Wafer positioning MAP positioning marking method

Abstract

The invention discloses a wafer positioning MAP positioning marking method, which comprises the following steps of: firstly, establishing a system coordinate system based on a pixel point drawing frame, generating a schematic diagram of a to-be-detected wafer in the system coordinate system according to information of the to-be-detected wafer, and acquiring system coordinates of each crystal grain in the system coordinate system; then any crystal grain is selected from the system coordinate system to serve as a benchmarking crystal grain, and benchmarking of the position of the benchmarking crystal grain in the system coordinate system and the actual position is completed; the appearances of all crystal grains are checked through an observation lens, when abnormal crystal grains are found, the displacement distances of the observation lens in the X-axis direction and the Y-axis direction are obtained, and the coordinates of the abnormal crystal grains in the system coordinate system are calculated; and finally, abnormal marking is performed on the abnormal crystal grains in the system coordinate system, and a corresponding marked wafer MAP is generated. According to the invention, the crystal grains are inspected through the artificial lens, and abnormal marking is carried out through the system after the defective products are found, so that the marking accuracy and marking efficiency of the defective products are greatly improved.

Description

Technical Field

[0001] The invention belongs to the technical field of wafer packaging, and in particular relates to a wafer positioning MAP positioning marking method. Background Art

[0002] In order to improve the yield of wafer packaging, wafers will be quality inspected before packaging. Unqualified products will be marked on the wafer electronic MAP. The marking file will be sent to the wafer welding process. The welding equipment will grab qualified wafers according to the wafer electronic MAP for welding and packaging. Unqualified products will be ignored directly, thereby improving wafer packaging efficiency and product yield. However, most of the current wafer quality inspections are manually inspected and judged, and after the judgment, they are manually marked on the wafer electronic MAP according to the coordinates. Manual marking is extremely inefficient and prone to errors and omissions, resulting in good products being incorrectly marked and bad products being missed, thereby reducing the overall yield of the product. Summary of the invention

[0003] The technical problem to be solved by the present invention is to provide a wafer positioning MAP positioning marking method in view of the deficiencies of the above-mentioned prior art, which can be quickly and effectively performed on the wafer electronic MAP diagram, effectively improving the yield rate of product packaging and improving the efficiency of wafer quality inspection.

[0004] The technical solution adopted by the present invention is: a wafer positioning MAP positioning marking method, comprising the following steps:

[0005] Step 1: construct a pixel frame based on S*S pixel units, establish a system coordinate system with the pixel frame, generate the grain distribution of the wafer to be tested in the system coordinate system according to the wafer information to be tested, and obtain the system coordinates of each grain on the wafer to be tested in the system coordinate system;

[0006] Step 2: Select any die in the system coordinate system as the reference die, move the wafer to be tested, place the reference die directly under the observation lens, and complete the reference of the reference die in the system coordinate system with the actual position;

[0007] Step 3: Move the wafer to be tested and check the appearance of all grains through the observation lens. When abnormal grains are found, take the actual position of the reference grain as the starting point, obtain the displacement distance of the wafer to be tested in the X-axis direction and the Y-axis direction, and calculate the coordinates of the abnormal grain in the system coordinate system, as follows:

[0008] Assume that the boundaries of the wafer to be tested are L pixel units, and the coordinates of the abnormal grain in the system coordinate system are:

[0009]

[0010] Among them, (X F, Y F ) is the coordinate of the actual position of the abnormal grain, (X0, Y0) is the coordinate of the actual position of the reference grain, (X T , Y T ) is the coordinate of the reference grain in the system coordinate system, X Axis The relative value of the reading per micron of the wafer to be tested moving in the X-axis direction, Axis is the relative value of the reading per micron of the wafer to be tested moving in the Y-axis direction, and D is the diameter of the wafer to be tested;

[0011] Utilizing X a and Y b Calculate the row and column number of the abnormal grain in the pixel frame, assuming that the width of the abnormal grain is W and the height is H:

[0012] R=(X a ÷W), R is X a The value that divides W, X sub is the remainder;

[0013] C=(Y b ÷H), C is Y b Divide the value of H, Y sub is the remainder;

[0014] The position of abnormal grains in the pixel frame is determined by judging the ratio of the remainder to the grain size. sub ≤80%×W, then the number of rows of abnormal grains in the pixel frame is RT=R+1, otherwise RT=R; when 20%×H≤Y sub ≤80%×H, then the number of columns of abnormal grains in the pixel frame CT=C+1, otherwise CT=C;

[0015] Step 4: Based on the number of rows and columns of the abnormal grains in the pixel frame obtained in step 3, the abnormal grains are abnormally marked in the pixel frame, and a corresponding marked wafer MAP file is generated.

[0016] Preferably, the wafer information to be tested in step 1 includes a wafer MAP file and a non-wafer MAP file;

[0017] The wafer MAP file is used to obtain the wafer information to be tested, including the wafer diameter, the total number of rows of grains, the total number of columns of grains and the Bin Code information of each grain;

[0018] The wafer-free MAP file obtains the information of the wafer to be tested, including the wafer diameter, the invalid area of ​​the wafer edge, and the width and height dimensions of each grain.

[0019] Preferably, the coordinate value of each grain center point of the wafer to be tested having the wafer MAP file in the system coordinate system is specifically calculated as follows:

[0020]

[0021] Wherein, Row is the total number of rows of grains in the wafer to be tested, Col is the total number of columns of grains in the wafer to be tested; a is the row number where the current grain is located, satisfying 1≤a≤Row; b is the column number where the current grain is located, satisfying 1≤b≤Col.

[0022] Preferably, the coordinate value of each grain center point of the wafer to be tested without wafer MAP file in the system coordinate system is specifically calculated as follows:

[0023]

[0024] Wherein, D is the diameter of the wafer to be measured, W is the width of the current grain, H is the height of the current grain, a is the row number where the current grain is located, satisfying 1≤a≤D / W, and b is the column number in the pixel frame where the current grain is located, satisfying 1≤b≤D / H;

[0025] satisfy It is the die outside the wafer to be tested;

[0026] satisfy It is the invalid grain at the edge of the wafer to be tested;

[0027] satisfy These are normal and valid grains in the wafer to be tested.

[0028] Preferably, the observation lens is a microscope lens, and the displacement distance of the wafer to be tested in the X-axis direction and the Y-axis direction is obtained by connecting an X-axis encoder and a Y-axis encoder to a moving tray on which the wafer to be tested is placed.

[0029] Preferably, in step 4, color marking is used to mark the abnormal grains, and the reference coordinate value of the center point of the abnormal grain in the system coordinate system is obtained. According to the reference coordinate value, several judgment points in the abnormal grain that are not collinear with the center point of the abnormal grain in the horizontal and vertical directions are calculated, and the color markings of several judgment points and the center point of the abnormal grain are read, and the color with the largest number is used as the color marking of the abnormal grain.

[0030] The beneficial effect of the present invention is that the present invention inspects the grains through an artificial lens, and after a defective product is found, an abnormality is marked through the system, which greatly improves the accuracy and marking efficiency of defective product marking compared to traditional manual inspection and manual marking. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 It is a schematic diagram of a pixel frame of the present invention;

[0032] Figure 2A five-point schematic diagram of the present invention for judging the background color of abnormal grains;

[0033] Figure 3 A schematic diagram of a labeled MAP file generated by the present invention. DETAILED DESCRIPTION

[0034] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0035] Example 1

[0036] The wafer positioning MAP positioning marking system provided in this embodiment includes the following steps:

[0037] Step 1: Construct a pixel frame based on S*S pixel units, and establish a system coordinate system with the pixel frame; Figure 1 As shown, in this embodiment, the XY system coordinate system is established with the upper left corner vertex of the pixel frame as the origin;

[0038] A grain state distribution diagram of the wafer to be tested is generated in the system coordinate system of the pixel frame according to the wafer information to be tested. The wafer to be tested in this embodiment has a MAP file. The diameter of the wafer to be tested, the total number of grain rows, the total number of grain columns and the Bin Code information of each grain are obtained through the MAP file. The Bin Code information of each grain includes "—" for grains other than the wafer; "01" for good products; "02", "03", "04" and "etc" all for waste products; after obtaining the relevant information of the wafer to be tested through the MAP file, the coordinate value of the center point of each grain in the system coordinate system of the pixel frame is calculated, and the specific calculation is as follows:

[0039]

[0040] Among them, (X T ,Y T ) is the coordinate value of the current die in the system coordinate system, the width and height of the pixel frame are S pixels, L pixels are left as boundaries on the top, bottom, left and right sides of the wafer to be tested, Row is the total number of rows of the die on the wafer to be tested, Col is the total number of columns of the die on the wafer to be tested; a is the row number of the current die, satisfying 1≤a≤Row; b is the column number of the current die, satisfying 1≤b≤Col;

[0041] After obtaining the coordinate value of each crystal grain in the system coordinate system of the pixel frame, each crystal grain is color-marked in the pixel frame according to the Bin Code information of each crystal grain. In this embodiment, crystal grains other than the wafer are displayed with a white background and a black frame, good crystal grains are displayed with a green background and a black frame, and defective crystal grains are displayed with a red background and a black frame;

[0042] Step 2: Select any grain in the system coordinate system of the pixel frame as the reference grain. The reference grain is generally a relatively special grain, preferably a grain that can be recognized at a glance;

[0043] Prepare a high-precision fixed tool, the opening of the inner frame of the fixed tool is F*F cm; prepare two digital encoders with a precision of 7200 and connect them to the moving trays on which the wafer to be tested is placed, one as an X-axis encoder to obtain the displacement distance of the wafer to be tested in the X-axis direction, and the other as a Y-axis encoder to obtain the displacement distance of the wafer to be tested in the Y-axis direction. In this embodiment, the observation lens is a microscope lens;

[0044] Place the fixture at the observation window of the observation and testing equipment, place the wafer to be tested in the mobile tray, and then place the mobile tray in the fixture, move the wafer to be tested, and place the reference grain of the wafer to be tested under the observation lens, so that the reference grain selected in the system coordinate system of the pixel frame and the reference grain under the actual observation lens are aligned. After the alignment is completed, read the X-axis encoder and Y-axis encoder readings of the mobile tray at this time, recorded as (X0, Y0). At this time, the coordinate value of the reference grain in the system coordinate system of the pixel frame is recorded as (X T ,Y T );

[0045] Step 3: Move the mobile tray and use the observation lens to check the appearance of all grains. At the same time, in order to ensure the reading accuracy of the X-axis encoder and Y-axis encoder of the mobile tray, it is necessary to check from time to time to obtain the relative reading values ​​of the X-axis encoder and Y-axis encoder at each micron, specifically:

[0046] Move the mobile pallet to a corner point of the fixed tooling as the starting point, and obtain the value X of the X-axis encoder and the Y-axis encoder. S and Y S Then move the mobile tray to the corner point diagonally opposite to the starting point as the end point, and obtain the value X of the X-axis encoder and the Y-axis encoder E and Y E , since the inner frame opening of the fixed fixture is F*F cm, the relative readings of the X-axis encoder and the Y-axis encoder in each micron are:

[0047]

[0048] After determining the relative reading values ​​of the X-axis encoder and the Y-axis encoder at each micron, move the moving tray to observe all the grains in the wafer one by one. When an abnormal grain is found, obtain the displacement distance of the wafer to be tested in the X-axis direction and the Y-axis direction, that is, the reading values ​​of the X-axis encoder and the Y-axis encoder of the moving tray when the abnormal grain is located under the observation lens, recorded as X F and Y F ;

[0049] Calculate the coordinates of the abnormal grain in the system coordinate system of the pixel frame as follows:

[0050]

[0051] Utilizing X a and Y b Calculate the row and column number of the abnormal grain in the pixel frame, assuming that the width of the abnormal grain is W and the height is H:

[0052] R=(X a ÷W), R is X a The value that divides W, X sub is the remainder;

[0053] C=(Y b ÷H), C is Y b Divide the value of H, Y sub is the remainder;

[0054] The position of abnormal grains in the pixel frame is determined by judging the ratio of the remainder to the grain size. In order to improve the calculation efficiency, the width and height are set to be greater than 20% and less than 80% before calculation; therefore, when 20%×W≤X sub ≤80%×W, then the number of rows of abnormal grains in the pixel frame is RT=R+1, otherwise RT=R; when 20%×H≤Y sub ≤80%×H, then the number of columns of abnormal grains in the pixel frame CT=C+1, otherwise CT=C;

[0055] Step 4: Based on the number of rows and columns of the abnormal grains in the pixel frame obtained in step 3, abnormal marking is performed on the abnormal grains in the pixel frame. The abnormal marking of the abnormal grains is marked with colors. In this embodiment, the abnormal grains are marked with a red background color.

[0056] Due to display problems on the monitor, sometimes a black or white horizontal or vertical line will appear, causing the background color of a point to not represent the color of a grain, resulting in abnormal background color of the grain, and it is impossible to determine whether the grain is good or bad. Therefore, in order to solve the display problem of the monitor, the background color of the 5-point coordinates on different horizontal and vertical lines is counted to determine the background color of the grain, that is, the color value with the largest number is the background color of the grain, thereby eliminating the color abnormality caused by the display problem;

[0057] The specific operations of this embodiment are as follows:

[0058] By calculating the coordinate value of the center point of each grain in the system coordinate system of the pixel frame in step 1, the reference coordinate value (X j ,Yj ), and calculate the four judgment points in the abnormal grain that are not collinear with the center point of the abnormal grain in both the horizontal and vertical directions according to the reference coordinate values, such as Figure 2 As shown, the

[0059] First point coordinates:

[0060] The coordinates of the second point:

[0061] The coordinates of the third point: (X j ,Y j )

[0062] Coordinates of the fourth point:

[0063] Fifth point coordinates:

[0064] When the abnormal grains are marked, the overall background color is red. Display problems may cause the center point to be displayed as black or white. By selecting the coordinates of 5 points on different horizontal and vertical lines and reading the colors of the corresponding points, the color value with the largest number is the background color of the abnormal grain.

[0065] After judging the background color of each die, a corresponding marked wafer MAP file is generated, and the Bin Code information of the MAP file is defined by the background color of each die; Figure 3 As shown, in this embodiment, red is represented by "22", green is represented by "01", and white is represented by "-".

[0066] Example 2

[0067] This embodiment is basically the same as the first embodiment, except that the method of obtaining the wafer information to be tested is different. The wafer to be tested in this embodiment has no MAP file, and the obtained wafer information to be tested includes the wafer diameter D, the invalid area M of the wafer edge, and the width W and height H of each grain.

[0068] The coordinate value of each grain center point in the system coordinate system of the pixel frame is calculated as follows:

[0069]

[0070] Wherein, D is the diameter of the wafer to be measured, W is the width of the current grain, H is the height of the current grain, a is the row number where the current grain is located, satisfying 1≤a≤D / W, and b is the column number in the pixel frame where the current grain is located, satisfying 1≤b≤D / H;

[0071] satisfy It is the die outside the wafer to be tested;

[0072] satisfy The invalid grains on the edge of the wafer to be tested are displayed with a black frame on a white background.

[0073] satisfy It is the normal and valid die in the wafer to be tested, displayed with a black frame on a green background.

Claims

1. A wafer positioning MAP positioning marking method, characterized in that: The following steps are involved: Step 1: construct a pixel frame based on S*S pixel units, establish a system coordinate system with the pixel frame, generate the grain distribution of the wafer to be tested in the system coordinate system according to the wafer information to be tested, and obtain the system coordinates of each grain on the wafer to be tested in the system coordinate system; Step 2: Select any die in the system coordinate system as the reference die, move the wafer to be tested, place the reference die directly under the observation lens, and complete the reference of the reference die in the system coordinate system with the actual position; Step 3: Move the wafer to be tested and check the appearance of all grains through the observation lens. When abnormal grains are found, take the actual position of the reference grain as the starting point, obtain the displacement distance of the wafer to be tested in the X-axis direction and the Y-axis direction, and calculate the coordinates of the abnormal grain in the system coordinate system, as follows: Assume that the boundaries of the wafer to be tested are L pixel units, and the coordinates of the abnormal grain in the system coordinate system are: Among them, (X F ,Y F ) is the coordinate of the actual position of the abnormal grain, (X0, Y0) is the coordinate of the actual position of the reference grain, (X T ,Y T ) is the coordinate of the reference grain in the system coordinate system, X Axis The relative value of the reading per micron of the wafer to be tested moving in the X-axis direction, Axis is the relative value of the reading per micron of the wafer to be measured moving in the Y-axis direction, and D is the diameter of the wafer to be measured; Utilizing X a and Y b Calculate the row and column number of the abnormal grain in the pixel frame, assuming that the width of the abnormal grain is W and the height is H: R=(X a ÷W), R is X a The value that divides W, X sub is the remainder; C=(Y b ÷H), C is Y b Divide the value of H, Y sub is the remainder; The position of abnormal grains in the pixel frame is determined by judging the ratio of the remainder to the grain size. sub ≤80%×W, then the number of rows of abnormal grains in the pixel frame is RT=R+1, otherwise RT=R; when 20%×H≤Y sub ≤80%×H, then the number of columns of abnormal grains in the pixel frame CT=C+1, otherwise CT=C; Step 4: Based on the number of rows and columns of the abnormal grains in the pixel frame obtained in step 3, the abnormal grains are abnormally marked in the pixel frame, and a corresponding marked wafer MAP file is generated.

2. A wafer positioning MAP positioning marking method according to claim 1, characterized in that: In step 1, the wafer information to be tested includes a wafer MAP file and a non-wafer MAP file; The wafer MAP file is used to obtain the wafer information to be tested, including the wafer diameter, the total number of rows of grains, the total number of columns of grains and the Bin Code information of each grain; The wafer-free MAP file obtains the information of the wafer to be tested, including the wafer diameter, the invalid area of ​​the wafer edge, and the width and height dimensions of each grain.

3. A wafer positioning MAP positioning marking method according to claim 2, characterized in that: The coordinate value of each grain center point of the wafer to be tested with the wafer MAP file in the system coordinate system is specifically calculated as follows: Wherein, Row is the total number of rows of grains in the wafer to be tested, Col is the total number of columns of grains in the wafer to be tested; a is the row number where the current grain is located, satisfying 1≤a≤Row; b is the column number where the current grain is located, satisfying 1≤b≤Col.

4. A wafer positioning MAP positioning marking method according to claim 2, characterized in that: The coordinate value of each grain center point of the wafer to be tested without wafer MAP file in the system coordinate system is specifically calculated as follows: Wherein, D is the diameter of the wafer to be measured, W is the width of the current grain, H is the height of the current grain, a is the row number where the current grain is located, satisfying 1≤a≤D / W, and b is the column number in the pixel frame where the current grain is located, satisfying 1≤b≤D / H; satisfy It is the die outside the wafer to be tested; satisfy It is the invalid grain at the edge of the wafer to be tested; satisfy These are normal and valid grains in the wafer to be tested.

5. A wafer positioning MAP positioning marking method according to claim 1, 2, 3 or 4, characterized in that: The observation lens is a microscope lens, and the displacement distance of the wafer to be tested in the X-axis direction and the Y-axis direction is obtained by connecting an X-axis encoder and a Y-axis encoder to a moving tray on which the wafer to be tested is placed.

6. A wafer positioning MAP positioning marking method according to claim 5, characterized in that: In step 4, the abnormal grains are marked with colors, the reference coordinate value of the center point of the abnormal grain in the system coordinate system is obtained, and several judgment points in the abnormal grain that are not collinear with the center point of the abnormal grain in the horizontal and vertical directions are calculated based on the reference coordinate value, and the color marks of several judgment points and the center point of the abnormal grain are read, and the color with the largest number is used as the color mark of the abnormal grain.

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