Defect positioning method of graphic silicon wafer on appearance equipment

Abstract

The invention provides a defect positioning method of a graphic silicon wafer on appearance equipment. For a small-size die product, defect detection is carried out by using a die merging method to obtain a defect graph, and each measurement area on the defect graph is composed of p * q merged die areas; measuring equipment is used for observing the defect map, calibration alignment point positions A (x1, y1) and B (x2, y2) are marked on the defect map, and the calibration alignment point positions comprise a plurality of suspected original points; and judging whether each suspected original point at the calibration alignment point positions A and B is a real original point or not by utilizing the geometrical relationship. According to the method, low-precision equipment can be reused, the equipment upgrading expenditure is reduced, and the operation cost of a company is reduced; the precision is improved, the efficiency is improved, and the confirmation of the merged die original point does not need defect positioning any more.

Description

Technical Field

[0001] The invention relates to the field of semiconductor technology, and in particular to a method for locating defects of a graphic silicon wafer on an appearance device. Background Art

[0002] When the single-side size of the product die is less than 1500mm, due to the single-row die number limit of the inspection machine, it is necessary to conduct inspection through mergedie (multiples of the actual die). Figure 1 After merging dies, the die size in the (2x2) map becomes larger, but the dies are the same under the microscope. It is difficult to determine which 4 adjacent dies are the origin of the merged die in the application. Figure 2 , it is not possible to confirm whether they are the 4 yellow dies or the 4 red dies, and manual positioning can only be guessed.

[0003] Common microscope positioning methods in existing technologies:

[0004] 1. Please refer to Figure 3 , the origin is roughly aligned (allowable deviation), and the solution of finding large-sized defects to correct the coordinates is used, but the accuracy is poor, the deviation is large, and there are certain requirements for the applicable wafers (large-sized defects). When the defects are small, this method cannot be applied;

[0005] 2. Please refer to Figure 4 The microscope adds an image processing module, takes a picture and stores it, and then uses the image search to locate it. However, the machine needs to be modified, which is costly; files need to be created for different wafers, and the reuse rate is low; when the image contrast is low, the image search will fail.

[0006] In order to solve the above problems, it is necessary to propose a new defect location method for graphic silicon wafers on appearance equipment. Summary of the invention

[0007] In view of the shortcomings of the prior art described above, an object of the present invention is to provide a defect location method for a graphic silicon wafer on an appearance device, which is used to solve the problem in the prior art that the die size in the defect map becomes larger after the dies are merged, but the dies are the same under a microscope, and it is difficult to determine which merged adjacent dies are the origin of the merged die in an application.

[0008] To achieve the above-mentioned purpose and other related purposes, the present invention provides a method for locating defects of a patterned silicon wafer on an appearance device, comprising:

[0009] Step 1: Use the die merging method to perform defect detection to obtain a defect map, where each measurement area on the defect map consists of p*q merged die areas;

[0010] Step 2: Use the measuring equipment to observe the defect map, mark the calibration points A (x1, y1) and B (x2, y2) on the defect map, and the calibration points include multiple suspected origins;

[0011] Step 3: Use geometric relationships to determine whether each suspected origin at the calibration alignment points A and B is the true origin.

[0012] Preferably, the single side of the die in step one is less than 1500um.

[0013] Preferably, p and q in step 1 are positive integers greater than or equal to 2.

[0014] Preferably, the measuring device in step 2 is a microscope.

[0015] Preferably, the calibration alignment points A (x1, y1) and B (x2, y2) in step 2 are located at 1 / 4 and 3 / 4 of the original diameter of the wafer respectively.

[0016] Preferably, the method for determining whether each suspected origin in step three is a true origin includes: the distance between any merged die angle coordinate and the starting die angle coordinate is a multiple of the die, obtaining the deviation value between the suspected origin and the starting die angle coordinate, and determining whether the suspected origin is a true origin based on the size of the deviation value.

[0017] Preferably, the method for obtaining the deviation value e in step three includes: the size of the combined die in the x and y directions is (u, v), the size of a single die in the x and y directions is (o, m), the starting die coordinates are (z, c), the deviation between the measurement equipment and the defect map is p, then the deviation multiple of the suspected origin in the x-axis direction from u is t=│(the distance between the suspected origin and the starting die in the x-axis + or -p) / u)│, and the deviation multiple of the suspected origin in the y-axis direction from u is t=│(the distance between the suspected origin and the starting die in the y-axis + or -p) / v)│; if the deviation value e of the suspected origin is e=│t-[t]│, [t] is a value rounded up or down; when the deviation values ​​e of the suspected origin in the x-axis direction and the y-axis direction are both < the error threshold, the suspected origin is defined as the true origin.

[0018] Preferably, the error threshold in step three is 0.1.

[0019] Preferably, step three also includes calculating the vertical coordinate position of the true origin at another calibration alignment point after calculating the true origin at one calibration alignment point, and when the deviation value e of the suspected origin at the other calibration alignment point in the x-axis direction is less than the error threshold, the suspected origin is defined as the true origin.

[0020] Preferably, the method for obtaining the horizontal points in step three includes: calibrating the slope m = │(y2 - y1) / (x2 - x1)│ of the alignment points A(x1, y1) and B(x2, y2). When the measuring device moves, there is a deviation δ: m = │[(y2 + δ) - (y1 + δ)] / (x2 - x1)│. After calculating the true origin at a calibrated alignment point, a slope threshold is set. If the maximum error slope is less than the slope threshold, the two points are defined to be on the same horizontal line.

[0021] Preferably, the method for determining whether each suspected origin is a true origin in step three includes: within a circle of known size, when the distance between any combined die corner coordinate and the starting die corner coordinate is a multiple relationship of the die, then the number of valid dies within the circle drawn with this combined die corner coordinate is equal to the number drawn with the starting die corner coordinate; conversely, there is an error tangent to the circumference, resulting in inconsistent numbers of valid dies; the number of valid dies within the circle drawn with the suspected origin is used to determine whether it is a true origin.

[0022] Preferably, the method for determining whether it is a true origin by the number of valid dies within the circle drawn with the suspected origin in step three includes: calculating the radius r of the circle based on the wafer size; calculating the distance from the outermost corner to the starting die corner coordinate using the Pythagorean theorem according to the starting die corner coordinate and the size of the die. If d > r, it is an invalid chip outside the circle; if d < r, it is a valid chip inside the circle, and the number of valid chips n is calculated; by positioning different suspected origins, the number of valid chips mx generated by different suspected origins is calculated. When mx = n, it indicates that this point is the true origin.

[0023] Preferably, a notch for rough alignment is formed in the lower half of the wafer in step three, and then the number of valid dies above the center point is calculated.

[0024] Preferably, if the deviation between the measuring device and the defect map in step three is p, then the number of valid chips generated by the non - deviation, x - axis + p deviation, x - axis - p deviation, y - axis + p deviation, and y - axis - p deviation of different suspected origins are calculated respectively.

[0025] Preferably, step three further includes determining whether it is a true origin according to the absolute deviation sum and data range of multiple groups of valid chip numbers of each suspected origin.

[0026] As described above, the method for defect location of the chip of the present invention on the appearance device has the following beneficial effects:

[0027] The method of the present invention enables the reuse of low - precision devices, reduces equipment upgrade expenses and lowers the company's operation costs; improves precision and efficiency, and the confirmation of the combined die origin no longer requires defect location. Description of the Drawings

[0028] Figure 1 Shown is a schematic diagram of a merged die in the prior art;

[0029] Figure 2 The merged die shown is difficult to identify schematic diagram of the prior art;

[0030] Figure 3 Shown is a schematic diagram of a defect location method in the prior art;

[0031] Figure 4 Shown is a schematic diagram of another defect location method of the present invention;

[0032] Figure 5 Shown is a schematic diagram of the process flow of the present invention;

[0033] Figure 6 Shown is a schematic diagram of finding a horizontal point according to the present invention;

[0034] Figure 7 The display is a defect image and a microscope image of a deviation identification method according to an embodiment of the present invention;

[0035] Figure 8 Displays a defect image and a microscope image of a counting and recognition method according to an embodiment of the present invention;

[0036] Fig. 9 It is a schematic diagram showing the counting and recognition method of one embodiment of the present invention for calculating the number of dies at different points. DETAILED DESCRIPTION

[0037] The following describes the embodiments of the present invention through specific examples, and those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified or changed in various ways based on different viewpoints and applications without departing from the spirit of the present invention.

[0038] See also Figure 5 The present invention provides a method for locating defects of a patterned silicon wafer on an appearance device, comprising:

[0039] Step 1: Use the die merging method to perform defect detection to obtain a defect map, where each measurement area on the defect map consists of p*q merged die areas;

[0040] In some embodiments, a single die in step 1 has a single side less than 1500 mm.

[0041] In some embodiments, p and q in step 1 are positive integers greater than or equal to 2.

[0042] Step 2: Use the measuring equipment to observe the defect map, mark the calibration points A (x1, y1) and B (x2, y2) on the defect map, and the calibration points include multiple suspected origins;

[0043] In some embodiments, the measuring device in step 2 is a microscope.

[0044] In some embodiments, the calibration alignment points A (x1, y1) and B (x2, y2) in step 2 are located at 1 / 4 and 3 / 4 of the original diameter of the wafer, respectively.

[0045] Step 3: Use geometric relationships to determine whether each suspected origin at the calibration alignment points A and B is the true origin.

[0046] In some embodiments, the method for determining whether each suspected origin is a true origin in step three includes: the distance between any merged die angle coordinate and the starting die angle coordinate is a multiple of the die, obtaining the deviation value between the suspected origin and the starting die angle coordinate, and determining whether the suspected origin is a true origin based on the size of the deviation value.

[0047] In some embodiments, the method for obtaining the deviation value e in step three includes: the size of the merged die in the x and y directions is (u, v), the size of a single die in the x and y directions is (o, m), the starting die coordinates are (z, c), and the deviation between the measurement equipment and the defect map is p, then the deviation multiple of the suspected origin in the x-axis direction from u is t=│(the distance between the suspected origin and the starting die in the x-axis + or -p) / u)│, and the deviation multiple of the suspected origin in the y-axis direction from u is t=│(the distance between the suspected origin and the starting die in the y-axis + or -p) / v)│; if the deviation value e of the suspected origin is e=│t-[t]│, [t] is a value rounded up or down; when the deviation values ​​e of the suspected origin in the x-axis direction and the y-axis direction are both < the error threshold, the suspected origin is defined as the true origin.

[0048] In some embodiments, the error threshold in step three is 0.1.

[0049] For example, see Figure 7 , Merge die size(2924,3704); die size(1462,1852); starting coordinates(-1483,-192);

[0050] Assume that the deviation between the 0,0 coordinates of the microscope stage and the test map is +-50um; the equipment calibration alignment points are located at 1 / 4 (-48267, 3512) and 3 / 4 (48225, 3512) of the original diameter;

[0051] Site1's methods for finding locations include:

[0052] X①=(48267(±50)-1483(starting point)) / 2924=16.02(15.98);

[0053] Y①=(3512(±50)+192(starting point)) / 3704=1.013(0.98);

[0054] X②=(48267(±50)-1462-1483) / 2924=15.52(15.48);

[0055] Y②=(3512(±50)+192) / 3704=1.013 (0.98), the point deviates by 0.48 die in the X direction;

[0056] X③=(48267(±50)-1483) / 2924=16.02(15.98);

[0057] Y③=(3512(±50)+192+1852) / 3704=1.513 (1.487), the point deviates in the Y direction by 0.48 die;

[0058] X④=(48267(±50)-1462-1483) / 2924=15.52(15.48);

[0059] Y④=(3512(±50)+192+1852) / 3704=1.513(1.487), the point deviates by 0.48 in the X and Y directions respectively;

[0060] When e<0.1, it is considered to be the error value of the machine, and this point is a multiple of the starting point.

[0061] When e>0.1, the surface deviation is much larger than the machine error and is considered to be a multiple of the starting point.

[0062] Site2's methods for finding locations include:

[0063] After identifying site1 (X①, Y①) as the origin, according to the horizontal line principle, the corresponding points of site2 are ⑤ and ⑥.

[0064] X⑤=(48225(±50)+1483(starting point)) / 2924=17.02(16.98);

[0065] Y⑤=(3512(±50)+192(starting point)) / 3704=1.01(0.99);

[0066] X⑥=(48225(±50)+1483+1462) / 2924=17.52(17.48);

[0067] Y⑥=(3512(±50)+192) / 3704=1.01(0.99).

[0068] Conclusion: If the deviation e of the two points from the integer is less than 0.1, the origin of site1 is ①, and the origin of site2 is ⑤.

[0069] In some embodiments, step three also includes calculating the vertical coordinate position of the true origin at another calibration alignment point after calculating the true origin at one calibration alignment point, and when the deviation value e of the suspected origin at the other calibration alignment point in the x-axis direction is < the error threshold, the suspected origin is defined as the true origin.

[0070] In some embodiments, the method for obtaining a horizontal point in step three includes: calibrating the slopes of the alignment points A (x1, y1) and B (x2, y2) m = │(y2-y1) / (x2-x1)│, there is a deviation δ when the measuring device moves: m = │[(y2+δ)-(y1+δ)] / (x2-x1)│, after calculating the true origin at a calibrated alignment point, setting a slope threshold, if the maximum error slope is less than the slope threshold, the two points are defined to be on the same horizontal line.

[0071] For example, see Figure 6 Due to the limitation of the defect detection equipment to test dies in the same row, when the single side of a small die is less than 1500um, it will be tested through merge die (2x2, 2x3...) and a defect map will be generated. This method is for such small dies and defect location after merge die testing.

[0072] The key to microscope positioning is wafer alignment. Figure 6 The defect images shown are site 1 and site 2. The example is displayed in 2x2 format, and the dies are neatly arranged under a microscope.

[0073] Methods for finding the horizontal points of site1 and site2 include:

[0074] site1:(-46784,11)site2:(52632,43);die size(1462,1852);

[0075] If the device error is set to 50um, the error slope range is:

[0076] M1 = │((43 + 50) - (11 - 50)) / (52632 + 46784)│ = 0.00133;

[0077] M2 = │((43 - 50) - (11 + 50)) / (52632 + 46784)│ = 0.00069;

[0078] The slope threshold takes the maximum value: M1 = 0.00133;

[0079] In Figure 6 the right figure of

[0080] M① = (43 + 1852 - 11) / (52632 + 46784) = 0.019;

[0081] M② = (43 - 11) / (52632 + 46784) = 0.0003;

[0082] M③ = │(43 - 1852 - 11) / (52632 + 46784)│ = 0.0183.

[0083] Conclusion: M② < M1, it is considered that the two points are on the same horizontal line, otherwise M① and M③ are not on the same horizontal line.

[0084] In some embodiments, the method for determining whether each suspected origin is a true origin in step three includes: within a circle of known size, when the distance between any combined die corner coordinate and the starting die corner coordinate is a multiple of the die, then the number of valid dies within the circle drawn with this combined die corner coordinate is equal to the number drawn with the starting die corner coordinate; conversely, there is an error tangent to the circumference, resulting in inconsistent numbers of valid dies; the number of valid dies within the circle drawn with the suspected origin is used to determine whether it is a true origin.

[0085] In some embodiments, the method for determining whether a suspected origin is a true origin by the number of valid dies within the circle drawn with the suspected origin in step three includes: calculating the radius r of the circle based on the wafer size; calculating the distance from the outermost angle to the starting die corner coordinate using the Pythagorean theorem based on the starting die corner coordinate and the die size, d > r means the chip is invalid outside the circle, d < r means the chip is valid inside the circle, and calculating the number of valid chips n; by positioning different suspected origins, calculating the number of valid chips mx generated by different suspected origins, when mx = n, it indicates that this point is the true origin.

[0086] In some embodiments, a notch for rough alignment is formed in the lower half of the wafer, then calculate the number of valid dies above the center point.

[0087] In some embodiments, if the deviation between the measurement device and the defect map in step three is p, then the number of valid chips generated without deviation, with a deviation of +p on the x-axis, -p on the x-axis, +p on the y-axis, and -p on the y-axis for different suspected origin points is calculated respectively.

[0088] In some embodiments, step three further includes determining whether each suspected origin point is a true origin based on the absolute deviation and data range (range) of multiple groups of valid chip numbers for each suspected origin point.

[0089] For example, please refer to Figure 8 , Merge die size(2924,3704); die size(1462,1852); starting coordinates (-1483,-192);

[0090] The counting identification method includes:

[0091] 1. Calculation of test die

[0092] According to the two-dimensional coordinate map automatically generated by the test machine, calculate the number of valid dies above the center point (there is a notch in the lower half, resulting in calculation errors);

[0093] Valid die: 1326.

[0094] 2. Discriminate the origin by calculating valid dies

[0095] Assume that the deviation between the coordinates of 0, 0 of the machine and the test map is +-50um, and the equipment calibration alignment points are at 1 / 4 (-48267, 3512) and 3 / 4 (48225, 3512) of the original diameter. Given the WaferSize (wafer size), MergeDieSize (merged die size), hypothetical origin coordinates, and circle radius r (100000um). Use progressive calculation to calculate the distance of the die corner farthest from the center of the circle:

[0096] For example, Die1 = √x^2 + y^2 = √1441^2 + 3517^2 = 3800 < r (inside the circle)

[0097] ……Die34 = √97933^2 + 3517^2 = 97996 < r (inside the circle)

[0098] Die35 = (100857, 3517) > r (outside the circle, not counted)

[0099] Please refer to Fig. 9 , according to points ① to ④, calculate the die quantity distribution as follows: the absolute deviation < 1 and range < 2 is the origin.

[0100] It should be noted that the illustrations provided in this embodiment are only used to illustrate the basic concept of the present invention in a schematic manner. Therefore, the drawings only show components related to the present invention rather than being drawn according to the number, shape and size of components in actual implementation. In actual implementation, the type, quantity and proportion of each component may be changed arbitrarily, and the component layout may also be more complicated.

[0101] In summary, the method of the present invention allows low-precision equipment to be reused, reducing equipment upgrade expenses and company operating costs; the accuracy is improved, the efficiency is improved, and the confirmation of the combined die origin does not require defect positioning. Therefore, the present invention effectively overcomes various shortcomings in the prior art and has a high industrial utilization value.

[0102] The above embodiments are merely illustrative of the principles and effects of the present invention, and are not intended to limit the present invention. Anyone familiar with the art may modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by a person of ordinary skill in the art without departing from the spirit and technical concept disclosed by the present invention shall still be covered by the claims of the present invention.

Claims

1. A method for locating defects of a patterned silicon wafer on an appearance device, characterized in that: At least: Step 1: Use the die merging method to perform defect detection to obtain a defect map, where each measurement area on the defect map consists of p*q merged die areas; Step 2: Use the measuring equipment to observe the defect map, mark the calibration points A (x1, y1) and B (x2, y2) on the defect map, and the calibration points include multiple suspected origins; Step 3: Use geometric relationships to determine whether each suspected origin at the calibration alignment points A and B is the true origin.

2. The defect location method of a patterned silicon wafer on an appearance device according to claim 1, characterized in that: The single side of the die in step 1 is less than 1500 mm.

3. The chip defect location method on the appearance device according to claim 1, characterized in that: In step 1, p and q are positive integers greater than or equal to 2.

4. The defect location method of a patterned silicon wafer on an appearance device according to claim 1, characterized in that: The measuring device in step 2 is a microscope.

5. The defect location method of a patterned silicon wafer on an appearance device according to claim 1, characterized in that: The calibration alignment points A (x1, y1) and B (x2, y2) in step 2 are located at 1 / 4 and 3 / 4 of the original diameter of the wafer respectively.

6. The defect location method of a patterned silicon wafer on an appearance device according to claim 1, characterized in that: The method for determining whether each suspected origin in step three is a real origin includes: the distance between any merged die corner coordinate and the starting die corner coordinate is a multiple of the die, obtaining the deviation value between the suspected origin and the starting die corner coordinate, and determining whether the suspected origin is a real origin based on the size of the deviation value.

7. The defect location method of a patterned silicon wafer on an appearance device according to claim 6, characterized in that: The method for obtaining the deviation value e in step three includes: the size of the combined die in the x and y directions is (u, v), the size of a single die in the x and y directions is (o, m), the starting die coordinates are (z, c), the deviation between the measurement equipment and the defect map is p, then the deviation multiple of the suspected origin in the x-axis direction from u is t=│(the distance between the suspected origin and the starting die in the x-axis + or -p) / u)│, and the deviation multiple of the suspected origin in the y-axis direction from u is t=│(the distance between the suspected origin and the starting die in the y-axis + or -p) / v)│; if the deviation value e of the suspected origin is e=│t-[t]│, [t] is a value rounded up or down; when the deviation values ​​e of the suspected origin in the x-axis direction and the y-axis direction are both < the error threshold, the suspected origin is defined as the true origin.

8. The defect location method of a patterned silicon wafer on an appearance device according to claim 7, characterized in that: The error threshold in step three is 0.

1.

9. The defect location method of a patterned silicon wafer on an appearance device according to claim 8, characterized in that: Step three also includes calculating the vertical coordinate position of the true origin at another calibration alignment point by using the method of obtaining horizontal points after calculating the true origin at one calibration alignment point. When the deviation value e of the suspected origin at the other calibration alignment point in the x-axis direction is less than the error threshold, the suspected origin is defined as the true origin.

10. The defect location method of a patterned silicon wafer on an appearance device according to claim 9, characterized in that: The method for obtaining the horizontal point in step three includes: calibrating the slope m of the alignment points A (x1, y1) and B (x2, y2) = |(y2-y1) / (x2-x1)|, there is a deviation δ when the measuring device moves: m = |[(y2+δ)-(y1+δ)] / (x2-x1)|, after calculating the true origin at a calibration alignment point, setting a slope threshold, if the maximum error slope is less than the slope threshold, the two points are defined to be on the same horizontal line.

11. The defect location method of a patterned silicon wafer on an appearance device according to claim 1, characterized in that: The method for determining whether each suspected origin in Step 3 is a true origin includes: within a circle of known size, when the distance between any combined die corner coordinate and the starting die corner coordinate is a multiple of the die, the number of valid dies within the circle drawn with this combined die corner coordinate is equal to the number drawn with the starting die corner coordinate; conversely, there is an error tangent to the circumference, resulting in inconsistent numbers of valid dies; determine whether it is a true origin based on the number of valid dies within the circle drawn with the suspected origin.

12. The defect location method of a patterned silicon wafer on an appearance device according to claim 11, characterized in that: The method for determining whether it is a true origin based on the number of valid dies within the circle drawn with the suspected origin in Step 3 includes: calculate the radius r of the circle based on the wafer size; calculate the distance between the outermost angle and the starting die corner coordinate using the Pythagorean theorem based on the starting die corner coordinate and the die size, where d > r means invalid die outside the circle and d < r means valid die inside the circle, and calculate the number of valid dies n; by locating different suspected origins, calculate the number of valid chips mx generated by different suspected origins, and when mx = n, it indicates that this point is the true origin.

13. The defect location method of a patterned silicon wafer on an appearance device according to claim 11, characterized in that: In Step 3, a notch for rough alignment is formed in the lower half of the wafer, then calculate the number of valid dies with the center point above.

14. The defect location method of a patterned silicon wafer on an appearance device according to claim 11, characterized in that: If the deviation between the measuring device and the defect map in Step 3 is p, then calculate the number of valid chips generated by different suspected origins without deviation, x-axis + p deviation, x-axis - p deviation, y-axis + p deviation, and y-axis - p deviation respectively.

15. The defect location method of a patterned silicon wafer on an appearance device according to claim 14, characterized in that: Step 3 also includes determining whether each suspected origin is a true origin based on the absolute deviation sum and data range of multiple groups of valid chip numbers of each suspected origin.

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