Patent ID: 12189285

DETAILED DESCRIPTION

Due to process variations in the template manufacturing process, or the like, the shapes finally formed on the template may deviate from the ideal shape that matches the design value. In view of such deviations from design values, the amount of resist dispensed in the imprint process based on design values may cause unintended patterning performance on the substrate, such as too little or too much resist in certain areas of the pattern.

Example embodiments describe a creation method for an improved droplet (“drop”) recipe and a pattern formation method utilizing the improved droplet recipe. A manufacturing method for a semiconductor device utilizing these methods is also described.

In general, according to one embodiment, a method for generating a droplet recipe to be used in imprint lithography process includes: acquiring feature data for a pattern shape formed on a template by measuring the pattern shape of a pattern formed on the template; calculating, based on the acquired feature data, a dispensing amount for resin to be dispensed on a substrate for filling of the pattern of the template during imprinting of the pattern of the template on the substrate; and calculating a dispensing amount for resin corresponding to a target thickness of a residual film portion formed on the substrate during the imprinting of the pattern of the template on the substrate. The droplet recipe for dispensing of resin during imprinting of the pattern of the template is then generated based on the calculated dispensing amounts.

Hereinafter, certain embodiments will be described with reference to the drawings. The same elements in different drawings are designated by the same reference numerals, and, in general, duplicate description of such elements may be omitted after an initial description.

First Embodiment

Schematic Configuration of Imprint Device

An imprint device10shown inFIG.1is a device for performing an imprint processing of molding a resist40on a transfer destination substrate30(“substrate30”) using a master template20. The resist40is made of resin. A replica template is formed by subjecting the substrate30on which the resist40has been molded to an etching processing or the like. The replica template is then used to form a pattern on a silicon wafer or the like in a manufacturing process of a semiconductor device. By creating a plurality of replica templates from the master template20, it is possible to improve manufacturing productivity.

As shown inFIG.1, the imprint device10includes a substrate stage11, a template stage12, a coating device13, an irradiation unit14, and a control device15.

The master template20and the substrate30are made of a material capable of transmitting ultraviolet light such as quartz glass. A pattern portion22(shown inFIG.3) is formed in a predetermined shot area21(shown inFIG.2) on the surface of the master template20by, for example, an electron beam lithography method. The shape of the pattern portion22inversely corresponds to the final shape of the resist40after molding (imprinting) on the substrate30. In the present embodiment, the shape of the pattern portion22corresponds to an intended device pattern shape.

As shown inFIG.4, the substrate30has a mesa portion31protruding from other portions. The upper surface of the mesa portion31is a transfer surface32on to which the pattern portion22of the master template20is transferred.

The substrate stage11, shown inFIG.1, holds the substrate30by a vacuum suction force, an electrostatic force, or the like. The substrate stage11has a function of displacing the substrate30in the X and Y directions, a function of positioning the substrate30, or the like.

The template stage12holds the master template20by a vacuum suction force, an electrostatic force, or the like. The template stage12has a function of displacing the master template20in the Z direction. As a result, it is possible to bring the pattern portion22of the master template20into contact with the resist40on the substrate30and then to separate the master template20from the resist40.

The coating device13is a device that applies the resist40on the substrate30. The coating device13has a supply unit130and a dispenser131. The supply unit130supplies the resist40, as an uncured resin (or resin precursor), to the dispenser131. The dispenser131has a plurality of nozzles, and dispenses the resist40from the nozzles onto the substrate30. The volume unit for the dispensing amount from the dispenser131can be referred to as a “drop” or a “droplet”, and the volume of each drop is approximately several picolitres in this example.

During the imprint processing, the irradiation unit14cures the resist40by irradiating the resist40with ultraviolet light.

The control device15may include a microcomputer having a CPU, a storage device150, and the like. The storage device150stores a drop recipe151or the like. The drop recipe151shows the dropping position, dropping amount, and the like for the resist40dispensed on to the substrate30. The control device15controls the substrate stage11, the template stage12, the coating device13, and the irradiation unit14based on the drop recipe151.

Next, an operation example of the imprint device10will be described.

As shown inFIG.5, the control device15first controls the template stage12to hold the master template20(step S10), and then (or concurrently) controls the substrate stage11to hold the substrate30(step S11). As shown inFIG.6A, a hard mask50is formed as a thin film on the transfer surface32of the substrate30. The hard mask50helps prevent the substrate30(comprising quartz glass) from being etched when removing unnecessary resist40(e.g., residual layer portions of resist40left between/below pattern portions22) from the substrate30.

Subsequently, as shown inFIG.5, the control device15reads the drop recipe151stored in the storage device150(step S12), and then applies the resist40on the substrate30based on the drop recipe151(step S13). Specifically, the control device15controls the ejection of droplets from each nozzle of the dispenser131based on the drop recipe151while moving the substrate30in the X direction.

Next, the control device15drives the substrate stage11to move the area applied with the resist40on the substrate30to a position directly under the master template20as shown inFIG.1(step S14). Then, the control device15drives the template stage12to bring the master template20closer to the substrate30and presses the pattern portion22of the master template20against the resist40on the substrate30(step S15). As a result, as shown inFIG.6B, the resist40flows into and fills the pattern portion22of the master template20with the passage of time.

After this, as shown inFIG.5, the control device15drives the irradiation unit14to irradiate the resist40on the substrate30with ultraviolet light for a predetermined time to cure the resist40(step S16). The control device15then separates the master template20from the substrate30by driving the template stage12(step S17). As a result, the resist40having a shape as shown inFIG.6Cis formed on the substrate30. The resist40has a residual film portion41and a patterned portion42protruding from the residual film portion41. In the present embodiment, the patterned portions42correspond to the transfer pattern portion.

After the resist40is molded on the substrate30in this way, processing is performed to remove portions of the resist residual film portion41between the patterned resist portions42. As a result, as shown inFIG.6D, in effect, only a part of the patterned resist portions42are left on the transfer surface32of the substrate30, and a portion of the hard mask50is exposed by removal of the portions of the residual film portion41between the patterned resist portions42.

Subsequently, as shown inFIG.7A, a portion of the transfer surface32of the substrate30is exposed by removing the exposed portions of hard mask50, and then etching processing is performed on the exposed transfer surface32of the substrate30. As a result, a recess is etched in the substrate30as shown inFIG.7B. At this time, the patterned resist portions42disappears or remains slightly. After that, by removing the hard mask50from the substrate30, a projecting portion remains in the substrate where the patterned resist portions42were present, as shown inFIG.7C. The substrate30has concave (recessed) portions at positions where the patterned resist portions42were not present. In this way, the replica template pattern is formed on the substrate30.

When forming a replica template through the above processes, when the pattern portion22of the master template20has an ideal shape matching design data as shown inFIG.8A, the film thickness of the resist residual film portion41tends to be substantially uniform, so that it is possible to manufacture a more accurate replica template. However, in reality, the dimensions and the etched depth of the pattern portion22of the master template20usually vary from ideal/design due to assorted variations in process accuracy when molding and transferring the pattern portion22on the master template20, or the like. As a result, as shown inFIG.8B, there is a possibility that the shape of the pattern portion22of the master template20deviates from the ideal shape. In such a case, when the resist40is applied on the substrate30using the drop recipe151established based on the ideal master template20(e.g., the design data for the pattern and expected etch depths), a mismatch occurs between the shape of the pattern portion22of the actual master template20and the volume of the resist40applied on the substrate30according to ideal/design data. As a result, the resist40may have an unintended thickness and shape on the substrate30and the molding accuracy of the replica template being formed may decrease.

Accordingly, in the present embodiment, the shape of the pattern portion22of the master template20is first measured, and then the drop recipe151is corrected according to the measurement result to create a more appropriate drop recipe151that corresponds to the actual shape of the pattern portion22of the master template20rather than simply the expected shape. Hereinafter, a creation method for the drop recipe151of the present embodiment will be described.

System Configuration

FIG.9shows a schematic configuration of an imprint system1of the present embodiment. As shown inFIG.9, the imprint system1includes a shape measurement device60in addition to the imprint device10shown inFIG.1.

The shape measurement device60is a device capable of measuring the relevant shapes and sizes of the pattern portion22of the master template20. The shape measurement device60is a device capable of measuring the shape by using, for example, the critical dimension small angle X-ray scattering (CD-SAXS) method. The shape measurement device60using the CD-SAXS method can measure three-dimensional dimensions with an accuracy better than 1 nm. CD-SAXS can measure not only the surface shape but also the internal structure. The shape measurement device60can obtain average information over a predetermined area, for example, an average shape within a predetermined area.

Drop Recipe Creation Procedure

Next, a creation procedure for the drop recipe151will be described. In the following, a case where each of projection portions220of the pattern portion22of the master template20has the same shape will be described as an example. That is, as depicted inFIG.3, a height H of each projection portion220is the same, and a width W of each projection portion220is also the same.

As shown inFIG.10, when creating the drop recipe151, the shape of the shot area21of the master template20is first measured by the shape measurement device60(step S20). Specifically, as shown by the alternating long and short dash lines inFIG.11, the shot area21is divided, for example, into 16 areas PM1to PM16, and then the shape of the projection portion220of the pattern portion22in each of the divided areas PM1to PM16is measured separately by the shape measurement device60.

For example, when the divided area PM1is measured by the shape measurement device60, the shape measurement device60outputs a cross-sectional shape matching the solid line inFIG.12Aas a measurement result. The cross-sectional shape shown by the solid line inFIG.12Ais taken as the average cross-sectional shape of the projection portion220within the divided area PM1as measured by the shape measurement device60. The alternating long and short dash line shown inFIG.12Ashows the ideal cross-sectional shape of the projection portion220. By measuring each shape of the divided areas PM1to PM16with the shape measurement device60, the measurement result of the cross-sectional shape such as shown inFIG.12Acan be obtained in each of the plurality of divided areas PM1to PM16.

Next, in the process ofFIG.20, the feature data of the pattern portion22of the master template20is calculated (step S21) based on the measurement results (from step S20). Specifically, when the shape shown inFIG.12Ais obtained as the average cross-sectional shape of the divided area PM1in the step S20, the area of the region shown by hatching inFIG.12A, (actual cross-sectional area AM1of the projection portion220) is calculated. The width used when obtaining the actual cross-sectional area AM1of the projection portion220is set in this example to the width of the ideal cross-sectional shape width of the projection portion220. The ideal cross-sectional shape is, for example, the cross-sectional shape based on design data. In the step S21, the average cross-sectional areas AM1to AM16of the projection portion220in each of the divided areas PM1to PM16is calculated. In the present embodiment, the information of the cross-sectional areas AM1to AM16of the projection portions220of each of the divided areas PM1to PM16corresponds to the feature data of the pattern portion22of the master template20.

As shown inFIG.10, a correction map M10for correcting the dropping amount of the resist40applied from the coating device13to the substrate30is then created (step S22). Specifically, assuming that the ideal shape of the projection portion220of the master template20is the shape shown inFIG.12B, the area of the region shown by hatching inFIG.12B, that is, the value of an ideal cross-sectional area A0of the projection portion220can be obtained from the design data of the master template20. At this time, a correction value α1of the dispensing amount of the resist40corresponding to the area PM1is set to “AM1/A0”. That is, assuming that “n=1, 2, . . . 16”, the correction value αnof the area PMnis set based on the following equation:
αn=AMn/A0(equation f1)

As a result, the creation of the correction map M10(FIG.13A) is completed. The correction map M10defines the correction values α1to α16for the base dropping amount of the resist40for each of the divided areas PM1to PM16in the shot area21. Each of the correction values α1to α16of the correction map M10can be set to a numerical value as shown inFIG.13B, for example. In the area in which the correction value is set to “1.0”, the base (uncorrected) dropping amount is used. In the area in which the correction value is smaller than “1.0”, the dropping amount is adjusted to be less than the base dropping amount. In the area in which the correction value is larger than “1.0”, the dropping amount is adjusted to be greater than the base dropping amount.

After creating the correction map M10in this way, the drop recipe151can be created by the procedure shown inFIG.14.

Based on the design data of the master template20, a basic dropping amount Dpb for the resist40is calculated (step S30). Next, based on the calculated basic dropping amount Dpb and the correction map M10(obtained by the procedure shown inFIG.10), dropping amounts Dp1to Dp16corresponding to each of the areas PM1to PM16of the shot area21is calculated (step S31). The following equation:
Dpn=αn×Dpb(equation f2)

where n=1 to 16 can be used in step S31.

In parallel with the calculation of the dropping amount Dp1to Dp16, a dropping amount Dr for the resist residual film portion41can also be calculated. Specifically, the surface area of the shot area21is calculated from the design data of the master template20(step S32). Then, the target thickness of the resist residual film portion41is set (step S33). The target thickness of the resist residual film portion41can be set according to subsequent processing parameters or the like.

After the steps S32and S33, the dropping amount Dr for the resist residual film portion41can be calculated based on the surface area of the shot area21and the target thickness of the resist residual film portion41(step S34). The surface area of the shot area21of the master template20is generally substantially equal to the surface area of the mesa portion31of the substrate30. Accordingly, the dropping amount Dr can be calculated by multiplying the surface area of the shot area21by the thickness of the resist residual film portion41.

In this way, after calculating the pattern portion dropping amount Dp1to Dp16and the residual film portion dropping amount Dr, the drop recipe151can be created by combining these values, respectively (step S35). After storing the drop recipe151in the storage device150of the control device15, the imprint device10is driven to imprint the dispensed resist40on the substrate30(step S36).

Effect

As described above, the creation method of the drop recipe151of the present embodiment has a measurement step (step S20;FIG.10), the dropping amount calculation step (steps S31and S34;FIG.14), and the drop recipe creation step (step S35). The measurement step of the step S20is a step of acquiring the cross-sectional area of the projecting portion220, which is feature data of the master template20, by measuring the shape on the master template20. The dropping amount calculation step of the step S31is a step of calculating the pattern portion dropping amounts Dp1to Dp16based on the cross-sectional area of the projecting portion220of the master template20. The dropping amount calculation step of step S34is a step of calculating the residual film portion dropping amount Dr. The drop recipe creation step of the step S35is a step of creating the drop recipe151based on the pattern portion dropping amounts Dp1to Dp16and the residual film portion dropping amount Dr. According to this method, it is possible to create a more appropriate drop recipe151corresponding to the actual shape of the master template20.

In the measurement step of the step S20, the cross-sectional shape of each of the plurality of areas PM1to PM16in the shot area21is measured. In other words, on the master template20, the cross-sectional shapes of a plurality of points in the pattern portion22are measured. According to this method, it is possible to acquire more appropriate feature data for the master template20.

MODIFICATION EXAMPLE

In the measurement step of the step S20, the cross-sectional shape of just one representative area of the areas PM1to PM16in the shot area21of the master template20could be measured. That is, only one point on the surface of the master template20on which the pattern portion22is formed could be measured and this representative value may be used for each of the areas PM1to PM16.

Second Embodiment

The differences from the first embodiment will be mainly described in this context.

As shown inFIG.15, in the creation method of the drop recipe151of the second embodiment, the resist40is imprinted on the substrate30in the step S36, and then the shape of the patterned resist portion42of the substrate30that has been imprinted is measured by the shape measurement device60(step S40). Based on this measurement result, the cross-sectional area of a projection portion420formed in the patterned resist portion42(as shown inFIG.8B) is calculated (step S41). The respective steps S40and S41correspond to the steps S20and S21(FIG.10) but are performed on the substrate30rather than the master template20. In the steps S40and S41, the average cross-sectional areas AR1to AR16of the projection portions420corresponding to the areas PR1to PR16are calculated. In the present embodiment, the information of the cross-sectional areas AR1to AR16of the projection portion420of each of the divided areas PR1to PR16corresponds to the feature data of the transfer pattern portion.

Following the step S41, it is determined whether a correction map M10needs to be adjusted (step S42). Specifically, each of the cross-sectional areas AR1to AR16is compared with the ideal cross-sectional area A0of the projection portion220of the master template20, and when any of the cross-sectional areas AR1to AR16deviates from the ideal cross-sectional area A0by some predetermined threshold value or more, it is determined that the correction map M10needs to be corrected (step S42: YES). In this case, the correction map M10is corrected (step S43). For example, when the cross-sectional area AR1deviates from the ideal cross-sectional area A0, a correction value α1of the correction map M10is set so that the deviation amount becomes small. After the correction map M10is corrected in this way, the corrected correction map M10can be used when the imprint processing is performed thereafter. By using the corrected correction map M10, the pattern portion dropping amount Dp1to Dp16is corrected.

In the process of step S42, when none of the cross-sectional areas AR1to AR16deviate from the ideal cross-sectional area A0by the predetermined threshold value or more, the correction map M10is not adjusted. That is, in this case, the same correction map M10is used when the imprint processing is performed thereafter.

The process of the steps S44to S46can be performed in parallel with the process of the steps S40to S43. In the process of the step S44, the actual thickness of the resist residual film portion41of the substrate30on which the resist40has been imprinted can be measured. As shown by the alternate long and dash line box inFIG.9, the imprint system1of the second embodiment further includes a film thickness measurement device61capable of measuring the thickness of the resist residual film portion41. The film thickness measurement device61is, for example, an optical film thickness measuring device. In the process of the step S44, for example, several hundred points on the resist residual film portion41on the transfer surface32of the substrate30shown inFIG.4are measured by the film thickness measurement device61, and then the average value can be used as the actual thickness of the resist residual film portion41.

Following the process of the step S44, it is determined whether the residual film portion dropping amount Dr needs to be adjusted (step S45). Specifically, the actual thickness of the resist residual film portion41obtained in the process of the step S44is compared with the previously set value for the thickness of the resist residual film portion41set in the process of the step S33, and when the actual thickness of the resist residual film portion41deviates from the set value by a predetermined value or more, it is determined to correct the residual film portion dropping amount Dr (step S45: YES). In this case, the residual film portion dropping amount Dr is corrected so that the deviation amount between the actual thickness of the resist residual film portion41and the set value becomes small (step S46). After the residual film portion dropping amount Dr is adjusted in this way, the corrected residual film portion dropping amount Dr can be used when the imprint processing is performed thereafter.

If it is determined in the process of the step S45that the residual film portion dropping amount Dr does not need adjustment (step S45: NO), the residual film portion dropping amount Dr is not changed. That is, in this case, the same residual film portion dropping amount Dr is used when the imprint processing is performed thereafter.

The creation method of the drop recipe151shown inFIG.15can be used for any substrates30that are subsequently molded. Accordingly, each time a substrate30is patterned, the correction map M10and the residual film portion dropping amount Dr can be feedback-corrected according to the shape of the resist residual film portion41and the patterned resist portion42for the substrate30specifically.

Effect

As described above, the creation method of the drop recipe151of the second embodiment further has the measurement step of the step S40and the correction step of the step S43. The measurement step of the step S40is a step of acquiring the cross-sectional area of the projection portion420, which is the feature data of the patterned resist portion42, by measuring the patterned resist portion42formed on a substrate30. The correction step of the step S43is a step of correcting the pattern portion dropping amount Dp1to Dp16by adjusting the correction map M10based on the cross-sectional areas of the projection portion420of the patterned resist portion42. According to this method, it is possible to feedback-correct the pattern portion dropping amount Dp1to Dp16according to the shape of the patterned resist portion42of the substrates30to be subsequently molded.

In the measurement step of the step S40, the feature data of the patterned resist portion42is acquired by measuring the cross-sectional shape of each of the plurality of divided areas PR1to PR16set on the transfer surface32of the substrate30. According to this method, it is possible to obtain more appropriate and detailed feature data of the patterned resist portion42.

The creation method of the drop recipe151of the second embodiment further has the measurement step of the step S44and the correction step of the step S46. The measurement step of the step S44is a step of acquiring the thickness by measuring the resist residual film portion41formed on the substrate30. The correction step of the step S46is a step of correcting the residual film portion dropping amount Dr based on the measured thickness of the resist residual film portion41. According to this method, it is possible to feedback-correct the residual film portion dropping amount Dr according to the thickness of the resist residual film portion41of a substrate30to be subsequently molded.

In the measurement step of the step S44, the thickness of the resist residual film portion41is acquired by measuring a plurality of points on the transfer surface32of the substrate30. According to this method, it is possible to obtain a more appropriate thickness of the resist residual film portion41.

First Modification Example

In the measurement step of the step S40, the cross-sectional shape of the area of any one of the plurality of divided areas PM1to PM16set on the transfer surface32of the substrate30may be measured. That is, on the master template20, only one point of the pattern portion22need be measured.

Second Modification Example

In the measurement step of the step S44, the thickness of the resist residual film portion41may be measured at only at one representative point on the transfer surface32of the substrate30.

Third Modification Example

In the correction step of the step S43, the correction map M10may be corrected by correcting the information of the cross-sectional areas AM1to AM16of the projection portion220of the master template20calculated in the processing of the step S21(FIG.10). Specifically, based on the cross-sectional areas AR1to AR16measured in the measurement step of the step S40, the information of the cross-sectional area AM1to AM16of the projection portion220of the master template20is corrected. Then, the correction map M10is corrected by performing the calculation of the above equation f1 again based on the information of the cross-sectional areas AM1to AM16after the correction. In this modification, the process of the step S43corresponds to the process of correcting the feature data of the master template20based on the feature data of the patterned resist portion42.

OTHER EMBODIMENTS

The present disclosure is not limited to the above specific examples.

For example, the measurement step of the step S20is not limited to the step of measuring the cross-sectional area of the projection portion220as the feature data of the master template20, but may be a step of measuring, for example, the width, height, or the like of the projection portion220.

Similarly, the measurement step of the step S40is not limited to the step of measuring the cross-sectional area of the projection portion420as the feature data of the patterned resist portion42of the substrate30, and may be, for example, a step of measuring the width, height, or the like of the projection portion420.

The imprint device10is not limited to a device that forms a pattern portion on a replica template by using the master template20, and may be, for example, a device that forms a pattern portion on a silicon wafer or the like by using the master template20or the replica template.

The disclosed creation method of a drop recipe of the above embodiment may also be used in manufacturing a semiconductor device.

Specifically, when manufacturing a semiconductor device, a processing target film110is formed on a semiconductor substrate100as shown inFIG.16A, and then as shown inFIG.16B, the resin120is dropped onto the processing target film110. Then, as shown inFIG.16C, a template230is made to face the processing target film110, and then a pattern231of the template230is brought into contact with the resin120on the substrate100as shown inFIG.16Dby raising the substrate stage or the like. Then, the resin120is cured by irradiating the resin120with ultraviolet light from the light source while still in the state shown inFIG.16D. Subsequently, as shown inFIG.16E, the substrate100and the template230are separated from each other, and then etching is performed on the substrate100. In the etching, the processing target film110is etched using the resin120as a mask.FIG.16Fschematically shows the cross-sectional structure of the substrate100immediately after the etching is performed.FIG.16Gschematically shows a cross-sectional structure of the substrate100from which the resin120has been removed by asking. Through such a process, a predetermined pattern is formed on the substrate100.

In such a manufacturing method of a semiconductor device, a droplet recipe is used for dispensing the resin120onto the processing target film110. As a creation method of the droplet recipe, it is possible to use the methods according to the above-described embodiments. Likewise, such droplet recipe creation methods may be used not only for the manufacturing of a semiconductor device but for any pattern formation for device fabrication.

While certain embodiments have been described, these embodiments have been presented by way of example only, and are not intended to limit the scope of the disclosure. Indeed, the novel embodiments described herein may be embodied in a variety of other forms; furthermore, various omissions, substitutions and changes in the form of the embodiments described herein may be made without departing from the spirit of the disclosure. The accompanying claims and their equivalents are intended to cover such forms or modifications as would fall within the scope and spirit of the disclosure.