Contact layer OPC hot spot repairing method
By simulating and inspecting the contact layer via pattern and gradually repairing it, the hot spot problem after optical proximity correction was solved, the via area and process window were improved, the product yield was increased, and the generation of new bridging hot spots was avoided.
Patent Information
- Application Number
- CN202511484009.9
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-10-16
- Publication Date
- 2026-02-03
AI Technical Summary
Existing technologies suffer from hotspot issues after optical proximity correction during contact layer pattern transfer, especially at the junction of oblique through-holes and through-holes at the intersection of dense and isolated patterns. This results in a smaller process window, affecting product performance and yield.
By simulating and inspecting the through-hole pattern of the contact layer, marking the pattern points smaller than the specification, and gradually repairing them until the simulated size reaches the predetermined specification, new bridging hot spots are avoided. The area hot spot repair method is adopted, and the edge of the pattern is moved to improve the through-hole area and spacing. The repair is repeated until the maximum number of cycles or the optimal solution is reached.
This effectively avoids the problems of small area and small process window caused by small X/Y direction dimensions of the contact layer via, improves the via area, avoids the generation of new bridging hot spots, and improves the process window and product yield.
Smart Images
Figure CN121454870A_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The present application relates to an optical proximity correction (OPC) hotspot repair method in the field of semiconductor technology, in particular to a contact layer OPC hotspot repair method, and more particularly to a method for repairing the hotspot of a contact layer after OPC correction of an active region or a polysilicon layer. BACKGROUND
[0002] With the continuous reduction of feature size, the pattern transfer of the via layer has become a challenge for the lithography process. In the case where the resolution of the pattern is not significantly improved, the size and area of the via layer pattern are small, and the target size can be adjusted within a narrow range, which becomes one of the bottlenecks of the lithography process. The via layer mainly includes a contact layer and a metal interconnection layer. Under the same technology node, the design size of the metal interconnection layer is relatively large, while the contact layer faces greater difficulty in pattern transfer. Although phase shift masks, off-axis illumination, and various pattern enhancement techniques such as optical proximity correction have been applied in the pattern transfer process of the contact layer, the size fluctuation of the via is still large due to factors such as mask manufacturing size deviation, optical correction model precision error, and lithography process fluctuation. Therefore, the pattern transfer precision of the contact layer still needs more process window budget.
[0003] Model-based optical proximity correction has been widely used in the pattern transfer process of the contact layer. By compensating for the size deviation caused by optical proximity effects, the pattern transfer precision of the contact layer and the process window of the lithography process can be significantly improved. In the 28nm and below technology nodes, in order to improve the correction precision of the contact layer and the overall process window, overall correction error algorithms and process window correction methods have been applied in the model-based optical proximity correction process. However, for some complex contact layer design patterns, such as diagonal via, dense pattern and isolated pattern junction via, due to factors such as high difficulty in adding sub-resolution auxiliary patterns, large mask error enhancement factor (MEEF), and other factors, there are still many optical proximity correction errors, small simulated process window after correction, and other optical proximity correction hotspots. These hotspots become potential lithography process hotspots or defects, which further affect the performance and yield of the product.
[0004] In order to improve the publishing efficiency, the optical proximity correction post hot spot repair has been widely applied in the optical proximity correction process, through the simulation inspection of the corrected pattern, the pattern point with the simulation size or the via spacing less than the specified specification is located, and then the gradual step-by-step repair and simulation inspection is carried out, until the simulation size after repair reaches the specified specification, and the existing hot spot is solved in the repair process, and no new other hot spot is caused. The simulation size inspection of the contact layer mainly includes simulation via size inspection (including normal process condition simulation and process window condition simulation), simulation via bridge inspection and simulation via and polysilicon layer bridge inspection and other inspection items, wherein the simulation via size inspection is divided into X direction simulation via size inspection and Y direction simulation via size inspection, in the existing repair process, the pattern points less than the specified specification in the above inspection items are mainly marked, and the via pattern edge which can improve the inspection item is selected, and then the step-by-step repair and simulation are carried out, until the simulation size after repair reaches the specified specification, but the above repair process often produces new bridge hot spot. SUMMARY
[0005] In view of the above-mentioned defects of the prior art, the purpose of the present application is to provide a contact layer OPC hot spot repair method for solving the problem of new bridge hot spot after repairing the contact layer pattern in the prior art.
[0006] In order to achieve the above-mentioned purpose and other related purposes, the present application provides a contact layer OPC hot spot repair method, comprising:
[0007] Step S1, input the initial OPC pattern;
[0008] Step S2, perform simulation inspection on the input OPC pattern, select the via pattern with the simulation via area less than the area specification to obtain the first marked pattern, select the pattern with the simulation via spacing less than the via spacing specification to obtain the second marked pattern, and select the pattern with the simulation via and polysilicon layer spacing less than the via and polysilicon spacing specification to obtain the third marked pattern;
[0009] Step S3, obtain the area hot spot OPC pattern according to the first marked pattern and the input OPC pattern;
[0010] Step S4, obtain the area repair pattern edge according to the area hot spot OPC pattern, the second marked pattern and the third marked pattern;
[0011] Step S5, move the area repair pattern edge to obtain the area repair pattern;
[0012] Step S6, combine the input OPC pattern and the area repair pattern to obtain the repair OPC pattern;
[0013] Step S7, judging whether the number of cycles reaches the maximum number of cycles, if not, repeating steps S2 to S6, if yes, ending the cycle and outputting the final repair OPC pattern.
[0014] Preferably, steps S2 to S6 constitute a hot spot repair cycle process.
[0015] Preferably, the maximum number of cycles is set to 4-6.
[0016] Preferably, in step S3, the area hot spot OPC pattern is obtained by selecting the via pattern in the input OPC pattern which is in contact with the first mark pattern.
[0017] Preferably, in step S4, the area repair pattern side is obtained by selecting the pattern side in the area hot spot OPC pattern which is not in contact with the second mark pattern and the third mark pattern.
[0018] Preferably, the area repair pattern side includes a first area repair pattern side and a second area repair pattern side in L shape.
[0019] Preferably, in step S5, the area repair pattern is obtained by moving the area repair pattern side N pattern grid points outside the area hot spot OPC pattern.
[0020] Preferably, the value of N is 2-4.
[0021] Preferably, in step S6, the un-repair OPC pattern is obtained by performing logical negation operation on the input OPC pattern and the area hot spot OPC pattern, and the repair OPC pattern is obtained by performing logical or operation on the un-repair OPC pattern and the area repair pattern.
[0022] Preferably, in step S7, when the number of cycles reaches the maximum number of cycles, if the optimal solution is obtained, the repair OPC pattern obtained by the last repair is taken as the final repair OPC pattern; if the optimal solution is not obtained, 2-3 sub-optimal solutions are outputted, whether it is a shock result is judged, if yes, the better solution in the sub-optimal solutions is selected as the final repair OPC pattern, if not, the final repair OPC pattern is determined through technical analysis.
[0023] As described above, the contact layer OPC hot spot repair method provided by the present application has the following beneficial effects: it can avoid the situation that the area and the process window are both small due to the fact that the X / Y direction size of the contact layer via is small, especially when the target size of the via in X / Y direction is different and the simulation size of the via is the same, the area of the contact layer via can be improved through area hot spot repair, and the simulation via spacing and the simulation via and polysilicon layer spacing are considered in the repair process, which can effectively avoid the generation of new bridge hot spot after area hot spot repair. BRIEF DESCRIPTION OF DRAWINGS
[0024] In order to more clearly illustrate the technical solutions in the specific embodiments or the prior art, the following will briefly introduce the drawings needed to be used in the specific embodiments or the prior art description. Obviously, the drawings described below are only some of the embodiments of the present application, and all other drawings obtained by those of ordinary skill in the art based on these drawings without creative effort are within the protection scope of the present application.
[0025] Figure 1 A flow chart of the contact layer OPC hot spot repair method provided by the embodiments of the present application is shown.
[0026] Figure 2 A schematic diagram of the initial OPC pattern in the contact layer OPC hot spot repair method provided by the embodiments of the present application is shown.
[0027] Figure 3 A schematic diagram of the first mark pattern, the second mark pattern and the third mark pattern in the contact layer OPC hot spot repair method provided by the embodiments of the present application is shown.
[0028] Figure 4 A schematic diagram of the area hot spot OPC pattern and the area repair pattern edge in the contact layer OPC hot spot repair method provided by the embodiments of the present application is shown.
[0029] Figure 5 A schematic diagram of the area repair pattern in the contact layer OPC hot spot repair method provided by the embodiments of the present application is shown. DETAILED DESCRIPTION
[0030] The specific embodiments of the present application are described below, and those skilled in the art can easily understand other advantages and effects of the present application from the content disclosed in the present specification. The present application can also be implemented or applied by different specific embodiments, and each detail in the present specification can be modified or changed based on different views and applications without departing from the spirit of the present application.
[0031] The technical solutions in the present application will be described in detail below with reference to the drawings. Obviously, the described embodiments are only some of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present application.
[0032] In the description of the present application, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer" and the like indicate the orientation or positional relationship, which are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation of the present application. In addition, the terms "first", "second", "third" are only for the purpose of description and cannot be understood as indicating or implying relative importance.
[0033] In the description of the present application, it should be noted that unless otherwise explicitly specified and limited, the terms "mounting", "connecting", "connecting" should be understood broadly, for example, it can be fixedly connected, or it can be detachably connected, or integrally connected; it can be mechanically connected, or it can be electrically connected; it can be directly connected, or it can be indirectly connected through an intermediate medium; it can be the internal communication of two elements, it can be wireless connection, or it can 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.
[0034] 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.
[0035] In the process of transferring the contact layer pattern, it is necessary to ensure that the silicon wafer size in X direction and Y direction and the process window meet the specifications at the same time, so as to ensure that the via can be completely opened to fill the contact layer material within a certain process range. When the simulated sizes in X direction and Y direction are close to the lower limit of the specified specifications at the same time, the simulated area of the via will be smaller, resulting in a smaller process window of the via. In order to solve such contact layer hot spot pattern, the area of the via after optical proximity correction is checked by simulation, and the via pattern smaller than the area specification is marked, and then progressive repair and simulation are performed until the simulated size after repair reaches the specified area specification.
[0036] Please refer to Figure 1 , which shows a flowchart of the contact layer OPC hot spot repair method provided by the embodiments of the present application.
[0037] As Figure 1 shown, the contact layer OPC hot spot repair method includes the following steps:
[0038] Step S1, input the initial OPC pattern;
[0039] Step S2: Perform simulation checks on the input OPC pattern, select the through-hole pattern whose simulated via area is smaller than the area specification to obtain the first marked pattern, select the pattern whose simulated via spacing is smaller than the via spacing specification to obtain the second marked pattern, and select the pattern whose simulated via-to-polysilicon layer spacing is smaller than the via-to-polysilicon layer spacing specification to obtain the third marked pattern.
[0040] Step S3: Obtain the area hotspot OPC graphic based on the first marked graphic and the input OPC graphic;
[0041] Step S4: Obtain the area repair graphic edge based on the area hotspot OPC graphic, the second marker graphic, and the third marker graphic;
[0042] Step S5: Move the edges of the area-repaired shape to obtain the area-repaired shape;
[0043] Step S6: Merge the input OPC graphic and the area repair graphic to obtain the repaired OPC graphic;
[0044] Step S7: Determine if the number of loops has reached the maximum number of loops. If the maximum number of loops has not been reached, repeat steps S2 to S6. If the maximum number of loops has been reached, end the loop and output the final repaired OPC graphic.
[0045] In step S1, as Figure 2 As shown, the initial OPC pattern includes a contact layer OPC pattern 100, a contact layer target pattern 101, an active region pattern 102, and a polysilicon layer pattern 103.
[0046] After inputting the initial OPC graph, the process also includes setting the maximum number of cycles for the hotspot repair loop, which is typically set to 4 to 6. Steps S2 to S6 constitute the hotspot repair loop process.
[0047] In step S2, the input OPC graph is simulated and checked to obtain the following results: Figure 3 The first marker graphic 105, the second marker graphic 106, and the third marker graphic 107 are shown.
[0048] In step S3, the through-hole pattern that contacts the first marker pattern 105 in the input OPC pattern is selected to obtain the following: Figure 4 The area hotspot OPC graph shown is 108.
[0049] In step S4, the graphic edges in the area hotspot OPC graphic 108 that do not contact the second marker graphic 106 and the third marker graphic 107 are selected to obtain the following: Figure 4 The first area repair graphic edge 109 and the second area repair graphic edge 110 are shown.
[0050] In step S5, the first area repair graphic edge 109 and the second area repair graphic edge 110N graphic grid points are simultaneously moved outside the area hotspot OPC graphic 108 to obtain the following result: Figure 5 The area repair graph 111 is shown. The grid point of this graph refers to the smallest unit of the graphic data, and the value of N is usually 2 to 4.
[0051] In step S6, a logical NOT operation is performed between the input OPC graphic and the area hotspot OPC graphic 108 to obtain the unrepaired OPC graphic, and a logical OR operation is performed between the unrepaired OPC graphic and the area repaired graphic 111 to obtain the repaired OPC graphic.
[0052] The above logical operation process is as follows: Repair OPC graphic = (Input OPC graphic - Area hotspot OPC graphic) + Area repair graphic.
[0053] In step S7, it is determined whether the number of cycles in the hot spot repair loop process has reached the set maximum number of cycles. If the maximum number of cycles has not been reached, steps S2 to S6 are repeated. If the maximum number of cycles has been reached, the hot spot repair loop process ends and the final repaired OPC graphic is output.
[0054] When the maximum number of iterations is reached, if the optimal solution is obtained, the repaired OPC graph obtained from the last repair is taken as the final repaired OPC graph; if the optimal solution is not obtained, 2 to 3 suboptimal solutions are output to determine whether they are oscillating results. If so, the better solution among the suboptimal solutions is selected as the final repaired OPC graph; if not, the final repaired OPC graph is determined through technical analysis.
[0055] It should be noted that the illustrations provided in this embodiment are only schematic representations of the basic concept of this application. Therefore, the drawings only show the components related to this invention and are not drawn according to the actual number, shape and size of the components. In actual implementation, the form, quantity and proportion of each component can be arbitrarily changed, and the layout of the components may also be more complex.
[0056] In summary, the contact layer OPC hotspot repair method provided in this application can avoid the situation where the X / Y dimensions of the contact layer vias are simultaneously too small, resulting in a smaller area and a smaller process window. Especially when the target dimensions of the vias in the X / Y directions are different while the simulated dimensions are the same, area hotspot repair can improve the via area. Furthermore, considering the simulated via spacing and the spacing between the simulated vias and the polysilicon layer during the repair process can effectively prevent the generation of new bridging hotspots after area hotspot repair. Therefore, this application effectively overcomes the various shortcomings of the prior art and has high industrial applicability.
[0057] The above embodiments are merely illustrative of the principles and effects of this application and are not intended to limit this application. Any person skilled in the art can modify or alter the above embodiments without departing from the spirit and scope of this application. Therefore, all equivalent modifications or alterations made by those skilled in the art without departing from the spirit and technical concept disclosed in this invention should still be covered by the claims of this application.
Claims
1. A method for repairing OPC hotspots in a contact layer, characterized in that, The method includes: Step S1: Input the initial OPC graph; Step S2: Perform a simulation check on the input OPC pattern, select a through-hole pattern whose simulated via area is smaller than the area specification to obtain a first marked pattern, select a pattern whose simulated via spacing is smaller than the via spacing specification to obtain a second marked pattern, and select a pattern whose simulated via-to-polysilicon layer spacing is smaller than the via-to-polysilicon layer spacing specification to obtain a third marked pattern. Step S3: Obtain the area hotspot OPC graphic based on the first marked graphic and the input OPC graphic; Step S4: Obtain the area repair graphic edge based on the area hotspot OPC graphic, the second marker graphic, and the third marker graphic; Step S5: Move the edges of the area repair graphic to obtain the area repair graphic; Step S6: Merge the input OPC graphic and the area repair graphic to obtain the repaired OPC graphic; Step S7: Determine whether the number of loops has reached the maximum number of loops. If the maximum number of loops has not been reached, repeat steps S2 to S6. If the maximum number of loops has been reached, end the loop and output the final repaired OPC graphic.
2. The method according to claim 1, characterized in that, Steps S2 to S6 constitute a hotspot repair cycle.
3. The method according to claim 1, characterized in that, The maximum number of cycles is typically set to 4 to 6.
4. The method according to claim 1, characterized in that, In step S3, the through-hole pattern that contacts the first mark pattern in the input OPC pattern is selected to obtain the area hotspot OPC pattern.
5. The method according to claim 1, characterized in that, In step S4, the area repair graphic edge is obtained by selecting the graphic edge in the area hotspot OPC graphic that does not contact the second mark graphic and the third mark graphic.
6. The method according to claim 5, characterized in that, The area repair graphic edges include a first area repair graphic edge and a second area repair graphic edge that are L-shaped.
7. The method according to claim 1, characterized in that, In step S5, the area repair graphic is obtained by moving N graphic grid points outside the area hotspot OPC graphic.
8. The method according to claim 7, characterized in that, The value of N is 2 to 4.
9. The method according to claim 1, characterized in that, In step S6, a logical NOT operation is performed between the input OPC graphic and the area hotspot OPC graphic to obtain an unpatched OPC graphic, and a logical OR operation is performed between the unpatched OPC graphic and the area patched graphic to obtain the patched OPC graphic.
10. The method according to claim 1, characterized in that, In step S7, when the number of iterations reaches the maximum number of iterations, if the optimal solution is obtained, the repaired OPC graphic obtained from the last repair is taken as the final repaired OPC graphic. If the optimal solution is not obtained, output 2 to 3 suboptimal solutions and determine whether it is an oscillation result. If so, select the better solution among the suboptimal solutions as the final repaired OPC graph. Otherwise, determine the final repaired OPC graph through technical analysis.