Semiconductor Vibration Package With Metal-Layer Lid Bonding
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Solution Overview
Problem
Existing vibration devices using piezoelectric vibrators face challenges in reducing size due to damage risks to semiconductor integrated circuits during lid attachment and difficulties in thinning the devices without compromising the circuit surfaces.
Innovation Solution
A vibration device design featuring a semiconductor substrate with an integrated circuit and a vibration element, where a lid with a recess is bonded to the substrate via a metal layer, allowing for reduced size and thickness without damaging the integrated circuit.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the lid is firmly attached with an adhesive to the semiconductor integrated part, then the lid and semiconductor integrated part can be securely attached, but the semiconductor integrated circuit is likely to be damaged due to high temperature and pressure requirements
Solution Approach 1:
A metal layer is introduced as an intermediary bonding layer between the lid and the semiconductor substrate. This metal layer enables bonding at lower temperatures and pressures compared to direct adhesive bonding, thereby protecting the integrated circuit from damage while still achieving secure attachment. The metal layer serves as a mediator that transfers and distributes the bonding forces without concentrating excessive heat or pressure on the sensitive circuit components.
2Reliability
If the lid area is arranged to not overlap with the semiconductor integrated circuit, then the integrated circuit is protected from damage, but the size of the piezoelectric oscillator increases
Solution Approach 1:
The metal layer acts as a protective intermediary that allows the lid to overlap with the integrated circuit area without causing damage. Since the metal layer enables low-temperature, low-pressure bonding, the lid can be positioned directly over the circuit components during assembly, and the bonding process occurs under conditions that do not damage the sensitive electronics, thus reducing the overall device size.
Solution Approach 2:
The bonding parameters (temperature and pressure) are changed to lower values through the introduction of the metal layer. This parameter change allows the lid to be bonded in positions that would previously have been unsafe, enabling direct overlap between the lid and circuit areas, thereby reducing the required device footprint.
3Length of stationary object
If the rear surface of the first substrate is ground or polished before the vibration element is mounted, then the thickness of the piezoelectric oscillator can be reduced, but the front surface where the circuit section is formed cannot be ground or polished
Solution Approach 1:
The substrate processing is segmented into two independent stages: (1) ground/polish the rear surface of the semiconductor substrate before mounting the vibration element to reduce thickness, and (2) after bonding the lid, ground/polish the contact surface of the lid to further reduce overall thickness. This segmentation allows each surface to be processed at the appropriate time without interfering with the other components.
Solution Approach 2:
The rear surface of the semiconductor substrate is ground or polished before the vibration element is mounted, which is a preliminary action that reduces the substrate thickness in advance. This preliminary processing eliminates the need to handle and process the fragile substrate after component mounting, simplifying the overall manufacturing process.
4Area of stationary object
If the vibration device size is reduced by mounting the piezoelectric vibrator on a semiconductor substrate and disposing a lid, then the device size decreases, but the integrated circuit is vulnerable to damage during lid attachment
Solution Approach 1:
The metal layer serves as a protective intermediary that enables size reduction through compact lid placement while simultaneously protecting the integrated circuit. The intermediary layer allows the lid to be positioned directly over the circuit area and bonded under gentle conditions, achieving both miniaturization and circuit protection.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution enables a reduction in the size of the vibration device while minimizing the risk of damaging the integrated circuit during assembly, and allows for easier thickness reduction of the device.
Implementation Method 1
the lid being bonded to the first surface via the contact surface
Implementation Method 2
Vibration devices using piezoelectric vibrators, such as quartz vibrators
Data Source
AI summary
A vibration device includes a semiconductor substrate having a first surface at which an integrated circuit is provided and a second surface that is a rear surface with respect to the first surface, which is a front surface, a vibration element disposed at the first surface, a lid having a recess that opens toward the first surface and a contact surface that is in contact with the first surface, the lid being bonded to the first surface via the contact surface, and a metal layer disposed between the first surface and the contact surface, and at least part of the integrated circuit overlaps with the metal layer in a plan view viewed in the direction of a normal to the first surface.