Force calculation method for picking up chip on blue film

Abstract

The invention relates to the technical field of chip picking, in particular to a force calculation method for picking a chip on a blue film, which comprises the following steps: S1, calculating the maximum force output coefficient kmax and the minimum force output coefficient kmin of a motor; s2, setting an adjustment coefficient of the motor by taking an interval between the maximum force output coefficient kmax and the minimum force output coefficient kmin of the motor as a criterion; s3, adjusting the height h of the ejector pin according to the requirement of the tested chip, recording the time of separating the chip from the blue film under different force output coefficient values in the interval of the maximum force output coefficient kmax and the minimum force output coefficient kmin, and after multiple tests, selecting a value with short separation time and good repeatability as an optimal force output coefficient value k; and S4, calculating the optimal force value F pickup of the chip separated from the blue film by adopting the optimal force output coefficient value k. According to the scheme, the chip pickup test process can be tested and calculated on the basis of the normal chip mounting equipment, and the chip pickup process efficiency and reliability can be improved.

Description

Technical Field

[0001] The invention relates to the technical field of chip picking, and in particular provides a force calculation method for picking up a chip on a blue film. Background Art

[0002] Chip picking refers to the process of picking up the chip from the wafer and transferring it safely and accurately to the circuit substrate for the subsequent packaging process. This process is a key step in electronic packaging and directly affects the production efficiency and production cost of electronic packaging. Since silicon-based chips are brittle materials and the chips are bonded to the blue film, it is easy for the chip to break or the back to be damaged during the actual picking and peeling process. At the same time, if the picking mechanism contacts the chip too fast and the picking force is too large, it is easy to over-press the chip, causing the bottom of the chip to break at the contact point with the ejector pin, seriously affecting 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 the key to improving chip packaging efficiency, which is of great significance for reducing packaging costs, increasing product yields and improving device reliability.

[0003] At present, the quantitative experimental research on chip picking process in the industry and academia mainly focuses on the bonding strength test of blue film. This test is usually carried out through a film peeling test platform. The peeling test can realize 90° and 180° peeling test. The blue film tested is peeled in two directions parallel to the bonded material, or peeled from the edge of one bonded material. After the nozzle of the upright mounting equipment sucks the chip, it directly picks it up vertically. Therefore, the test process and results of these two forces are not equivalent, and it is impossible to fundamentally optimize the process parameters, and the test process is more troublesome.

[0004] With the advancement of technology, the chip picking process experiment has been optimized and improved on the original basis. A force sensor is arranged above the pick-up head device, which can monitor the size of the pick-up force in real time and guide the reliability of the non-destructive chip peeling and vacuum pick-up process. However, this test technology solution requires the installation of sensors on the mechanical device. In the production and processing process experiment, it is often unrealistic to install sensors on the positive mounting equipment, and it is expensive and the complexity of the experimental device modification is high.

[0005] In summary, the existing technology mainly tests the bonding strength between the blue film and the chip through a film peeling experiment. The results of this experimental test often cannot fully characterize the chip picking force of the face-mounted SMT equipment, and cannot be optimized from a process perspective. Therefore, how to design a method that can characterize the chip picking force of the face-mounted SMT equipment to improve the process efficiency and reliability of chip picking is a problem that needs to be solved urgently. Summary of the invention

[0006] In order to solve the above problems, the present invention provides a force calculation method for picking up chips on a blue film, which can be applied to the maximum force test calculation of chips of different sizes separated from the blue film, can improve the process efficiency and reliability of chip picking, and can also assist stress simulation to complete the research on chip separation from the blue film.

[0007] The present invention provides a method for calculating the force of picking up a 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 k of the motor max and minimum force output coefficient k min Set the motor adjustment coefficient based on the interval;

[0010] S3: Adjust the ejector pin height h according to the requirements of the tested chip and record the maximum force output coefficient k max and minimum force output coefficient k min The time for the chip to separate from the blue film under different force output coefficient values ​​within the interval, after multiple tests, the best force output coefficient value k is selected;

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

[0012] Furthermore, in S1, the ejector pin and the blue film are first set to be in a micro-contact state, that is, the ejector pin is set to be in a state of an initial height of 0 μm; and 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 cannot make the nozzle pick up the chip, the maximum force output coefficient k is calculated. max .

[0014] Furthermore, when the motor force cannot lift the nozzle upward, calculate the minimum force output coefficient k 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 is the vacuum pressure value of the nozzle, S吸嘴 is the contact area of ​​the nozzle, G 吸嘴 is the gravity value of the nozzle, F 电 The force value provided to the motor.

[0018] Furthermore, the minimum force output coefficient k min The calculation formula is:

[0019] k min =G 吸嘴 / F 电

[0020] Among them, G 吸嘴 is the gravity value of the nozzle, F 电 The force value provided to the motor.

[0021] Furthermore, the optimal force F for separating the chip from the blue film in S4 is 拾取 The calculation formula is:

[0022] F 拾取 =F 电 *kG 吸嘴 -G 芯片

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

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

[0025] Furthermore, after adjusting the ejector height h in S3, at the maximum force output coefficient k max and minimum force output coefficient k min At the same force output coefficient value within the interval, the chip needs to be separated from the blue film for 5-10 tests.

[0026] Furthermore, in S3, when the same ejector height h appears, the maximum force output coefficient k max and minimum force output coefficient k min When the separation time of the tested chips from the blue film is the same and the consistency is high under different force output coefficient values ​​within the interval, it is necessary to take the average value under multiple groups of force output coefficient values ​​and select the optimal force output coefficient value k.

[0027] Compared with the prior art, the present invention can achieve the following beneficial effects: the present invention picks up the chip from the blue film by a suction nozzle, performs multiple groups of quantitative tests and picking tests, and establishes a simple and efficient maximum force test calculation method for separating chips of different sizes from the blue film. The method can improve the process efficiency and process reliability of chip picking, can assist stress simulation to complete the research on chip separation from the blue film, and solves the problem that chip picking of the upright patch equipment cannot be designed and optimized from a process perspective. It can be applied to the calculation of the motor output force coefficient and the picking force of chips of different sizes. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 is a schematic diagram of a chip picking preparation state according to an embodiment of the present invention;

[0029] Figure 2 is a schematic diagram of a chip picking completion state provided in accordance with an embodiment of the present invention;

[0030] Figure 3 4 is a graph showing the relationship between the ejection height of the ejector pin and the chip picking force provided in an embodiment of the present invention.

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

[0032] In the following, reference will be made to the Figure 1-3 Embodiments of the present invention are described. In the following description, the same modules are represented by the same reference numerals. In the case of the same reference numerals, their names and functions are also the same. Therefore, the detailed description thereof will not be repeated.

[0033] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the following Figure 1-3 It should be understood that the specific embodiments described herein are only used to explain the present invention and do not constitute a limitation of the present invention.

[0034] A method for calculating the force of picking up a chip on a blue film comprises the following steps:

[0035] S1: Since the motor current and its output force are linearly related and act on the nozzle, first calculate the motor maximum force output coefficient k max and minimum force output coefficient k min , when the ejector pin is in micro-contact state, the force output by the motor can be adjusted.

[0036] First, set the ejector pin 4 and the blue film 2 to be in micro-contact state, that is, Figure 1As shown, the ejector pin 4 is set to an initial height of 0 μm, the motor current is set to the maximum, and then the motor maximum force output coefficient k is calculated. max and minimum force output coefficient k min The ejector pin 4 is arranged in the ejector pin platform 5 .

[0037] S2: After determining the maximum and minimum coefficients of the motor output, set the motor adjustment coefficient to the range of the coefficients, that is, the maximum force output coefficient k of the motor max and minimum force output coefficient k min When adjusted to a certain value, the nozzle 4 is lifted up, but the chip 1 is not picked up. The force output by the motor can be exactly equal to the pressure of the nozzle 4 multiplied by the area minus the weight of the 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 nozzle 3 suck the chip 1, the maximum force output coefficient k is calculated. max . Maximum force output coefficient k max The calculation formula is:

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

[0040] Among them, P 吸嘴 is the vacuum negative pressure value of nozzle 3, S 吸嘴 is the contact area value of nozzle 3, G 吸嘴 is the gravity value of nozzle 3, F 电 The force value provided to the motor.

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

[0042] k min =G 吸嘴 / F 电

[0043] Among them, G 吸嘴 is the gravity value of nozzle 3, F 电 The force value provided to the motor.

[0044] 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 maxand 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 is determined after multiple tests to select the optimal force output coefficient value k. Here, a value with short separation time and good repeatability needs to be selected as the optimal force output coefficient value k.

[0045] At the same time, after adjusting the height h of the ejector pin 4, at the maximum force output coefficient k max and minimum force output coefficient k min At the same force output coefficient value within the interval, the chip 1 needs to be separated from the blue film 2 for 5-10 times to avoid test errors and improve test accuracy. 1 The value is tested 5-10 times and k is obtained. 1 The separation time of chip 1 from blue film 2 and the stability of separation time in 5-10 tests are taken as k 2 The value is tested 5-10 times and k is obtained. 2 The separation time of chip 1 from the blue film 2 and the stability of the separation time in 5-10 tests are measured under the value k, and so on, more values ​​within the interval can be taken to test the separation time of chip 1 from the blue film 2 and the stability of the separation time in 5-10 tests under the value k, and then select the best force output coefficient value k.

[0046] When the same ejector pin 4 height h is present, the maximum force output coefficient k max and minimum force output coefficient k min When the separation time of the chip 1 from the blue film 2 is the same and the consistency is high under different force output coefficient values ​​within the interval, it is necessary to take the average value under multiple groups of force output coefficient values ​​and select the best force output coefficient value k to ensure more accurate test data. 1 The separation time is 0.01 seconds and k 2 The separation time is 0.01 seconds, k 3 When the separation time is 0.01 seconds at the value, and the separation time at the force output coefficient values ​​in more intervals is 0.01 seconds, and the consistency of each force output coefficient value is high, it is necessary to take the average value of each force output coefficient value and then select the best force output coefficient value k. Figure 2 As shown, Figure 2 The state diagram for chip 1 picking up completion, Figure 3 Graph showing the relationship between the ejection height h of the ejector pin 4 and the pick-up pulling force of the chip 1 .

[0047] 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 optimal force F for separating chip 1 from blue film 2 拾取 The calculation formula is:

[0048] F拾取 =F 电 *kG 吸嘴 -G 芯片

[0049] Among them, F 电 is the force value provided by the motor, k is the optimal force output coefficient value of the motor, G 吸嘴 is the gravity value of nozzle 3, G 芯片 is the gravity value of chip 1.

[0050] Although the embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and cannot be understood as limiting the present invention. Those skilled in the art may change, modify, replace and modify the above embodiments within the scope of the present invention.

[0051] The above specific implementations of the present invention do not constitute a limitation on the protection scope of the present invention. Any other corresponding changes and modifications made based on the technical concept of the present invention should be included in the protection scope of the claims of the present invention.

Claims

1. A method for calculating the force of picking up a chip on a blue film, characterized in that: The steps include: S1: Calculate the maximum force output coefficient k of the motor max and minimum force output coefficient k min ; S2: The maximum force output coefficient k of the motor max and minimum force output coefficient k min Set the motor adjustment coefficient based on 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 and 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 .

2. The method for calculating the force of picking up a chip on a blue film according to claim 1, characterized in that: In S1, the ejector pin (4) and the blue film (2) are first set to a micro-contact state, that is, the ejector pin (4) is set to be at an initial height of 0 μm; then the maximum force output coefficient k of the motor is calculated. max and minimum force output coefficient k min .

3. The force calculation method for picking up a chip on a blue film according to claim 2, characterized in that: When the motor force cannot make the nozzle (3) suck the chip (1), calculate the maximum force output coefficient k max .

4. The method for calculating the force of picking up a chip on a blue film according to claim 3, characterized in that: When the motor force cannot lift the nozzle (3) upward, calculate the minimum force output coefficient k min .

5. The force calculation method for picking up a chip on a blue film according to claim 4, characterized in that: Maximum force output coefficient k max The calculation formula is: k max =(P 吸嘴 *S 吸嘴 -G 吸嘴 ) / F 电 Among them, P 吸嘴 is the vacuum pressure value of the suction nozzle (3), S 吸嘴 is the contact area value of the nozzle (3), G 吸嘴 is the gravity value of the nozzle (3), F 电 The force value provided to the motor.

6. The method for calculating the force of picking up a chip on a blue film according to claim 5, characterized in that: Minimum force output coefficient k min The calculation formula is: k min =G 吸嘴 / F 电 Among them, G 吸嘴 is the gravity value of the nozzle (3), F 电 The force value provided to the motor.

7. The method for calculating the force of picking up a chip on a blue film according to claim 6, characterized in that: The optimal force F for separating the chip (1) from the blue film (2) in S4 拾取 The calculation formula is: F 拾取 =F 电 *k-G 吸嘴 -G 芯片 Among them, F 电 is the force value provided by the motor, k is the optimal force output coefficient value of the motor, G 吸嘴 is the gravity value of the nozzle (3), G 芯片 is the gravity value of the chip (1).

8. The force calculation method for picking up a chip on a blue film according to claim 7, characterized in that: In S3, a value with short separation time and good repeatability needs to be selected as the optimal force output coefficient value k.

9. The method for calculating the force of picking up a chip on a blue film according to claim 8, characterized in that: After adjusting the height h of the ejector pin (4) in S3, the maximum force output coefficient k max and minimum force output coefficient k min At the same force output coefficient value within the interval, the chip (1) needs to be separated from the blue film (2) for 5-10 times.

10. The force calculation method for picking up a chip on a blue film according to claim 9, characterized in that: In S3, when the same ejector pin (4) height h appears, the maximum force output coefficient k max and minimum force output coefficient k min When the separation time of the tested chip (1) from the blue film (2) is the same and the consistency is high under different force output coefficient values ​​within the interval, it is necessary to take the average value under multiple groups of force output coefficient values ​​and select the optimal force output coefficient value k.

Images