Lead bonding machine and BTO-Y direction compensation method thereof
By performing BTO-Y direction calibration on the wire bonding machine and fitting the first relationship curve, the problems of large workload and low bonding efficiency caused by operators' frequent detection of BTO-Y direction values are solved, and a more efficient bonding process is achieved.
Patent Information
- Application Number
- CN202510020878.X
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-01-07
- Publication Date
- 2025-04-15
AI Technical Summary
When measuring the BTO-Y direction value, existing wire bonding machines require frequent inspection by operators, resulting in large workload and low bonding efficiency.
By performing BTO-Y direction calibration on the wire bonding machine, the first relation curve is obtained, and the Y direction values of different height bonding points are quickly calculated during the production process, reducing the number of measurements by the operator.
It reduces the workload of operators, improves bonding efficiency, and reduces the need for frequent detection of BTO-Y numerical values.
Smart Images
Figure CN119833459A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the technical field of wire bonding machines, and in particular to a wire bonding machine and a BTO-Y direction compensation method thereof. Background Art
[0002] A wire bonder is a device that uses ultrasound, heat, and pressure to electrically connect metal wires to semiconductor chips and pins. It uses a transducer and a splitter to apply ultrasonic vibrations to the bonding point, forming a fusion on the chip or pin that contacts the metal wire, thereby achieving a firm electrical connection. For each bonding point, the wire bonder needs to use a visual system to identify and calculate the position. Since the ultrasonic transducer and the porcelain nozzle block the bonding point, the visual recognition light path needs to be moved to an unobstructed position for bonding point recognition. After identifying the position, the porcelain nozzle moves to this position for bonding.
[0003] The distance between the splitter and the optical path identification is called the Bond tip offset, hereinafter referred to as BTO, which is divided into X-direction and Y-direction. Due to the design of the mechanical structure of the wire bonder, the BTO-X-direction value is generally the same for bonding points of different heights, but the BTO-Y-direction value is inconsistent. This is because the Z-direction movement is approximately replaced by the rotational movement. In order to ensure the bonding accuracy, the BTO-Y-direction value needs to be measured once for each bonding height so that the porcelain nozzle can accurately move to the bonding point after the visual recognition system recognizes the bonding point.
[0004] However, the existing measurement method has the following defects: it takes about 5 seconds to manually measure the BTO-Y value once. For some chips with complex structures, there may be thirty or forty bonding points of different heights. The operator will establish a reference system for each bonding point of each height. This requires more time to measure the BTO-Y value. Moreover, measuring multiple BTO-Y values at one time increases the workload of the operator. The more times the BTO Y-value measurements are required, the more time is consumed, and the lower the bonding efficiency will be. Therefore, in response to the above problems, it is necessary to provide a wire bonding machine and a BTO-Y compensation method thereof to reduce the workload of the operator and improve the bonding efficiency. Summary of the invention
[0005] One object of the present application is to provide a wire bonding machine BTO-Y compensation method.
[0006] Another object of the present application is to provide a wire bonding machine.
[0007] To achieve the above objectives, the technical solution adopted in the present application is: a wire bonding machine BOT-Y compensation method for determining the Y-direction values of bonding points of different heights on a chip, characterized in that it includes the following steps: S1. Providing a wire bonding machine, performing BOT-Y calibration on it, obtaining multiple sets of initial bonding heights and corresponding initial Y-direction values, and obtaining a first relationship curve by fitting the initial bonding heights and the initial Y-direction values, wherein the X-axis of the first relationship curve is the bonding height, and the Y-axis is the Y-direction value; S2. Placing the chip to be processed on the wire bonding machine, obtaining the current bonding height of the chip and the corresponding current Y-direction value, taking the current bonding height as the X-axis coordinate and the current Y-direction value as the Y-axis coordinate, and translating the first relationship curve to obtain a second relationship curve, wherein the Y-direction values of bonding points of different heights of the chip are all determined by the second relationship curve.
[0008] As a preferred embodiment, in step S1, the method for performing BOT-Y calibration on the wire bonding machine is as follows: S11. Provide a lower pressure plate with a substrate, and movably set the lower pressure plate under the porcelain nozzle, wherein a visual system is located above the porcelain nozzle, and the visual system is used to identify the traces left by the porcelain nozzle on the substrate, and the distance moved by the visual system in the Y direction is the initial Y direction value; S12. Move the lower pressure plate along the height direction, and the distance moved by the lower pressure plate is the initial bonding height; S13. Move the porcelain nozzle so that the porcelain nozzle leaves a porcelain nozzle trace on the substrate; S14. Repeat steps S11, S12 and S13 to obtain multiple sets of initial bonding heights and corresponding initial Y direction values.
[0009] Further preferably, in step S12, the lower pressing plate is moved downward along the height direction.
[0010] Further preferably, in step S13, the porcelain nozzle is moved so that a nozzle mark left by the porcelain nozzle on the substrate does not overlap with an existing nozzle mark.
[0011] Further preferably, in step S14, steps S11, S12 and S13 are repeated no less than 15 times.
[0012] Further preferably, obtaining the first relationship curve comprises the following steps: the initial bonding height and the initial Y-direction value are fitted into the first relationship curve using the least square method.
[0013] Further preferably, the first relationship curve is an arc shape, and the expression is (x+a) 2 +(y+b) 2 =r 2 , a and b are the coordinates of the center of the first relationship curve, and r is the radius of the first relationship curve.
[0014] Further preferably, the value range of a is: 0.8662≤a≤0.8717; the value range of b is: 84.231≤b≤84.241.
[0015] Further preferably, the wire bonding machine performs a wire bonding machine BTO-Y direction compensation method.
[0016] Compared with the prior art, the beneficial effects of this application are:
[0017] For the same type of wire bonding machines, BTO-Y-direction calibration is completed before leaving the factory to provide a first relationship curve. When producing chips, it is only necessary to measure the current Y-direction value and the current bonding height once more, and then adjust the first relationship curve to obtain a second relationship curve. In the subsequent production process, it is only necessary to measure the bonding height to calculate the corresponding Y-direction value through the second relationship curve. There is no need for operators to frequently check the Y-direction value, which reduces the workload of operators and greatly improves the bonding efficiency. BRIEF DESCRIPTION OF THE DRAWINGS
[0018] Figure 1 It is a schematic diagram of the partial structure of a wire bonding machine;
[0019] Figure 2 is the fitting diagram of the wire bonding machine;
[0020] Figure 3 It is a schematic diagram of the first relationship curve.
[0021] In the figure: 1. Lower pressure plate; 2. Ceramic nozzle; 3. Substrate; 4. Bonding head; 5. Visual recognition system. DETAILED DESCRIPTION
[0022] Below, the present application is further described in conjunction with specific implementation methods. It should be noted that, under the premise of no conflict, the various embodiments or technical features described below can be arbitrarily combined to form new embodiments.
[0023] In the description of the present application, it should be noted that directional words, such as the terms "center", "lateral", "longitudinal", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", etc., indicating directions and positional relationships are based on the directions or positional relationships shown in the accompanying drawings, which are only for the convenience of narrating the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and cannot be understood as limiting the specific scope of protection of the present application.
[0024] It should be noted that the terms "first", "second", etc. in the description and claims of the present application are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence.
[0025] The terms "including" and "having" and any variations thereof in the specification and claims of this application are intended to cover non-exclusive inclusions. For example, a process, method, system, product or apparatus comprising a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to these processes, methods, products or apparatuses.
[0026] Wire bonding equipment is widely used in the process of semiconductor packaging. Through bonding, the chip is electrically connected to the external pins or packaging substrate. Figure 1 Part of the device of the wire bonding equipment is shown in the figure, including: a lower pressure plate 1, a porcelain nozzle 2, a substrate 3, a bonding head 4 and a visual recognition system 5, wherein the substrate 3 is fixed on the lower pressure plate 1, and the lower pressure plate 1 can move back and forth in the height direction. During the operation of the wire bonding equipment, the chip is first fixed on the substrate, and fine-tuned through the visual system to accurately connect the chip and the lead. In order to ensure the bonding accuracy, it is necessary to perform a Y-direction value detection for each bonding height during welding so that the porcelain nozzle can accurately find the bonding point. The Y-direction value detection is manually detected by the operator. When the chip structure is complex, there may be dozens of bonding points of different heights, which leads to a large workload for the operator, requires a lot of time for repetitive work, and has low bonding efficiency. Therefore, according to the above description, the application provides a wire bonding machine BTO-Y-direction compensation method to ensure the reliability of the Y-direction value and improve the bonding efficiency.
[0027] Before the wire bonding machine is delivered from the factory, the factory operator is required to perform a BTO-Y calibration on the equipment to be delivered. The specific operations are as follows: First, adjust the position of the lower pressure plate 1 so that the lower pressure plate 1 moves downward in the height direction. The distance moved by the lower pressure plate 1 is the bonding height. If the lower pressure plate 1 moves multiple times, multiple initial bonding heights will be generated.
[0028] During the movement of the lower pressure plate 1, the porcelain nozzle 2 is moved and repeated for multiple times so that the porcelain nozzle marks left by the porcelain nozzle 2 on the substrate 3 do not overlap. The moving direction of the porcelain nozzle 2 can be in the X direction or the Y direction, or it can move in the X direction and the Y direction at the same time, which is determined according to the operating habits of the calibration personnel. It only needs to satisfy the requirement that the porcelain nozzle marks do not overlap with the existing porcelain nozzle marks, and no limitation is made here.
[0029] The visual center of the visual system 5 coincides with the porcelain mouth mark, and the distance that the visual system 5 moves in the Y direction is the Y-direction value. Thus, multiple initial Y-direction values can be obtained, and each initial bonding height has an initial Y-direction value corresponding thereto. The above operation is repeated for multiple times, and the number of repetitions is not less than 15 times. The more bonding heights and Y-direction values are obtained, the more accurate the first relationship curve is. Through multiple experiments, the following Table 1 is obtained: Table 1. Correspondence between bonding height and Y-axis value
[0030] Then, according to the experimental data in Table 1, the experimental data are fitted by the least squares method, and the following can be obtained: Figure 3 For the first relationship curve shown in , since the unit lengths of the ordinate and the abscissa are different, the curvature of the first relationship curve is more obvious, which is convenient for operators to observe the shape of the curve.
[0031] The expression of the first relationship curve is (x+a) 2 +(y+b) 2 =r 2 , then, according to the above experimental data, it can be concluded that Figure 3 The expression of the first relationship curve shown in is (x+0.8667) 2 +(y+84.236) 2 =84.4713 2 .
[0032] For ease of understanding, draw Figure 1 However, for the convenience of observation, the fitting diagram is rotated counterclockwise with the rotation center of the porcelain nozzle 2 as the origin, and the result is shown in the figure. Figure 2 , the movement direction of the bonding head 4 is the Y direction, and the height direction is the Z direction. Since the value in the X direction does not change during the bonding process, the X direction is not considered here. Point O is the center point of the movement trajectory of the porcelain nozzle 2, A0 is the position of the porcelain nozzle tip when the porcelain nozzle 2 is perpendicular to the plane of the worktable. At this time, the plane where the porcelain nozzle tip is located is called the Flat Level plane, A1 is a certain position of the porcelain nozzle tip when the porcelain nozzle 2 moves, A1' is the projection of A1 on the FlatLevel plane, and V is the projection of the visual system in the Y direction. Horizontally to the left, the Y axis is positive, and horizontally to the right, the Y axis is negative. The reason for fitting the above experimental data into a circle by the least squares method is: Assuming that the distance of OV is m, OA1 is the radius R, the distance of A1A1' is x, and VA1' is y, the following expression can be obtained according to the triangle formula: (y+m) 2 +x 2 =R 2 .
[0033] In the movement range of the porcelain nozzle 2, when the lower pressure plate 1 moves, the position of the porcelain nozzle 2 falls on the circumference of the circle. Therefore, the above experimental data can be fitted into a circle. According to the mechanical structure of the wire bonding machine, the visual system 5 can only move above the substrate 3. Therefore, the position of the porcelain nozzle 2 falls on the lower half of the circumference. Therefore, the lower half of the circumference is intercepted as the first relationship curve. After rotating the fitting graph counterclockwise, the following is obtained. Figure 2 .
[0034] Through experimental data and drawing results, such as Figure 2 As shown, within the range of movement of the porcelain nozzle 2, the y value falls on the upper half of the circle, so the first relationship curve is the upper half of the circle. Figure 3 A partial image of the first relationship curve is shown in FIG.
[0035] After obtaining the first relationship curve, when producing chips, the chip processing factory only needs to measure a certain reference system of the chip to obtain the current Y-axis value and the corresponding current bonding height. Through experiments, a set of experimental data was obtained: when the current bonding height is -0.97, the corresponding current Y-axis value is 0.240.
[0036] Among them, during the chip production process, the chip has multiple reference systems, such as chip reference system, substrate reference system, pad reference system, wire bonding reference system, part or component reference system and machine reference system, etc. Therefore, when measuring the chip, any reference system can be selected without limitation here.
[0037] After obtaining the current bonding height and the current Y-direction value, the first relationship curve is adjusted to obtain the second relationship curve. The specific operation is as follows: the current bonding height and the current Y-direction value are expressed as (-0.97, 0.240) in the coordinate system, and the first relationship curve is translated in the vertical direction so that the newly obtained second relationship curve can pass through the point (-0.97, 0.240).
[0038] Substitute the point (-0.97, 0.240) into the expression of the first relationship curve (x+0.8667) 2 +(y+84.236) 2 =84.4713 2 It can be concluded that on the first relationship curve, when x=-0.97, the corresponding y value is 0.235, and further it can be concluded that the vertical translation of the first relationship curve is the difference between 0.240 and 0.235. Then, the first relationship curve is translated upward by 0.005 units in the vertical direction to obtain the second relationship curve.
[0039] From the above analysis, we can know that the expression of the second relationship curve is: (x+0.8667)2 +(y+84.231) 2 =84.4713 2 In the subsequent chip production process, it is only necessary to substitute the bonding height into the expression of the second curve relationship to calculate the corresponding BTO-Y value. The operator does not need to repeatedly detect the corresponding BTO-Y value for different reference systems, which greatly reduces the workload of the operator and greatly improves the bonding efficiency of the wire bonder.
[0040] The wire bonding device provided in the present application implements the above-mentioned BTO-Y compensation method, and thus has all the beneficial effects of any of the above-mentioned technical solutions, which will not be repeated here.
[0041] The above describes the basic principles, main features and advantages of the present application. Those skilled in the art should understand that the present application is not limited by the above embodiments, and the above embodiments and the specification only describe the principles of the present application. The present application may have various changes and improvements without departing from the spirit and scope of the present application, and these changes and improvements fall within the scope of the present application for which protection is sought. The scope of protection claimed by the present application is defined by the attached claims and their equivalents.
Claims
1. A wire bonder BTO-Y compensation method, used to determine the Y-direction values of bonding points of different heights on a chip, characterized in that: The steps include: S1. Provide a wire bonding machine, perform BOT-Y calibration on it, obtain multiple sets of initial bonding heights and corresponding initial Y-direction values, and obtain a first relationship curve according to the initial bonding heights and the initial Y-direction values, wherein the X-axis of the first relationship curve is the bonding height, and the Y-axis is the Y-direction value; S2. Place the chip to be processed on the wire bonding machine, obtain the current bonding height of the chip and the corresponding current Y-axis value, take the current bonding height as the X-axis coordinate, and the current Y-axis value as the Y-axis coordinate, translate the first relationship curve to obtain the second relationship curve, and the Y-axis values of the bonding points at different heights of the chip are determined by the second relationship curve.
2. The wire bonding machine BOT-Y compensation method according to claim 1, wherein in step S1, the method for performing BOT-Y calibration on the wire bonding machine is: S11. A lower pressing plate provided with a substrate is provided, and the lower pressing plate is movably arranged below the porcelain nozzle, wherein a visual system is located above the porcelain nozzle, and the visual system is used to identify the traces left by the porcelain nozzle on the substrate, and the distance moved by the visual system in the Y direction is the initial Y direction value; S12. Moving the lower pressing plate in the height direction, the distance the lower pressing plate moves is the initial bonding height; S13. Move the porcelain nozzle so that the porcelain nozzle leaves a trace of the porcelain nozzle on the substrate; S14. Repeat steps S11, S12 and S13 to obtain multiple sets of the initial bonding heights and the corresponding initial Y-direction values.
3. The wire bonding machine BTO-Y compensation method according to claim 2, characterized in that: In step S12, the lower pressing plate is moved downward along the height direction.
4. The wire bonding machine BTO-Y compensation method according to claim 2, characterized in that: In step S13, the porcelain nozzle is moved so that the porcelain nozzle leaves a porcelain nozzle mark on the substrate which does not overlap with the existing porcelain nozzle mark.
5. The wire bonding machine BTO-Y compensation method according to claim 2, characterized in that: In step S14, steps S11, S12 and S13 are repeated no less than 15 times.
6. The wire bonding machine BTO-Y compensation method according to claim 1, characterized in that: The method for obtaining the first relationship curve includes the following steps: the initial bonding height and the initial Y-direction value are fitted into the first relationship curve using the least square method.
7. The wire bonding machine BTO-Y compensation method according to claim 1, characterized in that: The first relationship curve is an arc shape, and the expression is (x+a) 2 +(y+b) 2 =r 2 , a and b are the coordinates of the center of the first relationship curve, and r is the radius of the first relationship curve.
8. The wire bonding machine BTO-Y compensation method according to claim 6, characterized in that: The value range of a is: 0.8662≤a≤0.8717; the value range of b is: 84.231≤b≤84.
241.
9. A wire bonding machine, characterized in that: The wire bonding machine performs the wire bonding machine BTO-Y compensation method according to any one of claims 1 to 8.