Method for soldering semiconductor crystal oscillator

Abstract

The welding method of the semiconductor crystal oscillator comprises the following steps: surface treatment is performed on a welding area of the semiconductor crystal oscillator; an electrically conductive layer is formed on the welding area by electroplating; the welding area is aligned with a welding terminal, and a welding point is formed between the welding area and the welding terminal by using high-frequency current welding; and heat treatment is performed on the welding point. The present application realizes rapid, efficient and reliable welding of the semiconductor crystal oscillator by optimizing the welding process steps, thereby meeting the needs of high-frequency electronic equipment.

Description

Technical Field

[0001] This invention relates to the field of semiconductor manufacturing technology, and in particular to a method for welding semiconductor crystal oscillators. Background Technology

[0002] Semiconductor crystal oscillators are widely used frequency reference devices in electronic devices. Traditional crystal oscillator manufacturing methods typically employ low-frequency welding techniques, such as resistance welding or ultrasonic welding. However, with the ever-increasing frequency requirements of electronic devices, traditional low-frequency welding techniques can no longer meet the needs of practical applications, mainly due to the following problems: insufficient weld strength, making it difficult to meet the mechanical stability requirements of high-frequency applications; slow welding speed, affecting production efficiency; low welding reliability, with weld points prone to fatigue failure; and inability to achieve excellent high-frequency characteristics, limiting the application of crystal oscillators in high-frequency electronic devices.

[0003] Therefore, it is of great significance to develop a semiconductor crystal oscillator welding method suitable for high-frequency applications. Summary of the Invention

[0004] The purpose of this invention is to provide an improved method for welding semiconductor crystal oscillators. By optimizing the welding process steps, a fast, efficient and reliable welding method for semiconductor crystal oscillators can be achieved, meeting the needs of high-frequency electronic devices.

[0005] To achieve the above objectives, the present invention provides a semiconductor crystal oscillator welding method comprising the following steps:

[0006] Surface treatment is performed on the soldering area of ​​the semiconductor crystal oscillator;

[0007] A conductive layer is formed by electroplating on the welding area;

[0008] The welding area is aligned with the welding terminal, and a welding point is formed between them using high-frequency current welding; and

[0009] The weld joints are heat-treated.

[0010] Compared with the prior art, the present invention has the following advantages: the high-frequency welding current generates resistance heat during the welding process, which rapidly heats the welding interface and forms a dense welding point; the high-frequency welding current has strong penetration and can quickly melt the material at the welding interface, shortening the welding time; the subsequent heat treatment process can remove the stress in the welding point and improve the fatigue resistance of the welding point; the crystal oscillator welded by the method of the present invention has excellent high-frequency characteristics and is suitable for high-frequency electronic equipment.

[0011] Preferably, the surface treatment includes immersion in a hydrofluoric acid solution.

[0012] Preferably, the surface treatment further includes plasma cleaning or ultraviolet light irradiation.

[0013] Preferably, the electroplating includes: using one or more of gold, silver, and nickel, and controlling the current density to be 20-30 mA / cm². 2 .

[0014] Preferably, the conductive layer has a multilayer structure, including a bottom layer and a surface layer.

[0015] Preferably, the frequency of the high-frequency current is 50-200kHz.

[0016] Preferably, the current intensity of the high-frequency current is 50-80A.

[0017] Preferably, the heat treatment includes controlling the temperature at 120-300℃ for 1-2 hours.

[0018] Preferably, the heat treatment is a step-by-step heat treatment, in which heat treatment at 250-300℃ is followed by low-temperature annealing at 120-150℃.

[0019] Preferably, an inert gas or a reducing gas is introduced during the heat treatment. Detailed Implementation

[0020] To make the above-mentioned objectives, features, and advantages of this application more apparent and understandable, the specific implementation methods of this application are described in detail below with reference to some embodiments. Many specific details are set forth in the following description to provide a thorough understanding of this application. However, this application can be implemented in many other ways different from those described herein, and those skilled in the art can make similar modifications without departing from the spirit of this application. Therefore, this application is not limited to the specific embodiments disclosed below.

[0021] In the description of this application, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this application, "multiple" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0022] In this application, unless otherwise expressly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "on top of," and "over" the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0023] It should be noted that when an element is referred to as being "fixed to" or "set on" another element, it can be directly on the other element or there may be an intervening element. When an element is considered to be "connected to" another element, it can be directly connected to the other element or there may be an intervening element. The terms "vertical," "horizontal," "upper," "lower," "left," "right," and similar expressions used herein are for illustrative purposes only and do not represent the only possible implementation.

[0024] The following description, in conjunction with embodiments, further illustrates the semiconductor crystal oscillator welding method of the present invention, but does not limit the invention. The method of the present invention aims to provide an improved semiconductor crystal oscillator welding method, achieving rapid, efficient, and reliable welding of semiconductor crystal oscillators by optimizing welding process steps, thereby meeting the requirements of high-frequency electronic devices.

[0025] In one embodiment of the semiconductor crystal oscillator welding method of the present invention, the following steps are included:

[0026] Surface treatment is performed on the soldering area of ​​the semiconductor crystal oscillator;

[0027] A conductive layer is formed by electroplating on the welding area;

[0028] The welding area is aligned with the welding terminal, and a welding point is formed between them using high-frequency current welding; and

[0029] The weld joints are heat-treated.

[0030] The high-frequency welding current of this invention generates resistance heat during the welding process, rapidly heating the welding interface and forming a dense weld point. The high-frequency welding current has strong penetration, which can quickly melt the material at the welding interface and shorten the welding time. The subsequent heat treatment process can remove the stress in the weld point and improve the fatigue resistance of the weld point. The crystal oscillator welded by the method of this invention has excellent high-frequency characteristics and is suitable for high-frequency electronic equipment.

[0031] Specifically, in the surface treatment, the soldering area of ​​the semiconductor crystal oscillator is treated to remove oxide layers and contaminants. Optionally, it is immersed in a hydrofluoric acid solution for 2 minutes. In a preferred embodiment, after the hydrofluoric acid solution treatment, a plasma cleaning or ultraviolet irradiation step is added to further remove organic contaminants and surface impurities from the soldering area, improving the cleanliness and activity of the soldering interface.

[0032] In the electroplating process, a conductive layer is formed on the welding area of ​​the semiconductor crystal oscillator to improve the conductivity at the welding interface. Specifically, one or more of gold, silver, and nickel are used, and the current density is controlled at 20-30 mA / cm². 2The conductive layer has a thickness of 1-3 μm. In a preferred embodiment, the conductive layer has a multi-layer structure, including a bottom layer and a surface layer. For example, a multi-layer electroplating structure can be used, such as first plating a nickel layer (0.5 μm thick) as the bottom layer, and then plating a gold or silver layer (1 μm thick) as the surface layer, to improve the mechanical strength and corrosion resistance of the welding interface. Optionally, the electroplating current density and time can be optimized according to different semiconductor materials and welding requirements to achieve a more uniform electroplating layer.

[0033] In high-frequency welding, the semiconductor crystal is aligned with the welding terminals, and a welding point is formed between them using a high-frequency current. Preferably, the frequency of the high-frequency current is 50-200kHz, and the current intensity is 50-80A. The welding time is 100-300ms. Optionally, the high-frequency welding frequency range (e.g., 100kHz-150kHz) can be adjusted according to the material properties and size of the semiconductor crystal to achieve the best welding effect. Furthermore, the welding time can be dynamically adjusted based on real-time feedback during the welding process (e.g., resistance changes, temperature changes) to ensure the quality and consistency of the welding point.

[0034] In heat treatment, the weld joints are subjected to heat treatment to improve their strength and reliability. The temperature is controlled at 120-300°C for 1-2 hours. In a preferred embodiment, the heat treatment is a step-by-step process, involving heat treatment at 250-300°C for 1 hour, followed by low-temperature annealing at 120-150°C for 30 minutes. More preferably, an inert gas (such as argon) or a reducing gas (such as hydrogen) is introduced during the heat treatment process to prevent oxidation of the weld joints at high temperatures and improve their reliability.

[0035] This invention is particularly applicable to the manufacturing of semiconductor crystal oscillators in high-frequency electronic devices (such as 5G communication, millimeter-wave radar, and satellite communication), meeting their requirements for high-frequency characteristics and reliability. For semiconductor crystal oscillators made of different materials (such as quartz, gallium nitride, and sapphire), the welding process parameters are optimized to achieve the manufacturing of high-performance crystal oscillators. This invention can also be combined with microelectromechanical systems (MEMS) technology to develop high-frequency welding processes for miniaturized semiconductor crystal oscillators, meeting the needs of portable electronic devices and IoT devices.

[0036] In one specific embodiment, the soldering area of ​​the quartz crystal is first immersed in a hydrofluoric acid solution for 2 minutes. Then, a 1 μm thick layer of gold is electroplated onto the soldering area of ​​the quartz crystal at a current density of 20 mA / cm². 2Next, the quartz crystal was aligned with the metal terminals, and welding was performed using a high-frequency welding current of 100kHz, 50A, and 100ms. Finally, the weld joint was heat-treated at 250℃ for 1 hour. The resulting crystal oscillator exhibited excellent frequency stability at 100MHz, high weld strength, and good reliability.

[0037] In another specific embodiment, the welding area of ​​the gallium nitride crystal is first immersed in a hydrofluoric acid solution for 2 minutes. Then, a layer of silver with a thickness of 1 μm is electroplated onto the welding area of ​​the gallium nitride crystal at a current density of 20 mA / cm². 2 Next, the gallium nitride crystal was aligned with the copper terminals, and welding was performed using a high-frequency welding current of 100kHz, 50A, and 100ms. Finally, the weld joint was heat-treated at 250℃ for 1 hour. The resulting crystal oscillator exhibited excellent resonance characteristics at 1GHz, with high weld strength and good reliability.

[0038] In summary, the high-frequency welding current of the present invention generates resistance heat during the welding process, rapidly heating the welding interface and forming a dense weld point; the high-frequency welding current has strong penetration, which can quickly melt the material at the welding interface and shorten the welding time; the subsequent heat treatment process can remove the stress in the weld point and improve the fatigue resistance of the weld point; the crystal oscillator welded by the method of the present invention has excellent high-frequency characteristics and is suitable for high-frequency electronic equipment.

[0039] The above-disclosed embodiments are merely preferred embodiments of the present invention and should not be construed as limiting the scope of the present invention. Therefore, any equivalent variations made in accordance with the claims of the present invention are still within the scope of the present invention.

Claims

1. A method for welding a semiconductor crystal oscillator, characterized in that, Includes the following steps: Surface treatment is performed on the soldering area of ​​the semiconductor crystal oscillator; A conductive layer is formed by electroplating on the welding area; The welding area is aligned with the welding terminal, and a welding point is formed between them using high-frequency current welding; and The weld joints are heat-treated.

2. The semiconductor crystal oscillator welding method as described in claim 1, characterized in that, The surface treatment includes immersion in a hydrofluoric acid solution.

3. The semiconductor crystal oscillator welding method as described in claim 2, characterized in that, The surface treatment also includes plasma cleaning or ultraviolet light irradiation.

4. The semiconductor crystal oscillator welding method as described in claim 1, characterized in that, The electroplating process includes using one or more of gold, silver, and nickel, while controlling the current density to be 20-30 mA / cm². 2 .

5. The semiconductor crystal oscillator welding method as described in claim 1, characterized in that, The conductive layer has a multi-layer structure, including a bottom layer and a surface layer.

6. The semiconductor crystal oscillator welding method as described in claim 1, characterized in that, The frequency of the high-frequency current is 50-200kHz.

7. The semiconductor crystal oscillator welding method as described in claim 1, characterized in that, The current intensity of the high-frequency current is 50-80A.

8. The semiconductor crystal oscillator welding method as described in claim 1, characterized in that: The heat treatment includes controlling the temperature at 120-300℃ for 1-2 hours.

9. The welding method for a semiconductor crystal oscillator as described in claim 8, characterized in that: The heat treatment is a step-by-step heat treatment, which involves heat treatment at 250-300℃ followed by low-temperature annealing at 120-150℃.

10. The welding method for a semiconductor crystal oscillator as described in claim 1, characterized in that: Inert gas or reducing gas is introduced during the heat treatment.