A wafer positioning MAP positioning marking method

Abstract

The present invention discloses a wafer positioning MAP positioning marking method. First, a system coordinate system is established based on a pixel point frame. A schematic diagram of the wafer to be tested is generated in the system coordinate system according to the wafer information to be tested, and the system coordinates of each grain in the system coordinate system are obtained. Then, any grain is selected in the system coordinate system as a reference grain, and the position of the reference grain in the system coordinate system is aligned with the actual position. Then, the appearance of all grains is inspected through an observation lens. When an abnormal grain is found, the displacement distance of the observation lens in the X-axis and Y-axis directions is obtained, and the coordinates of the abnormal grain in the system coordinate system are calculated. Finally, the abnormal grain is marked as abnormal in the system coordinate system, and a corresponding marked wafer MAP diagram is generated. The present invention inspects the grains through an artificial lens, and marks the abnormalities through the system after defective products are found, which greatly improves the accuracy and efficiency of defective product marking.

Description

Technical Field

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

[0002] To improve the yield of wafer packaging, wafers are quality inspected before packaging. Unqualified products are marked on the wafer electronic map. The marking file is transmitted to the wafer welding process. The welding equipment grabs qualified wafers according to the wafer electronic map for welding and packaging, and unqualified products are directly ignored, thereby improving wafer packaging efficiency and product yield. However, current wafer quality inspection mostly relies on manual inspection and judgment, and after judgment, manual marking is performed 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 product yield. Summary of the Invention

[0003] The technical problem to be solved by the present invention is to address the deficiencies of the above-mentioned existing technologies and provide a wafer positioning MAP positioning marking method, which can be performed quickly and effectively 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 die 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 die 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 measured, and place the reference die directly under the observation lens to align the position of the reference die in the system coordinate system with the actual position;

[0007] Step 3: Move the wafer to be tested and inspect the appearance of all grains through the observation lens. When an abnormal grain is 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 and Y-axis directions, 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]

[0011] in,( ) is the coordinate of the actual position of the abnormal grain, ( ) is the coordinate of the actual position of the reference grain, ( ) is the coordinate of the reference grain in the system coordinate system, It is the relative value of the reading per micron of the wafer to be measured moving in the X-axis direction. 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;

[0012] use and Calculate the row and column numbers of the abnormal grain in the pixel frame, assuming the width of the abnormal grain is W and the height is H:

[0013] ), for Divide the value of W, is the remainder;

[0014] ), for Divide the value of H, is the remainder;

[0015] The position of abnormal grains in the pixel frame is determined by judging the ratio of the remainder to the grain size. , then the number of rows of abnormal grains in the pixel frame RT = , otherwise RT= ;when , then the number of columns of abnormal grains in the pixel frame CT = , otherwise CT= ;

[0016] Step 4: Based on the row and column numbers of the abnormal grains in the pixel frame obtained in step 3, the abnormal grains are marked as abnormal in the pixel frame, and a corresponding marked wafer MAP file is generated.

[0017] Preferably, the wafer information to be tested in step 1 includes a wafer MAP file and a wafer-free MAP file;

[0018] 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;

[0019] The wafer-free MAP file obtains information about the wafer to be tested, including the wafer diameter, the invalid area at the edge of the wafer, and the width and height of each grain.

[0020] Preferably, the coordinate value of the center point of each die of the wafer to be measured with the wafer MAP file in the system coordinate system is specifically calculated as follows:

[0021] (a- )

[0022] (b- )

[0023] in, is the total number of rows of dies on the wafer to be tested, is the total number of columns of the wafer to be tested; a is the row number of the current die, satisfying 1 ≤ a ≤ ; b is the column number of the current grain, satisfying 1 ≤ b ≤ .

[0024] Preferably, the coordinate value of each die center point of the wafer to be tested without the wafer MAP file in the system coordinate system is specifically calculated as follows:

[0025] (a- )

[0026] (b- )

[0027] Where D is the diameter of the wafer to be measured, W is the width of the current die, H is the height of the current die, a is the row number where the current die is located, satisfying 1 ≤ a ≤ D / W, and b is the column number in the pixel frame where the current die is located, satisfying 1 ≤ b ≤ D / H;

[0028] satisfy , are the dies outside the wafer to be tested;

[0029] satisfy , which are invalid grains at the edge of the wafer to be tested;

[0030] satisfy , are the normal and effective grains in the wafer to be tested;

[0031] Wherein, M is the invalid area at the edge of the wafer.

[0032] 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.

[0033] 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 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.

[0034] The beneficial effect of the present invention is that the present invention inspects the grains through an artificial lens and marks the abnormalities through the system after defective products are found. Compared with traditional manual inspection and manual marking, the accuracy and efficiency of defective product marking are greatly improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 This is a schematic diagram of a pixel frame of the present invention;

[0036] Figure 2 A five-point schematic diagram of the present invention for judging the background color of abnormal grains;

[0037] Figure 3 Schematic diagram of the marked MAP file generated by the present invention. DETAILED DESCRIPTION

[0038] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0039] Example 1

[0040] The wafer positioning MAP positioning marking system provided in this embodiment includes the following steps:

[0041] 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 coordinate system is established with the upper left corner vertex of the pixel frame as the origin;

[0042] A grain state distribution map 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. In this embodiment, the wafer to be tested 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 "—" indicating a grain outside the wafer; "01" indicating a good product; "02", "03", "04", and "etc." all indicating a defective product. 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. The specific calculation is as follows:

[0043] (a- )

[0044] (b- )

[0045] in,( ) 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 on the top, bottom, left and right sides of the wafer to be tested as boundaries. is the total number of rows of dies on the wafer to be tested, is the total number of columns of the wafer to be tested; a is the row number of the current die, satisfying 1 ≤ a ≤ ; b is the column number of the current grain, satisfying 1 ≤ b ≤ ;

[0046] After obtaining the coordinate value of each die in the system coordinate system of the pixel frame, each die is color-coded in the pixel frame according to its Bin Code information. In this embodiment, the die outside the wafer are displayed with a black frame on a white background, the good die are displayed with a black frame on a green background, and the defective die are displayed with a black frame on a red background.

[0047] Step 2: Select any grain in the system coordinate system of the pixel frame as the benchmark grain. The benchmark grain is generally a relatively unique grain, preferably a grain that can be recognized at a glance;

[0048] Prepare a high-precision fixed fixture with an inner frame opening of F*F cm; prepare two digital encoders with an accuracy of 7200 and connect them to the movable tray where the wafer to be tested is placed. One encoder is used as an X-axis encoder to obtain the displacement distance of the wafer to be tested in the X-axis direction, and the other encoder is used 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.

[0049] Place the fixture on the observation window of the observation and testing equipment, place the wafer to be tested on the mobile tray, then place the mobile tray on the fixture, move the wafer to be tested, and place the reference die of the wafer to be tested under the observation lens, so that the reference die selected in the system coordinate system of the pixel frame and the reference die 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, and record them as ( ), at this time, the coordinate value of the benchmark grain in the system coordinate system of the pixel frame is recorded as ( );

[0050] 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 obtain the relative reading values ​​of the X-axis encoder and Y-axis encoder at each micron from time to time. Specifically:

[0051] Move the mobile pallet to a corner point of the fixed tooling as the starting point and obtain the values ​​of the X-axis encoder and Y-axis encoder and Then move the movable tray to the corner point diagonally opposite to the starting point as the end point, and obtain the values ​​of the X-axis encoder and the Y-axis encoder and 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:

[0052]

[0053]

[0054] After determining the relative readings of the X-axis encoder and the Y-axis encoder at each micron, move the pallet and 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 readings of the X-axis encoder and the Y-axis encoder of the pallet when the abnormal grain is located under the observation lens, recorded as and ;

[0055] Calculate the coordinates of the abnormal grain in the system coordinate system of the pixel frame as follows:

[0056]

[0057]

[0058] use and Calculate the row and column numbers of the abnormal grain in the pixel frame, assuming the width of the abnormal grain is W and the height is H:

[0059] ), for Divide the value of W, is the remainder;

[0060] ), for Divide the value of H, is the remainder;

[0061] 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 , then the number of rows of abnormal grains in the pixel frame RT = , otherwise RT= ;when , then the number of columns of abnormal grains in the pixel frame CT = , otherwise CT= ;

[0062] Step 4: Based on the row and column numbers of the abnormal grains in the pixel frame obtained in Step 3, the abnormal grains are marked as abnormal in the pixel frame. The abnormal marking of the abnormal grains is marked with a color. In this embodiment, the abnormal grains are marked with a red background color.

[0063] Due to display problems, a black or white horizontal or vertical line may appear, causing the background color of a point to not represent the color of a single die. This results in abnormal background colors of the die and makes it impossible to determine whether the die is good or bad. To address this display problem, we use the background colors of the five points on the horizontal and vertical lines to determine the background color of the die. That is, the color with the largest number of points is used as the background color of the die, thus eliminating color anomalies caused by display problems.

[0064] The specific operations of this embodiment are as follows:

[0065] 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 of the center point of the abnormal grain in the system coordinate system is obtained. , ), calculate and obtain four judgment points in the abnormal grain that are not collinear with the center point of the abnormal grain in the horizontal and vertical directions according to the reference coordinate values, such as Figure 2 As shown, the

[0066] First point coordinates , )

[0067] The second point coordinates , )

[0068] The third point coordinates , )

[0069] Fourth point coordinates , )

[0070] Fifth point coordinates , )

[0071] When 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 with the largest number of points is used as the background color of the abnormal grain.

[0072] 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 "-".

[0073] Example 2

[0074] This embodiment is basically the same as the first embodiment, except that the method for obtaining the wafer information to be tested is different. In this embodiment, the wafer to be tested does not have a MAP file, so the wafer information to be tested obtained includes the wafer diameter D, the invalid area M at the edge of the wafer, and the width W and height H of each die.

[0075] The coordinate value of each grain center point in the system coordinate system of the pixel frame is calculated as follows:

[0076] (a- )

[0077] (b- )

[0078] Where D is the diameter of the wafer to be measured, W is the width of the current die, H is the height of the current die, a is the row number where the current die is located, satisfying 1 ≤ a ≤ D / W, and b is the column number in the pixel frame where the current die is located, satisfying 1 ≤ b ≤ D / H;

[0079] satisfy , are the dies outside the wafer to be tested;

[0080] satisfy , which are invalid grains at the edge of the wafer to be tested;

[0081] satisfy , which are normal and effective grains in the wafer to be tested.

Claims

1. A wafer positioning MAP positioning marking method, characterized by: 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 die 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 die 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 measured, and place the reference die directly under the observation lens to align the position of the reference die in the system coordinate system with the actual position; Step 3: Move the wafer to be tested and inspect the appearance of all grains through the observation lens. When an abnormal grain is 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 and Y-axis directions, 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: ， ； in,( ) is the coordinate of the actual position of the abnormal grain, ( ) is the coordinate of the actual position of the reference grain, ( ) is the coordinate of the reference grain in the system coordinate system, It is the relative value of the reading per micron of the wafer to be measured moving in the X-axis direction. 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; use and Calculate the row and column numbers of the abnormal grain in the pixel frame, assuming the width of the abnormal grain is W and the height is H: ), for Divide the value of W, is the remainder; ), for Divide the value of H, 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. , then the number of rows of abnormal grains in the pixel frame RT = , otherwise RT= ;when , then the number of columns of abnormal grains in the pixel frame CT = , otherwise CT= ; Step 4: Based on the row and column numbers of the abnormal grains in the pixel frame obtained in step 3, the abnormal grains are marked as abnormal 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: The wafer information to be tested in step 1 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 information about the wafer to be tested, including the wafer diameter, the invalid area at the edge of the wafer, and the width and height of each grain.

3. A wafer positioning MAP positioning marking method according to claim 2, characterized in that: The coordinate value of each die center point of the wafer to be measured with the wafer MAP file in the system coordinate system is specifically calculated as follows: (a- ) (b- ) in, is the total number of rows of dies on the wafer to be tested, is the total number of columns of the wafer to be tested; a is the row number of the current die, satisfying 1 ≤ a ≤ ; b is the column number of the current grain, satisfying 1 ≤ b ≤ .

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

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. The wafer positioning MAP marking method according to claim 5, characterized in that: In step 4, the abnormal grains are marked with colors, 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 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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