Gold wire bonding method on quartz pendulous reed and torquer binding post

Abstract

The invention discloses a gold wire bonding method on a quartz pendulous reed and a torquer binding post. The gold wire bonding method comprises the following steps: a) carrying out gold plating treatment on the surface of the quartz pendulous reed; b) processing the gold wire into a preset specification; c) fixing the quartz pendulous reed on a bonding tool, heating the quartz pendulous reed, and then bonding one end of the gold wire on the gold layer of the quartz pendulous reed through a chopper on the bonding tool under the action of preset ultrasonic frequency, contact time and pressure; and d) bonding the other end of the gold wire on a binding post of the torquer. According to the method, a wedge-shaped bonding mode of a gold wire bonding technology is adopted, and the problems that the gold wire welding efficiency of far ultraviolet optical quartz glass and a lower torquer binding post is low, the consistency and reliability of the parts are poor, and the quality of welding spots is poor are solved by heating the parts and utilizing parameters of ultrasonic frequency, contact time and pressure.

Description

Technical Field

[0001] The invention relates to the technical field of accelerometers, and in particular to a method for bonding gold wires on a quartz pendulum and a torquer terminal. Background Art

[0002] The quartz flexible accelerometer is one of the core components of the inertial navigation system, and the quartz flexible pendulum is regarded as a key component and its core part. Currently, the gold wire connecting the quartz pendulum and the torquer terminal is welded by manual soldering, which has low efficiency, poor reliability and consistency, and will leave excess materials on the pendulum, creating hidden dangers and affecting the accuracy of the accelerometer.

[0003] According to the existing technical situation, in order to improve the efficiency of accelerometer assembly, it is urgent to solve the problem of slow manual soldering of gold wire and improve the tensile strength of gold wire welding. The inconsistent size of solder joints caused by manual welding and the falling of excess materials causing product quality risks are also needed. Summary of the invention

[0004] In view of the above-mentioned deficiencies in the prior art, the technical problem to be solved by the present invention is to provide a method for gold wire bonding on a quartz pendulum and a torquer terminal, thereby solving the problems of low efficiency and poor quality of gold wire bonding in the prior art.

[0005] In order to solve the above technical problems, the present invention adopts the following technical solutions: A method for bonding gold wires between a quartz pendulum and a torquer terminal comprises the following steps: a) Gold-plating the surface of the quartz pendulum; b) Processing the gold wire into preset specifications; c) Fixing the quartz pendulum on the bonding tool, heating the quartz pendulum, and then bonding one end of the gold wire to the gold layer of the quartz pendulum by a splitter on the bonding tool under the action of a preset ultrasonic frequency, contact time and pressure; d) Bend the other end of the gold wire in the direction away from the quartz pendulum, and then use the splitter on the bonding tool to bond the free end of the gold wire to the terminal of the torquer under the preset ultrasonic frequency, contact time and pressure, thereby completing the gold wire bonding on the quartz pendulum and the terminal of the torquer.

[0006] As an optimization, in step a, before gold plating the surface of the quartz pendulum, chrome plating is first performed, and both chrome plating and gold plating are performed using a vacuum coating machine.

[0007] As an optimization, in step b, after the gold wire processing is completed, the gold layer bonding position of the quartz pendulum is cleaned with a brush dipped in isopropyl alcohol.

[0008] As an optimization, in step c, a wedge-shaped splitting cutter is used on the bonding tool.

[0009] As an optimization, in step c, the heating temperature of the heating treatment is 90°C-100°C.

[0010] As an optimization, in step c, the ultrasonic frequency is 125 Hz to 135 Hz.

[0011] As an optimization, in step c, the contact time is 340 ms to 345 ms.

[0012] As an optimization, in step c, the pressure is 45 mN to 50 mN.

[0013] As an optimization, in step c, after completing one bonding, the quartz pendulum or splitting knife is moved a preset distance, and multiple bondings are performed in sequence.

[0014] As an optimization, after step d is completed, step e is also included to check the bonding quality.

[0015] Compared with the prior art, this application has the following beneficial effects: 1. The processing method is simple and improves production efficiency.

[0016] 2. Good consistency and reliability, improving product quality.

[0017] 3. Avoid damage to the gold layer at the welding point. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 is a flow chart of the present invention; Figure 2 It is a schematic diagram of the bonding tool structure in the present invention; In the picture, 1 is a wedge-shaped cleaver, 2 is a quartz pendulum, 3 is a tooling, 4 is a heating key, 5 is a fire rod, and 6 is a gold wire. DETAILED DESCRIPTION

[0019] The present invention will be further described in detail below in conjunction with the accompanying drawings.

[0020] For specific implementation: see Figure 1 and Figure 2 , A method for bonding gold wires between a quartz pendulum and a torquer terminal comprises the following steps: a) Gold-plating the surface of the quartz pendulum. Specifically, a vacuum coating machine is used to first perform chrome plating on the far-ultraviolet optical quartz glass (quartz pendulum) to enhance the adhesion of the quartz glass surface, and then gold plating is performed. After completion, a probe is wrapped with glue to check whether the gold layer has fallen off and whether the surface resistance of the gold layer is qualified.

[0021] b) Process the gold wire into the preset specifications. Specifically, take the gold wire, cut it into 7mm~8mm, a total of 4 wires, and place it in a glass container for later use. Use a small brush to dip a small amount of isopropyl alcohol to clean the bonding area on the front of the quartz pendulum. The bonding area must be free of fibers, impurities, hair scraps and other foreign matter.

[0022] c) Install the quartz pendulum on the bonding tool, heat the quartz pendulum, and bond one end of the gold wire to the gold layer of the quartz pendulum through the splitting knife on the bonding tool under the preset ultrasonic frequency, contact time and pressure. Specifically, the bonding tool includes a supporting tool 3 and a welding tool. The supporting tool 3 has a pendulum positioning groove, and a heating device is provided below the pendulum positioning groove to heat the quartz pendulum 2. The welding tool has a cantilever, the free end of which extends above the supporting tool and is connected to a wedge-shaped splitting knife 1. The wedge-shaped splitting knife 1 is connected to the ultrasonic generator and the mobile control device through the cantilever, and relies on the high-frequency vibration generated by the ultrasonic generator and converts it into mechanical energy through the transducer, so that the wedge-shaped splitting knife 1 generates a certain frequency of vibration. The mobile control device is used to control the position of the wedge-shaped splitting knife 1, thereby adjusting the bonding pressure of the wedge-shaped splitting knife 1. Among them, the mobile control device, ultrasonic generator, transducer, etc. are all existing technologies and will not be described in detail. The welding tool also includes a spark rod, which is used to generate high-voltage discharge between the welding tool and the splitter during the welding process, burn the gold wire through electric sparks and produce gold balls, so that the gold wire melts into the gold layer, and achieves bonding connection with the vibration and pressure of the splitter. The spark rod is usually made of highly conductive, high-temperature and high-pressure resistant materials, such as tungsten steel or platinum. During operation, the quartz pendulum 2 is installed on the tool 3. When bonding, the heating key 4 of the tool 3 is turned on to heat the quartz pendulum 2, adjust the bonding parameters (such as ultrasonic frequency, contact time, heating temperature, spark current, spark time, etc.) and the position of the wedge-shaped splitter, and put down the spark rod 5 to bond one end of the gold wire 6 to the gold layer of the quartz pendulum 2.

[0023] Specifically, select and install a wedge-shaped splitter, fix the quartz pendulum on the tooling, ensure the effective bonding height, turn on the tooling heating key, adjust the bonding parameters, clamp one end of the gold wire with tweezers, aim at the splitter, put down the ignition rod, and melt one end of the gold wire into the gold layer of the quartz pendulum through the ultrasonic and pressure action of the tip. Move another 2mm, and complete the second bonding point according to the above operation to strengthen the bonding mechanical properties. According to the above operation, bond all four gold wires to the corresponding positions of force +, force -, transmission +, and transmission - of the quartz glass.

[0024] Among them, the choice of splitting knife: the imported splitting knife model suitable for 2mm gold wire wedge bonding is selected to help the effectiveness and applicability of the splitting knife. The aperture and wire width directly affect the bonding quality and work efficiency of gold wire bonding. The structural angle and V-groove at the end of the splitting knife are conducive to the bonding performance. The choice of the splitting knife material also directly affects its durability and use effect. High carbon steel is selected here.

[0025] Through a large number of parameter adjustment tests and verifications, the main parameters are confirmed to ensure that the gold wire and gold layer at the bonding point are not damaged, the connection point is firm, and mechanical verification is carried out.

[0026] Parts heating temperature: The optimal temperature range is 90℃~100℃. Purpose: To accelerate the molecular movement on the surface of the material, thereby increasing the contact area between them and generating sufficient adhesion.

[0027] Ultrasonic frequency: Based on the ductility of the bonding material, the diameter of the gold wire and the thickness of the gold layer, the friction and heat generated by ultrasonic vibration are used to determine the optimal frequency range to be between 125Hz and 135Hz.

[0028] Contact time: The length of the working time is controlled through experiments, and the optimal time range is confirmed to be 340ms to 345ms. A short working time cannot achieve mutual diffusion between atoms, resulting in the inability to form an effective bond; a long working time may cause the already formed bonding surface to be destroyed, resulting in a decrease in the reliability of the bonding point.

[0029] Contact pressure: Considering the diameter of the gold wire and the thickness of the gold layer, through the ratio analysis of pressure and time, after testing and verification, it is confirmed that the optimal pressure range is 45mN to 50mN. Too much pressure will destroy the bond strength that has been formed, causing over-bonding and easy peeling at the connection; too little pressure may lead to unreliable bonding and fail to achieve the expected connection strength.

[0030] d) Bend the other end of the gold wire away from the quartz pendulum, and then use the splitter on the bonding tool to bond the free end of the gold wire to the terminal of the torquer under the preset ultrasonic frequency, contact time and pressure to complete the gold wire bonding on the quartz pendulum and the terminal of the torquer. Specifically, move the tool handle, bend the gold wire, align the free end with the terminal, and apply pressure and ultrasonic energy to the splitter to obtain the bonded solder joint. According to the above operation, bond all four gold wires to the corresponding positions of the terminal force +, force -, transmission +, and transmission -.

[0031] e) Lift the splitter to check the tensile strength of the gold wire and the reliability of the bonding quality. Under a stereo microscope, wrap the probe with glue to remove foreign matter and impurities splashed during bonding. Then use a small brush dipped in isopropyl alcohol to repeatedly clean the bonding points and gold film. Put the cleaned parts into a glass container and isolate them for later use.

[0032] In summary, the present invention mainly gold-plates the quartz pendulum first, and then uses the selection of the splitter, temperature adjustment, ultrasonic frequency, contact time and contact pressure to determine the bonding process parameters, and bonds one end of the 2mm gold wire to the far-ultraviolet optical quartz glass plated with a gold layer, and the other end to the torquer terminal (the gold wire is cut to length, and there is no need to insert the gold wire into the splitter aperture. It is directly aligned under a microscope and bonded with the tip of the splitter). Finally, a mechanical reliability test is performed, tensile test: 8g weight, number of tests: more than 50 times. Finally, the original manual soldering process is replaced, the assembly efficiency is more than doubled, and the instability factors caused by human factors are effectively avoided, so that the consistency and reliability of the product are improved.

[0033] The present invention uses the gold wire bonding technology wedge bonding method to heat the parts and utilizes the ultrasonic frequency, contact time, and pressure parameters to improve the problems of low gold wire welding efficiency, poor parts consistency and reliability, and poor solder joint quality of far ultraviolet optical quartz glass and lower torquer terminal. It has the characteristics of simple processing method, improved production efficiency, good consistency and reliability, improved product quality, and avoidance of gold layer damage at solder joints.

[0034] Although the embodiments of the present invention have been shown and described, it is apparent to those skilled in the art that various changes, modifications, substitutions and variations may be made to these embodiments without departing from the principles and basis of the present invention. The scope of the present invention is defined by the appended claims and their equivalents. Therefore, the embodiments of the present invention are merely illustrative examples of the present invention. The embodiments of the present invention do not constitute limitations on the present invention from any point of view.

Claims

1. A method for bonding gold wires between a quartz pendulum and a torquer terminal, characterized in that: The following steps are included: a) Gold-plating the surface of the quartz pendulum; b) Processing the gold wire into preset specifications; c) Fixing the quartz pendulum on the bonding tool, heating the quartz pendulum, and then bonding one end of the gold wire to the gold layer of the quartz pendulum by a splitter on the bonding tool under the action of a preset ultrasonic frequency, contact time and pressure; d) Bend the other end of the gold wire in the direction away from the quartz pendulum, and then use the splitter on the bonding tool to bond the free end of the gold wire to the terminal of the torquer under the preset ultrasonic frequency, contact time and pressure, thereby completing the gold wire bonding on the quartz pendulum and the terminal of the torquer.

2. A method for bonding gold wires between a quartz pendulum and a torquer terminal according to claim 1, characterized in that: In step a, before gold plating the surface of the quartz pendulum, chrome plating is first performed, and both chrome plating and gold plating are performed using a vacuum coating machine.

3. A method for bonding gold wires between a quartz pendulum and a torquer terminal according to claim 1, characterized in that: In step b, after the gold wire processing is completed, the gold layer bonding position of the quartz pendulum is cleaned with a brush dipped in isopropyl alcohol.

4. The method for bonding gold wires between a quartz pendulum and a torquer terminal according to claim 1, characterized in that: In step c, the wedge-shaped wedge is used as the wedge on the bonding tool.

5. The method for bonding gold wires between a quartz pendulum and a torquer terminal according to claim 1, characterized in that: In step c, the heating temperature of the heating treatment is 90°C-100°C.

6. The method for bonding gold wires between a quartz pendulum and a torquer terminal according to claim 1, characterized in that: In step c, the ultrasonic frequency is 125 Hz to 135 Hz.

7. A method for bonding gold wires between a quartz pendulum and a torquer terminal according to claim 1, characterized in that: In step c, the contact time is 340 ms to 345 ms.

8. The method for bonding gold wires between a quartz pendulum and a torquer terminal according to claim 1, characterized in that: In step c, the pressure is 45 mN to 50 mN.

9. The method for bonding gold wires between a quartz pendulum and a torquer terminal according to claim 1, characterized in that: In step c, after completing one bonding, the quartz pendulum or the splitting knife is moved a preset distance, and multiple bondings are performed in sequence.

10. A method for bonding gold wires between a quartz pendulum and a torquer terminal according to claim 1, characterized in that: After step d is completed, step e is also included to check the bonding quality.

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