A method for preventing wafer MAP misplacement in semiconductor packaging

Abstract

This invention provides a method for preventing incorrect wafer MAP selection in semiconductor packaging, relating to the field of semiconductor device packaging technology. The method includes: S1. Designated personnel rotate the orientation of the wafer's MAP source file to a unified orientation and upload the rotated MAP to a MAP server. Technicians download the orientation-reversed MAP from the MAP server, avoiding manual verification of the MAP orientation in the source file. This method for preventing incorrect wafer MAP selection in semiconductor packaging ensures accurate positioning of each chip during the packaging process through an innovative combination of MAP orientation adjustment, inkjet marking, and reference chip marking. By unifying the notch orientation of the MAP, using star-shaped markings, and performing precise chip calibration, the risk of chip selection errors is greatly reduced. This method effectively avoids the problems of missing good chips and picking up defective chips, thereby significantly improving packaging yield.

Description

Technical Field

[0001] This invention relates to the field of semiconductor device packaging technology, specifically to a method for preventing incorrect wafer MAP selection during semiconductor packaging. Background Technology

[0002] With the development of the semiconductor industry, the requirements for chip performance and packaging technology are constantly increasing. A MAP (Map of Array of Pads) is a diagram generated during wafer testing that records the quality status of each chip on the wafer and indicates whether each chip is good or bad in character form. Therefore, accurately mapping the information in the MAP onto the wafer is a crucial step in ensuring semiconductor packaging quality. In actual semiconductor packaging operations, packaging technicians typically need to precisely position and package each chip on the wafer according to the MAP. This process involves matching the chips on the wafer to their corresponding positions on the MAP. This matching process needs to consider the notch direction on both the MAP and the wafer, as wafers are usually marked with notches during manufacturing to indicate their orientation. To ensure packaging accuracy, the chip positions on the MAP must precisely correspond to the chip positions on the wafer to ensure no errors occur during the packaging process.

[0003] However, the notch orientation of the MAP and the wafer are often not perfectly aligned. In some cases, the notch orientation of the MAP does not match the wafer's notch orientation, requiring technicians to rotate the MAP during operation to align its notch orientation with the wafer's. During MAP rotation, even a slight deviation can lead to incorrect chip selection, thus affecting the quality of the packaged product. Due to the lack of a clear reference point, technicians often face the risk of errors when matching the MAP to the wafer on the equipment. Summary of the Invention

[0004] To address the shortcomings of existing technologies, this invention provides a method for preventing incorrect wafer map selection during semiconductor packaging. The technical problem this invention aims to solve is: how to prevent incorrect map selection during semiconductor packaging by combining unified map orientation, inkjet marking, and reference chip marking, and by using automated equipment for precise calibration, thereby significantly improving packaging yield and product reliability.

[0005] To achieve the above objectives, the present invention provides the following technical solution: a method for preventing incorrect wafer MAP selection in semiconductor packaging, comprising:

[0006] S1. Designated personnel rotate the orientation of the MAP source file of the wafer to a unified orientation and upload the rotated MAP to the MAP server. Technicians download the orientation-converted MAP from the MAP server, avoiding the need for manual confirmation of the orientation of the MAP in the source file.

[0007] S2. Before the wafer is mounted on the machine, a special graphic mark that is different from common ink dots is marked on the fixed chip position of the wafer using an inkjet marking device, and the chip is marked with special characters in the MAP diagram corresponding to the fixed chip position, and the chip is used as the reference chip for MAP calibration.

[0008] S3. Before the wafer is mounted on the machine, the technicians confirm the notch direction of the wafer and adjust the rotation angle of the MAP according to the confirmed notch direction to ensure that the notch direction of the MAP is consistent with the notch direction of the wafer.

[0009] S4. After the wafer is mounted on the machine, a specific pattern is first taken out from a fixed area of ​​the wafer using the MAP take-off method to calibrate the MAP. If the pattern appears during the processing, the equipment will alarm to indicate that the MAP is misaligned and correct it in time to avoid large-area errors in the MAP.

[0010] S5. After the MAP is rotated and calibrated, the technicians continue to confirm the reference chip in the MAP by calibrating the marked reference chip position with the markings on the wafer to ensure the correct correspondence between the MAP and the wafer chip position.

[0011] S6. After confirming that the MAP diagram corresponds correctly with the wafer, the wafer packaging process will begin to ensure that no chip is picked up incorrectly during the entire packaging process.

[0012] Preferably, the orientation rotation of the MAP source file in S1 is achieved automatically using a programming language program, and the rotation angle is one of 0°, 90°, 180° or 270°, to ensure that the MAP map has a uniform orientation before uploading.

[0013] Preferably, the special graphic identifier in S2 is a star-shaped graphic, and the color of the special graphic identifier is different from the color of other chip identifiers, ensuring that technicians can easily identify the reference chip when confirming it.

[0014] Preferably, the specific pattern in S4 is a rectangular pattern. The rectangular pattern is taken out from the fixed area of ​​the wafer by MAP taking method and used for MAP calibration in subsequent processing to ensure that MAP pattern errors are detected and corrected in time during processing.

[0015] Preferably, the area of ​​the rectangular shape accounts for 1% of the area within the fixed region of the wafer.

[0016] Preferably, the orientation rotation of the MAP source file is performed automatically using a programming language program.

[0017] Preferably, the diameter of the star-shaped pattern used for marking by the inkjet marking equipment is 1 / 4 of the effective area diameter of the chip.

[0018] Preferably, the marking accuracy of the inkjet marking equipment reaches the micrometer level, ensuring that the marking pattern does not affect the function and quality of the chip.

[0019] This invention provides a method for preventing incorrect wafer map selection in semiconductor packaging. It has the following beneficial effects:

[0020] This method for preventing wafer map (MAP) errors in semiconductor packaging combines innovative MAP orientation adjustment, inkjet marking, and reference chip marking to ensure accurate positioning of each chip during the packaging process. By standardizing the notch orientation of the MAP, using star-shaped markings, and performing precise chip calibration, the risk of chip errors is significantly reduced. This method effectively avoids the problems of missing good chips and picking up bad chips, thereby significantly improving packaging yield. With this solution, the packaging yield can reach 99.5%, an improvement of approximately 4.5 percentage points compared to the 95% of traditional methods. Simultaneously, it reduces scrap generation and improves the reliability and stability of the final product.

[0021] Automated operation and intelligent calibration systems effectively reduce the impact of human error and visual fatigue. Through programmed MAP rotation and automatic equipment calibration, technicians no longer need to manually confirm MAP orientation, reducing orientation errors caused by improper operation. At each packaging stage, automated equipment monitors the correspondence between the MAP and the wafer in real time, preventing misalignment and erroneous operations. Automated calibration not only improves operational efficiency but also simplifies the process flow, significantly shortening the production cycle. Furthermore, the system's alarm function can promptly detect and correct errors, further improving the overall efficiency and stability of the production line. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of the wafer in the embodiment;

[0023] Figure 2 This is a schematic diagram of the wafer after inkjet marking by the inkjet marking machine in the embodiment;

[0024] Figure 3 This is a MAP diagram of the wafer source file in the embodiment;

[0025] Figure 4 This is a schematic diagram showing the MAP after being rotated by the utility program in the embodiment;

[0026] Figure 5 This is a schematic diagram illustrating the correspondence between the MAP diagram and the wafer used in the implementation column;

[0027] Figure 6 To establish the correspondence between the wafer and the map after extracting a specific pattern from a fixed region in the implementation column;

[0028] Figure 7 This is a MAP image opened by the program in the example;

[0029] Figure 8 This is the MAP diagram after the direction change. Detailed Implementation

[0030] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0031] like Figure 1-8 As shown, this embodiment of the invention provides a method for preventing incorrect wafer map selection in semiconductor packaging, including: S1. Designated personnel rotate the orientation of the wafer's MAP source file to a unified orientation and upload the rotated MAP to a MAP server. Technicians download the orientation-converted MAP from the MAP server, avoiding manual confirmation of the MAP orientation in the source file. The orientation rotation of the MAP source file is automatically achieved using a programming language program. The rotation angle is one of 0°, 90°, 180°, or 270°, ensuring that the MAP is in a unified orientation before uploading. The orientation rotation of the MAP source file is automatically performed using a programming language program.

[0032] S2. Before the wafer is mounted on the machine, a special graphic mark, different from common ink dots, is applied to the fixed chip position on the wafer using an inkjet marking device. The chip is then marked with special characters on the MAP map corresponding to the fixed chip position, and this chip is used as the reference chip for MAP calibration. The special graphic mark is a star shape, and the color of the special graphic mark is different from the color of other chip marks, ensuring that technicians can easily identify the reference chip. The diameter of the star shape used by the inkjet marking device is 1 / 4 of the effective area diameter of the chip. The marking accuracy of the inkjet marking device reaches the micron level, ensuring that the marking graphic does not affect the function and quality of the chip.

[0033] S3. Before the wafer is mounted on the machine, the technicians confirm the notch direction of the wafer and adjust the rotation angle of the MAP according to the confirmed notch direction to ensure that the notch direction of the MAP is consistent with the notch direction of the wafer.

[0034] S4. After the wafer is mounted on the machine, a specific pattern is first extracted from a fixed area of ​​the wafer using the MAP (Modular Mapping) method for MAP calibration. If this pattern appears during processing, the equipment will alarm, indicating MAP misalignment, and correct it promptly to avoid large-area errors in the MAP. The specific pattern is a rectangular pattern, which is extracted from the fixed area of ​​the wafer using the MAP method and used for MAP calibration in subsequent processing to ensure that MAP errors are detected and corrected in a timely manner. The area of ​​the rectangular pattern accounts for 1% of the fixed area of ​​the wafer.

[0035] S5. After the MAP is rotated and calibrated, the technicians continue to confirm the reference chip in the MAP by calibrating the marked reference chip position with the markings on the wafer to ensure the correct correspondence between the MAP and the wafer chip position.

[0036] S6. After confirming that the MAP diagram corresponds correctly with the wafer, the wafer packaging process will begin to ensure that no chip is picked up incorrectly during the entire packaging process.

[0037] Example 2

[0038] This embodiment uses the N150N020B chip as an example to illustrate in detail how to prevent incorrect wafer MAP (Metal Mapping) selection during semiconductor packaging. The entire process ensures the accuracy of wafer MAP selection through specific steps, thereby avoiding the omission of good chips or the removal of defective chips, improving the yield of the packaging process and the reliability of the product.

[0039] Step 1: Obtaining the MAP and Confirming the Direction

[0040] During implementation, the first step is to designate personnel to obtain the wafer MAP (Mapping Image) of that chip model. The wafer MAP is an image generated through testing; the status of each chip in the image is represented by a character, where "P" represents a good chip (good product), "F" represents a bad chip (defective product), and "." represents an empty chip. After obtaining the MAP, it is first necessary to confirm that the orientation in the MAP source file is notched downwards. After confirmation, according to regulations, the MAP is rotated 180° using a program to ensure that the notch orientation in the MAP is uniformly adjusted to notch upwards.

[0041] Each MAP contains 42×28 chip locations, for a total of 1176 test points.

[0042] The initial MAP plots have the gaps pointing downwards. After rotation, the gaps in all MAP plots are now pointing upwards.

[0043] Step 2: Inkjet marking and MAP modification

[0044] After the MAP diagram is aligned, the wafer is marked. According to regulations, all defective chips (marked with "F") in the first row of the wafer notch corresponding to the MAP diagram are specially marked using inkjet marking equipment. The marking pattern uses a shape different from common ink dots, such as a star. After marking, technicians mark the corresponding defective chip in the MAP diagram as "R" for special identification, ensuring that this chip is used as a reference chip for calibration in subsequent operations. The modified MAP diagram is saved and uploaded to the MAP server to ensure that every step of the entire process flow is operated according to the updated MAP diagram.

[0045] Each wafer contains approximately 15 defective chips, representing about 1.71% of the MAP.

[0046] The inkjet marking machine has an accuracy of ±5 micrometers, and the diameter of the star-shaped icon is 50 micrometers, ensuring that the marking does not affect the chip's function.

[0047] The modified MAP diagram is automatically updated by replacing the faulty chip markers and uploaded to the server.

[0048] Step 3: MAP download and equipment adjustment

[0049] In subsequent wafer fabrication processes, engineers download the uploaded MAP (Metal Assurance Map) from the server. According to regulations, the notch direction should be upwards when the wafer is loaded onto the worktable. Engineers confirm that the MAP has been correctly rotated so that the notch direction in the MAP aligns with the notch direction on the wafer. Specifically, engineers need to rotate and adjust the MAP on the equipment to ensure a 0° rotation angle, meaning the notch direction in the MAP is perfectly aligned with the notch direction on the wafer.

[0050] After downloading the MAP, the technicians adjusted the equipment rotation angle to 0° to ensure that the notch direction in the MAP was consistent with the notch direction on the wafer.

[0051] Each operation takes an average of 2 minutes for MAP download and rotation.

[0052] Step 4: Reference chip calibration and MAP correction

[0053] After confirming the rotation angle of the MAP map is correct, the technicians will then calibrate the wafer based on the star-shaped ink dot corresponding to the "R" mark on the MAP map. This mark allows the technicians to accurately confirm the correspondence between the MAP map and the wafer, ensuring the accuracy of the calibrated MAP map. After calibration, the technicians will use the MAP pick-up method to remove a specific rectangular pattern from a fixed area of ​​the wafer and perform the die-attachment operation. After removing this pattern, a second calibration will be performed to ensure that the pattern positions on the MAP map and the wafer perfectly match, ensuring accuracy in subsequent processing.

[0054] The specific rectangular pattern extracted is 2mm x 2mm in size and occupies approximately 0.01% of the total area of ​​the wafer, ensuring the correction of positional errors during the manufacturing process.

[0055] Each calibration process takes an average of 5 minutes, including image acquisition, calibration, and correction operations.

[0056] Step 5: Normal processing and packaging

[0057] After a series of calibrations, it is finally ensured that the MAP map corresponds one-to-one with the location of each chip on the wafer. At this point, normal wafer packaging processes can be carried out, ensuring that no MAP mis-picking occurs during the packaging process (i.e., good chips are missed or bad chips are removed).

[0058] After calibration, the position of each chip on the wafer is completely consistent with the MAP diagram, and the yield rate during packaging reaches 99.5%, which is 4.5 percentage points higher than the 95% before this method was used.

[0059] On the production line implementing this method, an average of about 3,000 chips are packaged per hour.

[0060] This embodiment utilizes programmed MAP rotation, inkjet marking equipment, MAP calibration, and automated equipment to ensure accurate chip placement on each wafer during the packaging process. This technical solution effectively avoids MAP misplacement caused by human error, equipment rotation errors, and unclear chip markings.

[0061] By using inkjet marking on the wafer surface and performing precise reference chip calibration, technicians can visually identify chips requiring special handling, significantly reducing the risk of incorrect chip extraction during the packaging process. Furthermore, the introduction of automated calibration and equipment alarm functions improves the efficiency and accuracy of the entire process, reducing the impact of human error and improper operation on product yield.

[0062] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A method for preventing incorrect wafer MAP selection in semiconductor packaging, characterized in that, include: S1. Designated personnel rotate the orientation of the wafer's MAP source file to a unified orientation and upload the rotated MAP image to the MAP server. Technicians then download the orientation-converted MAP image from the MAP server. S2. Before the wafer is mounted on the machine, a special graphic mark that is different from common ink dots is marked on the fixed chip position of the wafer using an inkjet marking device, and the chip is marked with special characters in the MAP diagram corresponding to the fixed chip position, and the chip is used as the reference chip for MAP calibration. S3. Before the wafer is mounted on the machine, the technicians confirm the notch direction of the wafer and adjust the rotation angle of the MAP according to the confirmed notch direction to ensure that the notch direction of the MAP is consistent with the notch direction of the wafer. S4. After the wafer is mounted on the machine, a specific pattern is first taken out from a fixed area of ​​the wafer using the MAP take-off method to calibrate the MAP. If the pattern appears during the processing, the equipment will alarm to indicate that the MAP is misaligned and correct it in time to avoid large-area errors in the MAP. S5. After the MAP is rotated and calibrated, the technicians continue to verify the reference chip in the MAP and calibrate it by matching the marked reference chip position with the markings on the wafer. S6. After confirming that the MAP diagram corresponds correctly with the wafer, the wafer packaging process will begin to ensure that no chip is picked up incorrectly during the entire packaging process.

2. The method for preventing wafer MAP errors in semiconductor packaging according to claim 1, characterized in that: The orientation rotation of the MAP source file mentioned in S1 is achieved automatically using a programming language program. The rotation angle is one of 0°, 90°, 180° or 270° to ensure that the MAP map has a uniform orientation before uploading.

3. The method for preventing wafer MAP errors in semiconductor packaging according to claim 1, characterized in that: The special graphic identifier mentioned in S2 is a star-shaped graphic, and the color of the special graphic identifier is different from the color of other chip identifiers.

4. The method for preventing wafer MAP errors in semiconductor packaging according to claim 1, characterized in that: The specific pattern mentioned in S4 is a rectangular pattern, which is taken out from the wafer fixing area by MAP wafer taking method.

5. A method for preventing wafer MAP errors in semiconductor packaging according to claim 4, characterized in that: The area of ​​the rectangular shape accounts for 1% of the fixed area of ​​the wafer.

6. A method for preventing wafer MAP errors in semiconductor packaging according to claim 1, characterized in that: The orientation rotation of the MAP source file is performed automatically using a programming language program.

7. A method for preventing wafer MAP errors in semiconductor packaging according to claim 1, characterized in that: The diameter of the star-shaped pattern used for marking by the inkjet marking equipment is 1 / 4 of the effective area diameter of the chip.

8. A method for preventing wafer MAP errors in semiconductor packaging according to claim 1, characterized in that: The marking accuracy of the inkjet marking equipment reaches the micrometer level.

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