Quartz resonator production process, which big brother tells the point

Quartz crystal resonator.

1.Concept: Quartz crystal resonator is also known as quartz crystal, commonly known as crystal oscillator. It is a resonant element made by using the piezoelectric effect of quartz crystals. When used together with semiconductor devices and resistor-capacitance elements, quartz crystal oscillators can be formed.

Piezoelectric effect: The mechanical force applied to certain dielectrics causes the relative displacement of the centers of positive and negative charges inside them, resulting in polarization, resulting in the appearance of bound charges with opposite signs on the surface of the two ends of the dielectric. Within a certain range of stress, the mechanical force has a linearly reversible relationship with the electric charge.

This phenomenon is called the piezoelectric effect.

Function: Provide system oscillation pulse, stabilize frequency, select frequency.

2.Main parameters:

a.Nominal frequency: The resonant center frequency of the crystal oscillator under specified conditions.

b.Adjustment Frequency Difference: The maximum deviation of the operating frequency at the reference temperature from the nominal frequency under specified conditions. (ppm)

c.Temperature Frequency Difference: The allowable deviation of the operating frequency relative to the reference temperature over the entire operating temperature range under specified conditions.

d.Load Resonant Resistance: The resistance value of the crystal oscillator in series with a specified external capacitor at the load resonant frequency.

e.Load capacitance: Refers to the effective external capacitance that determines the resonant frequency of the load together with the crystal oscillator. Commonly used standard values are: 12pf, 16pf, 20pf, 30pf

Cutting, grinding discs, silver spraying, calibration.

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Pro, the core equipment for the production of quartz crystal resonators is mainly as follows:1Crystal Cutting Machine:

It is used to cut the raw material of quartz crystals into wafers of a specific shape and size with high modulus for subsequent processing and preparation. 2.Crystal grinder:

Wafers are finely ground and polished to achieve high precision and surface finish requirements. 3.Welding machine:

The wafer is welded to the electrode to form the basic structure of the quartz crystal resonator. 4.Washing machine:

The soldered quartz crystals are cleaned and decontaminated to improve their quality and stability. 5.Frequency Measuring Instrument:

It is used to accurately measure and calibrate the frequency of the quartz crystal resonator to ensure the accuracy and reliability of the product. 6.Encapsulation Equipment:

The prepared quartz crystal resonator is encapsulated to protect its internal structure and circuit, and to facilitate the use and maintenance of the product. These equipment is an indispensable core equipment for the production of quartz crystal resonators, and their performance and accuracy directly affect the quality and performance of the product.

1. Quartz wafer: the basic material used to make crystal resonators, mainly quartz wafers, quartz wafer components and polycrystalline cutting services. 2. Clever and exciting training of photo-etching machine:

An important piece of equipment used to make crystal resonators, which can accurately engrave the pattern on the crystal wafer to the surface of the crystal scrambled key surface. 3. Electrode processing equipment: using electrolytic treatment technology, the metal electrode is welded to the wafer to make the crystal resonator more stable and reliable.

4. Bonding equipment: use ultrasonic, hot pressing or other technologies to tightly combine the wafer with the shell to make the crystal resonator more firm. 5. Testing equipment:

It is mainly a tester used to detect the parameters of the crystal resonator to ensure that the parameters of the crystal resonator meet the requirements.

(1) The finished quartz crystal resonator is marked with a nominal frequency, and the frequency stability is the highest when the circuit works at this nominal frequency. This nominal frequency is usually determined on a quartz crystal with a certain load capacitance before the finished product leaves the factory. In the actual composition of the quartz crystal oscillator, the load capacitor must be connected at both ends of the quartz crystal in parallel, and the load capacitance must meet the value specified in the technical conditions of the quartz crystal, and most of the capacitors are trimmed capacitors for adjustment.

The specified load capacitance value is set out in the manufacturer's product manual, usually 30pF (for high-frequency crystals), or 100pF (for low-frequency crystals, and the most common load capacitance for ordinary crystals) or marked as Tian (this means that there is no need for external load capacitors, which are usually used in series crystal oscillators).

2) The excitation level of the quartz crystal resonator should be within the specified range. When the quartz crystal resonator is excited in the oscillator, it needs to consume a certain amount of excitation power through the excitation current. In practical applications, the excitation power of the input quartz crystal should not exceed the rated value.

Excessive excitation power will increase the internal temperature of the quartz resonator, and increase the aging effect and frequency drift of the quartz wafer. Extremely strong excitation power can damage the mechanical vibration of the quartz wafer due to excessive vibration.

3) In a parallel quartz crystal oscillator, the quartz crystal can only work in the inductive region, but not in the capacitive region. Because if the crystal is used as a capacitive element, once the piezoelectric effect fails, it will still be capacitive, and the oscillator may still maintain oscillation, but the quartz crystal has lost its frequency stabilization.

4) Since the quartz resonator has a high frequency stability within a certain temperature range, when the frequency stability is required to be high, the use of constant temperature equipment or temperature compensation measures can be considered.

5) When the crystal oscillator starts oscillating in the oscillation circuit, it is equivalent to inductance, and the load capacitance and the equivalent inductance of the crystal oscillator form a resonance, which determines the oscillation frequency of the oscillator. The oscillation frequency of the oscillator is different depending on the load capacitance value, and the oscillation frequency can be changed by changing the size of the load capacitance. Therefore, by adjusting the load capacitance moderately, the oscillation frequency of the oscillator can generally be precisely adjusted to the standard value.

The load capacitance provided in the main parameters of the crystal oscillator data is a test condition, and it is also a condition that cannot be ignored, ignoring this load capacitance parameter will make the oscillation frequency deviate from the standard value, and when the deviation is too large, it will make the oscillator difficult to start and cause vibration stopping.

6) There are two types of load capacitance of crystal oscillator: high and low. The low one is generally only a dozen to a few hundred pf, while the high one is infinite, and the difference between the two is huge, and it must not be mixed, otherwise the oscillation frequency will deviate. The crystal oscillators of the two different types of load capacitors are used in very different ways.

Low-load capacitance crystal oscillators are connected in series with capacitors with a capacity of tens of pf; However, the high-load capacitance crystal oscillator not only cannot be connected in series capacitors, but also must be connected in parallel with several pf small capacitors (the distributed crystal oscillator capacitors of the external circuit can sometimes replace this parallel small capacitor).

We need to consider the above issues carefully, only in this way will the advantages of crystal oscillator be reasonably applied.

Piezoelectric effect: The mechanical force applied to certain dielectrics causes the relative displacement of the centers of positive and negative charges in their interiors, resulting in polarization, which leads to the appearance of binding charges with opposite signs on the surface of the two ends of the dielectric. Within a certain range of stress, the nucleus and mechanical forces have a linear reversible relationship with the charge.

This phenomenon is called the piezoelectric effect.

Function: Provide system oscillation pulse, stabilize frequency, select frequency.

Quartz crystal resonator, also known as quartz crystal, commonly known as crystal oscillator, is a resonant element made by using the piezoelectric effect of quartz crystal, and can be used together with semiconductor devices and resistor-capacitance elements to form a quartz crystal oscillator