Manufacturing Process of SMD2520 and SMD2016

As electronic devices shrink in size while demanding higher performance, ultra-miniature surface-mount device (SMD) quartz crystals—specifically the SMD2520 (2.5mm × 2.0mm) and SMD2016 (2.0mm × 1.6mm) packages—have become the industry standard for frequency control.

To achieve high stability, low equivalent series resistance (ESR), and excellent aging characteristics, the manufacturing of these micro-sized crystal resonators requires high-precision automated production lines and class-100 to class-10,000 cleanroom environments.

Below is a detailed look at the 7-step advanced manufacturing process of SMD2520 and SMD2016 crystal resonators at Xtalong.

Step 1: Quartz Blank Cleaning & Pre-treatment

The manufacturing starts with raw quartz blanks (wafers) cut at precise angles (usually AT-cut for temperature stability).

The Process: The quartz blanks undergo multi-stage ultrasonic chemical cleaning to remove organic residues, micro-particles, and trace impurities from the surface.

Why it matters: Even sub-micron contaminants can alter the mass of the blank, severely affecting the starting frequency and the Equivalent Series Resistance (ESR) of the final SMD2016/2520 resonator.

Step 2: Electrode Deposition (Vacuum Coating)

Electrodes must be applied to both sides of the cleaned quartz blank to enable piezoelectric excitation.

The Process: Utilizing advanced vacuum evaporation or sputtering systems, high-purity metal layers (typically Gold/Au or Silver/Ag with a Chromium/Cr adhesion layer) are deposited onto the quartz blank under ultra-high vacuum conditions.

Key Control: The thickness of the electrode layer must be strictly controlled at the nanometer level to ensure the nominal frequency stays close to the target range before fine-tuning.

Step 3: High-Precision Base Mount & Conductive Epoxy Dispensing

In the SMD2520 and SMD2016 packages, space is extremely constrained. The blank must be mechanically supported and electrically connected to the ceramic base.

The Process: Automated micro-dispensing systems apply a precise micro-dot of conductive adhesive (silver epoxy) onto the internal terminals of the ceramic package. High-speed pick-and-place systems then mount the coated quartz blank onto the base.

Curing: The assembled units are placed in a specialized baking oven to cure the conductive epoxy, establishing a robust mechanical and electrical bond.

Step 4: Frequency Fine-Tuning (Mass Adjustment)

After mounting, the physical frequency of the resonator will slightly deviate from the target specification.

The Process: We utilize high-speed automated frequency adjustment systems. By applying ion-beam milling (etching away metal) or micro-vacuum evaporation (depositing tiny amounts of metal), the mass of the electrode is adjusted dynamically while real-time electrical testing monitor the frequency until it reaches the exact target specification (e.g., ±10ppm).

Step 5: Hermetic Sealing (Welding under Nitrogen/Vacuum)

To protect the sensitive quartz blank from moisture and atmospheric aging, the ceramic base must be sealed with a metal lid in a controlled atmosphere.

The Process: SMD2520 and SMD2016 resonators are typically sealed using seam welding or glass sealing technology. This process is carried out in an inert gas glove box filled with high-purity Nitrogen (N2) or under high-vacuum conditions.

Result: A fully hermetic seal is created, isolating the internal crystal resonator from environmental hazards.

Step 6: Leak Detection (Hermetic Testing)

To ensure the long-term reliability and stability of the crystal, the hermetic seal must be verified.

Gross Leak Test: The sealed components are typically pressurized with fluorocarbon liquid to detect visible bubbles under heat.

Fine Leak Test: We utilize helium mass spectrometry leak detection. Resonators are placed in a helium chamber under pressure, and helium detectors measure any microscopic leaks.

Step 7: Thermal Aging & Final Parameter Screening

Before packaging, the crystals undergo a stabilization process to release any residual mechanical stresses.

The Process: The SMD2520 and SMD2016 crystals undergo high-temperature thermal aging (typically at 85°C to 125°C) and simulated reflow soldering tests.

Final Test: Automated Test Equipment (ATE) checks 100% of the production run for vital electrical parameters, including:

Nominal Frequency and Frequency Tolerance

Equivalent Series Resistance (ESR)

Drive Level Dependency (DLD)

Shunt Capacitance (C0) and Motional Capacitance (C1)

Units that pass these rigorous testing criteria are finally packed in standard embossed carrier tape (Tape & Reel) for automated SMT assembly lines.

Our Commitment to Precision

At Xtalong, our SMD2520 and SMD2016 quartz crystal resonators are manufactured using fully automated, high-precision equipment to guarantee exceptional stability and failure-free long-term performance. Whether for IoT, automotive, consumer electronics, or industrial communication, our manufacturing processes are designed to meet your strictest frequency control requirements.

Have questions about our crystal manufacturing or need custom specifications? Contact Xtalong Engineering Support today.