inclined side walls, reducing stress distribution and allowing for a wider arrangement of circuit elements, thereby minimizing stress impact on the integrated circuit and enhancing device accuracy and functionality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the base and lid are bonded by applying pressure, then the bonding strength is improved, but stress is generated in the base affecting circuit characteristics
Solution Approach 1:
The lid is designed with different wall thicknesses in different regions: a first wall thickness in the first region (overlapping the integrated circuit) and a second wall thickness in the second region, where the ratio is 0.5 to 2.0. This local variation in thickness distributes the bonding stress away from the integrated circuit region, maintaining bonding strength while protecting circuit characteristics.
Solution Approach 2:
The patent changes the physical parameter of wall thickness to control stress distribution. By adjusting the thickness ratio between different regions of the lid, the stress concentration during bonding is modified, allowing strong bonding without excessive stress on the integrated circuit.
2Volume of moving object
If the device size is reduced through WLP packaging, then integration is improved, but stress concentration on the integrated circuit increases
Solution Approach 1:
The lid structure implements local quality by having different thicknesses in different regions. The thinner region (first region) corresponds to the integrated circuit area, reducing stress concentration there, while the thicker region (second region) provides structural support, enabling miniaturization without excessive stress.
Solution Approach 2:
The patent addresses the two-dimensional stress concentration problem by introducing a third-dimensional solution: varying the thickness (vertical dimension) of the lid in different horizontal regions. This dimensional approach allows stress management within the compact WLP structure.
Data Source
AI summary
A vibrator device includes: a base including a semiconductor substrate having an integrated circuit disposed at a second surface; a vibration element electrically coupled to the integrated circuit; and a lid having an end surface of a side wall bonded to a first surface at a bonding portion. A first circuit of the integrated circuit includes a first circuit element disposed in a second region surrounded by a first region that overlaps 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.