Welding bonding head contact detection method, contact detection device and welding equipment

Abstract

The invention relates to the technical field of semiconductor packaging equipment, in particular to a welding bonding head contact detection method, a contact detection device and welding equipment. The target excitation signal is applied to the ultrasonic transducer, the response signal generated by the ultrasonic transducer in response to the target excitation signal is sampled to obtain the first feedback signal, and then whether the welding bonding head makes contact with the welding position or not is judged on the basis of the first feedback signal. The first feedback signal does not need to be transmitted among a plurality of mechanical mechanisms, the time for obtaining the first feedback signal can be effectively shortened, then whether the welding bonding head makes contact with the welding position or not is rapidly judged based on the first feedback signal, and the purpose of reducing detection delay is achieved.

Description

Technical Field

[0001] The present invention relates to the technical field of semiconductor packaging equipment, and in particular, to a welding bonding head contact detection method, a contact detection device, and a welding device. Background Art

[0002] In the welding process, the accurate identification of the contact point is a key factor to ensure the welding quality and process stability. At present, the mainstream contact detection methods are contact detection methods based on encoders or current feedback.

[0003] However, the contact detection methods based on encoders or current feedback have an inherent delay. For example, in the contact detection method based on an encoder, the bonding head and the bonding head encoder are connected by a mechanical structure, and the force on the contact point needs to be transmitted to the motor side through structures such as a coupling and a slider before it can be sensed by the encoder, resulting in mechanical hysteresis and the rigid filtering effect of the detection system. At the same time, the determination window or average filtering introduced at the algorithm level further exacerbates the response delay. Actual tests show that the contact moment detected by the detection system lags behind the actual contact moment by 1.5 - 2 ms, which may cause problems such as inconsistent solder joint penetration depth, material deformation, or welding failure, severely limiting the application of welding equipment (such as wire bonding machines) in high-precision and high-response welding processes. Summary of the Invention

[0004] Embodiments of the present invention provide a welding bonding head contact detection method, a contact detection device, and a welding device to solve the problem of response delay existing in the existing welding bonding head contact detection methods.

[0005] A welding bonding head contact detection method includes: Controlling an excitation signal generating device to apply a target excitation signal to an ultrasonic transducer, and obtaining a response signal generated by the ultrasonic transducer in response to the target excitation signal; Controlling a bonding head driving mechanism to drive the welding bonding head to probe downwards at a constant speed towards the welding position, and continuously sampling the response signal according to a preset first time window during the constant-speed downward probing process to obtain a first feedback signal; Comparing the first feedback signal with a pre-constructed reference line to determine whether the welding bonding head meets the contact condition; If the welding bonding head meets the contact condition, determining that the welding bonding head contacts the welding position; If the welding bonding head does not meet the contact condition, returning to execute the step of controlling the bonding head driving mechanism to drive the welding bonding head to probe downwards at a constant speed towards the welding position, and continuously sampling the response signal according to a preset first time window during the constant-speed downward probing process to obtain a first feedback signal.

[0006] For the above-mentioned welding bond head contact detection method, optionally, after controlling the excitation signal generating device to apply a target excitation signal to the ultrasonic transducer and obtaining the response signal generated by the ultrasonic transducer in response to the target excitation signal; The reference line is obtained in the following manner: Sample the response signal according to the second time window to obtain a second feedback signal; the second feedback signal is obtained by sampling the response signal of the ultrasonic transducer before constructing the reference line, and the first feedback signal is obtained by sampling the response signal of the ultrasonic transducer after constructing the reference line; Process the second feedback signal according to a preset signal processing algorithm to obtain the reference line, and the signal processing algorithm includes an average filtering algorithm, a median filtering algorithm or a sliding weighted algorithm.

[0007] For the above-mentioned welding bond head contact detection method, optionally, compare the first feedback signal with a pre-constructed reference line to determine whether the welding bond head meets the contact condition, including: Obtain the maximum amplitude and the minimum amplitude of the first feedback signal, and the reference value corresponding to the reference line; Calculate the first difference between the maximum amplitude and the reference value, and the second difference between the minimum amplitude and the reference value; Respectively determine whether the first difference and the second difference are greater than a preset difference threshold; If the first difference and / or the second difference is greater than the difference threshold, determine that the welding bond head meets the contact condition.

[0008] For the above-mentioned welding bond head contact detection method, optionally, the first feedback signal includes a main signal and an auxiliary signal, and the reference line includes a main reference line and an auxiliary reference line; Compare the first feedback signal with a pre-constructed reference line to determine whether the welding bond head meets the contact condition, including: Compare the main signal with the main reference line to determine whether the welding bond head meets the candidate condition; If the welding bond head meets the candidate condition, compare the auxiliary signal with the auxiliary reference line to determine whether the welding bond head meets the contact condition; If the welding bond head does not meet the candidate condition, return to execute the step of controlling the bond head driving mechanism to drive the welding bond head to uniformly descend towards the welding position, and continuously sample the response signal according to a preset first time window during the uniform descent to obtain the first feedback signal.

[0009] For the above-mentioned welding bond head contact detection method, optionally, compare the first feedback signal with a pre-constructed reference line to determine whether the welding bond head meets the contact condition, including: Construct a trigger line according to a preset trigger threshold and the reference line; Determine whether the first feedback signal exceeds the trigger line during the rising and / or falling process; If the first feedback signal exceeds the trigger line during the rising and / or falling process, determine that the welding bonding head meets the contact condition; If the first feedback signal does not exceed the trigger line during the rising and / or falling process, return to the step of controlling the bonding head driving mechanism to drive the welding bonding head to descend uniformly towards the welding position, and continuously sample the response signal according to a preset first time window during the uniform descent to obtain the first feedback signal.

[0010] For the above welding bonding head contact detection method, optionally, after the first feedback signal exceeds the trigger line during the rising and / or falling process and before determining that the welding bonding head meets the contact condition, it further includes: Determine whether the duration for which the first feedback signal continuously exceeds the trigger line exceeds a preset first duration; If the duration for which the first feedback signal continuously exceeds the trigger line exceeds the preset first duration, determine that the welding bonding head meets the contact condition; If the duration for which the first feedback signal continuously exceeds the trigger line does not exceed the preset first duration, return to the step of controlling the bonding head driving mechanism to drive the welding bonding head to descend uniformly towards the welding position, and continuously sample the response signal according to a preset first time window during the uniform descent to obtain the first feedback signal.

[0011] For the above welding bonding head contact detection method, optionally, the trigger threshold includes a first trigger threshold and a second trigger threshold, and the first trigger threshold is less than the second trigger threshold; Constructing the trigger line according to the preset trigger threshold and reference line includes: Construct a first trigger line based on the first trigger threshold and the reference line; Construct a second trigger line based on the second trigger threshold and the reference line.

[0012] For the above welding bonding head contact detection method, optionally, determining whether the first feedback signal exceeds the trigger line during the rising and / or falling process includes: Determine whether the first feedback signal continuously exceeds the first trigger line and the second trigger line during the rising and / or falling process; If the first feedback signal continuously exceeds the first trigger line and the second trigger line during the rising and / or falling process, determine whether the duration for which the first feedback signal continuously exceeds the first trigger line exceeds a preset second duration; If the duration for which the first feedback signal continuously exceeds the first trigger line exceeds the second duration, determine that the welding bonding head meets the contact condition; If the duration for which the first feedback signal continuously exceeds the first trigger line does not exceed the second duration, return to execute controlling the bonding head driving mechanism to drive the welding bonding head to descend uniformly towards the welding position, and continuously sample the response signal according to a preset first time window during the uniform descent process to obtain the first feedback signal.

[0013] A contact detection device, the contact detection device includes a processor and the excitation signal generating device, ultrasonic transducer, bonding head driving mechanism, and welding bonding head of any one of the above. The processor controls the excitation signal generating device, ultrasonic transducer, bonding head driving mechanism, and welding bonding head to implement the welding bonding head contact detection method of any one of the above.

[0014] A welding device, characterized in that the welding device includes the above-mentioned contact detection device.

[0015] The embodiments of the present invention provide a welding bonding head contact detection method, a contact detection device, and a welding device. By controlling the excitation signal generating device to apply a target excitation signal to the ultrasonic transducer, a response signal generated by the ultrasonic transducer in response to the target excitation signal is obtained; controlling the bonding head driving mechanism to drive the welding bonding head to descend uniformly towards the welding position, and continuously sample the response signal according to a preset time window during the uniform descent process to obtain the first feedback signal; comparing the first feedback signal with a pre-constructed reference line to determine whether the welding bonding head meets the contact condition; if the welding bonding head meets the contact condition, it is determined that the welding bonding head contacts the welding position; if the welding bonding head does not meet the contact condition, return to execute the step of controlling the bonding head driving mechanism to drive the welding bonding head to descend uniformly towards the welding position, and sample the response signal according to a preset time window during the uniform descent process to obtain the first feedback signal. It can be seen that the present invention applies a target excitation signal to the ultrasonic transducer to sample the response signal generated by the ultrasonic transducer in response to the target excitation signal to obtain the first feedback signal, and then determines whether the welding bonding head contacts the welding position based on the first feedback signal. Compared with the existing encoder-based contact detection method, the first feedback signal does not need to be transmitted between multiple mechanical mechanisms, which can effectively shorten the time to obtain the first feedback signal, and then quickly make a judgment on whether the welding bonding head contacts the welding position based on the first feedback signal, achieving the purpose of reducing detection delay. Description of the Drawings

[0016] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following will briefly introduce the drawings required for the description of the embodiments of the present invention. Obviously, the following drawings are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0017] Figure 1It is a flowchart of an implementation of a welding bonding head contact detection method disclosed in an embodiment of the present invention; Figure 2 It is another flowchart of an implementation of a welding bonding head contact detection method disclosed in an embodiment of the present invention; Figure 3 It is yet another flowchart of an implementation of a welding bonding head contact detection method disclosed in an embodiment of the present invention; Figure 4 It is yet another flowchart of an implementation of a welding bonding head contact detection method disclosed in an embodiment of the present invention; Figure 5 It is a schematic diagram of a trigger wire disclosed in an embodiment of the present invention; Figure 6 It is yet another flowchart of an implementation of a welding bonding head contact detection method disclosed in an embodiment of the present invention; Figure 7 It is a partial flowchart of an implementation of a welding bonding head contact detection method disclosed in an embodiment of the present invention; Figure 8 It is yet another flowchart of an implementation of a welding bonding head contact detection method disclosed in an embodiment of the present invention; Figure 9 It is yet another flowchart of an implementation of a welding bonding head contact detection method disclosed in an embodiment of the present invention; Figure 10 It is a schematic structural diagram of a contact detection device disclosed in an embodiment of the present invention. Detailed implementation manners

[0018] In order to make the technical problems, technical solutions and beneficial effects solved by the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0019] It should be understood that when used in the specification and appended claims of the present invention, the term "comprising" indicates the presence of the described features, wholes, steps, operations, elements and / or components, but does not exclude the presence or addition of one or more other features, wholes, steps, operations, elements, components and / or their combinations.

[0020] It should also be understood that the term "and / or" used in the specification and appended claims of the present invention refers to any combination and all possible combinations of one or more of the associated listed items, and includes these combinations.

[0021] As used in the specification of the present invention and the appended claims, the term "if" may be construed, depending on the context, as "when" or "once" or "in response to determining" or "in response to detecting". Similarly, the phrases "if determined" or "if [described condition or event] is detected" may be construed, depending on the context, to mean "once determined" or "in response to determining" or "once [described condition or event] is detected" or "in response to detecting [described condition or event]".

[0022] In addition, in the description of the specification of the present invention and the appended claims, the terms "first", "second", "third", etc. are used only for distinguishing descriptions and cannot be construed as indicating or implying relative importance.

[0023] Reference to "one embodiment" or "some embodiments" or the like described in the specification of the present invention means that a specific feature, structure, or characteristic described in connection with that embodiment is included in one or more embodiments of the present invention. Thus, statements such as "in one embodiment", "in some embodiments", "in other some embodiments", "in still other embodiments", etc. that appear in different places in this specification are not necessarily all referring to the same embodiment, but mean "one or more but not all embodiments", unless otherwise specifically emphasized in other ways. The terms "comprising", "including", "having", and their variants all mean "including but not limited to", unless otherwise specifically emphasized in other ways.

[0024] The present invention provides a welding bonding head contact detection method, a contact detection device and a welding device. By controlling an excitation signal generating device to apply a target excitation signal to an ultrasonic transducer, a response signal generated by the ultrasonic transducer in response to the target excitation signal is obtained; controlling a bonding head driving mechanism to drive the welding bonding head to descend uniformly towards the welding position, and continuously sampling the response signal according to a preset time window during the uniform descent to obtain a first feedback signal; comparing the first feedback signal with a pre-constructed reference line to determine whether the welding bonding head meets the contact condition; if the welding bonding head meets the contact condition, it is determined that the welding bonding head contacts the welding position; if the welding bonding head does not meet the contact condition, return to execute the step of controlling the bonding head driving mechanism to drive the welding bonding head to descend uniformly towards the welding position, and sampling the response signal according to a preset time window during the uniform descent to obtain a first feedback signal. It can be seen that the present invention applies a target excitation signal to the ultrasonic transducer to sample the response signal generated by the ultrasonic transducer in response to the target excitation signal to obtain a first feedback signal, and then determines whether the welding bonding head contacts the welding position based on the first feedback signal. Compared with the existing encoder-based contact detection method, the first feedback signal does not need to be transmitted between multiple mechanical mechanisms, which can effectively shorten the time to obtain the first feedback signal, and then quickly make a judgment on whether the welding bonding head contacts the welding position based on the first feedback signal, achieving the purpose of reducing detection delay. In addition, in this embodiment, by continuously sampling the response signal according to a preset time window to obtain a first feedback signal, continuous detection of the process of the welding bonding head descending uniformly can be realized, and the real-time performance of the detection result can be determined. The following is illustrated by specific embodiments.

[0025] In one embodiment, as Figure 1 shown, this embodiment discloses a welding bonding head contact detection method, which is applicable to a welding device equipped with a welding bonding head, such as a wire bonder, and specifically includes the following steps: S101: Control an excitation signal generating device to apply a target excitation signal to an ultrasonic transducer, and obtain a response signal generated by the ultrasonic transducer in response to the target excitation signal.

[0026] In an alternative implementation, the ultrasonic transducer in this embodiment is not limited to any one of a standard transverse vibration transducer, a longitudinal vibration transducer, a surface wave type transducer, or a non-linear resonance type transducer. The technical purpose of applying a target excitation signal to the ultrasonic transducer is to detect whether the welding bonding head contacts the welding position, rather than to perform welding processing on the welding bonding head. Therefore, the target excitation signal can be a low-power excitation signal. For example, the power of the target excitation signal can be between 1% and 5% of the welding power. For example, taking the welding power of the wire bonder as 50W as an example and calculating according to a ratio of 1%, the power of the target excitation signal can be 0.5W. In this embodiment, the specific power of the target excitation signal is not limited. It can be understood that applying a low-power target excitation signal to the ultrasonic transducer cannot cause the welding bonding head to produce a welding effect, but can achieve the contact detection of the welding bonding head.

[0027] In an alternative implementation, the excitation signal generating device in this embodiment can be an ultrasonic driver or a signal device composed of a low-power oscillator and an amplifier. When the excitation signal generating device in this embodiment is an ultrasonic driver, as one of the core components of the wire bonder, the method in this embodiment can be deployed on the wire bonder without modifying the wire bonder, which can effectively reduce the development cost of the wire bonder.

[0028] In an alternative implementation, when the excitation signal generating device in this embodiment outputs the target excitation signal, the PLL (phase-locked loop) can work simultaneously to lock the resonant frequency of the target excitation signal, thereby significantly improving the stability, accuracy, and anti-interference ability of the target excitation signal.

[0029] In an alternative implementation, the target excitation signal in this embodiment includes but is not limited to a constant frequency excitation signal and a frequency sweep excitation signal mode. The frequency of the target excitation signal can be set to be close to the resonant point of the ultrasonic transducer or scanned within a specific frequency range, which is beneficial to enhancing the sensitivity of the subsequent acquired first feedback signal. In addition, the target excitation signal in this embodiment can be any one of a continuous sine wave, a pulse train, a short-period burst signal, or a modulated waveform, which is beneficial to matching the response characteristics of different types of ultrasonic transducers. In this embodiment, the frequency, signal type, and waveform type of the target excitation signal are not limited.

[0030] In an alternative implementation, in this embodiment, after the excitation signal generating device is controlled to apply a target excitation signal to the ultrasonic transducer, the ultrasonic transducer will generate various response signals in response to the target excitation signal. The response signals include, but are not limited to, one or more of a voltage signal, a current signal, a phase signal, a resonant frequency, an impedance amplitude, a mutation slope (dφ / dt, df / dt), a multi-point fitting residual, a sliding window trend change, and power absorption. In this embodiment, the response signals are not limited.

[0031] S102: Control the bonding head driving mechanism to drive the welding bonding head to probe downward at a constant speed to the welding position, and continuously sample the response signals according to a preset time window during the constant-speed downward probing process to obtain a first feedback signal.

[0032] In an alternative implementation, in this embodiment, one or more of a voltage signal, a current signal, a phase signal, a resonant frequency, an impedance amplitude, and power absorption can be synchronously and continuously sampled. The more signals need to be sampled, the more first feedback signals are obtained. The more first feedback signals are obtained, the more contact detections need to be performed based on each first feedback signal respectively.

[0033] In an alternative implementation, in this embodiment, the response signals can be continuously sampled by a high-frequency sampling ADC, or signal features can be extracted from the response signals by using a digital phase-locked loop (PLL) or a phase detection module inside an existing driver to adapt to different hardware architectures of the ultrasonic transducer. In this embodiment, the method for sampling the response signals is not limited.

[0034] As an extension, in this embodiment, the acceleration, charge, and impact response at the moment when the welding bonding head makes contact can also be used as response signals. By integrating piezoelectric wafers or MEMS sensors on the ultrasonic transducer structure, the acceleration, charge, and impact response at the moment when the welding bonding head makes contact are detected, and the detected acceleration, charge, and impact response are used as the first feedback signal, and then the contact detection of the welding bonding head is performed based on the first feedback signal.

[0035] In an alternative implementation, in this embodiment, the bonding head driving mechanism includes, but is not limited to, any one of a motor and an encoder driving mechanism, a piezoelectric driving mechanism, a magnetic levitation driving mechanism, etc., as long as it has the ability to probe downward at a controlled constant speed. In this embodiment, the specific structure of the bonding head driving mechanism is not limited.

[0036] In an alternative implementation, the welding bonding head in this embodiment includes, but is not limited to, any one of a traditional ball bonding head, a wedge bonding head, a suspended bonding head, a dual transducer bonding head, and a composite structure bonding head for multi-wire welding, etc. In this embodiment, the specific structure of the welding bonding head is not limited.

[0037] In an alternative implementation, in this embodiment, the bonding head driving mechanism can be first controlled to drive the welding bonding head to move to the probing position, and then at the probing position, the bonding head driving mechanism is controlled to drive the welding bonding head to probe downward at a constant speed. During the constant-speed downward probing process, the response signal is continuously sampled according to a preset time window to obtain a first feedback signal. That is to say, a first feedback signal is sampled for each time window. Among them, the length of the time window can be 3 ms, 5 ms, 10 ms, etc., and the specific length of the time window is not limited in this embodiment.

[0038] For example, taking the length of the time window as 10 ms as an example, the response signal generated by the ultrasonic transducer from 1 to 10 ms is sampled according to the time window to obtain the first first feedback signal, and then the response signal generated by the ultrasonic transducer from 11 to 20 ms is sampled according to the time window to obtain the second first feedback signal, and so on. It is possible to continuously sample the response signal according to the preset time window to obtain the first feedback signal.

[0039] It should be noted that in this embodiment, after controlling the excitation signal generating device to apply the target excitation signal to the ultrasonic transducer, the response signal can be continuously sampled according to the preset time window to obtain the first feedback signal. It is not necessary to start sampling the response signal only when controlling the bonding head driving mechanism to drive the welding bonding head to probe downward at a constant speed to the welding position. The start time of sampling is not limited in this embodiment.

[0040] S103: Compare the first feedback signal with a pre-constructed reference line to determine whether the welding bonding head meets the contact condition.

[0041] In an alternative implementation, the reference line in this embodiment can be set manually. For example, the reference value corresponding to the reference line is input through the control page of the control system of the welding equipment, and then the corresponding reference line is generated based on the reference value. After obtaining the first feedback signal, the first feedback signal is compared with the pre-constructed reference line to determine whether the welding bonding head meets the contact condition. It should be noted that when multiple response signals are sampled simultaneously to obtain multiple first feedback signals, since the response signals sampled by different first feedback signals are different and there are significant differences between different first feedback signals, corresponding reference values and reference lines need to be set for each first feedback signal respectively.

[0042] In an alternative implementation, in this embodiment, before the bonding head contacts the welding position, the response signal can be sampled to obtain a second feedback signal for processing to construct a reference line. The methods for processing the second feedback signal include, but are not limited to, any one of an average filtering algorithm, a median filtering algorithm, or a sliding weighted algorithm. By using any one of the average filtering algorithm, the median filtering algorithm, or the sliding weighted algorithm to process the second feedback signal, a reference value corresponding to the second feedback signal is obtained, and then a reference line is constructed based on the reference value. For example, taking the average filtering as an example, by performing average filtering on the second feedback signal, the average value of the second feedback signal is obtained, and the straight line corresponding to the average value is determined as the reference line in the time-domain coordinate system. Among them, the second feedback signal is obtained by sampling the response signal of the ultrasonic transducer before the reference line is constructed, and the first feedback signal is obtained by sampling the response signal of the ultrasonic transducer after the reference line is constructed.

[0043] In a specific implementation, in this embodiment, the maximum amplitude and the minimum amplitude of the first feedback signal can be obtained, and then the differences between the maximum amplitude and the minimum amplitude and the reference value (such as the above-mentioned average value) of the reference line are calculated, and it is respectively determined whether the differences are greater than a preset difference threshold. When the difference is greater than the difference threshold, it is determined that the bonding head meets the contact condition.

[0044] As an extension, in this embodiment, a bonding head contact detection model can be pre-constructed, and the first feedback signal and the pre-constructed reference line are input into the bonding head contact detection model to obtain a bonding head contact detection result. Among them, in this embodiment, the feature vectors of signals such as phase signal, frequency signal, current signal, and power signal can be extracted from the first feedback signal, so that the bonding head contact detection model outputs a bonding head contact detection result based on the extracted feature vectors. Among them, the bonding head contact detection model includes, but is not limited to, any one of a decision tree model, a neural network model, or a support vector machine trained by a model.

[0045] It can be understood that in this embodiment, a corresponding bonding head contact detection model can be constructed for each first feedback signal respectively, and the bonding head contact detection results corresponding to each first feedback signal are obtained respectively, and then based on all the bonding head contact detection results, the final result is determined. For example, if all the bonding head contact detection results indicate that the bonding head contacts the welding position, then it is determined that the bonding head contacts the welding position, or if any one of the bonding head contact detection results indicates that the bonding head contacts the welding position, then it is determined that the bonding head contacts the welding position, or if the number of bonding head contact detection results indicating that the bonding head contacts the welding position exceeds a preset number, then it is determined that the bonding head contacts the welding position. No specific limitation is made in this embodiment.

[0046] S104: If the bonding head satisfies the contact condition, determine that the bonding head contacts the welding position.

[0047] If the bonding head satisfies the contact condition, determine that the bonding head contacts the welding position; if the bonding head does not satisfy the contact condition, it indicates that the bonding head has not yet contacted the welding position. Therefore, it is necessary to detect the continuously acquired first feedback signal, that is, return to execute the step of controlling the bonding head driving mechanism to drive the bonding head to probe downwards at a constant speed towards the welding position, and continuously sample the response signal according to a preset time window during the constant-speed downward probing process to obtain the first feedback signal. That is to say, return to execute step S102 and subsequent steps.

[0048] In a specific implementation, in this embodiment, the above control processes of steps S101 - S105 can be implemented by the main control processor of the welding device, where the main control processor includes, but is not limited to, any one of a digital signal processor (DSP), a field programmable gate array FPGA, a microcontroller unit MCU, or a system-on-chip SoC platform, etc. When determining that the bonding head contacts the welding position, the excitation signal generating device stops applying the target excitation signal to the ultrasonic transducer. That is to say, as long as it is in the contact detection stage, the excitation signal generating device will apply the target excitation signal to the ultrasonic transducer for contact detection. Then, the main control processor can control the ultrasonic driver to drive the bonding head to perform welding processing on the welding position (such as the inner lead of the semiconductor device placed at the welding position).

[0049] It should be noted that when sampling multiple response signals simultaneously to obtain multiple first feedback signals, it is necessary to perform contact detection based on each first feedback signal and the corresponding reference line respectively. When it is determined that the bonding head satisfies the contact condition based on any one of the first feedback signals, determine that the bonding head contacts the welding position, or when the number of first feedback signals based on which it is determined that the bonding head satisfies the contact condition reaches a preset number, determine that the bonding head contacts the welding position, or when it is determined that the bonding head satisfies the contact condition based on all the first feedback signals, determine that the bonding head contacts the welding position. In this embodiment, when sampling multiple first feedback signals, the specific method for determining whether the bonding head contacts the welding position is not limited.

[0050] In summary, the embodiment of the present invention provides a method for detecting the contact of a bonding head. By controlling the excitation signal generating device to apply a target excitation signal to the ultrasonic transducer, a response signal generated by the ultrasonic transducer in response to the target excitation signal is obtained; controlling the bonding head driving mechanism to drive the bonding head to descend uniformly towards the welding position, and continuously sampling the response signal according to a preset time window during the uniform descent to obtain a first feedback signal; comparing the first feedback signal with a pre-constructed reference line to determine whether the bonding head meets the contact condition; if the bonding head meets the contact condition, it is determined that the bonding head contacts the welding position; if the bonding head does not meet the contact condition, return to execute the step of controlling the bonding head driving mechanism to drive the bonding head to descend uniformly towards the welding position, and sampling the response signal according to a preset time window during the uniform descent to obtain a first feedback signal. It can be seen that the present invention applies a target excitation signal to the ultrasonic transducer to sample the response signal generated by the ultrasonic transducer in response to the target excitation signal to obtain a first feedback signal, and then determines whether the bonding head contacts the welding position based on the first feedback signal. Compared with the prior art's contact detection method based on an encoder, the first feedback signal does not need to be transmitted between multiple mechanical mechanisms, which can effectively shorten the time to obtain the first feedback signal, and then quickly make a judgment on whether the bonding head contacts the welding position based on the first feedback signal, achieving the purpose of reducing the detection delay.

[0051] In one embodiment, as Figure 2 shown, step S103 in the above embodiment can be implemented by the following steps: S201: Obtain the maximum amplitude and the minimum amplitude of the first feedback signal, and the reference value corresponding to the reference line.

[0052] S202: Calculate the first difference between the maximum amplitude and the reference value, and the second difference between the minimum amplitude and the reference value.

[0053] S203: Respectively determine whether the first difference and the second difference are greater than a preset difference threshold.

[0054] If the first difference and / or the second difference is greater than the difference threshold, it is determined that the bonding head meets the contact condition.

[0055] Among them, the maximum amplitude and the minimum amplitude are used to reflect the severity of the fluctuation of the first feedback signal. The larger the maximum amplitude, the more severe the upward fluctuation of the first feedback signal, and the smaller the minimum amplitude, the more severe the downward fluctuation of the first feedback signal.

[0056] It can be understood that when the welding bonding head contacts the welding position, the first feedback signal may fluctuate violently upward, or downward, or move violently both downward and upward simultaneously. Therefore, it is necessary to obtain the maximum amplitude and the minimum amplitude of the first feedback signal to determine whether the welding bonding head meets the contact condition based on the first feedback signal in two directions.

[0057] In summary, in this embodiment, by obtaining the maximum amplitude and the minimum amplitude of the first feedback signal to determine whether the welding bonding head meets the contact condition in two directions, it can effectively adapt to the first feedback signal sampled from different response signals of the ultrasonic transducer. That is to say, no matter which response signal is selected for sampling to obtain the first feedback signal during sampling, it can be realized to judge whether the welding bonding head meets the contact condition, improving the applicability of the contact detection method in this application.

[0058] In one embodiment, as Figure 3 shown, the first feedback signal includes a main signal and an auxiliary signal, and the reference line includes a main reference line and an auxiliary reference line. On this basis, step S103 in this embodiment can be implemented through the following steps: S301: Compare the main signal with the main reference line to determine whether the welding bonding head meets the candidate condition.

[0059] S302: If the welding bonding head meets the candidate condition, compare the auxiliary signal with the auxiliary reference line to determine whether the welding bonding head meets the contact condition.

[0060] If the welding bonding head does not meet the candidate condition, return to execute the step of controlling the bonding head driving mechanism to drive the welding bonding head to probe downward uniformly towards the welding position, and continuously sample the response signal according to a preset first time window during the uniform downward probing process to obtain the first feedback signal.

[0061] It can be understood that in this embodiment, different first feedback signals are divided into a main signal and an auxiliary signal. For example, taking the corresponding signal including a frequency signal and a current signal as an example, sample the frequency signal and the current signal respectively according to a preset time window to obtain the first feedback signal corresponding to the frequency signal and the first feedback signal corresponding to the current signal, use the first feedback signal corresponding to the frequency signal as the main signal, and use the first feedback signal corresponding to the current signal as the auxiliary signal.

[0062] In a specific implementation, in this embodiment, the judgment of whether the welding bonding head meets the contact condition is based on the main signal and the auxiliary signal respectively. Among them, the judgment of whether the welding bonding head meets the candidate condition is preferably based on the main signal and the main reference line. If the welding bonding head does not meet the candidate condition, there is no need to judge whether the welding bonding head meets the contact condition based on the auxiliary signal and the auxiliary reference line, and re-judge whether the welding bonding head meets the candidate condition based on the newly obtained first feedback signal, that is, return to execute the step of controlling the bonding head driving mechanism to drive the welding bonding head to descend uniformly towards the welding position, and continuously sample the response signal according to a preset first time window during the uniform descent to obtain the first feedback signal. If the welding bonding head meets the candidate condition, further judge whether the welding bonding head meets the contact condition based on the auxiliary signal and the auxiliary reference line.

[0063] In summary, in this embodiment, the double judgment is used to determine whether the welding bonding head meets the contact condition, avoiding the situation of misjudgment caused by the accidental triggering of a single condition, which is beneficial to improving the robustness and versatility of the contact detection method in this embodiment. At the same time, by setting the main signal and the auxiliary signal, it is avoided to detect the contact of the welding bonding head based on all the first feedback signals each time, reducing the load of the computing power resources of the welding equipment and being beneficial to improving the stability of the welding equipment.

[0064] In one embodiment, as Figure 4 shown, step S103 in this embodiment can also be implemented through the following steps: S401: Construct a trigger line according to a preset trigger threshold and reference line.

[0065] In a specific implementation, in this embodiment, the trigger line can be constructed by moving the baseline upward and / or downward according to the trigger threshold. It can be understood that by moving the baseline upward according to the trigger threshold, a trigger line is constructed, or by moving the baseline downward according to the trigger threshold, a trigger line is constructed, or by moving the baseline upward and downward respectively according to the trigger threshold, two trigger lines are constructed. In this embodiment, the trigger line can be constructed upward and / or downward according to actual needs, and this embodiment does not make a limitation. As Figure 5 shown, where a and b are two trigger lines respectively, and c is the reference line.

[0066] S402: Judge whether the first feedback signal exceeds the trigger line during the rising and / or falling process.

[0067] If the first feedback signal exceeds the trigger line during the rising and / or falling process, it is determined that the welding bonding head meets the contact condition; if the first feedback signal does not exceed the trigger line during the rising and / or falling process, return to execute the step of controlling the bonding head driving mechanism to drive the welding bonding head to probe downwards at a constant speed towards the welding position, and continuously sample the response signal according to a preset first time window during the constant-speed downward probing process to obtain the first feedback signal.

[0068] It can be understood that if the first feedback signal exceeds the trigger line during the rising and / or falling process, it is determined that the welding bonding head meets the contact condition; if the first feedback signal does not exceed the trigger line during the rising and / or falling process, it is determined that the welding bonding head does not meet the contact condition, and then a new contact determination is made based on the sampled new first feedback signal, that is, return to execute the step of controlling the bonding head driving mechanism to drive the welding bonding head to probe downwards at a constant speed towards the welding position, and continuously sample the response signal according to a preset first time window during the constant-speed downward probing process to obtain the first feedback signal.

[0069] In one embodiment, as Figure 6 shown, after the first feedback signal in this embodiment exceeds the trigger line during the rising and / or falling process and before it is determined that the welding bonding head meets the contact condition, the following steps may further be included: S601: Determine whether the duration for which the first feedback signal continuously exceeds the trigger line exceeds a preset first duration.

[0070] If the duration for which the first feedback signal continuously exceeds the trigger line exceeds the preset first duration, it is determined that the welding bonding head meets the contact condition.

[0071] If the duration for which the first feedback signal continuously exceeds the trigger line does not exceed the preset first duration, return to execute the step of controlling the bonding head driving mechanism to drive the welding bonding head to probe downwards at a constant speed towards the welding position, and continuously sample the response signal according to a preset first time window during the constant-speed downward probing process to obtain the first feedback signal.

[0072] It can be understood that when the first feedback signal exceeds the trigger line, if the duration for which the first feedback signal continuously exceeds the trigger line does not exceed the preset first duration, it indicates that the first feedback signal exceeding the trigger line may be caused by accidental noise interference or accidental spike interference, etc. At this time, it is considered that the welding bonding head does not yet meet the contact condition; if the duration for which the first feedback signal continuously exceeds the trigger line exceeds the preset first duration, the influence of noise interference or spike interference is excluded, and it is determined that the welding bonding head meets the contact condition.

[0073] In summary, in this embodiment, by determining whether the duration for which the first feedback signal continuously exceeds the trigger line exceeds the preset first duration, the influence of accidental noise interference or accidental spike interference, etc. on the contact detection of the welding bonding head is excluded, which is beneficial to improving the detection accuracy.

[0074] In one embodiment, as Figure 7 shown, the trigger thresholds in this embodiment include a first trigger threshold and a second trigger threshold, and the first trigger threshold is less than the second trigger threshold. On this basis, step S401 in the above embodiment can be implemented through the following steps: S701: Construct a first trigger line based on the first trigger threshold and the reference line.

[0075] S702: Construct a second trigger line based on the second trigger threshold and the reference line.

[0076] It can be understood that when the trigger thresholds include a first trigger threshold and a second trigger threshold, a trigger line can be constructed based on the first trigger threshold and the reference line, and another trigger line can be constructed based on the second trigger threshold and the reference line, that is, the first trigger line and the second reference line.

[0077] Specifically, in this embodiment, the reference line can be first moved upward and / or downward based on the first trigger threshold to construct the first trigger line; then the reference line can be moved upward and / or downward based on the second trigger threshold to construct the second trigger line, where the starting positions of the above two reference lines for movement are both the initial positions, that is, the construction of the first trigger line and the second trigger line are carried out separately, and the two construction processes do not affect each other.

[0078] On this basis, as Figure 8 shown, step S402 in the above embodiment can be implemented through the following steps: S801: Determine whether the first feedback signal continuously exceeds the first trigger line and the second trigger line during the rising and / or falling process; S802: If the first feedback signal continuously exceeds the first trigger line and the second trigger line during the rising and / or falling process, determine whether the duration for which the first feedback signal continuously exceeds the first trigger line exceeds a preset second duration.

[0079] If the duration for which the first feedback signal continuously exceeds the first trigger line exceeds the second duration, it is determined that the welding bonding head meets the contact condition.

[0080] If the duration for which the first feedback signal continuously exceeds the first trigger line does not exceed the second duration, return to execute the step of controlling the bonding head driving mechanism to drive the welding bonding head to uniformly probe downward to the welding position, and continuously sample the response signal according to a preset first time window during the uniform downward probing process to obtain the first feedback signal.

[0081] It can be understood that during the rising and / or falling process of the first feedback signal, only when it continuously exceeds the first trigger line and the second trigger line is it considered that the welding bonding head meets the candidate conditions. Then, it is determined whether the duration for which the first feedback signal continuously exceeds the first trigger line exceeds a preset second duration. That is to say, after the first feedback signal continuously exceeds the first trigger line and the second trigger line, without the first feedback signal continuously exceeding the second trigger line, as long as the duration for which the first feedback signal continuously exceeds the first trigger line exceeds the preset second duration, it can be determined that the welding bonding head meets the contact conditions; if the first feedback signal does not continuously exceed the first trigger line and the second trigger line, or the duration for which the first feedback signal continuously exceeds the first trigger line does not exceed the preset second duration, it is necessary to re-obtain the first feedback signal and re-perform contact detection based on the first feedback signal, that is, return to execute the step of controlling the bonding head driving mechanism to drive the welding bonding head to descend uniformly towards the welding position, and continuously sample the response signal according to a preset first time window during the uniform descent to obtain the first feedback signal.

[0082] In summary, in this embodiment, by setting high and low double trigger lines within a preset time window, it is possible to avoid repeated triggering of the first feedback signal at the trigger line boundary. At the same time, by determining whether the duration for which the first feedback signal continuously exceeds the first trigger line exceeds a preset first duration, it is possible to exclude the influence of accidental noise interference or accidental spike interference and other reasons on the contact detection of the welding bonding head, which is beneficial to improving the detection accuracy.

[0083] In one embodiment, as Figure 9 shown, after step S101, the reference line in this embodiment is obtained in the following manner: S901: Sample the response signal according to a second time window to obtain a second feedback signal.

[0084] Among them, the second feedback signal is obtained by sampling the response signal of the ultrasonic transducer before constructing the reference line, and the first feedback signal is obtained by sampling the response signal of the ultrasonic transducer after constructing the reference line.

[0085] S902: Process the second feedback signal according to a preset signal processing algorithm to obtain the reference line.

[0086] Among them, the length of the second time window may be the same as or different from the length of the first time window, which is not limited in this embodiment.

[0087] Specifically, the signal processing algorithm in this embodiment includes, but is not limited to, any one of an average filtering algorithm, a median filtering algorithm, or a sliding weighted algorithm. Based on the signal processing algorithm, the second feedback signal is processed to obtain a reference value corresponding to the second feedback signal, and then the reference line is constructed based on the reference value.

[0088] In summary, in this embodiment, a reference line is constructed based on the feedback signal. Compared with the artificially set reference line, it can ensure that the reference line is representative and robust to occasional interference. At the same time, whether the bonding head contacts the welding position is detected in real time on this reference line, which can avoid false triggering or missed judgment caused by differences in material reflectivity, transducer response fluctuations, or process parameter changes. This mechanism supports the normalization processing of feedback parameters and the adaptive adjustment of the judgment window, and has high versatility and automated deployment capabilities, and can be adapted to different materials, different welding structures, and various types of ultrasonic transducers.

[0089] It should be understood that the magnitudes of the sequence numbers of the steps in the above embodiments do not mean the order of execution. The order of execution of each process should be determined by its function and internal logic, and should not constitute any limitation to the implementation process of the embodiments of the present invention.

[0090] In one embodiment, a contact detection device is provided, as Figure 10 shown, which includes a processor and the excitation signal generating device, ultrasonic transducer, bonding head driving mechanism, and welding bonding head described in any of the above embodiments. The processor controls the excitation signal generating device, ultrasonic transducer, bonding head driving mechanism, and welding bonding head to implement the welding bonding head contact detection method described in any of the above embodiments. For example Figure 1 the welding bonding head contact detection method shown, or Figures 2 to 8 shown in, to avoid repetition, it will not be elaborated here.

[0091] In one embodiment, a welding device is provided, and this welding device includes the contact detection device described in the above embodiment.

[0092] The above-described embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: they can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements on some of the technical features; and these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention, and should all be included in the protection scope of the present invention.

Claims

1. A method for detecting the contact of a soldering head, characterized in that, Including: Controlling the excitation signal generating device to apply a target excitation signal to the ultrasonic transducer, and obtaining a response signal generated by the ultrasonic transducer in response to the target excitation signal; Controlling the bonding head driving mechanism to drive the welding bonding head to descend uniformly towards the welding position, and continuously sampling the response signal according to a preset first time window during the uniform descent to obtain a first feedback signal; Comparing the first feedback signal with a pre-constructed reference line to determine whether the welding bonding head meets the contact condition; If the welding bonding head meets the contact condition, determining that the welding bonding head contacts the welding position; If the welding bonding head does not meet the contact condition, return to execute the step of controlling the bonding head driving mechanism to drive the welding bonding head to descend uniformly towards the welding position, and continuously sampling the response signal according to a preset first time window during the uniform descent to obtain a first feedback signal.

2. The welding bond head contact detection method according to claim 1, wherein After controlling the excitation signal generating device to apply a target excitation signal to the ultrasonic transducer and obtaining a response signal generated by the ultrasonic transducer in response to the target excitation signal; The reference line is obtained by the following method: Sampling the response signal according to a second time window to obtain a second feedback signal; the second feedback signal is obtained by sampling the response signal of the ultrasonic transducer before constructing the reference line, and the first feedback signal is obtained by sampling the response signal of the ultrasonic transducer after constructing the reference line; Processing the second feedback signal according to a preset signal processing algorithm to obtain the reference line, and the signal processing algorithm includes an average filtering algorithm, a median filtering algorithm or a sliding weighted algorithm.

3. The welding bond head contact detection method according to claim 1, wherein Comparing the first feedback signal with a pre-constructed reference line to determine whether the welding bonding head meets the contact condition includes: Obtaining the maximum amplitude and the minimum amplitude of the first feedback signal, and the reference value corresponding to the reference line; Calculating a first difference between the maximum amplitude and the reference value, and a second difference between the minimum amplitude and the reference value; Respectively determining whether the first difference and the second difference are greater than a preset difference threshold; If the first difference and / or the second difference is greater than the difference threshold, determining that the welding bonding head meets the contact condition.

4. The welding bond head contact detection method according to claim 1, characterized in that, The first feedback signal includes a main signal and an auxiliary signal, and the reference line includes a main reference line and an auxiliary reference line; Comparing the first feedback signal with a pre-constructed reference line to determine whether the welding bonding head meets the contact condition includes: Comparing the main signal with the main reference line to determine whether the welding bonding head meets the candidate condition; If the welding bonding head meets the candidate condition, comparing the auxiliary signal with the auxiliary reference line to determine whether the welding bonding head meets the contact condition; If the welding bonding head does not meet the candidate condition, return to execute the step of controlling the bonding head driving mechanism to drive the welding bonding head to descend uniformly towards the welding position, and continuously sampling the response signal according to a preset first time window during the uniform descent to obtain a first feedback signal.

5. The welding bonding head contact detection method according to claim 1, characterized in that, Compare the first feedback signal with a pre-constructed reference line to determine whether the welding bonding head meets the contact condition, including: Construct a trigger line according to a preset trigger threshold and the reference line; Determine whether the first feedback signal exceeds the trigger line during the rising and / or falling process; If the first feedback signal exceeds the trigger line during the rising and / or falling process, determine that the welding bonding head meets the contact condition; If the first feedback signal does not exceed the trigger line during the rising and / or falling process, return to execute the step of controlling the bonding head driving mechanism to drive the welding bonding head to probe downwards at a constant speed towards the welding position, and continuously sample the response signal according to a preset first time window during the constant-speed downward probing process to obtain the first feedback signal.

6. The welding bond head contact detection method according to claim 5, wherein After the first feedback signal exceeds the trigger line during the rising and / or falling process and before determining that the welding bonding head meets the contact condition, it further includes: Determine whether the duration for which the first feedback signal continuously exceeds the trigger line exceeds a preset first duration; If the duration for which the first feedback signal continuously exceeds the trigger line exceeds the preset first duration, determine that the welding bonding head meets the contact condition; If the duration for which the first feedback signal continuously exceeds the trigger line does not exceed the preset first duration, return to execute the step of controlling the bonding head driving mechanism to drive the welding bonding head to probe downwards at a constant speed towards the welding position, and continuously sample the response signal according to a preset first time window during the constant-speed downward probing process to obtain the first feedback signal.

7. The welding bond head contact detection method according to claim 5, wherein The trigger threshold includes a first trigger threshold and a second trigger threshold, and the first trigger threshold is less than the second trigger threshold; Constructing a trigger line according to a preset trigger threshold and the reference line includes: Construct a first trigger line based on the first trigger threshold and the reference line; Construct a second trigger line based on the second trigger threshold and the reference line.

8. The welding bond head contact detection method according to claim 7, characterized in that, Determining whether the first feedback signal exceeds the trigger line during the rising and / or falling process includes: Determine whether the first feedback signal continuously exceeds the first trigger line and the second trigger line during the rising and / or falling process; If the first feedback signal continuously exceeds the first trigger line and the second trigger line during the rising and / or falling process, determine whether the duration for which the first feedback signal continuously exceeds the first trigger line exceeds a preset second duration; If the duration for which the first feedback signal continuously exceeds the first trigger line exceeds the second duration, determine that the welding bonding head meets the contact condition; If the duration for which the first feedback signal continuously exceeds the first trigger line does not exceed the second duration, return to execute the step of controlling the bonding head driving mechanism to drive the welding bonding head to probe downwards at a constant speed towards the welding position, and continuously sample the response signal according to a preset first time window during the constant-speed downward probing process to obtain the first feedback signal.

9. A contact detection device, characterized in that, The contact detection device includes a processor, an excitation signal generating device, an ultrasonic transducer, a bonding head driving mechanism, and a welding bonding head according to any one of claims 1-8, and the processor controls the excitation signal generating device, the ultrasonic transducer, the bonding head driving mechanism, and the welding bonding head to implement the welding bonding head contact detection method according to any one of claims 1-8.

10. A welding device, characterized in that, The welding device includes the contact detection device according to claim 9 above.

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