Manufacturing process of SMD2520 and SMD2016
Manufacturing process of SMD2520 and SMD2016
SMD2520 and SMD2016 are small size and low power consumption passive crystal oscillators.
The main components are: base, lid and quartz wafer. The production of small-size crystal oscillator puts forward higher and stricter requirements for manufacturing technology,
production equipment and quality control process. The manufacturing process of SMD2520 and SMD2016 are introduced as follows:
1. Wafer cleaning
Objective is to remove the grinding residue on the surface of the wafer again to ensure the adhesion of the silver (gold) layer.
2. Plating
A thin silver (gold) layer is evaporated on a clean quartz wafer to form electrode based on the principle of vacuum coating,
and the frequency crystal accuracy reaches the specified range.
3. Dispensing
The chip coated with silver (gold) electrode is mounted on the base, coated with conductive adhesive, and cured at high temperature.
The chip transmits the clock signal through the gold-plated pad.
4. Frequency tuning
Crystal accuracy is expressed in ppm, 1ppm = 1 ppm. To achieve more accurate frequency crystal , need to fine-tune.
The specific method is: use Ar ion to bombard the gold (silver) electrode on the surface of quartz wafer to etch the surplus gold (silver) atoms,
so as to fine tune the frequency crystal to meet the specified requirements.
5. Seal welding
Place the base and the upper cover in the environment full of nitrogen (or vacuum) for sealing,
so as to ensure that the annual aging rate of crystal oscillator products meets the requirements of the service life of electronic products.
6. Sealing inspection
There are two steps:
a. Gross leakage: There are bubble type and differential pressure type to check large air leakage.
b. Fine leak test: The commonly used method for checking tiny gas leakage is helium leakage detection.
7. Aging and simulated reflow soldering:
Aging: aging the product at high temperature for a long time to release the stress caused by hot working.
Reflow (IR reflow): to simulate the customer's use environment, the purpose is to expose manufacturing defects, so as to improve the deliverability.