TW201714232A - Method for checking overlay measurement recipe and overlay measurement process - Google Patents

Abstract

A method for checking an overlay measurement recipe, and an overlay measurement process are described, wherein the recipe includes a parameter concerning that the current-layer pattern of the overlay mark is at the inner or outer side of the same. The checking method include: after an overlay measurement recipe is set, determining whether the parameter is set correctly or not according to a height difference between the inner side and the outer side of the overlay mark. The process includes: if the setting of the parameter is determined to be correct, measuring overlay errors according to the overlay measurement recipe, or, if the setting of the parameter is determined to be wrong, correcting the setting of the parameter and then measuring overlay errors according to the new overlay measurement recipe.

Description

Method for checking overlapping measurement recipes and overlapping measurement procedures

SUMMARY OF THE INVENTION The present invention relates to the detection of integrated circuit processes, and more particularly to a method of inspecting an overlay measurement recipe, and an overlay measurement procedure utilizing the method.

In the integrated circuit process, in order to ensure the alignment degree between the layer pattern and the front layer pattern, overlapping marks are usually formed at multiple places on the wafer, and each overlapping mark includes a layer pattern and a front layer pattern for measurement. Overlap error across the wafer. If the overlap error exceeds the allowable range, the setting of the exposure machine is adjusted according to the measured overlap error to achieve the purpose of reducing the overlap error of subsequent wafers.

The types of conventional overlapping marks include a normal overlapping mark on the inner side of the layer pattern and an inverted overlap mark on the outer side of the layer pattern, wherein the height of the layer pattern is greater than the height of the front layer pattern. BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a schematic diagram showing a conventional normal overlap mark, wherein the small image (A) is a top view and the small image (B) / (C) is a B-B' / C-C' sectional view. Fig. 2 is a schematic view showing a conventional inverted overlap mark, wherein the small image (A) is a top view, and the small image (B)/(C) is a B-B'/C-C' sectional view. In Figs. 1 and 2, the substrate, the front layer pattern, and the layer pattern are denoted by reference numerals 10, 12, and 14, respectively.

Prior art, after setting the overlap measurement recipe, did not check whether the setting of the parameters of the layer pattern inside or outside the overlap mark is correct. If the setting is wrong, the overlapping measurement results will be wrong, and the alignment adjustment based on the erroneous overlapping measurement results will make the overlap deviation larger.

The present invention provides a method of inspecting an overlay measurement recipe to check whether the setting of the parameters of the layer pattern on the inside or the outside of the overlay mark is correct.

The present invention provides an overlay measurement procedure that utilizes the method of the present invention for examining overlapping measurement recipes to ensure that correct overlay measurements are obtained.

The overlap measurement recipe in the method of inspecting the overlap measurement recipe of the present invention includes parameters regarding the inside or outside of the overlay pattern when the layer pattern is included, the method comprising: after setting the overlap measurement recipe, according to the inner and outer sides of the overlap mark The height difference is used to judge whether the setting of the parameter is correct.

In an embodiment of the invention, the parameter is “When the layer pattern is outside the overlapping mark”, and the determining comprises: when the value of the parameter is YES, checking whether the height of the inner side of the overlapping mark is greater than the outer side, If yes, it means that the setting of the parameter is incorrect, if otherwise, the setting of the parameter is correct; and when the value of the parameter is no, it is checked whether the height of the inner side of the overlapping mark is greater than the outer side, if otherwise, the setting of the parameter is incorrect, If yes, the setting of this parameter is correct.

In an embodiment of the invention, the layer pattern is a photoresist pattern.

In an embodiment of the invention, the front layer pattern is a trench pattern.

An overlay measurement process comprising: feeding a substrate into an overlay measurement system; setting an overlay measurement recipe comprising parameters relating to the inside or outside of the overlay pattern on the overlay mark; and using the above check overlap measurement The method of formulating determines whether the setting of the parameter is correct, and if so, directly measures the overlap error according to the overlapping measurement formula, if otherwise, the parameter in the overlapping measurement formula is changed, and then the measurement is measured according to the overlapping measurement formula. Overlap error.

Based on the above, since the method for inspecting the overlap measurement recipe of the present invention can check whether the setting of the parameter of the layer pattern inside or outside the overlap mark is correct, it can be confirmed by changing the parameter immediately if the difference is found. Get the correct overlap measurement results.

The above described features and advantages of the invention will be apparent from the following description.

Referring again to FIG. 1, in the case of the normal overlapping mark, since the front layer pattern 12 is located outside the overlap mark, when the layer pattern 14 is located inside the overlap mark, the height of the layer pattern 14 must be greater than the height of the front layer pattern 12. Therefore, the height h _i of the inner side of the overlap mark is larger than the height h _{o of the} outer side. Therefore, if the parameter is set to the corresponding normal overlap mark when the overlap measurement recipe is set, but after the comparison, it is found that the height h _i of the inner side of the overlap mark is smaller than the outer height h _o , which means that the parameter is previously set wrong. On the other hand, if it is found later that the height h _i of the inner side of the overlap mark is larger than the height h _{o of the} outer side, it means that the setting of the previous parameter is correct.

Referring to FIG. 2 again, in the case of the inverted overlay mark, since the front layer pattern 12 is located inside the overlap mark, when the layer pattern 14 is located outside the overlap mark, and the height of the layer pattern 14 is greater than that of the front layer pattern 12 The height h, so the height h _i of the inner side of the overlap mark is smaller than the height h _{o of the} outer side. Therefore, if the parameter is set to the corresponding inverted overlap mark when the overlap measurement recipe is set, but after the comparison, it is found that the height h _i of the inner side of the overlap mark is larger than the outer height h _o , which means that the parameter is previously set wrong. On the other hand, if it is found later that the height h _i of the inner side of the overlap mark is smaller than the height h _{o of the} outer side, it means that the setting of the previous parameter is correct.

The parameter regarding the inside or outside of the overlay pattern on the inside or outside of the overlay mark is, for example, "Whether the layer pattern is outside the overlap mark", and the setting method is, for example, a check item of "reverse overlap mark" in the control interface, the core. The overlapping mark is regarded as the inverted overlap mark of the layer pattern outside the overlap mark, and the unchecked is regarded as the normal overlap mark of the layer pattern on the inner side of the overlap mark.

Also. The front layer pattern 12 is, for example, a trench pattern in the substrate 10, and the layer pattern 14 is, for example, a photoresist pattern on the substrate 10.

3 is a flow chart of an overlay measurement flow according to an embodiment of the present invention, including a method for checking an overlap measurement recipe according to an embodiment of the present invention.

Referring to FIG. 3, the substrate is first fed into the overlay measurement system, which is step 300. The substrate has been subjected to a process of the layer to form a normal or inverted overlay mark comprising the front layer pattern and the layer pattern.

The next step 302 is to set an overlay measurement recipe that includes the parameters "When the layer pattern is outside the overlap mark" and other required measurement parameters. If the operator thinks that the previously formed overlap mark is an inverted overlap mark, the value of the parameter is set to "Yes"; if the previously formed overlap mark is a normal overlap mark, the value of the parameter is set to "No".

The next step 304 is to take the value of this parameter. When the value of the parameter is "Yes" (reverse overlap mark), it is checked whether the height inside the overlap mark is larger than the outer side (step 306), and if it is (the case of the normal overlap mark: h _i > h _o ), it means The parameter setting is incorrect, and the parameter in the overlap measurement recipe must be modified (step 308) and the overlay error is measured according to the overlap measurement recipe (step 310); if not (h _i <h _o ), the parameter The parameters are set correctly, and the overlay error can be measured directly according to the overlap measurement recipe. When the value of the parameter is "No" (normal overlap flag), it is checked whether the height of the inner side of the overlap mark is larger than the outer side (step 306'), and if not (the case of the inverted overlap mark: h _i <h _o ) Indicates that the setting of the parameter is incorrect, and the parameter in the overlapping measurement formula must be modified (step 308') and the overlay error is measured according to the overlapping measurement formula (step 310), if (h _i >h _o ) Indicates that the parameter is set correctly, and the overlay error can be measured directly according to the overlap measurement recipe.

In summary, since the method for inspecting the overlap measurement formula of the present invention can check whether the setting of the parameter of the layer pattern in the outer or outer side of the overlap mark is correct, the parameter can be changed immediately if the difference is found, and It is ensured that the correct overlap measurement results are obtained.

Although the present invention has been disclosed in the above embodiments, it is not intended to limit the present invention, and any one of ordinary skill in the art can make some changes and refinements without departing from the spirit and scope of the present invention. The scope of the invention is defined by the scope of the appended claims.

10‧‧‧Substrate
12‧‧‧ Front layer graphics
14‧‧‧Development graphics
300, 302, 304, 306, 306', 308, 308', 310 ‧ ‧ steps
h _i ‧‧‧ Height of the inside of the overlapping mark
h _o ‧‧‧ Height of the outside of the overlapping mark

Figure 1 is a schematic diagram showing a conventional normal overlap mark, wherein the small image (A) is a top view, the small image (B) is a B-B' sectional view, and the small image (C) is a C-C' sectional view, and A schematic diagram of the height h _{i on the} inside of the overlap mark and the height h _o on the outside of the overlap mark to be obtained in the present invention is plotted. 2 is a schematic view showing a conventional inverted overlap mark, wherein the small image (A) is a top view, the small image (B) is a B-B' sectional view, and the small image (C) is a C-C' sectional view. A schematic diagram of the height h _{i on the} inside of the overlap mark and the height h _o on the outside of the overlap mark to be obtained in the present invention is also drawn. 3 is a flow chart of an overlay measurement flow according to an embodiment of the present invention, including a method for checking an overlap measurement recipe according to an embodiment of the present invention.

300, 302, 304, 306, 306', 308, 308', 310 ‧ ‧ steps

Claims (5)

A method for inspecting an overlay measurement recipe, wherein the overlap measurement recipe includes parameters regarding when the layer pattern is inside or outside the overlay mark, and when the height of the layer pattern is greater than the height of the front layer pattern, the method includes: setting the overlap measurement After the formulation, it is judged whether the setting of the parameter is correct according to the difference in height between the inside and the outside of the overlap mark. The method for checking an overlap measurement formula according to claim 1, wherein the parameter is whether the layer pattern is outside the overlap mark, and the determining step comprises: obtaining a value of the parameter; when the value of the parameter is If yes, check whether the height of the inner side of the overlap mark is greater than the height of the outer side. If yes, the setting of the parameter is incorrect, if otherwise, the setting of the parameter is correct; and when the value of the parameter is no, the inside of the overlap mark is checked. Whether the height is greater than the height of the outer side, if otherwise, the setting of the parameter is incorrect, and if so, the setting of the parameter is correct. A method of inspecting an overlap measurement formulation as described in claim 1 or 2, wherein the layer pattern is a photoresist pattern. A method of inspecting an overlap measurement recipe as described in claim 1 or 2, wherein the front layer pattern is a trench pattern. An overlapping measurement process comprising: feeding a substrate into an overlay measurement system; setting an overlap measurement recipe, the overlay measurement formula including parameters relating to the inner or outer side of the overlay pattern on the overlay mark; and using the patent application scope The method for checking the overlap measurement formula according to any one of items 1 to 4 to determine whether the parameter setting is correct, and if so, directly measuring the overlap error according to the overlap measurement formula, such as otherwise changing the overlap measurement formula. The parameter in the measurement is then used to measure the overlay error according to the overlap measurement recipe.