CN104238260A - Method for improving process window of semiconductor device - Google Patents

Abstract

The present invention relates to a method for improving the process window of a semiconductor device. The method at least includes: 1) setting a first target contour pattern, setting a mask according to the first target contour pattern, performing an optical proximity correction step, and obtaining The first target contour pattern; 2) setting a final target contour pattern, setting a mask according to the final target contour pattern, and performing an optical proximity correction step to obtain the final target contour pattern; wherein, the final target The outline pattern is square or circular. The present invention changes the method in the prior art that only includes one step for optical proximity correction, the method includes at least two steps, and the final target contour obtained by the method is a square or a circle, compared with the prior art device The performance of the process window is more excellent, and the performance of the device is improved. The method can be used for etching through holes or contact holes, but is not limited to through holes or contact holes.

Description

A method for improving the process window of semiconductor devices

technical field

The invention relates to the field of semiconductors, and in particular, the invention relates to a method for improving the process window of a semiconductor device.

Background technique

Integrated circuit manufacturing technology is a complicated process, and the technology is updated very quickly. A key parameter that characterizes integrated circuit manufacturing technology is the minimum feature size, that is, critical dimension (CD). With the development of semiconductor technology, the critical dimension of devices is continuously reduced. It is precisely because of the reduction of critical dimension that each It is possible to set millions of devices on a chip.

Photolithography is the driving force behind the development of integrated circuit manufacturing processes, and it is also one of the most complex technologies. Compared with other single manufacturing technologies, the improvement of lithography technology is of great significance to the development of integrated circuits. Before the lithography process starts, it is first necessary to copy the pattern on the mask plate through specific equipment, and then use the lithography equipment to generate light of a specific wavelength to copy the pattern structure on the mask plate to the silicon wafer for chip production. But due to the shrinking size of semiconductor devices, distortions that occur during the transfer of patterns to silicon wafers, if not eliminated, can lead to the failure of the entire manufacturing technology. Therefore, in order to solve the above problem, optical proximity correction (Optical ProximityCorrection, OPC) can be performed on the mask. Such that the amount of compensation is modified just enough to compensate for the optical proximity effect caused by the exposure system.

As the size of semiconductor devices continues to shrink, it is necessary to form vias or contact holes when forming electrical connections, wherein the vias or contact holes require OPC correction during the formation process , the method in the prior art is shown in Figure 1. First, select the value of the target contour as the critical dimension (mask CD) of the mask, and perform simulation (simulation) with the mask to obtain the first simulated contour, and then Adjust the empirical value according to the error of the first simulated contour, and then obtain the key size of the second mask, then perform the second simulation to obtain the second simulated contour, and then perform OPC calculation according to the contour error to obtain the third mask key dimension, and then loop through the operation for multiple consecutive convergence and correction, and finally after n times of simulation, the target contour is finally obtained. Not equal, the critical dimension of the mask is smaller than that of a square mask, which reduces the performance of the device. Therefore, the current OPC method needs to be improved in order to eliminate the above problems and improve Device performance and yield.

Contents of the invention

A series of concepts in simplified form are introduced in the Summary of the Invention, which will be further detailed in the Detailed Description. The summary of the invention in the present invention does not mean to limit the key features and essential technical features of the claimed technical solution, nor does it mean to try to determine the protection scope of the claimed technical solution.

The invention provides a method for improving the process window of a semiconductor device, the method at least comprising:

1) setting a first target contour pattern, setting a mask according to the first target contour pattern, and performing an optical proximity correction step to obtain the first target contour pattern;

2) setting the final target contour pattern, setting a mask according to the final target contour pattern, and performing an optical proximity correction step to obtain the final target contour pattern;

Wherein, the final target outline pattern is a square or a circle.

Preferably, at least one step is further included before the step 2), each of the at least one step sets a target contour pattern, sets a mask according to the target contour pattern, and performs optical proximity correction step, obtaining the target outline pattern set in each step. Preferably, the optical proximity correction step in step 1) includes the following sub-steps:

1-1) Setting a first mask according to the first target contour pattern, selecting the first mask for simulation, and obtaining a first simulated contour pattern;

1-2) Correcting the first mask according to the error between the first simulated contour pattern and the first target contour pattern to obtain a second mask;

1-3) Selecting the second mask for simulation to obtain a second simulated contour pattern;

1-4) Perform optical proximity correction calculation according to the error between the second simulated contour pattern and the first target contour pattern to obtain a third mask;

1-5) performing simulation according to the third mask to obtain a third simulated contour pattern;

Preferably, if the third simulated contour pattern is the same as the first target contour pattern, stop the correction;

If the third simulated contour pattern is different from the first target contour pattern, perform step 1-6) and repeat 1-1)-1-5), until the simulated contour pattern in step 1) is the same as the first target contour pattern The same as the first target outline pattern.

Preferably, the first target contour pattern in step 1) is ellipse or rectangle, its short axis or width is X, and its long axis or length is Y, where Y>X, and in the step of optical proximity correction, gradually Increase X, decrease Y.

Preferably, the first mask, the second mask and the third mask are square or rectangular.

Preferably, the optical proximity correction step in step 2) includes the following sub-steps:

2-1) Set the final first mask according to the final target outline pattern, select the final first mask for simulation, and obtain the final first simulated outline pattern;

2-2) Correcting the final first mask according to the error between the final first simulated contour pattern and the final target contour pattern to obtain a final second mask;

2-3) Selecting the final second mask for simulation to obtain the final second simulated outline pattern;

2-4) Perform optical proximity correction calculation according to the error between the final second simulated contour pattern and the final target contour pattern to obtain the final third mask;

2-5) performing simulation according to the final third mask to obtain the final third simulated outline pattern;

Preferably, if the third simulated contour pattern is the same as the final target contour pattern, stop the correction;

If the third simulated contour pattern is different from the final target contour pattern, perform step 2-6) and repeat 1-1)-1-5), until the simulated contour pattern in step 2) is the same as the final target contour pattern The target outline pattern is the same.

Preferably, the final first mask plate, the final second mask plate and the final third mask plate are square or rectangular.

Preferably, after the step 1), the X becomes larger, and in the step 2), the X remains unchanged in the optical proximity correction step, and the Y continues to decrease until the Until X=Y, the final target contour pattern in the form of a square or a circle is obtained, so as to improve the process window of the device.

Preferably, the final target outline pattern is a via hole or a contact hole.

The present invention changes the method in the prior art that only includes one step for optical proximity correction, the method includes at least two steps, wherein a target profile is set in each step, and the target profile in the last step is the final target Outline, the final target outline obtained by the method is a square or a circle, which is more excellent than the process window performance of the prior art device, and the performance of the device is improved. The method can be used for the etching of through holes or contact holes, but it does not Not limited to via holes or contact holes.

Description of drawings

The following drawings of the invention are hereby included as part of the invention for understanding the invention. Embodiments of the present invention and their descriptions are shown in the drawings to explain the device and principle of the present invention. In the attached picture,

Fig. 1 is the flow chart that utilizes mask plate to carry out OPC in the prior art;

Fig. 2 is the flow chart that utilizes mask plate to carry out OPC in a specific embodiment of the present invention;

Fig. 3 is the flow chart that the present invention utilizes mask plate to carry out OPC;

FIG. 4 is a process flow diagram of OPC using a mask plate in the present invention.

Detailed ways

In the following description, numerous specific details are given in order to provide a more thorough understanding of the present invention. It will be apparent, however, to one skilled in the art that the present invention may be practiced without one or more of these details. In other examples, some technical features known in the art are not described in order to avoid confusion with the present invention.

It should be noted that the terms used herein are for the purpose of describing specific embodiments only, and are not intended to limit exemplary embodiments according to the present invention. As used herein, singular forms are intended to include plural forms unless the context clearly dictates otherwise. In addition, it should also be understood that when the terms "comprising" and/or "comprising" are used in this specification, it indicates the presence of the features, integers, steps, operations, elements and/or components, but does not exclude the presence or One or more other features, integers, steps, operations, elements, components and/or combinations thereof are added.

Now, exemplary embodiments according to the present invention will be described in more detail with reference to the accompanying drawings. These example embodiments may, however, be embodied in many different forms and should not be construed as limited to only the embodiments set forth herein. It should be understood that these embodiments are provided so that this disclosure will be thorough and complete and will fully convey the concept of these exemplary embodiments to those of ordinary skill in the art. In the drawings, for the sake of clarity, the same reference numerals are used to designate the same elements, and thus their descriptions will be omitted.

The present invention provides a method for improving the process window of a semiconductor device, the method at least comprising:

1) setting a first target contour pattern, setting a mask according to the first target contour, and performing an optical proximity correction step to obtain the first target contour pattern;

2) setting the final target contour pattern, setting a mask according to the final target contour, and performing an optical proximity correction step to obtain the final target contour pattern;

Wherein, the final target outline pattern is a square or a circle.

Preferably, a plurality of steps are included before the step 2), in which each step sets a target contour pattern, sets a mask according to the target contour, and performs optical proximity The correction step is to obtain the target outline pattern set in each step.

The method for improving the process window of semiconductor devices described in the present invention is different from the one-step method in the prior art. The method includes at least two steps and may include multiple steps. The number of steps is not limited to a certain numerical range , can be done as needed.

Wherein, in the plurality of steps, each step sets a target contour pattern, and then sets a reasonable mask critical dimension according to the target contour pattern, performs optical proximity correction, and obtains the target contour set in this step pattern, wherein the target contour pattern set in the last step is the final target contour, in order to improve the performance of the device, the final target contour pattern is a squared (Squared) figure, such as a square or a circle.

Example 1

A preferred embodiment of the present invention will be further described below in conjunction with FIG. 2 .

As shown in FIG. 2 , the method for improving the process window of a semiconductor device includes two steps, each of which includes n sub-steps.

Firstly, in step 1), a first target contour pattern is set, a mask is set according to the first target contour, and an optical proximity correction step is performed to obtain the first target contour pattern;

Said step 1) includes the following sub-steps:

1-1) Set the first mask according to the first target outline, as shown in Figure 2, the first mask is square, including square or rectangle, and the critical dimension of the mask is X1 , Y1, wherein X1 is the length of the first mask, and the Y1 is the width of the first mask. The first mask is selected for simulation to obtain the first simulated contour pattern, wherein the first mask A simulated contour pattern is an ellipse, wherein its minor axis or width is X, its major axis or length is Y, wherein Y>X, and X is gradually increased and Y is decreased during the optical proximity correction step;

1-2) Correcting the first mask according to the error between the first simulated contour pattern and the first target contour to obtain a second mask;

1-3) Selecting the second mask for simulation to obtain a second simulated contour pattern;

1-4) performing an optical proximity correction calculation according to the error between the second simulated contour pattern and the first target contour to obtain a third mask;

1-5) performing simulation according to the third mask to obtain a third simulated outline pattern;

Preferably, if the third simulated contour pattern is the same as the first target contour pattern, stop the correction;

If the third simulated contour pattern is different from the first target contour pattern, more steps may be included in the OPC process, repeating steps 1-1)-1-5), until the nth mask in step 1) stencil, when the pseudo-contour pattern obtained after the nth mask is simulated is the same as the first target contour, stop the step 1).

Preferably, the first target outline pattern in the step 1) is oval or rectangular, its short axis or width is X, and its long axis or length is Y, where Y>X, in the step 1-1)-1 -n) gradually increases X and decreases Y through optical proximity correction steps.

Then perform step 2) setting the final target contour pattern, setting a mask according to the final target contour, and performing an optical proximity correction step to obtain the final target contour pattern;

Wherein, the final target outline pattern is a square or a circle.

The optical proximity correction step in the step 2) includes the following sub-steps:

2-1) Set the final first mask according to the final target outline, select the final first mask for simulation, and obtain the final first simulated outline pattern, wherein after the step 1), the X becomes large, in the sub-step, keep the X constant in the optical proximity correction step, continue to reduce the Y until the X=Y, and obtain the final square or circular shape Targeted contour patterns to improve the process window of the device;

2-2) Correcting the final first mask according to the error between the final first simulated contour pattern and the final target contour to obtain a final second mask;

2-3) Select the final second mask for simulation to obtain the final second simulated contour pattern, keep the X in the second simulated contour pattern, continue to reduce the Y, the X and The gap between Y decreases;

2-4) Perform optical proximity correction calculation according to the error between the final second simulated contour pattern and the final first target contour to obtain the final third mask;

2-5) Perform simulation according to the final third mask to obtain the final third simulated contour pattern, keep the X constant in the second simulated contour pattern, continue to reduce the Y, the X and The gap between Y is smaller;

As a preference, if the third simulated contour pattern is the same as the final target contour pattern, then stop the correction; if the third simulated contour pattern is not the same as the final target contour pattern, more steps may be included in the OPC process. Multi-step, repeat steps 2-1)---2-5), to the nth mask in step 2), when the nth mask is simulated, the pseudo-contour pattern obtained is the same as the final target contour , until the X=Y, obtain the final target contour pattern in the form of a square or a circle, so as to improve the process window of the device, and then stop the step 2).

Example 2

A preferred embodiment of the present invention will be further described below in conjunction with FIG. 3 .

As shown in FIG. 3 , the method for improving the process window of a semiconductor device includes n steps, wherein each step includes n sub-steps.

Firstly, in step 1), a first target contour pattern is set, a mask is set according to the first target contour, and an optical proximity correction step is performed to obtain the first target contour pattern;

Said step 1) includes the following sub-steps:

1-1) Set the first mask according to the first target outline, as shown in Figure 3, the first mask is square, including square or rectangle, and the critical dimension of the mask is X1 , Y1, wherein X1 is the length of the first mask, and the Y1 is the width of the first mask. The first mask is selected for simulation to obtain the first simulated outline pattern, wherein the first A simulated contour pattern is an ellipse, wherein its minor axis or width is X, its major axis or length is Y, wherein Y>X, and X is gradually increased and Y is decreased during the optical proximity correction step;

1-2) Correcting the first mask according to the error between the first simulated contour pattern and the first target contour to obtain a second mask;

1-3) Selecting the second mask for simulation to obtain a second simulated contour pattern;

1-4) Perform optical proximity correction calculation according to the error between the second simulated contour pattern and the first target contour to obtain a third mask;

1-5) performing simulation according to the third mask to obtain a third simulated outline pattern;

More steps can be included in the OPC process, repeating steps 1-1)-1-5), to the nth mask in step 1), when the nth mask is simulated, the pseudo-contour pattern and When the first target contours are the same, stop the step 1).

Preferably, the first target outline pattern in the step 1) is oval or rectangular, its short axis or width is X, and its long axis or length is Y, where Y>X, in the step 1-1)-1 -n) gradually increases X and decreases Y through optical proximity correction steps.

Then perform step 2) setting a second target contour pattern, setting a mask according to the second target contour, and performing an optical proximity correction step to obtain the second target contour pattern;

The optical proximity correction step in the step 2) includes the following sub-steps:

2-1) Setting the first mask in the second step according to the second target outline, selecting the first mask for simulation to obtain the first simulated outline pattern in the second step, wherein in the After step 1), the X becomes larger. In the sub-step, keep the X unchanged in the optical proximity correction step, continue to decrease the Y or increase X, and continue to decrease the Y;

2-2) According to the error between the first simulated contour pattern in step 2-1) and the second target contour, the first mask in the second step is corrected to obtain the second mask in the second step Two masks;

2-3) Select the second mask in the second step for simulation to obtain the second simulated contour pattern in the second step, the X in the second simulated contour pattern continues to increase, and the X value continues to decrease. said Y, the gap between said X and Y is reduced;

2-4) Perform optical proximity correction calculation according to the error between the second simulated contour pattern in the second step and the second target contour to obtain the third mask in the second step;

2-5) Carry out simulation based on the third mask in the second step to obtain the third simulated contour pattern in the second step, the X in the third simulated contour pattern continues to increase, and continues to decrease the said Y, the gap between said X and Y is smaller;

After the step 2), it also includes multiple steps, the multiple steps are basically the same as step 1) and step 2), and a target outline pattern is set in each step, the difference is that in the step Keep the X constant in the simulated contour pattern obtained during optical proximity correction, continue to decrease the Y, and the gap between the X and Y decreases.

Then perform step n) to set the final target contour pattern, set a mask according to the final target contour, and perform an optical proximity correction step to obtain the final target contour pattern;

Wherein, the final target outline pattern is a square or a circle.

The optical proximity correction step in said step n) includes the following sub-steps:

n-1) Set the final first mask according to the final target outline, select the final first mask for simulation, and obtain the final first simulated outline pattern, wherein after the step 1), the X becomes large, in the sub-step, keep the X constant in the optical proximity correction step, continue to reduce the Y until the X=Y, and obtain the final square or circular shape Targeted contour patterns to improve the process window of the device;

n-2) Correcting the final first mask according to the error between the final first simulated contour pattern and the final target contour to obtain a final second mask;

n-3) Select the final second mask for simulation to obtain the final second simulated outline pattern, keep the X in the second simulated outline pattern, continue to reduce the Y, the X and The gap between Y decreases;

n-4) performing an optical proximity correction calculation according to the error between the final second simulated contour pattern and the final first target contour to obtain a final third mask;

n-5) Perform simulation according to the final third mask to obtain the final third simulated contour pattern, keep the X constant in the second simulated contour pattern, continue to reduce the Y, the X and The gap between Y is smaller;

More steps can be included in the OPC process, repeat steps n-1)---n-5), to the nth mask in step n), when the nth mask is simulated, a pseudo-contour is obtained The pattern is the same as the final target contour, until the X=Y, the final target contour pattern in the form of a square or a circle is obtained to improve the process window of the device, and then stop the step n).

The present invention changes the method in the prior art that only includes one step for optical proximity correction, the method includes at least two steps, wherein a target profile is set in each step, and the target profile in the last step is the final target Outline, the final target outline obtained by the method is a square or a circle, which is more excellent than the process window performance of the prior art device, and the performance of the device is improved. The method can be used for the etching of through holes or contact holes, but it does not Not limited to via holes or contact holes.

Fig. 4 is the process flow diagram of utilizing mask plate to carry out OPC in the present invention, specifically comprises the following steps:

1) setting a first target contour pattern, setting a mask according to the first target contour pattern, and performing an optical proximity correction step to obtain the first target contour pattern;

2) setting the final target contour pattern, setting a mask according to the final target contour pattern, and performing an optical proximity correction step to obtain the final target contour pattern;

Wherein, the final target outline pattern is a square or a circle.

The present invention has been described through the above-mentioned embodiments, but it should be understood that the above-mentioned embodiments are only for the purpose of illustration and description, and are not intended to limit the present invention to the scope of the described embodiments. In addition, those skilled in the art can understand that the present invention is not limited to the above-mentioned embodiments, and more variations and modifications can be made according to the teachings of the present invention, and these variations and modifications all fall within the claimed scope of the present invention. within the range. The protection scope of the present invention is defined by the appended claims and their equivalent scope.

Claims (11)

1. A method for improving the process window of a semiconductor device, said method at least comprising: 1) setting a first target contour pattern, setting a mask according to the first target contour pattern, and performing an optical proximity correction step to obtain the first target contour pattern; 2) setting the final target contour pattern, setting a mask according to the final target contour pattern, and performing an optical proximity correction step to obtain the final target contour pattern; Wherein, the final target outline pattern is a square or a circle. 2. The method according to claim 1, characterized in that, before said step 2), at least one step is further included, in each step of said at least one step, a target contour pattern is set, and according to said target The outline pattern sets the mask plate, performs the optical proximity correction step, and obtains the target outline pattern set in each step. 3. The method according to claim 1, wherein the optical proximity correction step in step 1) includes the following sub-steps: 1-1) Setting a first mask according to the first target contour pattern, selecting the first mask for simulation, and obtaining a first simulated contour pattern; 1-2) Correcting the first mask according to the error between the first simulated contour pattern and the first target contour pattern to obtain a second mask; 1-3) Selecting the second mask for simulation to obtain a second simulated contour pattern; 1-4) Perform optical proximity correction calculation according to the error between the second simulated contour pattern and the first target contour pattern to obtain a third mask; 1-5) Perform simulation according to the third mask to obtain a third simulated outline pattern. 4. The method according to claim 3, wherein if the third simulated contour pattern is identical to the first target contour pattern, then stop the correction; If the third simulated contour pattern is different from the first target contour pattern, perform step 1-6) and repeat 1-1)-1-5), until the simulated contour pattern in step 1) is the same as the first target contour pattern The same as the first target outline pattern. 5. The method according to claim 1 or 3, wherein the first target outline pattern in step 1) is oval or rectangular, its short axis or width is X, and its long axis or length is Y, wherein Y>X, and X is gradually increased and Y is decreased in the optical proximity correction step. 6. The method according to claim 3, wherein the first mask, the second mask and the third mask are square or rectangular. 7. The method according to claim 1, wherein the optical proximity correction step in step 2) includes the following sub-steps: 2-1) Set the final first mask according to the final target outline pattern, select the final first mask for simulation, and obtain the final first simulated outline pattern; 2-2) Correcting the final first mask according to the error between the final first simulated contour pattern and the final target contour pattern to obtain a final second mask; 2-3) Selecting the final second mask for simulation to obtain the final second simulated outline pattern; 2-4) Perform optical proximity correction calculation according to the error between the final second simulated contour pattern and the final target contour pattern to obtain the final third mask; 2-5) Perform simulation according to the final third mask to obtain a final third simulated outline pattern. 8. The method according to claim 7, wherein if the third simulated contour pattern is identical to the final target contour pattern, then stop the correction; If the third simulated contour pattern is different from the final target contour pattern, perform step 2-6) and repeat 2-1)-2-5), until the simulated contour pattern in step 2) is the same as the final target contour pattern The target outline pattern is the same. 9. The method according to claim 7, wherein the final first mask, the final second mask and the final third mask are square or rectangular. 10. The method according to claim 5, wherein after said step 1), said X becomes larger, and in said step 2), said X is kept not in said optical proximity correction step change, continue to reduce the Y until the X=Y, and obtain the final target contour pattern in the form of a square or a circle, so as to improve the process window of the device. 11. The method according to any one of claims 1-10, wherein the final target outline pattern is a via hole or a contact hole.