METHOD FOR QUICKLY ESTABLISHING LITHOGRAPHY PROCESS CONDITION BY A PRE-COMPENSATION VALUE

Abstract

The present invention discloses a method for quickly establishing lithography process condition by a pre-compensation value, comprising: firstly determining a reference process condition of masks of which parameters are same, and then determining an optimum process condition of the first mask; thereafter, calculating a ratio of the optimum process condition of the first mask deviating from the reference process condition, wherein if the ratio is equal to or larger than a set threshold, the first mask is inspected, and if the ratio is less than the set threshold, an optimum process condition of the second mask is determined according to the ratio and the reference process condition of the second mask; and by analogy, determining optimum process conditions of the rest masks. The method of the present invention can quickly establish a lithograph process condition, reduce the trial production time for determining the optimum defocus amount and exposure amount.

Claims

1. A method for quickly establishing lithography process condition by a pre-compensation value, wherein, comprising the following steps of: S01: marking masks of which parameters are same as first mask, second mask . . . Nth mask, wherein the masks are respectively corresponding to first lithographic layer, second lithographic layer . . . Nth lithographic layer during a lithograph; wherein, N is a positive integer; S02: determining, in reference process conditions of the first mask, second mask . . . Nth mask, defocus amounts as F.sub.1BSL+/F.sub.1BSLW m, F.sub.2BSL+/F.sub.2BSLW m . . . F.sub.NBSL+/F.sub.NBSLW m, according to experimental values in a technology platform; and exposure amounts as E.sub.1BSL+/E.sub.1BSLW mJ.Math.cm.sup.2, E.sub.2BSL+/E.sub.2BSLW mJ.Math.cm.sup.2 . . . E.sub.NBSL+/E.sub.NBSLW mJ.Math.cm.sup.2, according to experimental values in a technology platform; S03: making a focal distance-energy matrix for a first lithographic layer corresponding to the first mask and determining the defocus amount as F.sub.1EXP m and exposure amount as E.sub.1EXP mJ.Math.cm.sup.2 in an optimum process condition; S04: calculating a ratio M of the optimum process condition of the first mask deviating from the reference process condition, the ratio M being divided into a defocus amount ratio M1 and an exposure amount ratio M2, and judging whether the ratio exceeds a set threshold, wherein if M1 or M2 is equal to or larger than the set threshold, the first mask is inspected, and the step S03 is repeated after a correction is performed, and if both of M1 and M2 are less than the set threshold, a step S05 is started; S05: according to the ratio and the reference process condition of the second mask, determining an optimum process condition of the second mask,
F.sub.2EXP=F.sub.2BSL+F.sub.2BSLWM1 m, E.sub.2EXP=E.sub.2BSL+E.sub.2BSLWM2 mJ.Math.cm.sup.2; S06: by analogy, according to the ratio M and the reference process condition of the Nth mask, determining an optimum process condition of the Nth mask,
F.sub.NEXP=F.sub.NBSL+F.sub.NBSLWM1 m, E.sub.NEXP=E.sub.NBSL+E.sub.NBSLWM2 mJ.Math.cm.sup.2.

2. The method for quickly establishing lithography process condition by a pre-compensation value according to claim 1, wherein the defocus amount ratio M1=(F.sub.1EXPF.sub.1BSL)/F.sub.1BSLW, and the value of M1 is within a range of 10% to 60%.

3. The method for quickly establishing lithography process condition by a pre-compensation value according to claim 1, wherein the exposure amount ratio M2=(E.sub.1EXPE.sub.1BSL)/E.sub.1BSLW and the value of M2 is within a range of 8% to 60%.

4. The method for quickly establishing lithography process condition by a pre-compensation value according to claim 1, wherein the masks of which the parameters are same satisfy three conditions that the types are the same, the specifications are the same, and the substrates for fabricating the masks are the same batch.

5. The method for quickly establishing lithography process condition by a pre-compensation value according to claim 4, wherein the type is one of a bipolar mask, a phase-shifting mask, and an alternating phase shift mask.

6. The method for quickly establishing lithography process condition by a pre-compensation value according to claim 4, wherein the specification includes a measurement graph type, maximum defect allowed in linewidth, magnification of zoom in or zoom out, and roughness.

7. The method for quickly establishing lithography process condition by a pre-compensation value according to claim 4, wherein the substrate for fabricating the mask is a substrate formed by depositing Cr or MoSi on a quartz substrate.

8. The method for quickly establishing lithography process condition by a pre-compensation value according to claim 1, wherein in the step S03, a small batch of trial production may be performed on the first lithographic layer corresponding to the first mask, to determine the optimum process condition as F.sub.1EXP m, exposure amount E.sub.1EXP mJ cm.sup.2.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0025] The optimization method and system for overlay error compensation of the present invention will be elucidated by reference to the following embodiments and the accompanying drawings, in which:

[0026] FIG. 1 is a schematic diagram of a method for determining an optimum lithograph process condition by using a focal distance-energy matrix.

[0027] FIG. 2 is a flow chart of an embodiment of the present invention.

DETAILED DESCRIPTION OF THE EMBODIMENTS

[0028] To make the object, the feature and the advantage of the present invention clearer, the specific embodiments of the present invention are described in detail below in combination with drawings.

[0029] Specifically, the method for quickly establishing lithography process condition by a pre-compensation value provided in the present invention comprises the following steps of:

[0030] S01: marking masks of which parameters are same as first mask, second mask . . . Nth mask, wherein the masks are respectively corresponding to first lithographic layer, second lithographic layer . . . Nth lithographic layer during the lithograph. Wherein, N is a positive integer.

[0031] In same embodiment of the present invention, the parameters being identical indicate that the first mask, second mask . . . Nth mask all satisfy three conditions that the types are the same, the specifications are the same, and the substrates for fabricating the masks are the same batch.

[0032] Wherein, the first mask, second mask . . . Nth mask may be one type of a bipolar mask, a phase-shifting mask or an alternating phase shift mask. The measurement graph type, the maximum defects allowed in the linewidth, magnification of zoom in or zoom out, and roughness are the same in the first mask, second mask . . . Nth mask.

[0033] In addition, the mask substrates for fabricating the first mask, second mask . . . Nth mask are the same batch, that is, the substrates for fabricating the masks are substrates formed by depositing Cr or MoSi with the same density and the same thickness on quartz substrates with the same specifications.

[0034] S02: determining, in reference process conditions of the first mask, second mask . . . Nth mask, defocus amounts as F.sub.1BSL+/F.sub.1BSLW m, F.sub.2BSL+/F.sub.2BSLW nm . . . F.sub.NBSL+/F.sub.NBSLW m, and exposure amounts as E.sub.1BSL+/E.sub.1BSLW mJ.Math.cm.sup.2, E2BSL+/E2BSLW mJ.Math.cm.sup.2 . . . E.sub.NBSL+/E.sub.NBSLW mJ.Math.cm.sup.2, according to experimental values in a technology platform.

[0035] In this step, the defocus amount and the exposure amount in the reference process conditions are determined mainly by the previous lithograph process conditions stored in the technology platform, in other words, the reference process conditions of the different photomasks in the same batch are determined according experimental values.

[0036] S03: making a focal distance-energy matrix for a first lithographic layer corresponding to the first mask and determining the defocus amount as F.sub.1EXP m and exposure amount as E.sub.1EXP mJ.Math.cm.sup.2 in the optimum process condition.

[0037] In this step, the focal distance-energy matrix indicates a test pattern in two-dimensional distribution of difference exposure energy and focal distance in one silicon wafer.

[0038] In other words, the different exposure amount setting is adopted in each of different regions in a horizontal/vertical direction, and the different defocus amount setting is adopted in each of different regions in a vertical/horizontal direction, so as to realize to adopt different exposure amount setting and/or different defocus amount setting in each region and to finally form the same image in each region by the lithography and measure the image formed in each region, thereby obtaining CD value of the image formed in different regions on the wafer and the whole data set of the corresponding exposure amounts and defocus amounts.

[0039] And the optimum defocus amount and exposure amount in the lithograph finally are determined according to the obtained optimum CD value of the image.

[0040] In addition, in this step, the optimum process condition of the first mask can also be determined by a small batch of trial production. That is, the lithograph can be performed by setting the different process conditions many times, and the pattern after the lithograph of each time is measured, thereby determining the optimum process condition according to CD values of the different patterns.

[0041] S04: calculating a ratio M of the optimum process condition of the first mask deviating from the reference process condition, the ratio M being divided into a defocus amount ratio M1 and an exposure amount ratio M2, and judging whether the ratio M exceeds a set threshold, wherein if M1 or M2 is equal to or larger than the set threshold, the first mask is inspected, and the step S03 is repeated after a correction is performed, and if both of M1 and M2 are less than the set threshold, a step S05 is started.

[0042] In the step S04, the defocus amount ratio M1=(F.sub.1EXPF.sub.1BSL)/F.sub.1BSLW, and the value of M1 is within a range of 10% to 60%.

[0043] The exposure amount ratio M2=(E.sub.1EXPE.sub.1BSL)/E.sub.1BSLW and the value of M2 is within a range of 8% to 60%.

[0044] In the production process, the specific values of M1 and M2 are determined according to the experimental values stored in the technology platform.

[0045] S05: according to the ratio and the reference process condition of the second mask, determining an optimum process condition of the second mask,

F.sub.2EXP=F.sub.2BSL+F.sub.2BSLWM1 m, E.sub.2EXP=E.sub.2BSL+E.sub.2BSLWM2 mJ.Math.cm.sup.2.

[0046] S06: by the analogy, according to the ratio M and the reference process condition of the Nth mask, determining an optimum process condition of the Nth mask,

F.sub.NEXP=F.sub.NBSL+F.sub.NBSLWM1 m, E.sub.NEXP=E.sub.NBSL+E.sub.NBSLWM2 mJ.Math.cm.sup.2.

[0047] Since the parameters of the first mask, the second mask . . . the Nth mask are the same, the optimum process condition of the masks in one batch can corrected by using the pre-compensation value of the present invention, thus the optimum process condition of one batch masks with the same parameters can be obtained by only making an exposure amount-defocus amount matrix one time.

[0048] Therefore, the present invention can quickly establish the lithography process condition, effectively reduce the trial production time for determining the optimum defocus amount and exposure amount of the lithography process. And the new products can be produced rapidly, and the production capability is improved.

EMBODIMENT 1

[0049] S01: marking masks of which parameters are same as first mask, second mask . . . Nth mask, wherein the masks are respectively corresponding to first lithographic layer, second lithographic layer . . . Nth lithographic layer during the lithograph.

[0050] S02: according to the experimental values in a technology platform, determining, in reference process conditions of the first mask, second mask . . . Nth mask.

[0051] The defocus amounts as F.sub.1BSL+/F.sub.1BSLW=0+/100 m, F.sub.2BSL+/F.sub.2BSLW=0+/120 m . . . F.sub.NBSL+/F.sub.NBSLW=0+/110 m, the exposure amounts as E.sub.1BSL+/E.sub.1BSLW=23+/2 mJ.Math.cm-2, E.sub.2BSL/.Math.E.sub.2BSLW=23+/2.5 mJ.Math.cm.sup.2 . . . E.sub.NBSL+/E.sub.NBSLW=23+/3.0 mJ.Math.cm.sup.2.

[0052] S03: making a focal distance-energy matrix for a first lithographic layer corresponding to the first mask and determining the defocus amount as F.sub.1EXP=+10 m and exposure amount as E.sub.1EXP=23.5 mJ.Math.cm.sup.2 in the optimum process condition.

[0053] S04: calculating a ratio M of the optimum process condition of the first mask deviating from the reference process condition, the ratio M being divided into a defocus amount ratio M1 and an exposure amount ratio M2, M1=(F.sub.1EXPF.sub.1BSL)/F.sub.1BSLW=10%, M2=(E.sub.1EXPE.sub.1BSL)/E.sub.1BSLW=25% and judging whether the ratio exceeds a set threshold, wherein the technology platform determines that a threshold for M1 is 30%, a threshold for M2 is 45%, and it can be seen that M1<30%, M2<45%.

[0054] S05: according to the ratio and the reference process condition of the second mask, determining an optimum process condition of the second mask,

F.sub.2EXP=F.sub.2BSL+F.sub.2BSLWM1=12 m, E.sub.2EXP=E.sub.2BSL+E.sub.2BSLWM2=23.6 mJ.Math.cm.sup.2.

[0055] S06: by that analogy, according to the ratio M and the reference process condition of the Nth mask, determining an optimum process condition of the Nth mask,

F.sub.NEXP=F.sub.NBSL+F.sub.NBSLW.Math.M1=11 m, E.sub.NEXP=E.sub.NBSL+E.sub.NBSLWM2=23.8 mJ.Math.cm.sup.2.

[0056] The above is only the preferred embodiment of the present invention. Said embodiment is not intended to limit the patent protection scope of the present invention. Therefore, all the equivalent structural changes made using the contents of the specification and drawings of the present invention, should be encompassed in the protection scope of the present invention in a similar way.