Method for improving bonding strength of gold wire ball bonding

Abstract

The invention provides a method for improving the bonding strength of gold wire ball bonding, and the method comprises the step of adding a pretreatment step for removing a gold ball and an oxide layer on the surface of a to-be-bonded region and redundant materials before formal welding. A pretreatment step is added before formal welding. According to the method, the oxide layer and the redundancy on the bonding surface are effectively removed, so that the gold wire and the metal surface can be better combined during formal bonding, the bonding strength is improved, and the packaging reliability of an electronic device is improved. The problem that the gold wire ball bonding strength is insufficient due to the fact that the bonding surface is contaminated or an oxide layer is thick is solved.

Description

Technical Field

[0001] This invention relates to the field of electronic device packaging technology, and in particular to a method for improving the bonding strength of gold wire ball bonding. Background Technology

[0002] In gold wire bonding, the principle is based on multiple mechanisms to achieve a reliable connection between the gold wire and the chip electrodes and substrate pins. Mechanical action involves capillary pressure applying pressure to bring the gold wire into close contact with the metal surface, breaking down the surface oxide layer and achieving direct contact. Ultrasonic vibration causes the gold wire and the bonding surface to vibrate at high frequency, removing contaminants and oxide layers, enhancing atomic activity and diffusion capabilities, and promoting inter-atomic diffusion and bonding. Thermal effects, through appropriate heating, increase the atomic diffusion rate and reduce material hardness, facilitating the fusion of the gold wire and the metal surface to form metallic bonds.

[0003] However, when the bonding surface is contaminated or has a thick oxide layer, the bonding strength is significantly affected. Conventional gold ball bonding processes struggle to guarantee bonding quality in such situations, leading to reduced reliability of electronic device packages. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to provide a method for improving the bonding strength of gold wire ball bonding, which addresses the shortcomings of the prior art.

[0005] The technical solution of the present invention to solve the above-mentioned technical problems is as follows: a method for improving the bonding strength of gold wire ball bonding, comprising: before formal welding, adding a pretreatment step for removing the oxide layer and excess material from the surface of the gold ball and the area to be bonded.

[0006] The beneficial effects of adopting the technical solution of this invention are: It adds a pretreatment step before formal soldering. This effectively removes the oxide layer and excess material from the bonding surface, allowing the gold wire to better bond with the metal surface during formal soldering, thereby improving bonding strength and enhancing the reliability of electronic device packaging. It also solves the problem of insufficient gold wire ball soldering bonding strength caused by contamination or a thick oxide layer on the bonding surface.

[0007] Furthermore, the pretreatment step is a pre-pressure welding step.

[0008] The beneficial effects of adopting the above-mentioned further technical solution are: adding a pre-pressure welding step before the formal welding. This causes high-frequency friction between the gold ball in front of the bonding head and the bonding surface to be processed. During this process, the oxide layer or excess material on the surface of the gold ball and the area to be bonded is removed. Effective removal of the oxide layer and excess material on the bonding surface allows for better bonding between the gold wire and the metal surface during the formal bonding process, thereby improving the bonding strength and enhancing the reliability of electronic device packaging.

[0009] Furthermore, the pre-pressure welding step includes: setting the power to the normal welding power, adjusting the pressure to be lower than the normal welding pressure, and extending the time.

[0010] The beneficial effects of adopting the above-mentioned further technical solution are: maintaining constant power, extending the pre-pressure bonding time, and reducing pressure, causing high-frequency friction between the gold balls in front of the bonding head and the bonding surface to be processed. During this process, the oxide layer or excess material on the surface of the gold balls and the area to be bonded is removed. Effective removal of the oxide layer and excess material from the bonding surface allows for better bonding between the gold wire and the metal surface during the actual bonding process, thereby improving bonding strength and enhancing the reliability of electronic device packaging. This process only requires adding a pre-pressure bonding step to the existing gold wire ball bonding process and adjusting the corresponding time and pressure parameters; it requires no complex equipment or high costs and is easy to implement in production.

[0011] Further, before the step of setting the power to the normal welding power, adjusting the pressure to a level lower than the normal welding pressure, and extending the time, the process includes: preparing the gold wire ball bonding equipment, the chip to be bonded, and the substrate; after the step of setting the power to the normal welding power, adjusting the pressure to a level lower than the normal welding pressure, and extending the time, the process includes: starting the gold wire ball bonding equipment, making the gold balls in front of the bonding head contact the bonding surface, performing a pre-pressure bonding operation, causing the gold balls in front of the bonding head to rub against the bonding surface to be processed, removing the oxide layer and excess material from the gold balls and the surface of the area to be bonded.

[0012] The beneficial effects of adopting the above-mentioned further technical solution are as follows: Prepare the gold wire ball bonding equipment, the chip to be bonded, and the substrate, ensuring that all equipment parameters are adjustable and operating normally. Maintain constant power, extend the pre-pressure bonding time, and reduce the pressure to generate high-frequency friction between the gold ball in front of the bonding head and the bonding surface to be processed. During this process, the oxide layer or excess material on the surface of the gold ball and the area to be bonded is removed. Effective removal of the oxide layer and excess material from the bonding surface allows for better bonding between the gold wire and the metal surface during the actual bonding process, thereby improving bonding strength and enhancing the reliability of electronic device packaging. This process only requires adding a pre-pressure bonding step to the existing gold wire ball bonding process and adjusting the corresponding time and pressure parameters; it requires no complex equipment or high costs and is easy to implement in production.

[0013] Furthermore, in the step of setting the power to the normal welding power, adjusting the pressure to be lower than the normal welding pressure, and extending the time, the pressure is adjusted to half of the normal welding pressure, and the time is extended to twice the normal time.

[0014] The beneficial effects of adopting the above-mentioned further technical solution are: maintaining constant power, extending the pre-pressure bonding time, and reducing pressure, causing high-frequency friction between the gold balls in front of the bonding head and the bonding surface to be processed. During this process, the oxide layer or excess material on the surface of the gold balls and the area to be bonded is removed. Effective removal of the oxide layer and excess material from the bonding surface allows for better bonding between the gold wire and the metal surface during the actual bonding process, thereby improving bonding strength and enhancing the reliability of electronic device packaging. This process only requires adding a pre-pressure bonding step to the existing gold wire ball bonding process and adjusting the corresponding time and pressure parameters; it requires no complex equipment or high costs and is easy to implement in production.

[0015] Furthermore, the step of adding a pretreatment step to remove the oxide layer and excess material from the surface of the gold balls and the bonding area before formal welding includes: after completing the pretreatment step, formal bonding is performed according to normal time, normal pressure and normal power.

[0016] The beneficial effects of adopting the above-mentioned further technical solution are: after pretreatment, formal bonding is performed according to normal time, pressure, and power parameters, thus completing the connection between the gold wire and the chip electrodes and substrate pins.

[0017] Furthermore, after completing the pretreatment step, the formal bonding step, performed according to normal time, normal pressure, and normal power, includes: after completing the connection between the gold wire and the chip electrode and the substrate pin, the bonding strength is tested by a testing device to verify the bonding strength improvement effect.

[0018] The beneficial effect of adopting the above-mentioned further technical solution is that the bonding strength is tested using testing equipment, and the bonding strength data before and after the pretreatment are compared to verify the bonding strength improvement effect.

[0019] Furthermore, the testing equipment is a tensile testing machine.

[0020] The beneficial effects of adopting the above-mentioned further technical solutions are: using a tensile testing machine facilitates the detection of bond strength, improves work efficiency, reduces testing costs, and verifies the bond strength improvement effect by comparing the bond strength data before and after pretreatment.

[0021] Furthermore, the pretreatment step involves cleaning the bonding surface with flux before bonding.

[0022] The beneficial effect of adopting the above-mentioned further technical solution is that the flux is used to clean the bonding surface before bonding.

[0023] Furthermore, the pretreatment step involves performing pretreatment using ultrasonic vibrations of different frequencies before the actual welding.

[0024] The beneficial effect of adopting the above-mentioned further technical solution is that pretreatment with ultrasonic vibration of different frequencies before formal welding is carried out to improve the bonding strength.

[0025] The advantages of additional aspects of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0026] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0027] Figure 1 This is one of the schematic flowcharts of a method for improving the bonding strength of gold wire ball bonding according to an embodiment of the present invention.

[0028] Figure 2 This is a second schematic flowchart illustrating a method for improving the bonding strength of gold wire ball bonding according to an embodiment of the present invention. Detailed Implementation

[0029] The principles and features of the present invention are described below with reference to the accompanying drawings. The embodiments described are only for explaining the present invention and are not intended to limit the scope of the present invention.

[0030] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0031] Therefore, the following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without inventive effort are within the scope of protection of the invention.

[0032] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0033] In the description of the embodiments of the present invention, it should be noted that if terms such as "upper", "lower", "horizontal", "inner" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship in which the product of the invention is usually placed during use, they are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the present invention.

[0034] In the description of the embodiments of the present invention, it should also be noted that, unless otherwise explicitly specified and limited, the terms "set," "install," "connect," and "link" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in the present invention according to the specific circumstances.

[0035] like Figure 1 As shown, this embodiment of the invention provides a method for improving the bonding strength of gold wire ball bonding, including: before formal welding, adding a pretreatment step for removing the oxide layer and excess material from the surface of the gold ball and the bonding area.

[0036] The beneficial effects of adopting the technical solution of this invention are: It adds a pretreatment step before formal soldering. This effectively removes the oxide layer and excess material from the bonding surface, allowing the gold wire to better bond with the metal surface during formal soldering, thereby improving bonding strength and enhancing the reliability of electronic device packaging. It also solves the problem of insufficient gold wire ball soldering bonding strength caused by contamination or a thick oxide layer on the bonding surface.

[0037] This invention aims to solve the problem of insufficient bonding strength in gold wire ball bonding caused by contamination or thick oxide layers on the bonding surface, and provides a method to effectively improve bonding strength (Method for Improving Gold Wire Ball Bonding Strength). The method of this invention (Method for Improving Gold Wire Ball Bonding Strength) can add a pre-pressure welding step before the formal welding. The specific operation is as follows: keeping the power constant, extending the pre-pressure welding time and reducing the pressure, causing high-frequency friction between the gold ball in front of the bonding head and the bonding surface to be processed. During this process, the oxide layer or excess material on the surface of the gold ball and the area to be bonded is removed. After completing the pre-pressure welding, the formal bonding is performed according to the normal time, pressure, and power parameters.

[0038] 1. Improved Bonding Strength: The pre-bonding step effectively removes the oxide layer and excess material from the bonding surface, allowing the gold wire to better bond with the metal surface during the actual bonding process. This significantly improves the bonding strength and enhances the reliability of electronic device packaging.

[0039] 2. Simple process: It only requires adding a pre-pressure welding step to the existing gold wire ball welding process and adjusting the corresponding time and pressure parameters. It does not require complex equipment and high costs, and is easy to implement in production.

[0040] Furthermore, the pretreatment step is a pre-pressure welding step.

[0041] The beneficial effects of adopting the above-mentioned further technical solution are: adding a pre-pressure welding step before the formal welding. This causes high-frequency friction between the gold ball in front of the bonding head and the bonding surface to be processed. During this process, the oxide layer or excess material on the surface of the gold ball and the area to be bonded is removed. Effective removal of the oxide layer and excess material on the bonding surface allows for better bonding between the gold wire and the metal surface during the formal bonding process, thereby improving the bonding strength and enhancing the reliability of electronic device packaging.

[0042] Furthermore, the pre-pressure welding step includes: setting the power to the normal welding power, adjusting the pressure to be lower than the normal welding pressure, and extending the time.

[0043] The beneficial effects of adopting the above-mentioned further technical solution are: maintaining constant power, extending the pre-pressure bonding time, and reducing pressure, causing high-frequency friction between the gold balls in front of the bonding head and the bonding surface to be processed. During this process, the oxide layer or excess material on the surface of the gold balls and the area to be bonded is removed. Effective removal of the oxide layer and excess material from the bonding surface allows for better bonding between the gold wire and the metal surface during the actual bonding process, thereby improving bonding strength and enhancing the reliability of electronic device packaging. This process only requires adding a pre-pressure bonding step to the existing gold wire ball bonding process and adjusting the corresponding time and pressure parameters; it requires no complex equipment or high costs and is easy to implement in production.

[0044] The normal welding power can be 100W, the normal welding pressure can be 50g, and the normal welding time can be 120ms.

[0045] Further, before the step of setting the power to the normal welding power, adjusting the pressure to a level lower than the normal welding pressure, and extending the time, the process includes: preparing the gold wire ball bonding equipment, the chip to be bonded, and the substrate; after the step of setting the power to the normal welding power, adjusting the pressure to a level lower than the normal welding pressure, and extending the time, the process includes: starting the gold wire ball bonding equipment, making the gold balls in front of the bonding head contact the bonding surface, performing a pre-pressure bonding operation, causing the gold balls in front of the bonding head to rub against the bonding surface to be processed, removing the oxide layer and excess material from the gold balls and the surface of the area to be bonded.

[0046] The beneficial effects of adopting the above-mentioned further technical solution are as follows: Prepare the gold wire ball bonding equipment, the chip to be bonded, and the substrate, ensuring that all equipment parameters are adjustable and operating normally. Maintain constant power, extend the pre-pressure bonding time, and reduce the pressure to generate high-frequency friction between the gold ball in front of the bonding head and the bonding surface to be processed. During this process, the oxide layer or excess material on the surface of the gold ball and the area to be bonded is removed. Effective removal of the oxide layer and excess material from the bonding surface allows for better bonding between the gold wire and the metal surface during the actual bonding process, thereby improving bonding strength and enhancing the reliability of electronic device packaging. This process only requires adding a pre-pressure bonding step to the existing gold wire ball bonding process and adjusting the corresponding time and pressure parameters; it requires no complex equipment or high costs and is easy to implement in production.

[0047] Furthermore, in the step of setting the power to the normal welding power, adjusting the pressure to be lower than the normal welding pressure, and extending the time, the pressure is adjusted to half of the normal welding pressure, and the time is extended to twice the normal time.

[0048] The beneficial effects of adopting the above-mentioned further technical solution are: maintaining constant power, extending the pre-pressure bonding time, and reducing pressure, causing high-frequency friction between the gold balls in front of the bonding head and the bonding surface to be processed. During this process, the oxide layer or excess material on the surface of the gold balls and the area to be bonded is removed. Effective removal of the oxide layer and excess material from the bonding surface allows for better bonding between the gold wire and the metal surface during the actual bonding process, thereby improving bonding strength and enhancing the reliability of electronic device packaging. This process only requires adding a pre-pressure bonding step to the existing gold wire ball bonding process and adjusting the corresponding time and pressure parameters; it requires no complex equipment or high costs and is easy to implement in production.

[0049] Furthermore, the step of adding a pretreatment step to remove the oxide layer and excess material from the surface of the gold balls and the bonding area before formal welding includes: after completing the pretreatment step, formal bonding is performed according to normal time, normal pressure and normal power.

[0050] The beneficial effects of adopting the above-mentioned further technical solution are: after pretreatment, formal bonding is performed according to normal time, pressure, and power parameters, thus completing the connection between the gold wire and the chip electrodes and substrate pins.

[0051] Furthermore, after completing the pretreatment step, the formal bonding step, performed according to normal time, normal pressure, and normal power, includes: after completing the connection between the gold wire and the chip electrode and the substrate pin, the bonding strength is tested by a testing device to verify the bonding strength improvement effect.

[0052] The beneficial effect of adopting the above-mentioned further technical solution is that the bonding strength is tested using testing equipment, and the bonding strength data before and after the pretreatment are compared to verify the bonding strength improvement effect.

[0053] Furthermore, the testing equipment is a tensile testing machine.

[0054] The beneficial effects of adopting the above-mentioned further technical solutions are: using a tensile testing machine facilitates the detection of bond strength, improves work efficiency, reduces testing costs, and verifies the bond strength improvement effect by comparing the bond strength data before and after pretreatment.

[0055] Furthermore, the pretreatment step involves cleaning the bonding surface with flux before bonding.

[0056] The beneficial effect of adopting the above-mentioned further technical solution is that the flux is used to clean the bonding surface before bonding.

[0057] Furthermore, the pretreatment step involves performing pretreatment using ultrasonic vibrations of different frequencies before the actual welding.

[0058] The beneficial effect of adopting the above-mentioned further technical solution is that pretreatment with ultrasonic vibration of different frequencies before formal welding is carried out to improve the bonding strength.

[0059] like Figure 2 As shown, 1. Preparation: Prepare the gold wire ball bonding equipment, the chip to be bonded and the substrate, and ensure that all parameters of the equipment are adjustable and operating normally.

[0060] 2. Pre-pressure welding: Set the power to the normal welding power and adjust the pressure to be lower than the normal welding pressure. For example, if the normal pressure is P, adjust it to 0.5P. At the same time, extend the time. For example, if the normal welding time is t, set the pre-pressure welding time to 2t. Start the equipment to make the gold ball in front of the bonding head contact the bonding surface. Perform the pre-pressure welding operation under the set parameters to generate high-frequency friction between the gold ball and the bonding surface, removing the surface oxide layer and excess material.

[0061] 3. Formal bonding: After the pre-pressure bonding is completed, the time and pressure are restored to the normal welding parameters, while the power remains unchanged, and the formal bonding operation is performed to complete the connection between the gold wire and the chip electrode and substrate pin.

[0062] 4. Testing: Use professional testing equipment, such as a tensile testing machine, to test the bond strength and compare the bond strength data before and after using the method of this embodiment of the invention to verify the bond strength improvement effect.

[0063] This invention provides an improved gold wire ball bonding process by adding a pre-pressure bonding step. The parameters for time, pressure, and power during the pre-pressure bonding process are set, and this process is applied to enhance the bonding strength of gold wire ball bonding. It achieves the technical effect of improving bonding strength by adding a pre-pressure bonding step before the actual gold wire ball bonding, and by adjusting the time and pressure parameters, utilizing high-frequency friction between the gold ball and the bonding surface to remove the oxide layer and excess material.

[0064] As an alternative to the aforementioned pre-compression welding step, it is possible to develop fluxes to clean the bonding surfaces before bonding, or to explore the use of ultrasonic vibrations of different frequencies for pretreatment before formal welding, thereby improving bonding strength.

[0065] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for improving the strength of gold ball wire bonding, characterized by, include: Before the actual welding, a pretreatment step is added to remove the oxide layer and excess material from the gold balls and the surface of the area to be bonded.

2. The method for improving the bonding strength of gold wire ball bonding according to claim 1, characterized in that, The pretreatment step is a pre-pressure welding step.

3. The method for improving the bonding strength of gold wire ball bonding according to claim 2, characterized in that, The pre-pressure welding step includes: setting the power to the normal welding power, adjusting the pressure to be lower than the normal welding pressure, and extending the time.

4. The method for improving the bonding strength of gold wire ball bonding according to claim 3, characterized in that, The steps of setting the power to the normal welding power, adjusting the pressure to a level lower than the normal welding pressure, and extending the time include: preparing the gold wire ball bonding equipment, the chip to be bonded, and the substrate; The steps following the setting of the power as normal welding power, adjusting the pressure to below normal welding pressure, and extending the time include: Start the gold wire ball bonding equipment to bring the gold balls in front of the bonding head into contact with the bonding surface and perform a pre-pressure bonding operation. This causes the gold balls in front of the bonding head to rub against the bonding surface to be processed, removing the oxide layer and excess material from the gold balls and the surface of the area to be bonded.

5. The method for improving the bonding strength of gold wire ball bonding according to claim 4, characterized in that, In the step of setting the power to the normal welding power, adjusting the pressure to be lower than the normal welding pressure, and extending the time, the pressure is adjusted to half of the normal welding pressure, and the time is extended to twice the normal time.

6. The method for improving the bonding strength of gold wire ball bonding according to claim 1, characterized in that, The step of adding a pretreatment step to remove the oxide layer and excess material from the gold balls and the surface of the bonding area before formal welding includes: after completing the pretreatment step, formal bonding is performed according to normal time, normal pressure and normal power.

7. A method for improving the bonding strength of gold wire ball bonding according to claim 6, characterized in that, After completing the pretreatment step, the formal bonding step is carried out according to the normal time, normal pressure and normal power, including: after completing the connection of the gold wire to the chip electrode and the substrate pin, the bonding strength is detected by the detection equipment to verify the bonding strength improvement effect.

8. A method for improving the bonding strength of gold wire ball bonding according to claim 7, characterized in that, The testing equipment is a tensile testing machine.

9. A method for improving the bonding strength of gold wire ball bonding according to claim 1, characterized in that, The pretreatment step involves cleaning the bonding surface with flux before bonding.

10. A method for improving the bonding strength of gold wire ball bonding according to claim 1, characterized in that, The pretreatment step involves performing pretreatment using ultrasonic vibrations of different frequencies before the actual welding.

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