CN115327862A - OPC method - Google Patents

Abstract

The invention provides an OPC method, which comprises the following steps: defining feature variables of a target graph of the convex graph: convex height, convex width and edge; setting the characteristic conditions and the correction evaluation rules of the convex graphics; acquiring an influence factor of the elevation; applying the influence factor of the convex height to carry out OPC correction; acquiring an intersection point of a simulation graph of the convex graph and a target graph of the convex graph on the convex height; and judging whether the intersection point accords with the correction evaluation rule, and finishing OPC correction if the intersection point accords with the correction evaluation rule. This application is through obtaining the influence factor of convexity height, and utilize the influence factor of convexity height carries out OPC processing to protruding class figure, and the nodical accord with of reevaluation is again corrected evaluation rule, can avoid the condition of reporting mistakes in the OPC revision process when reducing OPC correction number of times like this, improved protruding class figure and to the coverage of inside through-hole layer, saved OPC correction time, improved OPC correction efficiency.

Description

OPC method

technical field

The present application relates to the technical field of semiconductor manufacturing, in particular to an OPC method.

Background technique

In the deep submicron semiconductor manufacturing process, the connection between the metal layer and the via layer plays a vital role in the performance of the device. If the coverage of the metal layer and the via layer is not up to standard, it will lead to the conduction performance between different metal layers. Poor or even failure, and ultimately reduce product yield.

With the continuous reduction of technology nodes, OPC (Optical proximity correction) is a necessary key technology to improve graphics resolution and increase the process window of the development process. Affected by the fillet effect, the metal layer convex pattern will reduce its coverage of the through hole layer pattern arranged in the raised area of the metal layer convex pattern. The conventional OPC correction method has a recommended number of iterations according to the platform technology and the complexity of OPC, and performs OPC correction according to the number of iterations, and then checks the results after OPC. If there is a process risk in the error report, continue to optimize OPC to solve the error report; if there is no process risk in the error report, directly confirm that the OPC correction is completed. Even if the target value is not 100%, but because there is no process risk, the post-OPC process can also be carried out. However, this limited number of OPC corrections will inevitably encounter various error reports during the OPC processing process, and cannot quickly and effectively improve the coverage of the convex graphics on the internal through-hole layer, thereby greatly increasing the OPC processing time.

Contents of the invention

This application provides an OPC method, which can solve the problems of limited number of OPC corrections, error reporting during OPC processing, low coverage of convex graphics on the internal through-hole layer, long OPC correction time, and low OPC correction efficiency. at least one of the other questions.

On the one hand, the embodiment of the present application provides an OPC method. The graphics participating in the OPC correction include: convex graphics, wherein a through-hole graphic is set in the raised area of the convex graphics; the OPC method includes:

The first step: defining the characteristic variables of the target graph of the convex graph; wherein, the characteristic variables of the target graph of the convex graph include: convex height, convex width and limb;

The second step: according to the characteristic variable of the target graph of the convex graph, setting the characteristic condition of the convex graph, and setting the modified evaluation rule;

The third step: moving the convex height with a certain step size to obtain the influencing factor of the convex height;

The fourth step: applying the influencing factor of the convex height to the convex height, and performing OPC processing;

The fifth step: obtaining the simulated graph of the convex graph, and obtaining the intersection point of the simulated graph of the convex graph and the target graph of the convex graph on the convex height;

The sixth step: judging whether the intersection point conforms to the modified evaluation rule, if the intersection point conforms to the modified evaluation rule, the OPC correction is completed; if the intersection point does not comply with the modified evaluation rule, return to execute the first Three steps.

Optionally, in the OPC method, the characteristic condition of the convex graph is set to:

N ₁ ×D _w ≤(T _w , T _h )≤N ₂ ×D _w ;

T _L ≥ N ₃ ×D _w ;

Among them, D _w is the minimum design size of the convex figure; T _h is the convex height; T _w is the convex width, T _L is the border; 0.5≤N ₁ ≤1.5; 1.0≤N ₂ ≤2.5; N ₃ ≥ 2.

Optionally, in the OPC method, the modified evaluation rule is set as follows: the intersection of the simulated graph of the convex graph and the target graph of the convex graph on the convex height is located at 1% of the convex height. /2 height to 3/4 height range.

Optionally, in the OPC method, the sixth step includes: judging whether the intersection point is located within the range from 1/2 height to 3/4 height of the convex height, if the intersection point is located in the 1/2 height to 3/4 height of the convex height, the OPC correction is completed; if the intersection point is not in the range of 1/2 height to 3/4 height of the convex height, return to execute the first Three steps.

Optionally, in the OPC method, the third step includes:

moving the convex height in steps of 5 nm at least three times without moving the convex width;

According to the weight value in each movement, the movement amount of the convex height in each movement, and the edge placement error of the convex width in each movement, the influence factor of the convex height is obtained.

Optionally, in the OPC method, the calculation formula of the impact factor of the convex height is:

Wherein, k is the influence factor of described convex height; W _i is the weight value in each moving, and M _Thi is the moving amount of described convex height in each moving; EPE _Twi is the described convex width in each moving Edge placement error.

Optionally, in the OPC method, the third step also includes:

According to the edge placement error of the convex width in the previous movement and the edge placement error of the convex width in the current movement, the difference between the edge placement error of the convex width is obtained;

According to the difference of the edge placement error of the convex width, the correction situation of the convex graphics in the current movement is acquired.

Optionally, in the OPC method, the fourth step includes:

In each iteration, according to the edge placement error of the convex width, the movement amount of the convex width is obtained;

performing OPC correction on the convex width according to the movement amount of the convex width;

In each iteration, according to the influence factor of the convex height, the edge placement error of the convex width and the edge placement error of the convex height, the movement amount of the convex height is obtained;

OPC correction is performed on the convex height according to the moving amount of the convex height.

Optionally, in the OPC method, the calculation formula of the moving amount of the convex width is:

Among them, M _Twj is the movement amount of the convex width in each iteration; feedback is the attenuation coefficient; EPE _Twj is the edge placement error of the current convex width.

Optionally, in the OPC method, the calculation formula of the moving amount of the convex height is:

Among them, M _Thj is the movement amount of the convex height in each iteration; k is the influencing factor of the convex height; feedback is the attenuation coefficient; EPE _Twj is the edge placement error of the current convex width _; The edge placement error of the above convex height.

The technical solution of the present application at least includes the following advantages:

This application obtains the influence factor of the convex height, applies the influence factor of the convex height to the convex height, performs OPC processing, and then uses the modified evaluation rules set in advance to evaluate the simulated graphics of the convex graphics after OPC correction Whether the intersection with the target graph of the convex graph on the convex height conforms to the correction evaluation rule, so that while reducing the number of OPC corrections, it is possible to avoid the occurrence of an error during the OPC process, and improve the convex graph. The coverage of the internal through-hole layer saves the OPC correction time and improves the OPC correction efficiency.

Description of drawings

In order to more clearly illustrate the specific embodiments of the present application or the technical solutions in the prior art, the following will briefly introduce the accompanying drawings that need to be used in the description of the specific embodiments or prior art. Obviously, the accompanying drawings in the following description The drawings are some implementations of the present application, and those skilled in the art can obtain other drawings based on these drawings without creative work.

Fig. 1 is the schematic diagram of the target graph of the convex graph of the embodiment of the present invention;

Fig. 2 is the flowchart of the OPC method of the embodiment of the present invention;

Fig. 3 is a schematic diagram of a convex graph after completing OPC correction according to an embodiment of the present invention;

Wherein, the reference signs are explained as follows:

11-Convex graphics, 12-Through-hole graphics, 13-Convex graphics target graphics after OPC correction contour, 14-Convex graphics simulation graphics contour.

Detailed ways

The technical solutions in this application will be clearly and completely described below in conjunction with the accompanying drawings. Apparently, the described embodiments are part of the embodiments of this application, not all of them. Based on the embodiments in this application, all other embodiments obtained by persons of ordinary skill in the art without making creative efforts belong to the scope of protection of this application.

In the description of this application, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer" etc. The indicated orientation or positional relationship is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the referred device or element must have a specific orientation, use a specific orientation construction and operation, therefore should not be construed as limiting the application. In addition, the terms "first", "second", and "third" are used for descriptive purposes only, and should not be construed as indicating or implying relative importance.

In the description of this application, it should be noted that unless otherwise specified and limited, the terms "installation", "connection", and "connection" should be understood in a broad sense, for example, it can be a fixed connection or a detachable connection. Connection, or integral connection; it may be mechanical connection or electrical connection; it may be direct connection or indirect connection through an intermediary, or it may be the internal communication of two components, which may be wireless connection or wired connection connect. Those of ordinary skill in the art can understand the specific meanings of the above terms in this application in specific situations.

In addition, the technical features involved in the different embodiments of the present application described below may be combined as long as they do not constitute a conflict with each other.

The inventors have found that after a predetermined number of OPC corrections, the EPE (Edge Placement Error) of the convex area of the convex pattern is relatively large, resulting in the position of the convex area, the coverage of the convex pattern for the through-hole pattern is at most only up to 70%.

Based on this, an embodiment of the present application provides an OPC method. Referring to FIG. 1, FIG. 1 is a schematic diagram of a target graph of a convex graph in an embodiment of the present invention, and the graphs participating in OPC correction include: a convex graph 11, wherein the A through-hole pattern 12 is arranged in the raised area of the above-mentioned convex pattern 11 . The convex graph 11 in Fig. 1 is the target graph.

Referring to FIG. 2 , FIG. 2 is a flowchart of an OPC method according to an embodiment of the present invention.

Specifically, the OPC method includes:

The first step S1: defining the characteristic variables of the target graph of the convex graph 11; wherein, the characteristic variables of the target graph of the convex graph 11 include: convex height T _h , convex width T _w and limb T _L .

It is worth noting that the inventors have found that the main reason that the coverage rate of the convex pattern for the through-hole pattern can only reach 70% at present is that the EPE of the convex height T _h is relatively large, which leads to the fact that it should be the same as the through-hole pattern. The convex width T _w of the hole pattern 12 at a certain distance is actually located in the through hole pattern 12 when it is transferred to the photoresist.

The second step S2: according to the characteristic variables of the target graph of the convex graph 11, set the characteristic condition of the convex graph 11, and set the modified evaluation rule.

In this embodiment, the characteristic condition of the convex graph can be set as:

N ₁ ×D _w ≤(T _w , T _h )≤N ₂ ×D _w ;

T _L ≥ N ₃ ×D _w ;

Among them, D _w is the minimum design size of the convex figure; T _h is the convex height; T _w is the convex width, T _L is the border; 0.5≤N ₁ ≤1.5; 1.0≤N ₂ ≤2.5; N ₃ ≥ 2.

In this embodiment, the minimum design dimension D _w of the convex figure can be selected as 0.16; N1 can be selected as 0.5; _N2 can be selected as _{1.5 ;} N3 can be selected as 2.5.

Further, the modified evaluation rule may be set as follows: the intersection point P of the simulation graph of the convex graph and the target graph of the convex graph on the convex height is located between 1/2 and 3 of the convex height. /4 height range.

The third step S3: moving the convex height with a certain step size, and obtaining the influencing factor of the convex height. Specifically, the third step may include:

S3.1: moving the convex height at least three times with a step size of 5 nm, while not moving the convex width;

S3.2: According to the weight value in each movement, the movement amount of the convex height in each movement, and the edge placement error of the convex width in each movement, obtain the influence factor of the convex height.

Preferably, the calculation formula of the influence factor of the convex height is:

Wherein, k is the influence factor of described convex height; W _i is the weight value in each moving, and M _Thi is the moving amount of described convex height in each moving; EPE _Twi is the described convex width in each moving Edge placement error. In this embodiment, i takes a value of 3.

Referring to Table 1, Table 1 is the OPC running results of three moves in the third step of the embodiment of the present invention. In this embodiment, the weight value can be set by the user according to the actual situation. The weight value is 50 for the first move, 30 for the second move, and 20 for the third move. The EPE of the bump height in the first move is -46, the EPE of the bump height in the second move is -40.5, and the EPE of the bump height in the third move is -36.

Table I

step movement EPE ΔEPE Weights S0 / -54 / / S1 5 -46 8 50 S2 10 -40.5 5.5 30 S3 15 -36 3.5 20

Preferably, the third step may further include: S3.11: According to the edge placement error EPE of the convex width in the previous movement and the edge placement error EPE of the convex width in the current movement, obtain the convex The difference ΔEPE of the wide edge placement error; S3.12: According to the difference of the convex wide edge placement error, obtain the correction status of the convex figure in the current movement. The ΔEPE of the convex height in the first movement is 8, the ΔEPE of the convex height in the second movement is 5.5, and the ΔEPE of the convex height in the third movement is 3.5. It can be seen that with each movement, the ΔEPE of the convex height gradually decreases.

The fourth step S4: applying the influencing factor k of the convex height to the convex height, and performing OPC processing.

Specifically, the fourth step may include:

S4.1: In each iteration, obtain the movement amount of the convex width according to the edge placement error of the convex width;

S4.2: Perform OPC correction on the convex width according to the movement amount of the convex width;

S4.3: In each iteration, according to the influence factor of the convex height, the edge placement error of the convex width and the edge placement error of the convex height, obtain the movement amount of the convex height;

S4.4: Perform OPC correction on the convex height according to the moving amount of the convex height.

In this embodiment, the calculation formula of the moving amount of the convex width is:

Among them, M _Twj is the movement amount of the convex width in each iteration; feedback is the attenuation coefficient; EPE _Twj is the edge placement error of the current convex width.

In this embodiment, the calculation formula of the moving amount of the convex height is:

Among them, M _Thj is the movement amount of the convex height in each iteration; k is the influencing factor of the convex height; feedback is the attenuation coefficient, wherein, feedback can be a fixed value, which can be provided before OPC or According to the actual OPC situation, adjust during the OPC cycle; EPE _Twj is the edge placement error of the current convex width; EPE _Thj is the edge placement error of the current convex height; j is the number of loop iterations, which can be adjusted according to the actual situation set up.

Referring to FIG. 3 , FIG. 3 is a schematic diagram of a convex graph after OPC correction in an embodiment of the present invention. It can be seen from Fig. 3 that since both the convex height and the convex width have been corrected by OPC, the contour line 13 of the target figure of the convex figure after OPC correction is slightly higher than the original contour line of the target figure of the convex figure.

The fifth step S5: obtaining the simulated figure of the convex figure, and obtaining the intersection point of the simulated figure of the convex figure and the target figure of the convex figure on the convex height. Specifically, as shown in FIG. 3 , the OPC-corrected contour line 13 of the target graph of the convex graph and the contour line 14 of the simulation graph of the convex graph respectively have an intersection point P on the left and right sides of the convex height.

The sixth step S6: judging whether the two intersection points P comply with the modified evaluation rules, if the intersection points comply with the modified evaluation rules, the OPC correction is completed; if the intersection points do not comply with the modified evaluation rules, then Return to execute the third step S3.

Specifically, the sixth step may include:

S6: Judging whether the OPC-corrected contour line 13 of the target figure of the convex type and the contour line 14 of the simulated figure of the convex type figure are located at the 1/2 height of the convex height on the left and right sides of the convex height In the interval T _evaluate to 3/4 height, if the intersection point P is in the interval from 1/2 height to 3/4 height of the convex height, OPC correction is completed; if the intersection point P is not in the convex height In the range from 1/2 height to 3/4 height, return to the third step and continue OPC correction. It can be seen from FIG. 3 that the contour line 14 of the simulated pattern of the convex pattern is the convex pattern actually transferred onto the photoresist, and it can be seen that the coverage of the convex pattern on the through-hole pattern reaches 100%.

This application obtains the influencing factor k of the convex height, and applies the influencing factor k of the convex height to the convex height, performs OPC processing, and then uses the modified evaluation rules set in advance to evaluate the convex shape after the OPC correction. Whether the intersection point P of the simulation graph and the target graph of the convex graph on the convex height conforms to the correction evaluation rule, so that while reducing the number of OPC corrections, it is possible to avoid the occurrence of an error in the OPC process, and improve the The coverage of the convex pattern on the internal through-hole layer saves the OPC correction time and improves the OPC correction efficiency.

Apparently, the above-mentioned embodiments are only examples for clear description, rather than limiting the implementation. For those of ordinary skill in the art, other changes or changes in different forms can be made on the basis of the above description. It is not necessary and impossible to exhaustively list all the implementation manners here. However, the obvious changes or changes derived therefrom are still within the protection scope of the invention of the present application.

Claims (10)

1. A kind of OPC method, it is characterized in that, the figure that participates in OPC correction comprises: Convex figure, wherein, a through-hole figure is set in the raised area of described Convex figure; Described OPC method comprises: The first step: defining the characteristic variables of the target graph of the convex graph; wherein, the characteristic variables of the target graph of the convex graph include: convex height, convex width and limb; The second step: according to the characteristic variable of the target graph of the convex graph, setting the characteristic condition of the convex graph, and setting the modified evaluation rule; The third step: moving the convex height with a certain step size to obtain the influencing factor of the convex height; The fourth step: applying the influencing factor of the convex height to the convex height, and performing OPC processing; The fifth step: obtaining the simulated graph of the convex graph, and obtaining the intersection point of the simulated graph of the convex graph and the target graph of the convex graph on the convex height; The sixth step: judging whether the intersection point conforms to the modified evaluation rule, if the intersection point conforms to the modified evaluation rule, the OPC correction is completed; if the intersection point does not comply with the modified evaluation rule, return to execute the first Three steps. 2. OPC method according to claim 1, is characterized in that, the characteristic condition of described convex class figure is set to: N ₁ ×D _w ≤(T _w , T _h )≤N ₂ ×D _w ; T _L ≥ N ₃ ×D _w ; Among them, D _w is the minimum design size of the convex figure; T _h is the convex height; T _w is the convex width, T _L is the border; 0.5≤N ₁ ≤1.5; 1.0≤N ₂ ≤2.5; N ₃ ≥ 2. 3. OPC method according to claim 1, is characterized in that, the correction evaluation rule is set to: the intersection point of the simulated figure of described convex figure and the target figure of described convex figure on described convex height is located in the In the range of 1/2 height to 3/4 height of the convex height. 4. The OPC method according to claim 3, wherein the sixth step comprises: judging whether the intersection point is located in the interval between 1/2 height to 3/4 height of the convex height, if the If the intersection point is within the range from 1/2 to 3/4 of the convex height, the OPC correction is completed; if the intersection is not within the range from 1/2 to 3/4 of the convex height, return The third step is carried out. 5. OPC method according to claim 1, is characterized in that, described 3rd step comprises: moving the convex height in steps of 5 nm at least three times without moving the convex width; According to the weight value in each movement, the movement amount of the convex height in each movement, and the edge placement error of the convex width in each movement, the influence factor of the convex height is obtained. 6. OPC method according to claim 5, is characterized in that, the calculating formula of the influence factor of described convex height is:

Wherein, k is the influence factor of described convex height; W _i is the weight value in each moving, and M _Thi is the moving amount of described convex height in each moving; EPE _Twi is the described convex width in each moving Edge placement error. 7. OPC method according to claim 1, is characterized in that, described 3rd step also comprises: According to the edge placement error of the convex width in the previous movement and the edge placement error of the convex width in the current movement, the difference between the edge placement error of the convex width is obtained; According to the difference of the edge placement error of the convex width, the correction situation of the convex graphics in the current movement is acquired. 8. OPC method according to claim 1, is characterized in that, described 4th step comprises: In each iteration, according to the edge placement error of the convex width, the movement amount of the convex width is obtained; performing OPC correction on the convex width according to the movement amount of the convex width; In each iteration, according to the influence factor of the convex height, the edge placement error of the convex width and the edge placement error of the convex height, the movement amount of the convex height is obtained; OPC correction is performed on the convex height according to the moving amount of the convex height. 9. OPC method according to claim 8, is characterized in that, the calculating formula of the displacement of described convex width is:

Among them, M _Twj is the movement amount of the convex width in each iteration; feedback is the attenuation coefficient; EPE _Twj is the edge placement error of the current convex width. 10. OPC method according to claim 8, is characterized in that, the calculating formula of the displacement of described convex height is:

Among them, M _Thj is the movement amount of the convex height in each iteration; k is the influencing factor of the convex height; feedback is the attenuation coefficient; EPE _Twj is the edge placement error of the current convex width _; The edge placement error of the above convex height.

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