JP2003233162A - Post exposure modification of critical dimensions in mask fabrication - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a system and method for modifying an exposure image in a radiation sensitive layer with a heterogeneous and non-uniform post exposure thermal treatment. <P>SOLUTION: The treatment may include providing different thermal flux to different regions of the radiation sensitive layer to concurrently create different temperatures in those regions. The different temperatures may cause different physicochemical transformation of the regions that may be used to reduce critical dimension errors in those regions. A post exposure bake hot plate may be configured to provide heterogeneous radiant energy flux to a radiation sensitive layer by providing adjustable spacers that adjust a separation distance between the hot plate and the layer. The adjustable spacers may be adjusted prior to exposure image modification by using an adjustment plate having openings to provide access to and adjustment of the adjustable spacers. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present application is filed on Sep. 26, 2001.
U.S. patent application Ser. No. 09, entitled "Method of Correcting After Exposure of Critical Dimension in Mask Manufacturing" filed
/ 965,280 claims priority.

The present invention relates generally to the field of semiconductor mask manufacturing. More particularly, the present invention relates to mask manufacturing systems and methods using post-exposure modification of exposed images.

[0003]

BACKGROUND OF THE INVENTION Masks are often used in the manufacture of semiconductor devices and logic circuit products. FIG. 1 shows a mask 13
1 illustrates an exemplary lithographic system 100 used to fabricate a semiconductor device based on 0. The system 100 produces radiation 120, which is directed to a mask 130.
A radiation source 110 for transmitting to the. Mask 130
Includes a circuit pattern 140 that generates and transmits patterned radiation 150. Typically, the patterned radiation 150 is only a portion of the radiation 120.

The patterned radiation 150, including circuit information, is provided to the semiconductor manufacturing process 160. Typically, the patterned radiation 150 is used to selectively print or expose portions of the resist layer,
Subsequent processes are then used to manufacture the semiconductor device or logic circuit product based on the exposure.

[0005]

SUMMARY OF THE INVENTION One problem with the prior art is that the mask 130 and patterned radiation 140 contain inaccuracies, errors, or both. Is. Inaccuracies or errors are caused by many factors such as incorrect manufacturing equipment, improperly configured manufacturing equipment, and other factors. Regardless of the cause, the error is transferred to the semiconductor manufacturing process 160 by the patterned radiation 150 and incorporated into the manufactured semiconductor device. As a result, a large percentage of semiconductor devices do not meet the specifications and performance drops,
It becomes useless.

The novel features of the invention are set forth in the appended claims. The present invention is illustrated by way of example and not limitation in the accompanying drawings in which like elements are numbered the same. However, the invention itself as well as its preferred modes of use, will be best understood by reference to the following detailed description of exemplary embodiments, which is read in conjunction with the accompanying drawings.

[0007]

DETAILED DESCRIPTION OF THE INVENTION In the following description, numerous specific details are set forth for purposes of explanation in order to provide a thorough understanding of the present invention. However, it will be apparent to one skilled in the art that the present invention may be practiced without some of these specific details. In other cases, well-known structures and devices are shown in block diagrams.

Mask Manufacturing The term "mask" is used broadly to refer to structures containing functional patterns that act as selective barriers to the passage of radiation. The mask should be such that when the radiation-sensitive layer is positioned with respect to the mask and exposed to radiation, the radiation-transmissive portion that transmits the radiation to the radiation-sensitive layer and certain areas of the radiation-sensitive layer are not exposed sufficiently. A substantially flat plate having a radiopaque portion therein. The radiolucent portion may be a support to which a radiopaque pattern has been applied. For example, the mask may be a transparent quartz plate, with one side of the quartz plate patterned with impermeable chrome. In another aspect, the mask is not quartz and chrome, but other radiolucent materials suitable for the intended application, such as glass, plastics, films, and other opaque materials such as plastics and other metals. May be manufactured from.

The pattern may be associated with a circuit to be formed on a semiconductor device or logic circuit product, but the invention is not so limited. The term "semiconductor logic circuit product" and like terms are used to refer to any digital semiconductor logic circuit product device including, but not limited to, digital memories, microprocessors, coprocessors, and core logic chipsets. used. The semiconductor logic circuit product is an object code comparable to the semiconductor logic circuit product of Intel Corporation of Santa Clara, California. The pattern corresponds to one of a number of processing layers used in the manufacture of semiconductor logic circuit products.

FIG. 2 illustrates, in block diagram form, a method 200 for making a mask according to one embodiment. The method begins at block 201 and then proceeds to block 210 where a radiation sensitive layer is applied to the mask substrate. The term "radiation sensitive layer" and similar terms refer to
Widely used to refer to materials made of materials that physically or chemically change shape when exposed to radiation (light, ultraviolet, electromagnetic radiation such as X-rays or particle beams such as electron beams) . Radiation typically assists in selectively facilitating or making it difficult to remove the radiation-sensitive layer during development. The radiation-sensitive layer may be a positive resist whose shape is changed so that the exposed portion of the layer can be easily and selectively removed by dissolution in a solvent or the like. In another aspect, the layer may be a negative resist that changes morphology such that the exposed resist is relatively difficult to remove.

The radiation sensitive layer may be a prior art radiation sensitive layer applied using conventional methods. For example, a mask substrate (eg, chromium on quartz with an antireflective oxide coating) is pre-treated to remove potential contaminants by washing with deionized water,
After gentle etching with O ₂ plasma, a layer of resist was deposited on the mask substrate, about 100 nm to 600 nm,
Alternatively, it is preferably spin-coated to a sufficiently uniform and typically predetermined layer thickness of about 400 nm. After applying the resist layer, the temperature is raised for a time sufficient to form the layer for subsequent process addition. Depending on the particular layer provided, this step may be performed to dry the layer, evaporate the solvent, improve contact with the substrate, promote a chemical reaction, or for other reasons. For example, depending on the thermal properties of the layer and the solvent, the mask substrate and radiation sensitive layer may be placed on a hot plate at about 80 ° C. for about 5 to 30 minutes.
To about 100 ° C, or preferably about 9 over 25 minutes.
It is better to bake at 0 ° C. to evaporate the solvent.

The method begins at block 210 and ends at block 22.
Proceed to 0, where the radiation sensitive layer is exposed to patterned radiation. Conventional systems for producing patterned radiation can be used, including conventional light systems and electron beam systems. For example, radiation sensitive layer, a voltage of about 10kV to 100 kV, or preferably intensity of about 20kV is about 1 [mu] C / cm ² to 20 [mu] C / cm ^2, preferably using an electron beam exposure system of about 6μC / cm ² It may be exposed and the actuation of a mirror may be used to form patterned radiation.

The patterned radiation exposes or prints a portion of the radiation sensitive layer. Typically, the patterned radiation received at the radiation sensitive layer is
It exposes or prints features with critical dimensions (CD). "Critical dimension", "CD", and like terms are used to refer to a dimension or distance associated with a patterned radiation feature or shape. For example, C
D may be the width of a feature (eg, a line), the separation between two features (eg, the distance between two lines), and other distances in the pattern. The CD can be monitored and compared to predetermined and specific design dimensions as an indication of process performance, maintaining acceptable mask manufacturing standards and tolerances.

The patterned radiation that enters the radiation-sensitive layer may expose or print a CD with a CD error. "Critical dimensional error", "CD error", and like terms refer to an unintentional, undesired, or erroneous difference between an exposed CD and a given particular or desired CD. Widely used for. CD error is
There are types (eg, undersizing or oversizing) and sizes. In a mask having a CD error over the entire area, the type and magnitude of the CD error of the mask are determined by the position on the mask. For example, the CD error increases in magnitude as it moves from right to left along the radiation sensitive layer. CD error is typically undesirable and, if uncorrected, adversely affects semiconductor devices manufactured using the mask.

The method is block 220 through block 23.
0, where the variable thermal energy is sufficiently uneven and uneven.
The radiation sensitive layer is modified by the Nergi interaction. Mutual
The action includes the first heat energy input to the first region of the exposed layer and the first heat energy input to the first region.
Substantially different second thermal energy to the second region of the exposed layer
Input is included. Typically, these different thermal energy
The gear input includes different heat flux to the first and second regions.
This causes different temperatures in the layers in these areas.
It The term "flux" refers to a radiation sensitive layer.
Amount of heat energy transferred to a given area per unit time
(For example, 1 cm ² Energy of 1J is transmitted to the
Used). Depending on these various temperatures
Variability of physicochemical layer transformations
And its properties can occur. These uneven
To the process of block 220 by the physicochemical transformation of
Thus changing the exposure image previously formed on the layer
You can In this way, any desired kind of unevenness
The exposed image can be modified using various thermal energy interactions.
It

Such a modification corrects the exposed image, reduces inaccuracies or errors in the exposed image, corrects the CD, reduces inaccuracies or errors in the CD, and increases the size of the CD. It can be used to positively define the depth and shape, to reduce the CD, and to make other desired modifications. For example, a first heat flux can be provided to a first region of a layer that includes a first CD having a first CD error of a particular type and size to reduce the first CD error, and a first heat error of a different type, size or both. Second with 2CD error
The second region of the CD-containing layer may be provided with a second heat flux that is significantly different to reduce the second CD error. Thus, these different processes can vary the CD error type, magnitude, or both by varying the CD size.

Thermal correction can be provided by a thermal correction system with variable heat input performance. In conventional mask manufacturing,
Post-exposure bake (PEB) systems were often used to cure the radiation-sensitive layer exposed prior to development by providing a uniform and constant heat to the radiation-sensitive layer. A properly functioning PEB system has very small unintentional temperature changes, traditionally less than about 1 ° C across the surface, but sufficient to correct intentional or exposed images in any desired way. Does not provide a uniform heat flux. According to one embodiment, the PEB system, in addition to its conventional functionality, can be modified to provide a non-uniform heat flux to various portions of the exposed image to effect modification of the exposed image, ie, the exposed image. To provide a fix to. Preferably, the use of improved existing equipment allows exposure image modification without introducing additional process steps.

The method proceeds from block 230 to block 240.
Proceed to. In this block, the radiation sensitive layer is developed.
Various developments may be useful, depending on the particular embodiment and physicochemical properties of the radiation sensitive layer. For example, about 1-5 of tetramethylammonium hydroxide (TMAH).
Using an aqueous alkaline developer containing a solution of 1% by weight or preferably 2-3% by weight, the part of the layer is made almost in contact by immersing the layer in a predetermined volume of developer for a time of about 3 to 30 minutes. Dissolve at room temperature and rinse with fresh solvent to remove solvent. Alternatively, other methods and developers can be used, including conventional methods and organic solvents such as methyl isobutyl ketone (MIBK).

The method proceeds from block 240 to block 250.
Proceed to. In this block, etching is performed to form a mask pattern. For example, a metal etchant suitable for removing the chromium layer can be used. This can be done using conventional materials and methods. The method ends at block 260.

Critical Dimension Correction and Error Reduction FIG. 3 illustrates CD error reduction during mask fabrication according to one embodiment. A radiation sensitive layer 310A is provided on a mask substrate 305A having a layer of chromium 320A on quartz 330A. Electron beam radiation 340 containing pattern information is applied to the radiation sensitive layer 310B. Radiation 340 is part 342,3
44, and 346, each of which is applied to various regions of layer 310B. Radiation portion 346 is shown conceptually as the missing half of the erroneous radiation portion. As shown, the error indicates that radiation was lost due to radiation blocking or transmission error, but the error is another type that causes a CD error in the exposed image formed on the radiation sensitive layer 310B by the radiation portion 346. Should be more broadly considered to include the error of. For example, the error is due to misalignment of the radiation 346.

Radiation 340 exposes radiation sensitive layer 310B to form radiation sensitive layer 310C with exposed image 350. Image 350 includes a pattern of exposed and non-exposed areas. This includes the non-exposed areas 351, 35
3, 355, and 357 and exposed areas 352C, 35
4C and 356C are included. The width of the exposed area is the CD. The radiation portion 346 is a region 356 having a CD error.
Expose C.

By reducing the CD error corresponding to the exposed area 356C, the CD can be brought closer to the desired CD. This is the area containing the CD error, ie 356C
, 357, or other adjacent regions 358 with reduced CD error. As discussed above, CD error reduction 3
58 produces a temperature in the area of applied layer 310C that is different from the temperature of the other areas of layer 310C. This causes a non-uniform physicochemical transformation in layer 310C and image 350.

After processing by CD error reduction 358, layer 31
Develop 0C. The specific development indicated by 310D is
The non-exposed regions 351, 353, 355, and 357 are removed, leaving exposed portions 352D, 354D, 356D. This is because development, treatment 358, or both may selectively make them difficult to remove during development. The CD error reduction 358 increases the CD in area 356D and reduces the CD error corresponding to area 356C.

Regions 352D, 354D, and 356D,
And layer 320D is etched to form a mask 360 having a pattern 370 including chrome regions 372, 374, and 376 on quartz 330E. Chrome area 37
The CD of 6 has an exposure area 35 due to the CD error reduction 358.
It is more similar to the CD of region 356D than the CD of 6C.
Preferably, the CD error reduction by 358 is performed before the development and etching processes to provide a mask with improved patterns. Typically, this leads to improvements in semiconductor devices.

Exemplary Critical Dimensional Error FIG. 4 illustrates an exemplary type of CD error, according to one embodiment. The CD error may be an oversizing type or an undersizing type, and may have various sizes.

The feature oversizing error 420 is represented by the actual oversize feature 430, which is larger in size than the intended feature 440 shown by the dashed line. The size and shape of the desired feature corresponds to a given or specific design patterned radiation. The feature oversizing error has a magnitude associated with the magnitude difference between the actual feature and the desired feature. The actual oversized features are the actual oversized CD432 and the desired CD.
CD oversizing error having a magnitude associated with the dimensional length difference between 442 and 442. As shown,
The CD oversizing error includes a potentially unequal error contribution 450. These oversizing errors are also referred to as positive error due to the actual feature or dimension being larger than the desired feature or dimension.

Undersize feature 48 of actual size
The feature undersizing error 460 is represented by the intended feature 470, which is indicated by a dashed line greater than zero. The feature undersizing error has a magnitude associated with the magnitude difference between the actual feature and the desired feature. The actual undersize feature includes a CD undersizing error having a magnitude associated with the dimensional length difference between the intended CD 472 and the actual undersize CD 482. As shown, the CD undersizing error includes a potentially unequal error contribution 490. These undersizing errors are also referred to as negative error resulting from the actual feature or dimension being smaller than the desired feature or dimension.

Thermal Correction System FIG. 5 illustrates a thermal correction system 550 according to one embodiment that reduces the CD error 540 by providing a CD error reduction process 560.
The radiation-sensitive layer 510 shows the exposed image 5 including the characteristic portion 530.
Have twenty. As an example, feature 530 is associated with a desired circuit pattern to be formed on a mask used to form a semiconductor device.

The characteristic portion 530 is a CD including a CD error 540.
Have. The thermal correction system 550 provides a CD error reduction process or dose 560 to the radiation sensitive layer 5 including features 530.
Add to area 10. Process 560 includes a thermal process that uses thermal energy to raise the temperature of the region containing feature 530. This process, including the magnitude of thermal energy, is based on the type and magnitude of the CD error. This process causes the magnitude of the CD error to be current, as indicated by the reduced CD error 570.

[Influence of Radiation Sensitive Layer] The heat treatment is performed according to the characteristics of the radiation sensitive layer. For example, the process for reducing the feature oversizing error for a negatively acting chemically amplified resist is not the same as the process for reducing the feature oversizing error for a positive acting chemically amplified resist. Totally different.

According to one embodiment, the radiation-sensitive layer acts in a negative-acting chemically amplified form with a species that assists the physico-chemical transformation of the layer both on exposure to radiation and on the post-exposure thermal pathway. It may be a resist that has been processed. The chemical species may be a catalyst that is activated by radiation to promote an increased molecular weight crosslinking reaction physicochemical transformation. The way in which a chemical species affects the transformation depends on crosslinking kinetics, diffusion, catalyst deactivation kinetics, and other factors. This cross-linking reduces the solubility during development and improves durability. Therefore, the modification can be modified by modifying the post-exposure thermal path of the chemical species. Preferably, such corrections can be used to correct exposed images and reduce CD error.

The exemplary negative acting chemically amplified resist acts on a commercially available negative acting available from Shipley, Inc. of Marlborough, Mass., A subsidiary of Rohm and Haas, Philadelphia, PA. Chemically amplified resist S
It is better to include AL-601. Resist SAL-601
Includes a base polymer, a radiation activated acid catalyst generator, and a crosslinker. Exposure to radiation can generate an activated catalyst exposure image having radiation activated catalyst areas and unexposed inactive areas. After exposure and at a sufficiently high temperature, the acid catalyst diffuses and promotes a crosslinking reaction between the melamine crosslinker on the polymer chain and the corresponding adjacent hydroxide functionality on another polymer chain. Cross-linking selectively makes removal of exposed areas with aqueous alkaline developers more difficult than unexposed areas. The exact method of producing this transformation is determined by factors including, but not limited to, cross-linking kinetics, catalyst diffusion rate, catalyst deactivation rate (catalysts are typically exposed after thermal decomposition or cross-linking, etc.). Deactivated during baking).

Such a crosslinking process comprises at least
It is temperature dependent because it is well known that reaction kinetics and diffusion rates are temperature dependent. The method of varying the resist temperature between exposure and development affects the extent and nature of the transformed region of the resist. By introducing inhomogeneities or inhomogeneities in the heat treatment path of the exposed image, various modifications of the activated catalyst exposed image can be made. The different processing routes provide different heat fluxes to different parts of the layer and apply different temperature profiles to these parts over time, thereby modifying the cross-linking for these different parts. This includes affecting the density of the crosslinking reaction, affecting the "reach" of crosslinking at the edges between exposed and unexposed features. For example, a temperature scenario that increases diffusion as a whole increases the spread of the bridge region, while a temperature scenario that decreases diffusion as a whole
Reduces the spread of cross-linked areas. Therefore, various post-exposure heat corrections are added to and reflect the layer portions exposed to different temperatures at different times. Advantageously, this can be used to affect the desired post-exposure correction of the exposed image, the wrong critical dimension, or both.

With such a resist, both undersizing error or negative error and oversizing error or positive error can be reduced. In the case of undersizing errors or negative CD errors, these processes can provide significantly more thermal energy than the process used to reduce small size undersizing CD errors, zero error CDs, or oversizing CD errors. In a shorter time, it can be reduced by a high heat flux treatment applied to the layer region containing undersized features. Without limitation, this additional energy is added during the period before the period when the activity of the acid catalyst is reduced and is no longer available to catalyze the crosslinking reaction.
Undersize CD Exposed-Promotes crosslinking near the unexposed border. In this way, a high heat flux treatment can be used to reduce undersizing CD error by generating favorable conditions for crosslinking outside the initial active catalyst exposed image.

Similarly, thermal energy that is significantly less than the process used to reduce CD oversizing error, CD with zero error, or CD undersizing error of small magnitude is in close proximity to the CD error, or the CD error is Low heat flux treatment applied to the region of the containing layer can reduce oversizing error or positive CD error. Without limitation, this reduced energy does not prevent or promote crosslinking near the exposed-unexposed boundary of the feature when the catalyst is in the activated state. In this way, the reach of the crosslinking reaction can be limited and reduced compared to other regions where high temperatures due to high heat energy flux are applied. Such cross-linking limitations can be effectively shrunk by limiting cross-linking growth of oversized CDs to a greater extent than other CDs that receive high heat flux.

According to a variant, the radiation-sensitive layer acts chemically in a positive-working manner on the basis of the exposure and on the basis of the post-exposure temperature treatment, with chemically amplified species which assist the transformation of the layer. It may be an amplified resist. The resist can operate based on a deprotection mechanism where removal of exposed portions is selectively facilitated by development.

A positive acting chemically amplified resist based on deprotection chemistry is t-butoxycarbonyl (tBOC) available from IBM Corp. of Armonk, NY. The tBOC resist contains a lipophilic group (oil roving group) and an acid catalyst generator that generates an acid catalyst when exposed to radiation. At elevated temperatures, the catalyst physicochemically transforms the resist by cleaving the lipophilic groups to generate developer-soluble hydrophilic groups. The transformation is determined by the temperature that allows modification of the transformation by modifying the post-exposure temperature of the resist. The exposed image can be modified in various ways by introducing non-uniformities or inhomogeneities in the heat treatment path of the exposed image. Thus, treating different parts of the resist with different thermal energy input fluxes will result in different temperatures in the layer parts at different times, which results in different "reach" of cleavage / deprotection transformations and different feature resolutions. . Post exposure thermal modification of other resists is possible. For example, it is believed that any resist having a temperature-dependent post-exposure transformation mechanism can be modified by applying non-uniform post-exposure heat treatment to various portions of the exposed image. The idea is that various negative acting resists, positive acting resists, chemically amplified resists, and such mechanistic reactions that depend on temperature (eg, deprotection, depolymerization, rearrangement, intermolecular It is considered applicable to resists based on transformations including dehydration, condensation, cationic polymerization, diffusion).

A simple study can be used to determine the following post-exposure heat correction for any type of radiation sensitive layer. That is, (1) exposing a plurality of features of substantially the same size to the resist, (2) treating a plurality of first subsets with a baseline heat flux, and treating a second subset with a relatively low heat flux. Treating, and treating the third subset with a relatively high heat flux, and (3) determining whether the size of the second or third subset is on average expanded relative to the first subset, It shows that the undersizing error can be reduced thermally. As desired, a simple study can be successful with a more sophisticated study involving heat flux timing and other parameters.

[CD error is determined by mask position] FIG. 6
Indicates that the CD error is determined by its position on the mask 600, according to one embodiment. The type, size, or both, change regularly on the mask or some portion thereof. Some errors are global (glob
al) can be called an error.

The mask 600 includes a reference CD error 610 whose CD error magnitude is proportional to the magnitude shown. The mask further includes other CD errors 620, 630, 640 that differ in magnitude from the CD error 610 depending on their position on the mask. In detail, the CD error 620 is the line 61 parallel to the x-axis.
It is larger than the CD error 610 because it is separated by some distance from the CD error 610 along the 5. Similarly,
The CD error 630 is the CD along the line 625 parallel to the y-axis.
Some distance away from the error 610,
It is larger than the CD error 610. CD error 640 is separated from CD error 610 by some distance along line 635, which represents any optional line on the mask, thus
It is larger than the error 610.

The mask 600 may, in another aspect, include other global CD errors. For example, CD error 66
0, 665, 670, and 675 are larger (or smaller) than the CD error 650, depending on the radius, as shown. Although the above discussion discusses individual CD errors, in general, the CD error in regions such as region 680 is larger (or smaller) on average than other regions such as region 690. The exposure image correction is accomplished by monitoring the CD error of previously manufactured masks and using this monitoring information to adjust the thermal correction system to
Performing error reduction according to one embodiment can be used to improve mask manufacturing. The table provides exemplary CD error data collected during mask manufacture.

[0042]       Date CD error in x direction CD error in y direction                     Increase (nm) increase (nm) 6-13-01 A B 6-20-01 0.1A 2.5B 6-27-01 0.5A-2B 7-04-01 -A -1.5B 7-11-01 -A -4B In the first column, there are many mask error mask manufacturing machines.
The date the disc was manufactured is listed. Second and third Photoshop
The frame contains daily CD error data for A and B.
Here, A and B are the x direction of date 6-13-01 and
It represents the optional increase in CD error in the y-direction. In more detail
In the second column, x is from x = 0 to x = x _maxIncreased to
Includes an average increase in CD error along the mask as
In the third column, y is 0 to y_maxThe same as when growing up
Including the increase of.

As shown, the average magnitude and position dependence of the CD error drifts or changes over time.
For example, as shown in Table 1, initially the CD error increases in both the x and y directions across the mask, but later C
The D error tends to decrease as x and y approach x _max and y _max , respectively. Knowledge of this kind of conventional CD error can be used to perform CD error reduction.
For example, in the case of a chemically amplified resist of substantially negative CD undersizing and negative tone, date 7-02.
The CD error reduction process for −01 approaches (0,0) by adding more thermal energy to the CD error and (x _max , y _max ) by adding a relatively small energy to the CD error. Can be predicted.

[Reduction of CD error by adjusting heat input] FIG. 7
Shows a thermal correction system 700 that can be used to reduce CD error. This system reduces the CD error of layer 710 by transferring varying amounts of thermal energy to the radiation-sensitive layer via the transport medium, so that the radiation-sensitive layer 710 and the thermal energy transport medium 760 are coupled together.
And a variable heat input system 770.

The radiation sensitive layer has a first CD error 730 on the left side 720 of the system and a second CD error 750 on the right side 740 of the system. The heat energy transport medium may be any medium capable of transferring heat energy. For example, the thermal energy transport medium may include a chrome layer on a quartz layer. Media 760, depending on the particular embodiment.
May include other media, such as gas-filled voids, that interface to system 770. As desired, the medium 760 provides a sufficiently consistent and even heat flux to the layer 7
10 can be provided.

As an example, the radiation sensitive layer 710 may be a negative chemically amplified resist having an acid catalyst that diffuses and accelerates the crosslinking reaction. The first CD error is CD
Adjusting, forming, or first adjusting the variable heat input system based on knowledge or estimation that it is an undersizing error.
Can instruct reduction of CD error. This is done by applying a high heat energy flux treatment on the left side. That is, by a thermal correction system that includes a variable heat input system that imparts a relatively large energy flux to the undersizing error 730 as compared to a CD with less undersizing error, a CD-free error, or a CD oversizing error, C
The D undersizing error 730 can be reduced.

In a variant, the second CD error 750 is a CD oversizing error and can be reduced by exerting a low heat energy flux on the right side 740. That is, C
The D oversizing error 750 is reduced by the system that provides a relatively small bundle to the oversizing error 750 compared to the bundle provided to the CD with less oversizing error, substantially no CD error, or CD undersizing error. it can.

Various types of variable heat input system 770 are contemplated. An example of a system that provides variable thermal energy by conduction, convection, and radiation is discussed below. Other examples are possible.

As a first example, system 770 can provide a variable heat input by conduction from a surface having a variable unequal temperature, each controlled by a temperature control system having different temperature set points. Each of the different temperature set points corresponds to a different area of layer 710, such as a quadrant area, grid, radial grid, or other area.

As a second example, the system 770 can provide variable heat input by forced or natural convection. In the case of forced convection, different temperature gases are provided in different regions, or different flow rates of the same temperature gas are provided in different regions. In another aspect, this can be done by contacting the gas in the natural convection zone with surfaces of different temperature or of different thermal conductivity by natural convection.

As a third example, system 770 can provide variable radiant heat energy to layer 710 by radiant heat lamps, radiant flux from hot surfaces, or other means. For radiant heat lamps, different intensities for different regions of layer 710, different exposure durations for different regions,
Radiant heat input can be provided by infrared heat lamps that deliver different radiation wavelengths to different regions.

Radiant heat input can also be provided by radiant heat flux from hot surfaces. The radiant heat flux can be varied and made uneven by a variety of methods. The first method involves providing a hot surface with variable and unequal temperatures. The radiant heat flux from such surfaces may be variable and unequal because it transfers different heat energies to different regions of layer 710 to bring them to different temperatures. For example, the surface may have a hot right side that provides a high radiant flux on the right side and a relatively cold left side that provides a low radiant energy flux on the left side.

The second method involves varying the separation distance between the hot surface of substantially uniform temperature and the layer 710. The amount of radiant heat energy transferred to the layer 710 by the hot surface decreases as the separation distance between the layer 710 and the hot surface increases. This allows layer 710
The amount of radiant heat energy provided to the area of layer 710 can be adjusted by adjusting the separation distance between the area and the corresponding adjacent area of the hot surface. Thereby, the temperature of the first region including the first CD error and the temperature of the second region including the second CD error can be made different. Such adjustments
This is done by adjusting the various separation distances between these areas and the corresponding areas of the variable heat input system that transfer many direct radiant energy fluxes to these areas.
As explained in more detail below, such adjustments include
This can be done by providing one or more height adjustable spacers to control the separation between a portion of layer 710 and the post-exposure bake hot plate surface where the temperature is substantially equal. it can.

Error Reduction System with Adjustable Spacers FIG. 8 illustrates a thermal correction system 800 with adjustable spacers that can be used to reduce CD error according to one embodiment of the present invention. This system includes a heat energy transport medium 8
A thermal energy transport medium is coupled to a variable heat input system 870 including a radiation sensitive layer 810 coupled to 60. The thermal energy transport medium includes a radiopaque layer 862 (eg, chrome) attached to a radiation permeable layer 864 (eg, quartz) and a void 866 filled with a gas (eg, air). The variable heat input system includes a thermal energy source 872, an adjustable first spacer 874 having a separation 875, and an adjustable second spacer 877 having a separation 877.
Includes a spacer 876 and a distance determination system 880.
The thermal energy source has a separation distance 87 that varies across the void space.
Radiant heat is transferred to different heat energy transport media based on 5 and 877. In one embodiment, the thermal energy source 872 is at a substantially uniform baking temperature of about 90 ° C. Based on the different separation distances, different regions of the radiation sensitive layer receive different radiant energy inputs and reach different temperatures. These temperatures can advantageously be used for exposure image correction and CD error reduction, as discussed above.

First spacer 874 and second spacer 87
6 couples the thermal energy source to the radiation permeable layer (or some other structure supporting the radiation permeable layer) at respective separation distances 875 and 877. These separation distances 875 and 87
Increasing 7 reduces the radiant energy to be transferred to layer 810. Similarly, these distances 87
By reducing 5 and 877, more radiant energy is transferred to layer 810. Distance 87
If 5 and 877 are different, variable unequal radiant energy is transferred to left side 820 and right side 840. For example,
If distance 877 is less than distance 875, more energy is transferred to the right side 840 of layer 810. Without limitation, the amount of, for example, radiant heat energy transferred to the right side 840 of layer 810 varies substantially proportional to the square of distance 877. As shown, spacers 874 and 876 are
It may be located near the periphery, such as the sides or corners of the thermal energy source.

First CD error 830 and second CD error 85
A zero CD error reduction is performed based on layer 810, CD error type, and CD error magnitude. For example, for chemically-actuated negative acting resists with large undersizing CD error 830 and small undersizing CD error 850, the adjustable first spacer 874 may cause the radiant energy transferred to the CD error 850 to The distance 875 can be adjusted to be reduced compared to the distance 877 so that more radiant energy is transferred to the CD error 830.

First and second adjustable spacers 874
And 876 are preferably spacers of any type sufficient to connect the radiation sensitive layer to a source of thermal energy at adjustable spacings 875 and 877. These spacers allow the separation distance to be accurately and reliably adjusted in desired increments for a particular embodiment. For example, depending on the particular embodiment, the spacers can reliably adjust these distances with an accuracy of about 50 μm or more, or preferably 5 μm or more.

Spacers 874 and 876 are typically used.
Operates by receiving energy and adjusting heights 875 and 877, respectively. The spacers are mechanically adjustable; they receive mechanical energy (eg, rotation, translation, pressure / volume, or other conventional form) from a person or device (eg, motor) and adjust height Then, the separation distance between the radiation sensitive layer and the heat energy source is changed. For example, the spacer provides a jack that can be adjusted based on translational energy applied through a lever or rotational energy applied through a gear, a piston that is adjustable based on pressure, a linear movement that is adjustable and based on rotational energy input. Screws, translational energy adjustable nails or spikes, and other conventional height adjustment systems.

According to a variant, the spacers 874 and / or 876 directly receive the electrical energy and have a height 875.
And / or an electrically adjustable spacer for adjusting 877. For example, these spacers may be piezoelectric spacers that generate a certain predetermined mechanical force that corresponds to the input voltage and that is related to the distance.

Spacers 874 and / or 876 may be of various constructions including but not limited to metals (eg stainless steel, aluminum, chrome), plastics (eg polystyrene), ceramics, glass, quartz, or other materials. It should be made of material. The desired material should have a sufficiently low thermal conductivity to reduce the thermal energy that is conductively transferred from the source of thermal energy to the radiation sensitive layer. In another aspect, a low thermal conductivity insulating spacer is operably coupled between the energy source 872 and the layer 810. For example, a piece of polyamide or O-ring is attached to the spacer 874 to contact the radiation transmissive layer 864.

System 800 preferably includes a distance determination system 880 for determining or measuring the distance associated with spacer 874. Conventional distance measuring systems and methods can be used. For example, the distance determination system is preferably an electrical metrology system that measures electrical properties such as conductivity, resistance, capacitance, or other properties of the length of void 866 associated with distance 875. In another embodiment, a laser based system can be used to measure distance. The distance measuring system includes a scale of distance intervals as provided on the ruler. Desirably, the distance determination system is capable of measuring distance with a resolution that affects the temperature generated in the radiation sensitive layer. For example, the distance determination system can accurately measure distances with an error of about 5 μm or less, or preferably about 2 μm or less.

The thermal energy source 872 may be a thermal energy source that provides thermal energy by conventional thermal energy exchange forms such as conduction, convection, and radiation. According to one embodiment, the thermal energy source may be a hot radiant energy source that transfers radiant energy through medium 860.
The medium includes a cavity 866 containing a gas (eg, nitrogen, air, dry air, etc.) to transfer radiant energy to the radiation sensitive layer 810 via layers 864 and 862. For example, the thermal energy source is similar to a hot plate, and the electrical energy source (eg, outlet, generator, or battery)
Draws electrical energy from the heat coil, resistor,
Electrical energy to an electrical energy conversion means such as.
In another aspect, the thermal energy source 880 includes a lamp (eg, a radiant energy lamp or an infrared lamp).

Exemplary Temperature Distribution FIG. 9 shows an exemplary temperature distribution for post-exposure heat treatment of the radiation sensitive layer according to one embodiment. The two curves shown by the white squares and the white triangles indicate the different temperatures obtained in the radiation-sensitive layer at different times by the non-uniform and non-uniform post-exposure heat treatment of the radiation-sensitive layer.

As shown by these curves, the temperature of the layer ranges from a starting temperature, which is approximately room temperature, to a final temperature of about 2 to 5 times, preferably about 3.5 times higher than this starting temperature. It rises during a period of about 3 to 5 minutes, preferably about 4 minutes. Different parts receive different heat fluxes and reach different temperatures at different times. The curve indicated by the white squares is labeled as "high temperature portion" to indicate that it corresponds to the portion of the radiation sensitive layer that receives a high heat flux. Similarly, the curve shown by the white triangle is
It is labeled "cold part" to indicate that it corresponds to the part that receives a lower heat flux and reaches a relatively low temperature. The temperature difference varies from near zero initially to the desired large values during the periods listed above. While showing a particular maximum difference of about 5 ° C, larger or smaller differences are considered useful in modifying other layers. For example, C
About 10 ℃ for a layer in which the magnitude of the D error changes significantly
You can use the maximum difference of.

The first part of the time when the temperature is above about 50 ° C. to 70 ° C. has a much stronger effect on the correction of the exposed image than before the lower temperature or for the subsequent higher temperature. In the case of Shipley resist, the crosslinking reaction is slow at a temperature of 40 ° C. or lower, and the catalyst is deactivated at a high temperature and a long time that follow, or surrounded by a crosslinking region. Therefore, the difference between the two curves during these periods can be used to influence the non-uniform correction of the exposed image. In detail, the difference is effective in variously balancing the kinetic acceleration of the cross-linking reaction, the diffusion of the acid catalyst, and the deactivation of the acid catalyst in the resist such as Shipley SAL resist. To do. For example, using such a non-uniform post-exposure heat treatment of the layers, a high temperature treatment "grows" the undersize features, and oversizes with a negative chemically amplified resist such as Shipley SAL resist. Relatively "shrinkage (sh
link) ”.

As desired, elevated temperatures should be maintained for a time sufficient to cure the radiation sensitive layer, cure the layer, remove moisture, diffuse radiation sensitive components, and develop well. For example, the temperature may be maintained at about 80 ° C. to 120 ° C. for about 5 minutes to 30 minutes, or at about 90 ° C. to 100 ° C. for about 10 minutes.

Different heat treatments are also conceivable. The temperature is raised more slowly than shown in FIG. For example, increase the temperature from about room temperature at 0 minutes to about 30-40 ° C. at 1 minute and about 70 degrees at 2 minutes.
C. to 80.degree. C., then at about 3 minutes to about 80.degree. C. to 90.degree. In another aspect, the rate of change of temperature may be constant. For example, increasing the temperature of the bed at a constant rate,
Keep the temperature acceleration constant or the temperature deceleration constant.
Alternatively, rather than these heat treatments and treatments equivalent to those heat treatments, one skilled in the art can determine effective treatments for any type of radiation sensitive layer. These effective processes allow post-exposure modifications to be made to the exposed image without undue experimentation in accordance with the present disclosure. This is done by empirically examining a number of different temperature gradient distributions and confirming that the distributions achieve the desired exposed image modification.

The table lists exemplary thermal energy gradient data corresponding to system 800 according to one embodiment.
The data shows the system 800 after 1 minute of ramping according to the ramp profile of FIG. 9 when the temperature of the thermal energy source 872 is about 60 ° C.

[0069] Difference between distances (μm) Difference between temperatures (℃) 0 0 15 5 25 7 45 5 10 70 13 The first column describes the difference in distance between the radiation sensitive layer 810 and the thermal energy source for various conditioning conditions. The differences mentioned in the first column mainly consider the distance between the distances 875 and 877. In the second column,
The difference in temperature between the right side 840 corresponding to distance 877 and the left side 820 corresponding to distance 875 is noted. As shown, the temperature difference in the second column increases as the difference between the distances increases. A relatively short distance corresponds to a relatively high temperature. The difference in temperature is due to the reduction in radiant heat energy reaching the radiation sensitive layer as well as other factors that contribute to this (eg, free convection due to hot gas rising from source 872).

CD Error Reduction Temperature FIG. 10 is an exemplary illustration that can be used to determine the CD error reduction temperature for a system, such as system 800, according to one embodiment that includes a negative chemically amplified resist, such as Shipley SAL resist. Correlation is shown conceptually. This exemplary correlation is associated with time after 1 minute of slope according to the slope distribution shown in FIG.

Correlation is associated with the magnitude of the _{CD error} and the difference between the CD error reduction temperature (T _{CD error} ) and the zero error conceptual CD and the corresponding baseline temperature (T _{NO error} ). For example, an oversizing error of magnitude +5 corresponds to a CD error reduction temperature of 10 ° C lower than the conceptual zero CD error temperature, and an undersizing error of magnitude -5 corresponds to a conceptual zero CD error. 1 compared to temperature
Corresponds to a temperature as high as 0 ° C. This exemplary linear correlation is useful in many embodiments, especially over a narrow CD error range, but more sophisticated non-linear correlations are possible.

[Decrease in Amplification of Catalyst Concentration] FIG. 11
Shows the decrease in active catalyst concentration over time for certain negative-type chemically amplified resists. At high temperatures, the active catalyst concentration decreases from the initial concentration (C _O ) to near zero in a few minutes. In this particular example, the concentration decreases to half of the initial concentration (ie C _O / 2) about 1 minute after the start of the temperature ramp,
About 4 minutes after the start of the temperature ramp, it decreases to almost zero. Without limitation, such reduction in active catalyst concentration is due to thermal decomposition, steric hindrance, or both. It will be apparent to those skilled in the art, after reading this disclosure, that the application of the present invention is not limited to the modification of exposed images based on reduced catalyst concentration. This is because the invention is more generally applicable to any post-exposure transformation that is temperature dependent.

Thread Spacer FIG. 12 illustrates an exemplary adjustable thread spacer according to one embodiment. The term "screw" is widely used to refer to a device for producing a substantially linear movement based on rotational energy input. The screw includes a cylindrical shaft 1210 and a beveled flat thread 1220. The thread is connected to a shaft and spirals across the shaft. The threads may be glued or scored into the shaft as desired. The threads have at least one pitch length 1230, which is about 0.1 mm to 1 m depending on the particular embodiment.
m. Long pitch lengths make them more robust and more economical to manufacture, but shorter pitch lengths are desirable for very precise height adjustments and longer pitch lengths for very coarse height adjustments. Is desirable. Embodiments with many different pitches, as well as embodiments where the pitch varies along the shaft, are also contemplated. Shaft diameter is typically about 1 mm
To 20 mm, but preferably about 1 mm to 10 m
m.

Illustrative Adjustable Screw Spacer 1200
Also has a sturdy head 1250. The diameter 1260 of this head is larger than the diameter 1240, for example:
Diameter 1240 is at the minimum of the given range. Head 1
250 often provides a rotational energy interface 1270. It comprises at least one slotted groove to interface with or engage a source of rotational energy, such as a screwdriver. The screw is further provided with a low thermal conductivity insulation 1280, which is a polyamide O-ring that reduces heat transfer by conduction between the high temperature heat source and the radiation sensitive layer.

Adjustable screw spacer 1200 may be any conventional type of screw. For example, the spacer 1200 includes a slotted screw, a leveling screw, a screw jack, a round head screw, an interlap screw, a socket head screw, a pan head screw, a right screw, a left screw, a Phillips machine screw, a Phillips head screw, an Allen screw. , A ball screw, a fine adjustment screw, a circulation tangent screw, a thumbscrew, a step screw, a stage screw, or another type of screw. Preferably,
The use of one of these conventional types of screws, especially commercially available types of screws, provides economic advantages. In another aspect, the screw spacer 1200 may be a custom-made screw having the performance shown and described, or which will be apparent to one of ordinary skill in the art based on this disclosure. For example, depending on the particular embodiment,
Spacers with predetermined design specifications can be obtained from Sigma Meltec Co., Ltd. in Aso-ku, Kawasaki, Japan.

FIG. 13A shows an adjustable screw spacer 133 screwed into a thermal energy source 1310 according to one embodiment.
0 shows a plan view of 0. The thermal energy source may include a post-exposure bake oven hot plate. The thermal energy source includes a threaded hole 1320 that rotatably receives the threads of the spacer 1330. A screwdriver is inserted into slot 1350 of spacer 1330 and rotated, and the screw spacer is adjusted by rotation. Shown is the top surface of the head of the screw 1330, to which a heat insulating O-ring 1340 is attached. This is to prevent the upper surface (for example, metal) of the screw, which has better thermal conductivity than the O-ring, from coming into contact with the mask placed above the thermal energy source.

FIG. 13B is a side view of an adjustable screw spacer 1330 according to one embodiment screwed into a heat energy source. As shown, the screw 1330 is adjusted such that the top surface of the head extends above the top surface of the thermal energy source,
The O-ring 1340 makes the height even higher. This actually increases the separation distance between the radiation sensitive layer present on the surface of the mask 1360 and the thermal energy source. As shown, this may result in a tilt angle between the mask and the thermal energy source if the other spacer adjustments are different. Due to such an inclination angle, a non-uniform radiant heat flux is applied to the mask. The screw can be rotated for further adjustment. In one alternative adjustment, both the screw head and the O-ring are submerged below the top surface of the thermal energy source. This can be used to return the source of thermal energy to its unconditioned state where uniform and non-uniform heat input is provided to the mask. Hole 13 as shown
20 should be provided with sufficient void space to allow such adjustment.

FIG. 14 illustrates an exemplary adjustable piezoelectric spacer system 1400 according to one embodiment. The spacer system 1400 receives a voltage 1420 from a power source,
It includes a voltage regulator 1430 that regulates the magnitude of the voltage provided to the piezoelectric spacer 1410. This voltage regulator
The voltage is adjusted based on predetermined adjustments or settings (eg, set points) provided by humans or systems. For example, the adjuster 1430 may use industrial manufacturing quality control data (eg, to determine the type and magnitude of the CD error determined for a particular area associated with the spacer 1410).
CD error (as confirmed by an operating electron microscope) can be accessed and a predetermined command can be added to correlate the data with the output voltage.

After determining the output voltage, the voltage regulator applies a first voltage 1440 to the piezoelectric spacer 1410. For illustrative purposes, the piezoelectric spacer 1410 has a first state 14 having a first distance or height 1455 corresponding to the first voltage 1440.
It is shown at 50. As an example, the first state and height are C
The D undersizing error can be reduced. System 14
00 is adjustable so that when a CD error of different type or magnitude is encountered, the voltage regulator will output a second different voltage 146.
0 is applied to bring the piezoelectric spacer into the second state 1470.
This condition is, in this case, an additional distance or height 147.
Have 5. As an example, the second state and height 1475 is C
The D oversizing error can be reduced.

CD Error Reduction System with Removable Spacers FIG. 15 shows a thermal correction system 1500 incorporating removable spacers according to one embodiment. The system has a thermal energy source 1510, which is preferably a hot plate conventionally used in post-exposure baking operations. The thermal energy source 1510 is
Four cavities 1512, 1515, 1516, and 151
8 and are configured to receive one of the removable spacing systems 1522, 1524, 1526, and 1528, respectively. Vacant space 1512
Are voids of a cubic, rectangular, cylindrical, triangular, or other form of thermal energy source 1510, and corresponding solids 15 of spacing system 1522 of approximately the same size and shape.
32 are accommodated. The solid 1532 fits well, snugly and consistently in the void 1512, and
Increase the reliability of 500. As shown, the void 1512
May be provided along the sides of the source 1510.
In another aspect, the void 1512 is in another perimeter such as a corner,
Alternatively, it may be provided at an internal position. The spacing system 1522 may be formed of the same material as the thermal energy source 1510, or may be formed of a different material. Typically, for different materials, the coefficients of thermal expansion of the materials are close to each other so that stress and mismatch do not occur during the temperature ramp.

Spacing systems 1522, 1524, 152
6 and 1528 are each a spacer 1552, 155.
4, 1556, and 1558, the spacers having respective functional upper surfaces 1542, 1544, 1546,
And above 1548. These upper surfaces 1542-
1548 may be substantially coplanar with the functional top surface of thermal energy source 1510, or thermal energy source 1515.
It may be raised or retracted as desired with respect to the upper surface of 10. Spacer 1552-155
8 can provide variable heat input to the radiation-sensitive layer for system 700 and system 800, or both of these systems.

According to one embodiment, spacer 1552-1
558 is adjustable. For example, the spacer 15
52 is a screw spacer 1552B which can be adjusted by rotation.
May be Solid 1532 has a cylindrical cavity (not shown) open to surface 1542 through a circular opening.
Have. The cylindrical cavity may be provided with a structure that corresponds to the threads and shafts of the screw spacer 1552B.
The spacer 1552 further includes a polyamide O-ring 15
A heat insulator such as 60 may be provided. Spacer 1552
Such a system 1522 incorporating B removes the solid 1532 from the cavity 1512 and removes the spacer 15
The spacer 1552B is precisely adjusted with a screwdriver so that 52B provides the desired distance to the functional upper surface of the thermal energy source 1510, the desired distance is accurately measured if desired, and solid 1532 is used prior to use. Can be used by returning to the empty space 1512.

In another aspect, the systems 1522-152
8 may not be an adjustable spacing system 1522-1528, but may be a predetermined spacing system with different non-adjustable spacing heights. Multiple such predetermined systems can be provided for use in reducing CD errors of various magnitudes and types. As a result, one spacing system with the desired spacing height can be selected and used without adjustment. Heat Correction System for In-Situ Adjustment FIG. 16 shows that the adjustment of the screw spacers can be done quickly via an adjustment plate provided with an adjustment-enabling opening (in this case a hole). 2 shows a top view of a thermal correction system 1600 according to one embodiment. The system includes a hot plate having an upper surface 1610 onto which four adjustable screw spacers 1630A-D are threaded.
Four heat insulators 1640A-D on top of hot plate
Are attached by fasteners 1650A-D, and these insulations are in contact with the tops of the four adjustable screw spacers. The system includes an adjustment plate 166.
Further includes 0. This adjustment plate includes screw spacers 1630A- when the adjustment plate is positioned on the upper surface.
Hole 167 to allow in-situ adjustment of D
0A-D are provided.

The top surface 1610 of the hot plate is typically at least as large as the mask to be heat treated, so that heat can be provided from the top surface to all areas of the mask. The hotplate is provided with four holes with threads for receiving the screw spacers.

Screw the four screw spacers 1630A-D into the four holes. The head of the screw spacer is a heat insulator 16.
Slots are provided that have a top surface that supports 40A-D and that allow these spacers to be adjusted by screwing or rotating by other means. The screw spacers can be rotated to position the top surface of the head in various positions relative to the top surface of the hot plate.
These various positions include a first position in which the top surface of the head extends above the top surface of the hot plate and a second position in which the top surface of the head is positioned below the top surface of the hot plate. In the first position, the upper surface of the screw head lifts the insulation from the upper surface of the hot plate, effectively adding a separation distance to either the conditioning plate or the mask located on the hot plate plate surface.

The heat insulators 1640A-D are fasteners 165.
0A-D (e.g., bolts, screws, rivets, staples, nails, adhesive, or other desired fastener means) attached to the hotplate top surface 1610.
The insulation is designed so that there is no direct contact between the conductive parts of the hot plate and the adjustable screw spacer and the mask located above the hot plate top surface, which reduces heat transfer, Thin (eg less than 200 μm or less than 100 μm), flexible, thermally stable,
It may be a small sheet of insulation (eg a rectangular strip). If the screw spacers are adjusted and placed under the top surface of the hot plate, the insulation rests on the top surface of the hot plate. If the screw spacers are adjusted to project above the top surface of the hot plate, these spacers lift the insulation away from the top surface of the hot plate. The insulation is provided with holes (through which holes the screw spacers are visible). The diameter of these holes is smaller than the diameter of the head of the screw spacer to engage and rest on the top of the screw spacer, but large enough to allow a screwdriver or other means to access and adjust the slot. .

Various thermal insulators are contemplated for the thermal insulators 1640A-D. For example, insulators include films of polymeric materials, polymeric foams, composites, low thermal conductivity ceramics and glasses, cloth or weaves of thermal insulation, glass fibers, asbestos pads, ceramic fibers,
Metal matrix materials, etc. are included. The desired quality of insulation material is readily available, successfully pre-used in similar environments, at least about 25 ° C.
Thermally stable over a temperature range from about 120 ° C to about 120 ° C, stable and low thermal conductivity between about 25 ° C to about 120 ° C, and from about 25 ° C to about 120 ° C. It is stable between and has a low coefficient of thermal expansion.

According to one embodiment, the insulation 1640A-D.
Is an E.I. of Wilmington, Del. I. Kapton (Kapton is a registered trademark) available from DuPont High Performance Materials Company, a subsidiary of DuPont.
Includes polyimide film. Such a film is thin (for example, about 25 μm to about 70 μm), is thermally stable over a wide temperature range (for example, about −269 ° C. to about 400 ° C.), and has excellent heat insulating properties (heat conduction). The rate is about 0.
1-0.5 W / m / ° C), which provides sufficient heat insulation even when applied as a thin film.

The adjustment plate 1660 includes a screw spacer 1660 to allow the screw spacer to be rotated and adjusted in-situ with respect to the adjustment plate on the top surface of the hot plate.
630A-D with hole 1670A- potentially in position
Have D. The adjustment plate may be substantially the same in length, width and thickness as the mask to be manufactured. To manufacture the spacers 1630A-D with the adjustment plate, the following operations are performed. That is, (a) place the adjusting plate at a predetermined position on the upper working surface of the hot plate,
(B) adjusting an adjustable screw spacer through a hole in the adjusting plate, and (c) using a distance determination system between the upper surface of the adjusting plate and the upper surface of the hot plate proximate each of the screw spacers 1630A-D. Measuring a number of distances, (d) determining if further adjustments are needed to reach the desired morphology, (e) (b), (c), and until the desired adjustment is obtained. Repeat (d),
(F) Take out the adjusting plate from the upper working surface. Preferably, by using such an adjustment plate with holes, the screw spacers can be adjusted quickly while the distance determination is made in concert with each other. If such an adjustment plate is not used, the screw spacers may be adjusted many times by placing the mask in place for distance measurement and removing the mask for adjustment. Repeated time-consuming work is required.

FIG. 17 is a side view of a portion of a heat correction system 1700 that includes a conditioning plate 1750 with openings such as holes 1760. The holes 1760 provide access and adjustment to the screw spacers 1720 when the adjustment plate is in place on the thermal energy source 1710 (eg, hot plate), according to one embodiment. The system further includes a sheet of insulating film 1730 attached to the thermal energy source by fasteners 1740 and in contact with the upper working surface of the thermal energy source and the upper surface of the screw. Showing a particular adjustment of the spacer 1720,
Other adjustments are possible, and these adjustments include rotating the screw spacer so that its upper surface extends above the upper surface of the heat energy source, thereby vertically moving the screw spacer, insulation film, and adjustment plate. Includes moving adjustments. The system further includes a distance determination system 1770 for determining the separation distance by detecting the position of the top surface of the adjustment plate. The clearance includes any clearance due to the adjustable screw spacer.

MODIFIED EXAMPLES The present invention is not limited to the particular contexts and examples described above. As an example, according to a variant, the invention can be used to modify the exposed image of the radiation-sensitive layer for purposes other than mask production. For example, an exposed image mounted on a silicon wafer of a semiconductor logic circuit product being manufactured based on lithographic exposure using a mask can be modified by a variable post-exposure heat treatment. Other embodiments will be apparent to those of skill in the art upon reading this disclosure.

In conclusion, the present invention provides a system and method for modifying the exposed image of the radiation sensitive layer by providing the exposed image with an uneven and non-uniform thermal energy input.

In the above description, the present invention has been explained with reference to specific embodiments thereof. It will be apparent, however, that various changes and modifications may be made without departing from the spirit and scope of the invention. Therefore, the specification and the accompanying drawings are to be considered as illustrative rather than limiting.

[Brief description of drawings]

FIG. 1 illustrates a conventional lithography system that uses a mask to manufacture a semiconductor device.

FIG. 2 is a diagram showing a block diagram of a mask manufacturing method according to an embodiment.

FIG. 3 illustrates a mask manufacturing process incorporating a critical dimension error reduction process according to one embodiment.

FIG. 4 is a diagram showing different types of critical dimension errors according to one embodiment.

FIG. 5 illustrates a thermal correction system for reducing critical dimensional error according to one embodiment.

FIG. 6 is a diagram showing a critical dimension error determined by a mask position according to an embodiment.

FIG. 7 illustrates a thermal correction system with variable heat input according to one embodiment.

FIG. 8 illustrates a thermal correction system with adjustable spacers, according to one embodiment.

FIG. 9 illustrates example temperatures for post-exposure heat treatment, according to one example.

FIG. 10 illustrates an exemplary correlation between critical dimensional error and error reduction temperature, according to one embodiment.

FIG. 11 illustrates an exemplary decrease in active catalyst concentration over time, according to one example.

FIG. 12 illustrates an adjustable screw spacer according to one embodiment.

FIG. 13 is a plan and side view of an adjustable screw spacer screwed into a heat energy source, according to one embodiment.

FIG. 14 illustrates an adjustable piezoelectric spacer system according to one embodiment.

FIG. 15 illustrates a thermal correction system with removable spacers, according to one embodiment.

FIG. 16 is a plan view of a thermal correction system having an adjustable screw spacer and an adjustment plate with apertures that allow adjustment of the spacer, according to one embodiment.

FIG. 17 is a side view of a thermal modification system having an adjustable plate with adjustable screw spacers and apertures that allow adjustment of the spacers, according to one embodiment.

[Explanation of symbols]

110 radiation source 140 patterns 305A mask base material 310A Radiation sensitive layer 320A chrome 330A quartz 340 electron beam radiation 350 exposed image

Continued front page    (72) Inventor Hiroyuki Inomata             1-1-1, Ichigaya-Kagacho, Shinjuku-ku, Tokyo             Dai Nippon Printing Co., Ltd. (72) Inventor Shiho Sasaki             1-1-1, Ichigaya-Kagacho, Shinjuku-ku, Tokyo             Dai Nippon Printing Co., Ltd. (72) Inventor Masaaki Kurihara             1-1-1, Ichigaya-Kagacho, Shinjuku-ku, Tokyo             Dai Nippon Printing Co., Ltd. (72) Inventor Takeshi Ofuji             5-6 Tokodai, Tsukuba City, Ibaraki Prefecture (72) Inventor Osamu Katata             110-1 Shimoasao, Aso-ku, Kawasaki-shi, Kanagawa (72) Inventor Akira Takano             110-1 Shimoasao, Aso-ku, Kawasaki-shi, Kanagawa F-term (reference) 2H095 BB05 BB27 BB28 BB38                 2H096 AA24 FA01                 5F046 KA04 LA18

Claims (24)

[Claims] 1. A step of mounting an adjusting plate on an upper working surface of a heat energy source so that an opening of the adjusting plate can approach an adjustable spacer of the heat energy source; Adjusting through an opening, and removing the adjusting plate from above the upper working surface of the thermal energy source. 2. The method of claim 1, wherein a mask substrate having an exposed radiation sensitive layer is disposed on the upper working surface of the thermal energy source, and various exposed radiation sensitive layers. The method further comprising the step of modifying the exposed radiation-sensitive layer by simultaneously treating the exposed regions with a non-uniform heat flux based on the adjusted spacers. 3. The method of claim 2, further comprising the step of forming a mask by developing the modified radiation sensitive layer and etching based on this development. 4. A mask formed by the method according to claim 3. 5. The method according to claim 1, wherein the adjustment comprises
A method comprising rotating an adjustable screw spacer. 6. The method of claim 1, wherein the spacing distance is determined in association with adjustment of an adjustable spacer when the adjustment plate rests on the upper working surface of the thermal energy source. The method further comprising the step of: 7. The method of claim 6, wherein the determining step comprises: determining a first position on the top surface of the adjustment plate proximate the opening and a thermal energy source proximate an adjustable spacer. A method comprising the step of determining a distance between a second position on the working surface. 8. A thermal energy source having a top surface that provides radiant heat to a radiation sensitive layer provided on the mask substrate when the mask substrate is placed on the top surface, the radiation sensitive layer and the top surface. An adjustable screw spacer rotatably coupled to the heat energy source for adjusting a separation distance between the heat energy source and the top of the heat energy source. An adjustable screw spacer that is adjusted by rotating it to a predetermined position; and an adjustment plate to be placed on the upper surface of the heat energy source in front of the mask substrate, the adjustable screw spacer A system including an adjustment plate having an opening aligned with the adjustable screw spacer to allow rotation of the. 9. The system of claim 8, wherein a plurality of additional adjustments rotatably coupled to the thermal energy source to adjust a plurality of separation distances between the radiation sensitive layer and the top surface. An adjustable screw spacer, wherein the top of the additional adjustable screw spacer is adjusted by rotating it to various positions on the top surface of the heat energy source; A system including a plurality of additional openings aligned with the additional adjustable screw spacers such that the additional adjustable screw spacers can be rotated. 10. The system according to claim 9, wherein the plurality of additional openings includes holes provided in the periphery of the adjustment plate. 11. The system of claim 8, wherein the thermal energy source is in contact with the adjustable screw spacer at a location where the top of the adjustable screw spacer is on the top surface of the thermal energy source. The system, further comprising an attached thermal insulator. 12. The system according to claim 11, wherein:
The system, wherein the insulation comprises a sheet of polyimide film having a thickness of about 200 μm or less. 13. An adjustable heat correction system for heating a radiation-sensitive layer provided on the mask substrate, the mask substrate being provided when the mask substrate is positioned in the heat correction system. A thermal correction system including an adjustable spacer that is adjustable to displace; and allowing adjustment of the spacer when the adjustable spacer is positioned in the thermal correction system A system that includes an adjustment plate with an opening to permit 14. The system of claim 13, wherein the adjustable spacer comprises an adjustable screw spacer, and the opening in the adjustment plate is smaller than the head of the adjustable screw spacer. 15. The system according to claim 13, wherein
The system further comprising thermal insulator means for reducing conductive heat transfer between the adjustable screw spacer and the mask substrate. 16. A thermal energy source for heating a mask substrate having an exposed radiation-sensitive layer, which has an upper surface at least as large as the mask substrate and has a plurality of screw holes on the upper surface. A heat energy source having various positions, and a plurality of adjustable screw spacers screwed into the plurality of screw holes, having a head having a slot and a head upper surface, and the head upper surface with respect to a hot plate upper surface. A plurality of screw spacers operable to be rotated to move and to be rotated to extend the head upper surface above the hot plate upper surface; and a plurality of screw spacers attached to the thermal energy source. A heat insulator having a top surface in contact with the mask base material and a bottom surface in contact with the head top surface of the corresponding adjustable screw spacer, each of which has a corresponding adjustment. Each having a hole accessible to free the screw spacer slots and a plurality of insulation system. 17. The system according to claim 16, wherein
Further comprising an adjusting plate that can adjust the plurality of adjustable screw spacers before heating the mask substrate, the thickness of the adjusting plate is substantially the same as the thickness of the mask substrate, the adjusting plate, A system having a lower surface in contact with the upper surface of the plurality of insulators, the adjustment plate having a plurality of holes each corresponding to a hole in the insulator that is accessible to a slot in a corresponding adjustable screw spacer. 18. The system according to claim 16, wherein
The system, wherein the plurality of insulators comprises a polymeric film having a thickness of about 100 μm or less. 19. The system according to claim 18, wherein
The system, wherein the polymer film comprises polyimide. 20. An opening that allows access and adjustment to an adjustable spacer of the thermal correction system when positioned above the upper working surface of the thermal correction system,
Adjustment plate. 21. The adjustment plate of claim 20, wherein the adjustment plate is positioned on a plurality of adjustable spacers of the thermal correction system when positioned above the upper working surface of the thermal correction system. An adjustment plate having a plurality of openings to allow access and adjustment, the plurality of openings including holes provided in the adjustment plate. 22. The adjustment plate of claim 20, wherein the adjustable spacers include adjustable screw spacers, the adjustable screw spacers comprising a head of a predetermined head diameter and a rotational engagement interface. An adjustment plate having a diameter of an opening of the adjustment mask large enough to allow access to an adjustable screw spacer and rotational adjustment, and smaller than a head diameter. 23. The conditioning plate of claim 20, wherein the thickness of the conditioning plate is about the same as the thickness of the mask substrate having the exposed image to be modified by the thermal modification system. . 24. The adjustment plate of claim 20, further comprising a plurality of additional openings that allow access and adjustment to a plurality of additional adjustable spacers of the thermal correction system.