Method for calculating the force for picking up a chip on a blue film

Abstract

The present application relates to the technical field of chip picking, and particularly relates to a force calculation method for picking up a chip on a blue film, which comprises the following steps: S1: calculating a maximum force output coefficient k max and a minimum force output coefficient k min of a motor; S2: setting an adjustment coefficient of the motor according to the maximum force output coefficient k max and the minimum force output coefficient k min of the motor; S3: adjusting a height h of a needle according to a requirement of a tested chip, recording a time for the chip to separate from the blue film under different force output coefficient values in the maximum force output coefficient k max and the minimum force output coefficient k min , and selecting a value with a short separation time and good repeatability as an optimal force output coefficient value k after multiple tests; and S4: calculating an optimal force value F 拾取 for the chip to separate from the blue film by using the optimal force output coefficient value k. The present application can test and calculate during a chip picking test process based on a normal mounting device, and can improve process efficiency and reliability of chip picking.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of chip picking, and particularly provides a force calculation method for picking up a chip on a blue film. BACKGROUND

[0002] Chip picking refers to picking up a chip from a wafer disc and safely and accurately transferring it to a circuit substrate for subsequent packaging process, which is a key step of electronic packaging and directly affects the production efficiency and cost of electronic packaging. Since the silicon-based chip is a brittle material and the chip is bonded to the blue film, chip fragmentation or back surface damage may occur during the actual picking and peeling process. Meanwhile, if the picking mechanism contacts the chip at too high a speed or with too large a picking force, the chip may be pressed too hard, causing the chip bottom to fragment at the contact position with the needle, which seriously affects the chip transfer efficiency and packaging process. Therefore, accurately controlling the output force of the picking mechanism and testing the optimal picking force value for separating the chip from the blue film are key to improving the chip packaging efficiency, and are of great significance to reducing packaging costs, improving product yield and improving device reliability.

[0003] Currently, the industry and academia mainly focus on testing the adhesive strength of the blue film in quantitative experimental research on chip picking process. This test is usually performed on a film peeling experimental platform. The peeling experimental test can achieve 90° and 180° peeling tests. The tested blue film and the adhered material are peeled in two directions in parallel, or peeled from the edge of the adhered material. However, the suction nozzle of the surface mount device directly picks up the chip vertically upward after sucking it. Therefore, the testing process and results of the two forces are not equivalent, and the process parameters cannot be fundamentally optimized. Moreover, the testing process is cumbersome.

[0004] With the advancement of technology, chip picking process experiments are optimized and improved by arranging force sensors above the picking head device, which can monitor the picking force in real time and guide the reliability of non-destructive chip peeling and vacuum picking process. However, this testing technology requires the installation of sensors on the mechanical device. In production and processing experiments, it is often unrealistic to install sensors on the surface mount device, which is expensive and has high complexity in experimental device modification.

[0005] In summary, the existing technology mainly tests the adhesive strength between the blue film and the chip through film peeling experimental testing. The results of this experimental test often cannot fully represent the chip picking force of the surface mount device, and the process cannot be designed and optimized from the process perspective. Therefore, how to design a method that can represent the chip picking force of the surface mount device to improve the process efficiency and reliability of chip picking is a pressing problem. SUMMARY

[0006] To address the aforementioned problems, this invention provides a force calculation method for picking up chips on a blue film. This method is applicable to the maximum force value test calculation for chips of different sizes separating from the blue film, which can improve the process efficiency and reliability of chip picking. At the same time, it can assist in stress simulation to complete the research on chip separation from the blue film.

[0007] The present invention provides a force calculation method for a pickup chip on a blue film, which specifically includes the following steps:

[0008] S1: Calculate the maximum force output coefficient k of the motor max and minimum force output coefficient k min ;

[0009] S2: The maximum force output coefficient of the motor, k max With minimum force output coefficient k min The adjustment coefficient of the motor is set based on the range.

[0010] S3: Adjust the ejector pin height h according to the requirements of the chip being tested, and record the maximum force output coefficient k. max With minimum force output coefficient k min The time it takes for the chip to separate from the blue film under different force output coefficient values ​​within the range was determined by conducting multiple tests, and the optimal force output coefficient value k was selected.

[0011] S4: Calculate the optimal force F for chip separation from the blue film using the optimal force output coefficient value k. 拾取 .

[0012] Furthermore, in S1, the contact between the ejector pin and the blue film is first set to a micro-contact state, that is, the ejector pin is set to the initial height of 0μm; then the maximum force output coefficient k of the motor is calculated. max and minimum force output coefficient k min .

[0013] Furthermore, when the motor force is insufficient to allow the nozzle to pick up the chip, the maximum force output coefficient k is calculated. max .

[0014] Furthermore, when the motor force is insufficient to lift the nozzle upwards, the minimum force output coefficient k is calculated. min .

[0015] Furthermore, the maximum force output coefficient k max The calculation formula is:

[0016] k max =(P 吸嘴 *S 吸嘴 -G 吸嘴 ) / F 电

[0017] Among them, P 吸嘴 S represents the vacuum negative pressure value of the suction nozzle.吸嘴 G is the gravity value of the suction nozzle 吸嘴 F is the force value provided by the motor 电 F is the force value provided by the motor

[0018] Further, the minimum force output coefficient k min is calculated by the formula:

[0019] k min = G 吸嘴 / F 电

[0020] G is the gravity value of the suction nozzle 吸嘴 F is the force value provided by the motor 电 F is the force value provided by the motor

[0021] Further, the optimal force value F 拾取 for separating the chip from the blue film in S4 is calculated by the formula:

[0022] F 拾取 = F 电 *k-G 吸嘴 -G 芯片

[0023] F is the force value provided by the motor 电 k is the optimal force output coefficient value of the motor 吸嘴 G is the gravity value of the suction nozzle 芯片 G is the gravity value of the chip

[0024] Further, in S3, a value with short separation time and good repeatability needs to be selected as the optimal force output coefficient value k.

[0025] Further, in S3, after adjusting the height h of the needle, 5-10 tests of separating the chip from the blue film are needed under the same force output coefficient value within the interval of the maximum force output coefficient k max and the minimum force output coefficient k min .

[0026] Further, in S3, when the same needle height h is used, different force output coefficient values within the interval of the maximum force output coefficient k max and the minimum force output coefficient k min are obtained, and the separation time of the chip from the blue film is the same and has high consistency, the average value of multiple force output coefficient values is taken and the optimal force output coefficient value k is selected.

[0027] Compared with the prior art, the present application has the following beneficial effects: the present application picks up the chip from the blue film through the suction nozzle, carries out multiple quantitative tests and pickup tests, establishes a simple and efficient maximum force test calculation method for separating different size chips from the blue film, which can improve the process efficiency and process reliability of chip pickup, can assist stress simulation to complete the research on chip separation from the blue film, solves the problem that the chip pickup of the surface mount device cannot be designed and optimized from the process point of view, and can be suitable for different size chips to calculate the motor output force coefficient and calculate the pickup force. BRIEF DESCRIPTION OF DRAWINGS

[0028] Fig. 1 is a schematic diagram of a preparation state of chip pickup according to an embodiment of the present application;

[0029] Fig. 2 is a schematic diagram of a completion state of chip pickup according to an embodiment of the present application;

[0030] Fig. 3 is a relationship diagram of the ejecting height of the ejector pin and the chip pickup tension according to an embodiment of the present application.

[0031] The reference signs therein include: chip 1, blue film 2, suction nozzle 3, ejector pin 4, ejector pin table 5. DETAILED DESCRIPTION

[0032] In the following, embodiments of the present application will be described with reference to the accompanying drawings. Figs. 1-3 Embodiments of the present application will be described below. In the following description, the same modules are denoted by the same reference signs. In the case of the same reference signs, their names and functions are also the same. Therefore, the detailed description thereof will not be repeated.

[0033] In order to make the objectives, technical solutions and advantages of the present application clearer, the present application will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and do not constitute a limitation on the present application. Figs. 1-3 In order to make the objectives, technical solutions and advantages of the present application clearer, the present application will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and do not constitute a limitation on the present application.

[0034] A force calculation method for picking up a chip on a blue film includes the following steps:

[0035] S1: Since the current of the motor and the force output therefrom present a linear relationship and act on the suction nozzle, first, the maximum force output coefficient k of the motor is calculated max and the minimum force output coefficient k min When the ejector pin is in a micro-contact state, the size of the force output by the motor can be adjusted.

[0036] First, the micro-contact state between the ejector pin 4 and the blue film 2 is set, i.e. Fig. 1As shown, the ejector pin 4 is set to be at the initial height of 0 μm, the current of the motor is set to be the maximum, and the maximum force output coefficient k of the motor is calculated max and the minimum force output coefficient k min of the motor are calculated. Wherein, the ejector pin 4 is arranged in the ejector pin platform 5.

[0037] S2: After the maximum and minimum coefficients of the motor are determined, the adjustment coefficient of the motor is set to be the interval of the coefficients, i.e. the maximum force output coefficient k max and the minimum force output coefficient k min of the motor are set as the adjustment coefficient of the motor. When the adjustment is to a certain value, the suction nozzle 4 is lifted up, but the chip 1 is not picked up, the force output by the motor can be just equal to the pressure of the suction nozzle 4 multiplied by the area minus the weight of the suction nozzle 4, at this time, the coefficient of the force is determined to be the maximum output coefficient k max .

[0038] Therefore, when the motor force cannot make the suction nozzle 3 suck the chip 1, the maximum force output coefficient k max is calculated. The calculation formula of the maximum force output coefficient k max is:

[0039] k max = (P 吸嘴 *S 吸嘴 -G 吸嘴 ) / F 电

[0040] Wherein, P 吸嘴 is the vacuum negative pressure value of the suction nozzle 3, S 吸嘴 is the contact area value of the suction nozzle 3, G 吸嘴 is the gravity value of the suction nozzle 3, and F 电 is the force value provided by the motor.

[0041] Combined with the gravity of the suction nozzle 4, when the adjustment is to a certain force coefficient value, the suction nozzle 4 cannot be lifted up, and the critical coefficient is taken as the minimum output coefficient, therefore, when the motor force cannot lift the suction nozzle 3 up, the minimum force output coefficient k min is calculated. The calculation formula of the minimum force output coefficient k min is:

[0042] k min =G 吸嘴 / F 电

[0043] Wherein, G 吸嘴 is the gravity value of the suction nozzle 3, and F 电 is the force value provided by the motor.

[0044] S3: The height h of the ejector pin 4 is adjusted according to the requirements of the tested chip 1, and the maximum force output coefficient k maxThe minimum force output coefficient k min The time of the chip 1 separating from the blue film 2 under different force output coefficient values in the interval, after multiple tests, the optimal force output coefficient value k is selected, and the value with shorter separation time and good repeatability is selected as the optimal force output coefficient value k.

[0045] Meanwhile, after adjusting the height h of the ejector pin 4, the maximum force output coefficient k max The minimum force output coefficient k min Under the same force output coefficient value in the interval, 5-10 tests of the chip 1 separating from the blue film 2 are required to avoid test errors and improve the accuracy of the test. For example, under the height h, the k1 value is tested 5-10 times, the separation time of the chip 1 from the blue film 2 and the stability of the separation time in 5-10 tests are obtained when the k1 value is taken, the k2 value is tested 5-10 times, the separation time of the chip 1 from the blue film 2 and the stability of the separation time in 5-10 tests are obtained when the k2 value is taken, and so on. More values in the interval can be taken, the separation time of the chip 1 from the blue film 2 and the stability of the separation time in 5-10 tests under the taken values are tested, and the optimal force output coefficient value k is selected.

[0046] When the maximum force output coefficient k max The minimum force output coefficient k min When the separation time of the chip 1 from the blue film 2 under different force output coefficient values in the interval is the same and the consistency is high, the average value under multiple force output coefficient values is taken and the optimal force output coefficient value k is selected to ensure that the test data is more accurate. For example, when the separation time is 0.01 seconds under the k1 value, the separation time is 0.01 seconds under the k2 value, the separation time is 0.01 seconds under the k3 value, and the separation time under more force output coefficient values in the interval is 0.01 seconds, and the consistency under each force output coefficient value is high, the average value is taken in each force output coefficient value, and the optimal force output coefficient value k is selected. For example Fig. 2 As shown in Fig. 2 is a state diagram of the completion of the pickup of the chip 1, Fig. 3 is a diagram of the relationship between the height h of the ejector pin 4 and the pickup force of the chip 1.

[0047] S4: The optimal force value F 拾取 of the chip 1 separating from the blue film 2 is calculated by using the optimal force output coefficient value k. 拾取 The calculation formula of the optimal force value F 拾取 of the chip 1 separating from the blue film 2 is:

[0048] F 电 = F 吸嘴 *k-G 芯片 -G

[0049] wherein, F电 G is a force value provided to the motor, k is an optimal force output coefficient value of the motor, G 吸嘴 G is a force value provided to the motor, k is an optimal force output coefficient value of the motor, G 芯片 G is a force value provided to the motor, k is an optimal force output coefficient value of the motor, G

[0050] Although the embodiments of the present application have been shown and described above, it should be understood that the above-described embodiments are exemplary and should not be construed as limiting the present application. Those skilled in the art can make various changes, modifications, replacements, and variations to the above-described embodiments within the scope of the present application.

[0051] The above detailed description of the present application is not intended to limit the scope of the present application. Various other corresponding changes and modifications according to the technical concept of the present application should be included in the scope of the claims of the present application.

Claims

1. A method of calculating a force for picking up a chip on a blue film, characterized by, The method comprises the following steps: S1: Calculate the maximum motor force output coefficient k max and the minimum force output coefficient k min ; In S1, the micro-contact state between the probe needle (4) and the blue film (2) is first set, that is, the probe needle (4) is set to an initial height of 0 μm; then the maximum motor force output coefficient k max and the minimum force output coefficient k min ; When the motor force cannot suck the chip (1) through the suction nozzle (3), the maximum force output coefficient k max ; When the motor force cannot lift the suction nozzle (3) upward, the minimum force output coefficient k min； Maximum force output coefficient k max The calculation formula is: k max = (P 吸嘴 * S 吸嘴 -G 吸嘴 ) / F 电 Wherein, P 吸嘴 is the vacuum negative pressure value of the suction nozzle (3), S 吸嘴 is the contact area value of the suction nozzle (3), G 吸嘴 is the gravity value of the suction nozzle (3), F 电 is the force value provided by the motor; Minimum force output coefficient k min The calculation formula is: k min =G 吸嘴 / F 电 wherein G 吸嘴 is the value of the weight force of the mouthpiece (3), F 电 is the value of the force provided by the motor; S2: with the maximum force output coefficient k of the motor max with the minimum force output coefficient k min The adjustment coefficient of the motor is set according to the interval S3: Adjust the height h of the ejector pin (4) according to the requirements of the tested chip (1), and record the maximum force output coefficient k max The minimum force output coefficient k min The time for the chip (1) to separate from the blue film (2) at different force output coefficient values within the interval, after multiple tests, the best force output coefficient value k is selected; S4: Calculate the optimal force value F for separating the chip (1) from the blue film (2) using the optimal force output coefficient value k 拾取 ; the calculation formula of the optimal force value F for separating the chip (1) from the blue film (2) in S4 is: 拾取 ​ F 拾取 =F 电 *k-G 吸嘴 -G 芯片 Wherein, F 电 The force value provided by the motor, k is the optimal force output coefficient value of the motor, G 吸嘴 The gravity value of the suction nozzle (3), G 芯片 The gravity value of the chip (1).

2. The force calculation method for the pickup chip on the blue film according to claim 1, characterized in that, In S3, a value with short separation time and good repeatability is selected as the optimal force output coefficient value k.

3. The force calculation method for the pickup chip on the blue film according to claim 2, characterized in that, S3, the height h of the ejector pin (4) is adjusted, and the maximum force output coefficient k max and the minimum force output coefficient k min The same force output coefficient value within the interval, the chip (1) from the blue film (2) is separated 5-10 times.

4. The force calculation method for the pickup chip on the blue film according to claim 3, characterized in that, S3 in the same height h, the maximum force output coefficient k max With the minimum force output coefficient k min The test chip (1) from the blue film (2) on the separation time is the same and the consistency is high, the average value of the force output coefficient value in the interval is taken and the best force output coefficient value k is selected.

Images