Oscillator Package Layout for Uniform Flip-Chip Bonding Pressure
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Solution Overview
Problem
In oscillators with a ceramic package using flip chip bonding, the thickness variation due to external terminal placement leads to uneven pressure distribution during IC packaging, potentially deteriorating IC performance.
Innovation Solution
The oscillator design includes a package with external terminals on its mounting surface, where at least three of the closest pads to the corners of the IC overlap these terminals in a plan view, ensuring uniform pressure distribution during bonding by positioning bump members to overlap external terminals, thereby reducing height imbalances and excessive pressure on pads.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the distance between external terminals is decreased to reduce oscillator size, then the oscillator size is reduced, but height difference occurs between pad mounting positions due to package thickness variation
Solution Approach 1:
The patent applies local quality by making the package thickness non-uniform in a controlled manner. Specifically, the package is designed with a first thickness in a first region and a second thickness different from the first thickness in a second region. This localized thickness variation compensates for the height differences caused by external terminal positions, ensuring that all pads are mounted at substantially the same height despite the reduced oscillator size.
2Volume of moving object
If the distance between external terminals is decreased, then the oscillator size is reduced, but uneven pressure is applied to pads during flip chip bonding
Solution Approach 1:
The patent uses local quality to create specific thickness regions in the package that correspond to the positions of external terminals. By making the package thicker in regions where external terminals are located, the patent compensates for the height differences these terminals create, ensuring uniform pressure distribution across all pads during flip chip bonding.
Solution Approach 2:
The patent applies preliminary anti-action by pre-compensating for the height differences that would otherwise occur during bonding. The package thickness is designed in advance with variations that counteract the height differences caused by external terminal positions, so that when bonding occurs, all pads are at substantially the same height and experience uniform pressure.
3Adaptability or versatility
If external terminals are positioned on the reverse surface, then terminal layout flexibility is improved, but thickness variation occurs in the package
Solution Approach 1:
The patent resolves the conflict between terminal layout flexibility and package thickness uniformity by intentionally creating local thickness variations. The package is designed with different thicknesses in different regions, with thicker regions positioned under external terminals on the reverse surface. This controlled non-uniformity maintains both layout flexibility and functional uniformity.
Data Source
AI summary
An oscillator includes a package having a plurality of external terminals disposed on a mounting surface, a circuit element housed in the package, and a resonator which is housed in the package, and is electrically coupled to the circuit element, wherein the circuit element is electrically coupled to the package with a plurality of pads each of which is bonded to the package via a bump member, the circuit element has a rectangular shape in a plan view, and at least three of closest ones to four corners of the circuit element out of the bump members are bonded to the package at respective positions overlapping the plurality of external terminals in the plan view.