Global critical dimension uniformity improvement for mask fabrication with negative-tone chemically amplified resists by zone-controlled postexposure bake

Berger, L.; Dress, Peter; Gairing, Thomas M.; Chen, Chia-Jen; Hsieh, R. L.; Lee, Hsin-Chang; Hsieh, Han-Chang

doi:10.1117/1.1683338

Cited by 10 publications

(4 citation statements)

References 8 publications

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“…Improvements to CD uniformity have been made through optimization of various lithography sequences. They include die-to-die exposure dose optimization [2], focus control [3], grid size adjustment for optical proximity correction [4], writing a multitude of shading elements inside the mask to adjust wafer level CD uniformity [5], and post-exposure bake temperature profile optimization by adjusting heater power in a multi-zone controlled bake plate [6][7][8]. Photoresist thickness variation is one of the major contributors of CD variations [9].…”

Section: Introductionmentioning

confidence: 99%

Statistical parameter evaluation for swing curves for the 1.2 μm and 1.8 μm resist thickness in CMOS photolithography process technology

Adam

Hashim

2012

2012 International Conference on Statistics in Science, Business and Engineering (ICSSBE)

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The swing curve is depending on the rotation speed of the spinner and the thickness of the photoresist. The thickness should be thick enough to prevent the unexposed area from being etched. It is also need to be uniform so that the image of the pattern to be developed later is in focus at all points on the resist surface. The variation of the photoresist thickness will impact the overall yield of the devices. In this respect, the photoresist thickness needs to be characterized carefully. Therefore, an experiment was set up to determine the right thickness and exposure time to control the critical dimension of the pattern. Photoresist coater and stepper are the main equipment used in this experiment. Positive photoresist is utilized as a pattern transfer medium and elipsometer is employed for film thickness measurement. 24 wafers are used in this experiment. The wafers are separated into 2 sets, each set which consists of 12 wafers have all the thickness variation. This to test the effect of standing resist before exposure and development to the dose-to-clear. The first set is coated, exposed and development. However, the second set is exposed and developed two days after being coated. After the wafer went through the standard cleaning procedure, the wafers were then coated using standard recipes which the spin speed ranging from 6500 to 7600 rpm in 100 rpm incremental with the designated rpm fro 1.2 µm photoresist thicknesses is in the middle. Subsequently, the photoresist thickness of each wafer is measured using elipsometer. Then, the exposure process is done by creating job that will expose the wafers in 20 by 10 arrays of small squares of open field with size 2x2 mm. The exposure is done in such a way where the exposure time will step up to the right and step down to the left from the center after each column. The center of the exposure energy time/step is 240/5. Then the graph is plotted to see the different. From the results we obtained that the minima for the dose-to-clear is at 7200 rpm where the thickness is 1.22 µm. whereby the first set and the second set of wafers produce a slight variation in clearing point.

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Section: Introductionmentioning

confidence: 99%

Statistical parameter evaluation for swing curves for the 1.2 μm and 1.8 μm resist thickness in CMOS photolithography process technology

Adam

Hashim

2012

2012 International Conference on Statistics in Science, Business and Engineering (ICSSBE)

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“…Since existing physical models are insufficient to achieve the required precision, existing control schemes for multiple source heating plates depend on data-driven models [5] or various lumped models [6]- [12].…”

Section: Introductionmentioning

confidence: 99%

“…Existing control schemes for multiple source heating plates also utilize offline calibration methods like wireless temperature sensor arrays [5] because no observability models for multiple spatially distributed heating sources were known. Meanwhile, there exist observer design based approaches for one-dimensional thermal problems using boundary [13,14] or in-domain control and measurement [15], however if these are applicable to multiple spatially distributed heating sources problems, requires further investigation.…”

Section: Introductionmentioning

confidence: 99%

Modeling of a multiple source heating plate

Scholz,

Berger

2020

Preprint

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Heating plates describe the transfer of heat from actuators to a target object. In other words, they separate the heat sources and heated object and can be further used to apply a specific heat distribution on this object. Therefore, an exact description of their thermal dynamics and an efficient coordination of their actuators is necessary to achieve a desired time-dependent temperature profile accurately. In this contribution, the thermal dynamics of a multiple source heating plate is modeled as a quasi-linear heat equation and the configuration of the spatially distributed actuators and sensors are discussed. Furthermore, the distributed parameter system is approximated using a Finite Volume scheme, and the influence of the actuators' spatial characterization on the plate's thermal dynamics is studied with the resulting high-dimensional system.

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“…The single-zone feed-forward controller eliminated the temperature disturbance caused by the placement of a cold wafer on a single-zone bake plate. 2,3 The latest state-of-the-art bake plate uses multiple-zone heaters for various purposes, such as achieving resist thickness uniformity (using different soft-bake temperature for different zones 4,5 ) and improving critical dimension uniformity (using different post-exposure bake temperature for different zones 6,7 ). However, when we apply the single-zone feed-forward algorithm from refs 2 and 3 on the multizone bake plate, complete elimination of the temperature disturbance could not be achieved.…”

Section: Introductionmentioning

confidence: 99%

Optimal Feed-Forward Control for Multizone Baking in Microlithography

Tay

Chen

et al. 2007

Ind. Eng. Chem. Res.

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An algorithm for feed-forward control to improve the performance of a multizone baking system used for lithography in semiconductor manufacturing is derived in this paper. It uses linear programming optimization of the heat transfer in a multizone bake plate to produce a predetermined heating sequence. The objective is to minimize the temperature disturbance induced by the placement of a wafer at ambient temperature on the hot multizone bake plate, and the improvement is verified experimentally.

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Global critical dimension uniformity improvement for mask fabrication with negative-tone chemically amplified resists by zone-controlled postexposure bake

Cited by 10 publications

References 8 publications

Statistical parameter evaluation for swing curves for the 1.2 μm and 1.8 μm resist thickness in CMOS photolithography process technology

Statistical parameter evaluation for swing curves for the 1.2 μm and 1.8 μm resist thickness in CMOS photolithography process technology

Modeling of a multiple source heating plate

Optimal Feed-Forward Control for Multizone Baking in Microlithography

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Global critical dimension uniformity improvement for mask fabrication with negative-tone chemically amplified resists by zone-controlled postexposure bake

Cited by 10 publications

References 8 publications

Statistical parameter evaluation for swing curves for the 1.2 &#x03BC;m and 1.8 &#x03BC;m resist thickness in CMOS photolithography process technology

Statistical parameter evaluation for swing curves for the 1.2 &#x03BC;m and 1.8 &#x03BC;m resist thickness in CMOS photolithography process technology

Modeling of a multiple source heating plate

Optimal Feed-Forward Control for Multizone Baking in Microlithography

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Product

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Statistical parameter evaluation for swing curves for the 1.2 μm and 1.8 μm resist thickness in CMOS photolithography process technology

Statistical parameter evaluation for swing curves for the 1.2 μm and 1.8 μm resist thickness in CMOS photolithography process technology