Wafer drum ring width measurement method

Abstract

The application relates to the technical field of semiconductor integrated circuit manufacturing, in particular to a wafer drum ring width measuring method. The wafer drum ring width measuring method comprises the following steps: determining a fixed point on a drum ring; aligning a focal plane with an inner edge of the drum ring, obtaining a first image, and the fixed point is located in the first image; measuring a first distance between the fixed point and the inner edge of the drum ring based on the first image; aligning the focal plane with an outer edge of the drum ring, obtaining a second image, and the fixed point is located in the second image; measuring a second distance between the fixed point and the outer edge of the drum ring based on the second image; and determining a ring width of the drum ring based on the sum of the first distance and the second distance. The wafer drum ring width measuring method can solve the problem of inaccurate drum ring ring width measurement in the related art.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of semiconductor integrated circuit manufacturing, in particular to a wafer drum ring width measurement method. BACKGROUND

[0002] The drum ring prepared through the drum thinning process can provide support force for the wafer in manufacturing and reduce wafer warping problems. In the process of making the drum ring, edge detection needs to be performed on the drum ring to determine the ring width, so as to ensure the stability of the machine table, make the wafer thinning process concentric without deviation, and avoid the problem of broken pieces in the later process.

[0003] Figure 1 A sectional view of a wafer with a drum ring is shown in FIG. 1. Figure 1 As can be seen from FIG. 1, the drum ring includes a main ring area 110 and an arc surface area 120 located at the outer edge of the main ring area 110. However, the actual width of the arc surface area 120 is difficult to determine, so the related art usually estimates the ring width of the drum ring by actually measuring the width of the main ring area 110 plus a fixed adjustment value of the arc surface area 120.

[0004] However, the size of the arc surface area varies for different batches of wafers, and it is inevitable that the estimated ring width of the drum ring will deviate from the actual ring width by using a fixed adjustment value of the arc surface area, which is not conducive to the judgment of the ring width by the machine table. SUMMARY

[0005] The present application provides a wafer drum ring width measurement method, which can solve the problem of inaccurate drum ring width measurement in the related art.

[0006] In order to solve the technical problems described in the background art, the present application provides a wafer drum ring width measurement method, which comprises the following steps:

[0007] determining a fixed point from the drum ring;

[0008] aligning the focal plane with the inner edge of the drum ring to obtain a first image, and the fixed point is located in the first image;

[0009] measuring a first distance between the fixed point and the inner edge of the drum ring based on the first image;

[0010] aligning the focal plane with the outer edge of the drum ring to obtain a second image, and the fixed point is located in the second image;

[0011] measuring a second distance between the fixed point and the outer edge of the drum ring based on the second image;

[0012] determine a ring width of the tambour ring based on the sum of the first distance and the second distance.

[0013] Optionally, the step of measuring the first distance between the fixed point and the inner edge of the tambour ring based on the first image comprises:

[0014] establishing a first coordinate system in the first image;

[0015] obtaining coordinate information (x1, y1) of the fixed point in the first coordinate system from the first image;

[0016] obtaining a curve function f(x, y) = 0 of the inner boundary line of the tambour ring in the first coordinate system from the first image, and setting a first random point (u, v) as an arbitrary point on the inner boundary line, i.e. f(u, v) = 0;

[0017] determining a first vector function W1 = (u, v) - (x1, y1) from the fixed point to the first random point based on the coordinate information (x1, y1) of the fixed point in the first coordinate system and the curve function f(x, y) = 0 of the inner boundary line in the first coordinate system, wherein f(u, v) = 0;

[0018] determining a minimum value of the first vector function as the first distance between the fixed point and the inner edge of the tambour ring.

[0019] Optionally, the step of obtaining the curve function f(x, y) = 0 of the inner boundary line of the tambour ring in the first coordinate system from the first image comprises:

[0020] obtaining coordinate information of at least three points on the inner boundary line from the first image;

[0021] determining center coordinate information and a radius of the inner boundary line in the first coordinate system based on the coordinate information of the at least three points on the inner boundary line;

[0022] determining the curve function f(x, y) = 0 of the inner boundary line in the first coordinate system based on the center coordinate information and the radius of the inner boundary line in the first coordinate system.

[0023] Optionally, the step of measuring the second distance between the fixed point and the outer edge of the tambour ring based on the second image comprises:

[0024] establishing a second coordinate system in the second image;

[0025] obtaining coordinate information (m2, n2) of the fixed point in the second coordinate system from the second image;

[0026] obtaining a curve function f(m, n)=0 of the outer boundary line of the tambour ring in the second coordinate system from the second image, and setting a second random point (p, q) as an arbitrary point on the outer boundary line, i.e. f(p, q)=0;

[0027] determining a second vector function W2=(p, q)-(m2, n2) from the fixed point to the second random point based on the coordinate information (m2, n2) of the fixed point in the second coordinate system and the curve function f(m, n)=0 of the outer boundary line in the second coordinate system, wherein f(p, q)=0;

[0028] determining a minimum value of the second vector function as a second distance between the fixed point and the outer edge of the tambour ring.

[0029] Optionally, the step of obtaining the curve function f(m, n)=0 of the outer boundary line of the tambour ring in the second coordinate system from the second image comprises:

[0030] obtaining coordinate information of at least three points on the outer boundary line from the second image;

[0031] determining center coordinate information and a radius of the outer boundary line in the second coordinate system based on the coordinate information of the at least three points on the outer boundary line;

[0032] determining the curve function f(m, n)=0 of the outer boundary line in the second coordinate system based on the center coordinate information and the radius of the outer boundary line in the second coordinate system.

[0033] Optionally, the fixed point is located at an arbitrary position of the tambour ring.

[0034] Optionally, in the first image, the inner edge of the tambour ring is displayed as a clear inner boundary line.

[0035] Optionally, in the second image, the outer edge of the tambour ring is displayed as a clear outer boundary line.

[0036] The technical scheme of the present application has at least the following advantages: by respectively aligning a focal plane with an inner edge and an outer edge of a tambour ring to obtain a first image and a second image, wherein in the first image, the inner edge of the tambour ring is displayed as a clear inner boundary line, and in the second image, the outer edge of the tambour ring is displayed as a clear outer boundary line, the sum of a distance between a fixed point and the inner boundary line and a distance between the fixed point and the outer boundary line is calculated as a ring width of the tambour ring, so that the calculated ring width of the tambour ring is closer to an actual value, and the problem of inaccurate ring width measurement is avoided. BRIEF DESCRIPTION OF DRAWINGS

[0037] In order to more clearly illustrate the technical solutions in the specific embodiments of the present application or the prior art, the accompanying drawings needed to be used in the specific embodiments or prior art description will be briefly introduced. Obviously, the accompanying drawings in the following description are some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative effort based on these drawings.

[0038] Figure 1 A wafer cross-section structure schematic diagram with a drum ring in the related art is shown;

[0039] Figure 2 A wafer drum ring width measurement method flowchart provided by an embodiment of the present application is shown;

[0040] Figure 3 A schematic diagram of measuring a first distance between the fixed point and the inner edge of the drum ring in the first image is shown;

[0041] Figure 4 A schematic diagram of measuring a second distance between the fixed point and the outer edge of the drum ring in the second image is shown. DETAILED DESCRIPTION

[0042] The technical solutions in the present application will be described in detail below with reference to the accompanying drawings. Obviously, the described embodiments are only some of the embodiments of the present application, not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative effort fall within the scope of the present application.

[0043] In the description of the present application, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc. indicate the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the present application. In addition, the terms "first", "second", "third" are only for descriptive purposes and cannot be understood as indicating or implying relative importance.

[0044] In the description of the present application, it should be noted that unless specifically defined and limited otherwise, the terms "mount", "connect", "connection" should be understood broadly, for example, can be fixed connection, can also be detachable connection, or integrally connected; can be mechanical connection, can also be electrical connection; can be directly connected, can also be indirectly connected through an intermediate medium, can also be the internal communication of two elements, can be wireless connection, can also be wired connection. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0045] In addition, the technical features involved in the different embodiments of the present application described below can be combined with each other as long as there is no conflict between them.

[0046] Figure 2 The flow chart of the wafer drum ring width measurement method provided by an embodiment of the present application is shown, from Figure 2 It can be seen from the wafer drum ring width measurement method that the wafer drum ring width measurement method comprises the following steps S1 to S6, wherein:

[0047] Step S1: determining a fixed point from the drum ring.

[0048] The fixed point can be located at any position of the drum ring.

[0049] Step S2: aligning the focal plane with the inner edge of the drum ring, obtaining a first image, and the fixed point is located in the first image.

[0050] Since the focal plane is aligned with the inner edge of the drum ring in step S2, the inner edge of the drum ring is displayed as a clear inner boundary line in the first image.

[0051] Step S3: measuring the first distance between the fixed point and the inner edge of the drum ring based on the first image.

[0052] The first image obtained after step S2 includes a clear inner boundary line that can represent the inner edge of the drum ring, and the fixed point is located in the first image, so that the first distance D1 between the fixed point and the inner edge of the drum ring can be accurately measured according to the first image.

[0053] Figure 3 A schematic diagram of measuring the first distance between the fixed point and the inner edge of the drum ring in the first image is shown.

[0054] The process of obtaining the first distance in step S3 can be realized by the following steps S31 to S35 in sequence, which will be described below: Figure 3

[0055] ​Step S31: Establishing a first coordinate system in the first image.

[0056] Step S32: Obtaining coordinate information (x1, y1) of the fixed point in the first coordinate system from the first image.

[0057] Step S33: Obtaining a curve function f(x, y)=0 of the inner boundary line of the taiko ring in the first coordinate system from the first image, and setting a first random point (u, v) as an arbitrary point on the inner boundary line, i.e. f(u, v)=0.

[0058] Where x represents a horizontal coordinate variable in the first coordinate system, and y represents a vertical coordinate variable in the first coordinate system.

[0059] Step S34: Based on the coordinate information (x1, y1) of the fixed point in the first coordinate system, and the curve function f(x, y)=0 of the inner boundary line in the first coordinate system, determining a first vector function W1=(u, v)-(x1, y1) from the fixed point to the first random point, where f(u, v)=0.

[0060] Step S35: Determining the minimum value of the first vector function as the first distance between the fixed point and the inner edge of the taiko ring.

[0061] Wherein, the process of step S33 for obtaining the curve function f(x, y)=0 of the inner boundary line in the first coordinate system can be performed by the following steps S331 to S333:

[0062] Step S331: Obtaining coordinate information of at least three points on the inner boundary line from the first image.

[0063] Step S332: Based on the coordinate information of the at least three points on the inner boundary line, determining the center coordinate information and the radius of the inner boundary line in the first coordinate system.

[0064] Step S333: Based on the center coordinate information and the radius of the inner boundary line in the first coordinate system, determining the curve function f(x, y)=0 of the inner boundary line in the first coordinate system.

[0065] Step S4: Aligning the focal plane to the outer edge of the taiko ring, obtaining a second image, and the fixed point is located in the second image.

[0066] Since the focal plane is aligned to the outer edge of the taiko ring in step S4, the outer edge of the taiko ring is displayed as a clear outer boundary line in the second image.

[0067] Step S5: measuring a second distance between the fixed point and the outer edge of the drum ring based on the second image.

[0068] The second image obtained after step S5 includes a clear outer boundary line that can represent the outer edge of the drum ring, and the fixed point is located in the second image, so that the second distance D2 between the fixed point and the outer edge of the drum ring can be accurately measured according to the second image.

[0069] Figure 4 A schematic diagram of measuring the second distance between the fixed point and the outer edge of the drum ring in the second image is shown.

[0070] The process of obtaining the second distance in step S5 can be achieved by the following steps S51 to S55 in sequence, which will be described below in combination with Figure 4 :

[0071] Step S51: establishing a second coordinate system in the second image.

[0072] The second coordinate system can be the same coordinate system as the first coordinate system, or can be a different coordinate system.

[0073] Step S52: obtaining coordinate information (m2, n2) of the fixed point in the second coordinate system from the second image.

[0074] Step S53: obtaining a curve function f(m, n)=0 of the outer boundary line of the drum ring in the second coordinate system from the second image, and setting a second random point (p, q) as an arbitrary point on the outer boundary line, i.e. f(p, q)=0.

[0075] Where m represents the horizontal coordinate variable in the second coordinate system, and n represents the vertical coordinate variable in the second coordinate system.

[0076] Step S54: determining a second vector function W2=(p, q)-(m2, n2) of the fixed point to the second random point based on the coordinate information (m2, n2) of the fixed point in the second coordinate system and the curve function f(m, n)=0 of the outer boundary line in the second coordinate system, where f(p, q)=0.

[0077] Step S55: determining the minimum value of the second vector function as the second distance between the fixed point and the outer edge of the drum ring.

[0078] Wherein, the process of step S53 to obtain the curve function f(m, n)=0 of the outer boundary line in the second coordinate system can be performed by the following steps S531 to S533:

[0079] Step S531: Obtain coordinate information of at least three points on the outer boundary line from the second image.

[0080] Step S532: Determine the center coordinate information and the radius of the outer boundary line in the second coordinate system based on the coordinate information of the at least three points on the outer boundary line.

[0081] Step S533: Determine the curve function f(m, n) = 0 of the outer boundary line in the second coordinate system based on the center coordinate information and the radius of the outer boundary line in the second coordinate system.

[0082] Step S6: Determine the ring width of the taiko ring based on the sum of the first distance and the second distance.

[0083] That is, the ring width of the taiko ring = the first distance D1 + the second distance D2.

[0084] As can be seen from the above, the embodiments of the present application obtain the first image and the second image by respectively aligning the focal plane to the inner edge and the outer edge of the taiko ring, wherein in the first image, the inner edge of the taiko ring is displayed as a clear inner boundary line, and in the second image, the outer edge of the taiko ring is displayed as a clear outer boundary line. The sum of the distance between a fixed point and the inner boundary line and the distance between the fixed point and the outer boundary line is calculated as the ring width of the taiko ring, so that the calculated ring width of the taiko ring is closer to the actual value, and the problem of inaccurate ring width measurement is avoided.

[0085] Obviously, the above embodiments are merely examples for clear illustration, and are not intended to limit the embodiments. Based on the above description, other different forms of changes or variations can be made by those of ordinary skill in the art. Here, all the embodiments do not need to be exhausted, and the obvious changes or variations derived therefrom are still within the protection scope of the present application.

Claims

1. A method of measuring the width of a wafer drum ring, characterized by, The wafer drum ring width measurement method comprises the following steps: determining a fixed point on the drum ring, the fixed point being located at any position of the drum ring; aligning the focal plane to the inner edge of the drum ring, obtaining a first image, the fixed point being located in the first image, in which the inner edge of the drum ring is displayed as a clear inner boundary line; measuring a first distance between the fixed point and the inner edge of the drum ring based on the first image; aligning the focal plane to the outer edge of the drum ring, obtaining a second image, the fixed point being located in the second image, in which the outer edge of the drum ring is displayed as a clear outer boundary line; measuring a second distance between the fixed point and the outer edge of the drum ring based on the second image; determining the ring width of the drum ring based on the sum of the first distance and the second distance.

2. The wafer drum ring width measurement method of claim 1, wherein, The step of measuring the first distance between the fixed point and the inner edge of the drum ring based on the first image comprises: establishing a first coordinate system in the first image; obtaining coordinate information (x1, y1) of the fixed point in the first coordinate system from the first image; obtaining a curve function f(x, y)=0 of the inner boundary line of the drum ring in the first coordinate system from the first image, and setting a first random point (u, v) as any point on the inner boundary line, i.e. f(u, v)=0; determining a first vector function W1=(u, v)-(x1, y1) from the fixed point to the first random point based on the coordinate information (x1, y1) of the fixed point in the first coordinate system and the curve function f(x, y)=0 of the inner boundary line in the first coordinate system, wherein f(u, v)=0; determining the minimum value of the first vector function as the first distance between the fixed point and the inner edge of the drum ring.

3. The wafer drum ring width measurement method of claim 2, wherein, The step of obtaining the curve function f(x, y)=0 of the inner boundary line of the drum ring in the first coordinate system from the first image comprises: obtaining coordinate information of at least three points on the inner boundary line from the first image; determining the coordinate information of the center of the circle and the radius of the inner boundary line in the first coordinate system based on the coordinate information of the at least three points on the inner boundary line; determining the curve function f(x, y)=0 of the inner boundary line in the first coordinate system based on the coordinate information of the center of the circle and the radius of the inner boundary line in the first coordinate system.

4. The wafer drum ring width measurement method of claim 1, wherein, The step of measuring the second distance between the fixed point and the outer edge of the drum ring based on the second image comprises: establishing a second coordinate system in the second image; obtaining coordinate information (m2, n2) of the fixed point in the second coordinate system from the second image; obtaining a curve function f(m, n)=0 of the outer boundary line of the drum ring in the second coordinate system from the second image, and setting a second random point (p, q) as any point on the outer boundary line, i.e. f(p, q)=0; determining a second vector function W2=(p, q)-(m2, n2) from the fixed point to the second random point based on the coordinate information (m2, n2) of the fixed point in the second coordinate system and the curve function f(m, n)=0 of the outer boundary line in the second coordinate system, wherein f(p, q)=0; determining the minimum value of the second vector function as the second distance between the fixed point and the outer edge of the drum ring. determining a second vector function W2= (p, q) - (m2, n2) of the fixed point to the second random point based on the coordinate information (m2, n2) of the fixed point in the second coordinate system and the curve function f(m, n)=0 of the outer boundary line in the second coordinate system, wherein f(p, q)=0; determining a minimum value of the second vector function as a second distance between the fixed point and the outer edge of the drum ring.

5. The wafer drum ring width measurement method of claim 4, wherein, The step of obtaining the curve function f(m, n)=0 of the outer boundary line of the drum ring in the second coordinate system from the second image comprises: obtaining coordinate information of at least three points on the outer boundary line from the second image; determining the center coordinate information and the radius of the outer boundary line in the second coordinate system based on the coordinate information of the at least three points on the outer boundary line; determining the curve function f(m, n)=0 of the outer boundary line in the second coordinate system based on the center coordinate information and the radius of the outer boundary line in the second coordinate system.

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