Patent Application
20230408935
This application is based upon and claims the benefit of priority from Japanese Patent Application No. 2022-099537, filed Jun. 21, 2022, the entire contents of which are incorporated herein by reference.
Embodiments described herein relate generally to a pattern forming method using imprint lithography, a semiconductor device manufacturing method, and a template for use in imprint lithography.
In a semiconductor device manufacturing process, an imprint process for transferring a pattern of a template to a resist film to form a desired pattern may be performed. However, when the pattern coverage (pattern density) within a pattern transfer region is different, air bubbles or the like may form in the resist film where the pattern is sparse and thus cause a resist pattern formation defect.
Embodiments concern a pattern forming method, a semiconductor device manufacturing method, and a template by which a resist pattern formation defect can be prevented in imprint lithography.
In general, according to one embodiment, a pattern forming method includes: placing a resin material on a film to be processed; pressing a template having a plurality of patterns protruding from a reference plane against the resin material to form a first resin film having first and second patterns, which are separated from each other in a first direction, and a third pattern between the first and second patterns; forming a second resin film to cover the first resin film; exposing and developing the second resin film to expose the first and second patterns; and processing the film to be processed via the first and second resin films to transfer the first and second patterns to the film to be processed.
Certain example embodiments of the present disclosure are described below with reference to the drawings. The present disclosure is not limited to these example embodiments.
Embodiment 1 is described below with reference to the drawings.
As illustrated in
The stacked body LM on the source line SL has a configuration in which a plurality of word lines WL are stacked. Examples of the word lines WL include a tungsten layer and a molybdenum layer. The number of stacked word lines WL is, for example, about several tens to hundreds. Though not illustrated in
The stacked body LM includes memory regions MR, contact regions PR, and a through contact region TP, and a plurality of pillars PL and a plurality of contacts CC and C4 are provided in each region. The entire stacked body LM is covered with an insulating film 52 such as a silicon oxide film.
The plurality of pillars PL each penetrate the stacked body LM and reach the source line SL. Detailed configurations of the pillars PL are illustrated in
As illustrated in
The channel layer CN is, for example, a semiconductor layer such as a polysilicon layer or an amorphous silicon layer. The core layer CR, the tunnel insulating layer TN, and the block insulating layer BK are, for example, silicon oxide layers. The charge storage layer CT is, for example, a silicon nitride layer.
With such a configuration, a plurality of memory cells MC located in the height direction are formed at intersections of the pillars PL and the word lines WL. By applying a predetermined voltage from the word line WL to the memory cell MC at the same height position, charges are accumulated in the charge storage layer CT of the memory cell MC or charges are extracted from the charge storage layer CT so that data can be written to and read from the memory cell MC. The data read from the memory cell MC is transmitted to a sense amplifier via information plug of the pillar PL, an upper layer wiring, and the like.
Each of the contacts CC reaches a depth position corresponding to one of the plurality of word lines WL provided in the stacked body LM and is electrically connected to that corresponding word line WL. Further, each of the plurality of contacts CC is connected to the contacts C4 via the upper layer wirings and plugs.
The plurality of contacts C4 penetrate the stacked body LM and the source line SL and reach the insulating film 51 below the stacked body LM. In the insulating film 51, the lower end portions of the plurality of contacts C4 are connected to the transistor TR of the peripheral circuit CUA via the lower layer wiring, vias, contacts, and the like.
With such a configuration, a predetermined voltage can be applied from the peripheral circuit CUA to each memory cell MC via the contacts C4 and CC to electrically operate the memory cells MC.
In the semiconductor device MDV having the above configuration, a configuration having a three-dimensional shape with a highly advanced three-dimensional structure can be easily formed by, for example, an imprint process using a template. Examples of the configuration having a highly advanced three-dimensional structure include a dual damascene structure DD in which vias and wiring for electrically connecting the contact C4 and the peripheral circuit CUA are collectively (simultaneously) formed and the contacts CC respectively reach word lines WL at different depths of the stacked body LM.
Next, a configuration example of an imprint apparatus 1 used in a process of manufacturing the semiconductor device MDV described above is described with reference to
Next, a template 10 that transfers a pattern to a resist on a wafer 30 is provided in the imprint apparatus 1. The template 10 is configured with a transparent member such as quartz and is located so that a transfer pattern faces the wafer stage 82 on which the wafer 30 is mounted. The wafer 30 is, for example, a disk-shaped silicon substrate and is later cut into chips to be the substrates SB of the semiconductor devices MDV described above.
The wafer stage 82 includes a wafer chuck 82b and a main body 82a. The wafer chuck 82b fixes the wafer 30 to a predetermined position on the main body 82a. The reference mark 85 is provided on the wafer stage 82. The reference mark 85 is used for alignment when the wafer 30 is loaded onto the wafer stage 82.
The wafer stage 82 mounts the wafer 30 and moves in a plane parallel to the mounted wafer 30 (in a horizontal plane). The wafer stage 82 moves the wafer 30 below the template 10 when a transfer process to the wafer 30 is performed.
The stage base 88 supports the template 10 by the template stage 81 and moves in a vertical direction (perpendicular direction) to press the transfer pattern of the template 10 against the resist on the wafer 30.
The alignment unit 86 is provided onto the stage base 88. The alignment unit 86 detects the position of the wafer 30 and the position of the template 10 based on alignment marks provided on the wafer 30 and the template 10, respectively.
The alignment unit 86 includes a detection system 86a and an illumination system 86b. The illumination system 86b irradiates the wafer 30 and the template 10 with light. The detection system 86a detects images of alignment marks of the wafer 30 and the template 10 by the alignment scope 83 and aligns the wafer 30 and the template 10 based on the detection results. When the template 10 is pressed against the resist of the wafer 30, the detection system 86a detects by the spread scope 84 whether the resist fills the transfer pattern of the template 10.
The detection system 86a and the illumination system 86b respectively include mirrors 86x and 86y such as dichroic mirrors that function as image forming units. The mirrors 86x and 86y form images from the wafer 30 and the template 10 with the light from the illumination system 86b.
Specifically, the light Lb from the illumination system 86b is reflected by the mirror 86y downward where the template 10 and the wafer 30 are located. Light La from the wafer 30 and the template 10 is reflected by the mirror 86x toward the detection system 86a and travels to spread scope 84. Light Lc from the wafer 30 and the template 10 passes through the mirrors 86x and 86y and travels to the alignment scope 83 above.
The light source 89 is a device for emitting light such as ultraviolet light capable of curing the resist and is provided above the stage base 88. The light source 89 emits the light from above the template 10 while the template 10 is being pressed against the resist. However, as long as the resist can be cured, the light emitted from the light source 89 may be infrared light, visible light, electromagnetic waves, or the like, other than ultraviolet light.
The control unit 90 is an information processing device that performs various processes for controlling the imprint apparatus 1. The control unit 90 includes, for example, a central processing unit (CPU), a read only memory (ROM), and a random access memory (RAM) and includes a computer that performs a predetermined arithmetic process and a predetermined control process according to programs.
The control unit 90 controls the template stage 81, the wafer stage 82, the stage base 88, the light source 89, and the like, based on the observation images acquired by the alignment scope 83, the spread scope 84, and the like.
Next, a configuration example of the template 10 used for the imprint process by the imprint apparatus 1 is described with reference to
As illustrated in
The actual patterns AC and the dummy patterns DM are provided in the mesa portion MS. The actual patterns AC are patterns that are to be transferred to a film to be processed (“process film”) and form a part of the semiconductor device MDV. The dummy pattern DM is a dummy pattern that disappears without being transferred to the process film.
As illustrated in
Each actual pattern AC includes therein a plurality of the columnar-shaped patterns CL having different protrusion heights from the reference plane RP. In the example of
In the example of
A pair of dummy patterns DM sandwich each actual pattern AC from both sides along one direction. That is, one dummy pattern DM of the pair is located on each side of the plurality of actual patterns AC in one direction. A plurality of dummy patterns DM can be located between otherwise adjacent actual patterns AC. Each of the dummy patterns DM is a convex pattern having a convex shape and can be located over the entire surface of the mesa portion MS (except for the positions where the actual patterns AC are located) with a predetermined interval from each other.
Hereinafter, with reference to
As illustrated in
A resist film 91 is formed on the process film PF. The resist film 91 is, for example, a photocurable resin film or the like and is formed by applying a resist material onto the process film PF using, for example, a spin coating method or the like.
At this time, the resist film 91 is formed, for example, so as to cover the entire region on the process film PF to which the actual patterns AC and the dummy patterns DM in the mesa portion MS of the template 10 are transferred. The resist film 91 is in an uncured state at this stage.
The process of forming the resist film 91 as described above may be performed by another device such as a chemical liquid coating device, for example, before the wafer 30 is loaded into the imprint apparatus 1.
In order to transfer the plurality of columnar-shaped patterns CL of the template 10 onto the resist film 91, the surface on which the columnar-shaped patterns CL are formed faces the process film PF and thus the resist film 91 thereon.
As illustrated in
By maintaining this state for a predetermined period of time, the resist film 91 penetrates between the plurality of columnar-shaped patterns CL and between the plurality of dummy patterns DM. After the resist film 91 spreads between the columnar-shaped patterns CL and between the dummy patterns DM, while the template 10 is pressed against the resist film 91, the resist film 91 is irradiated with light such as ultraviolet light through the template 10. Accordingly, the resist film 91 is cured.
As illustrated in
The contact patterns PP correspond in position to the actual patterns AC of the template 10 are transferred (imprinted) versions of the actual patterns AC. The plurality of contact patterns PP are separated from each other in the same manner as the actual patterns AC, and each contact pattern PP has a plurality of hole patterns CP corresponding in position to the columnar-shaped patterns CL of the template 10. The contact pattern CP has pattern features with different depths That is, contact pattern CP is a multi-depth pattern or pattern with multi-depth portions.
The plurality of recess patterns DP correspond in position to the dummy patterns DM are transferred (imprinted) versions of the dummy patterns DM and thus have recessed (concave) shapes. The recess patterns DP are single depth patterns. The plurality of recess patterns DP sandwich the plurality of contact patterns PP and are located between the plurality of contact patterns PP.
As described above, the resist film 91 is cured while a gap exists between the template 10 and the process film PF, and thus the resist pattern 91p has residual resist films 91r in bottom portions of the deepest hole patterns CP of the hole patterns CP. Similarly, the resist pattern 91p has the residual resist films 91r in the bottom portions of the recess patterns DP.
In a photolithographic technique, it is difficult to collectively (simultaneously) form resist patterns with different reaching depths into the resist film, such as like the resist pattern 91p. For this reason, a process cycle of repeating formation of a resist film, exposure and development, and processing of a film (a process film) several times is required to achieve similar multi-depth patterning.
However, according to the technique using the template 10, a plurality of patterns having different reaching depths in the resist film 91 are formed by one imprint process on the resist film 91.
As illustrated in
The resist film 92 may also be formed by a device other than the imprint apparatus 1, such as a chemical liquid coating device. In this case, the wafer 30 on which the resist pattern 91p is formed can be unloaded from the imprint apparatus 1 and then loaded into the light exposure device after the resist film 92 is formed by the chemical liquid coating device. In addition, before the resist film 92 is formed, the front surface of the resist pattern 91p may be subjected to surface treatment such as a vacuum ultraviolet (VUV) process.
As illustrated in
The light shielding film pattern 42p has a plurality of openings 42op. The plurality of openings 42op are located at positions vertically overlapping with the plurality of contact patterns PP formed on the resist pattern 91p on the process film PF. The plurality of openings 42op are larger than the regions in which the plurality of contact patterns PP are formed, and the individual contact patterns PP entirely fall in a position below the openings 42op.
With the photomask 40 facing the resist film 92, the resist film 92 is irradiated with exposure light that passes through the openings 42op of the photomask 40. As a result, portions of the resist film 92 that cover the plurality of contact patterns PP are exposed.
As illustrated in
As illustrated in
As illustrated in
Further, the film thickness of the resist pattern 91p is reduced by using oxygen plasma or the like to remove the residual resist films 91r in the bottom portions of the hole patterns CP adjacent to the deepest hole patterns CP, so that the process film PF is newly exposed. At this time, the film thickness of the resist pattern 92p is also reduced together with the resist pattern 91p.
As illustrated in
Further, the film thickness of the resist pattern 91p is reduced by using oxygen plasma or the like to newly expose the process film PF from the bottom portion of the hole pattern CP adjacent to the newly formed contact hole CH.
As illustrated in
As illustrated in
As illustrated in
In this manner, the region where the plurality of contact holes CH are formed becomes the contact region PR (see
With the above, the pattern forming process using the template 10 is completed.
In the above imprint process, for example, when the rectangular columnar-shaped pattern CL of the template 10 is transferred to the resist film 91, the columnar-shaped pattern CL may be transferred into a shape in which the corner portions are rounded. Further, when the plurality of contact holes CH are formed in the process film PF by using the resist pattern 91p, the corner portions of the contact holes CH may be processed to be further rounded.
Further, in the above example of
Thereafter, the pillars PL (see
Further, the contacts CC respectively connected to the word lines WL at different depths are formed by covering the sidewalls of the plurality of contact holes CH formed using the template 10 with an insulating layer and then filling with a metal layer.
As described above, the contact holes CH formed in the stacked body LM each have, for example, a shape in which the corner portions are rounded by the processes illustrated in
As described above, the semiconductor device MDV of Embodiment 1 is manufactured.
Next, with reference to
As described above, when the template 10 is to be manufactured, a master template 10m is first manufactured to be used as the original plate (master template) for the template 10. A plurality of templates 10 having the same configuration can be manufactured from one master template 10m.
As illustrated in
The mesa portion of the transparent substrate is formed, for example, by grinding a transparent substrate by machine processing. The convex pattern CVX of the mesa portion is formed by laser processing or etching processing using a mask film or the like. The hole patterns 71h can be formed by processing a mask film by an electron drawing technique using an electron beam or the like.
As illustrated in
At this time, among these convex patterns CVX, the ends of the convex patterns CVX, on which the mask pattern 71p is formed, on the side away from each other are exposed.
That is, in
The convex pattern CVX is processed via the mask pattern 71p exposed from the resist pattern 101p to form a hole pattern HL reaching a predetermined depth of the convex pattern CVX.
As illustrated in
Further, the hole pattern HL reaching a predetermined depth of the convex pattern CVX is newly formed by processing the convex pattern CVX via the mask pattern 71p exposed from the resist pattern 101p. Also, at this time, the already formed hole pattern HL is processed deeper. As a result, hole patterns HL having different reaching depths in the convex pattern CVX are formed.
As illustrated in
Further, a hole pattern HL reaching the predetermined depth of the convex pattern CVX is newly formed by processing the convex pattern CVX via the mask pattern 71p exposed from the resist pattern 101p. Also, at this time, the hole patterns HL that are already formed are processed deeper to form hole patterns HL with reaching depths in the convex pattern CVX that are sequentially increased.
As illustrated in
In the above description, the hole patterns 71h of the mask pattern 71p are sequentially exposed by causing the end portion of the same resist pattern 101p to recede by slimming. However, in other examples, whenever one hole pattern 71h is to be exposed to form a new hole pattern HL, the already formed resist pattern 101p can be removed by asking to permit a new resist pattern 101p to be formed and the end portion (edge) of this new resist pattern 101p can be processed or positioned to expose a position where the next hole pattern 71h is to be formed.
When the processing of the resist pattern 101p with high accuracy by slimming is difficult, formation of hole patterns HL can be generally be performed with higher accuracy by repeatedly performing exposure and development of resist patterns 101p instead of slimming of a single resist pattern 101p.
As illustrated in
The mesa portion MS of the transparent substrate BA is formed, for example, by grinding the transparent substrate BA by machine processing, as in the case of the master template 10m described above. The resist film 102 is, for example, a photocurable resin film or the like that can be cured by irradiation with ultraviolet rays or the like. The resist film 102 can be formed applying a resist material by spin coating or by dispensing the resist material by an inkjet method. At this time, after the initial coating/dispensing the resist film 102 is in an uncured state.
In order to transfer the convex pattern CVX and the hole pattern HL of the master template 10m to the resist film 102, the surface on which the convex pattern CVX and the hole pattern HL are formed faces the template 10 side to cause the master template 10m to face the resist film 102.
As illustrated in
As a result, a part of the resist film 102 is filled between the convex patterns CVX and inside the hole pattern HL of the master template 10m. In this state, when the resist film 102 is irradiated with light such as ultraviolet light passing through the master template 10m while the master template 10m is pressed against the resist film 102, the resist film 102 is cured.
As illustrated in
As illustrated in
As illustrated in
Thereafter, the processing of the mesa portion MS via the resist pattern 102p is further continued. As a result, the upper surface of the mesa portion MS exposed from the resist pattern 102p is further removed, and the protrusion amounts of the dummy patterns DM and the columnar-shaped patterns CL from the upper surface of the mesa portion MS relatively increase. Further, among the resist patterns 102p on the columnar-shaped patterns CLb, the resist pattern 102p having the next thinnest film thickness disappears.
In the columnar-shaped patterns CL from which the resist pattern 102p disappear first, the upper end portion is further removed, and the protrusion amount from the upper surface of the mesa portion MS becomes smaller than that of the other columnar-shaped patterns CL.
As illustrated in
The upper end portion of the columnar-shaped patterns CL that are already exposed due to the disappearance of the resist pattern 102p are further removed, and the protrusion amount from the upper surface of the mesa portion MS becomes smaller than that of the other columnar-shaped patterns CL.
As illustrated in
As illustrated in
With the above, the template 10 of Embodiment 1 is manufactured.
The method for manufacturing the template 10 described above is merely an example, and the template 10 of Embodiment 1 may be manufactured by a method other than the above. For example, the template 10 may be manufactured without using a master template 10m.
In such a case, the plurality of dummy patterns DM and the plurality of the columnar-shaped patterns CL may be directly drawn on the upper surface of the mesa portion MS of the transparent substrate BA by an electron beam or the like. Alternatively, the plurality of dummy patterns DM and the plurality of the columnar-shaped patterns CL may be formed by etching by using a mask pattern using a chromium film or the like and a resist pattern using a resist film or the like.
In a semiconductor device manufacturing process, a plurality of contact holes having different reaching depths in a process film or a dual damascene structure in which vias and wiring are collectively formed may be formed. If these structures were to be formed by just using a photolithographic technique, the manufacturing process would be complicated and costly due to the need for repetition of the exposure and development of the resist film a plurality of times.
However, with an imprint process using a template, contact holes having different depths, a dual damascene structure, and the like can be formed in a single imprint process.
However, such an imprint process also has some problems. An example of the imprint process using a template 10x of the comparative example is described below with reference to
As illustrated in
In this way, the template 10x according to the comparative example has a configuration with a large difference between a dense region in which a plurality of actual patterns ACx are located and a sparse region in which no pattern is located, that is, a large pattern density difference between different regions.
As illustrated in
In the imprint process, instead of the resist film 91, droplets of a resist material may be located on the process film PF by an inkjet method. In such imprint process using an inkjet method, air bubbles are trapped more easily.
As illustrated in
In this way, in the imprint process using the template 10x with a large pattern density difference, it requires time to fill the resist film 91, and the efficiency of the imprint process may be lowered. Further, a formation defect of the resist pattern 91x may occur. Further, in the template 10x with a large pattern density difference, there is also a drawback that the actual pattern ACx protruding from the mesa portion MSx is easily damaged.
In the pattern forming method according to Embodiment 1, the resist pattern 91p including the plurality of contact patterns PP separated in the direction along the contact surface of the template 10 of the resist film 91 with the reference plane RP and the recess patterns DP located between the plurality of contact patterns PP is formed, the resist film 92 that covers the resist pattern 91p is formed, the resist film 92 is exposed and developed, the plurality of contact patterns PP are exposed, the process film PF is processed via the resist patterns 91p and 92p, and the plurality of contact patterns PP are transferred to the process film PF.
In this way, by forming the recess patterns DP between the plurality of contact patterns PP, the pattern density difference of the template 10 is reduced. As a result, the time for filling the resist film 91 between the actual patterns AC of the template 10 is shortened, and the efficiency of the imprint process can be improved. Further, formation of voids or the like in regions between the plurality of contact patterns PP is prevented, and formation defects of the resist pattern 91p can be prevented.
By covering the recess pattern DP that does not contribute to the configuration of the semiconductor device MDV with the resist pattern 92p, the recess pattern DP can disappear without being transferred to the process film PF.
The template 10 includes the reference planes RP, the actual patterns AC protruding from the reference planes RP, and the plurality of dummy patterns DM that protrude from the reference planes RP and sandwich the actual patterns AC in the direction along the reference planes RP.
As a result, the actual patterns AC protruding from the reference planes RP can be protected by the dummy patterns DM, and damage to the actual patterns AC can be prevented. Therefore, the manufacturing cost of the semiconductor device MDV can be reduced by extending the lifespan of the template 10.
In Embodiment 1, as an example of a configuration having a highly advanced three-dimensional structure, an example in which a plurality of contacts CC respectively reaching word lines WL at different depths in the stacked body LM are formed in the semiconductor device MDV is described.
However, like a dual damascene structure DD or the like in which vias and wirings for electrically connecting the contacts C4 and the peripheral circuit CUA are collectively formed, the method according to Embodiment 1 can be applied to a configuration having a highly advanced three-dimensional structure in addition to the plurality of contacts CC.
For example, when the dual damascene structure DD in which vias and wirings for electrically connecting the contact C4 and the peripheral circuit CUA are collectively formed is formed by the imprint process, various processes described above can be performed by using the insulating film 51 of
In Embodiment 1, after the resist pattern 91p is formed, the resist pattern 91p is covered with the positive resist film 92. However, instead of the positive resist film 92, a negative resist film may be used.
As illustrated in
In the semiconductor device manufacturing method according to Modification 1, a negative resist film 94 that covers the resist pattern 91p is formed. The resist film 94 is a photosensitive negative resist film used in photolithography or the like and is formed by applying a negative resist material onto the resist pattern 91p by using a spin coat method or the like.
As illustrated in
With the photomask 40a facing the resist film 94, the light shielding film pattern 43p shields the plurality of contact patterns PP from light to selectively irradiate the resist film 94 by exposure light passing through the other portions of the photomask 40a. As a result, portions other than those that cover the plurality of contact patterns PP are exposed.
As illustrated in
Thereafter, for example, by performing the processes of
By the pattern forming method according to Modification 1, the negative resist film 94 is exposed and developed to expose the plurality of contact patterns PP of the resist pattern 91p. At this time, unexposed portions of the negative resist film 94 are removed. Therefore, the resist film 94 that enters the bottom portions of the hole patterns CP as the deep holes can be removed without exposure. That is, the risk that the exposure light does not reach the bottom portions of the hole patterns CP can be avoided, and the resist film 94 can be exposed and developed more easily and more reliably.
In addition to the above, the pattern forming method according to Modification 1 exhibits the same effects as those of Embodiment 1 described above.
Next, a semiconductor device manufacturing method according to Modification 2 of Embodiment 1 is described with reference to
In this Modification 2, a semiconductor device MDV as illustrated in
As illustrated in
The dummy pattern DMb includes a convex pattern having a convex shape and occupies a larger area on the reference plane RP of the template 11 than the plurality of dummy patterns DM. As a result, the dummy pattern DMb is located across the region between the plurality of actual patterns AC.
As illustrated in
and the dummy patterns DM and DMb of the template 11 are pressed against the resist film 91 on the process film PF. After this state is maintained for a predetermined period of time, and the resist film 91 spreads between the actual patterns AC and the dummy patterns DM and DMb, the resist film 91 is irradiated with light such as ultraviolet light passing through the template 11 and cured.
As illustrated in
The recess pattern DPb is a recess pattern to which the dummy pattern DMb is transferred and is located between the plurality of contact patterns PP. As a result, the plurality of contact patterns PP each are sandwiched between the recess patterns DP and DPb.
As illustrated in
As illustrated in
Like the light shielding film pattern 42p described above, the light shielding film pattern 44p includes the plurality of openings 42op larger than the plurality of contact patterns PP at positions of vertically overlapping with the plurality of contact patterns PP. Further, the light shielding film pattern 44p has a plurality of openings 44op at positions vertically overlapping with the recess pattern DPb. The plurality of openings 44op are located, for example, without protruding from the region overlapping with the recess pattern DPb.
With the photomask 40b facing the resist film 92, the resist film 92 is irradiated with exposure light such as ultraviolet light passing through the openings 42op and 44op of the photomask 40b. As a result, portions of the resist film 92 that cover the plurality of contact patterns PP and certain portions of the resist film 92 on the recess pattern DPb are exposed.
As illustrated in
As illustrated in
As illustrated in
As illustrated in
In this way, the regions in which the plurality of memory holes MH are formed are the memory regions MR in the semiconductor device MDV described above (see
As described above, the pattern forming process using the template 11 of Modification 2 is completed.
Thereafter, the pillars PL obtained by stacking the multilayer structure including the channel layer CN in the plurality of memory holes MH to form the memory cell MC (see
With the above, the semiconductor device manufacturing method according to Modification 2 is completed.
By the pattern forming method according to Modification 2, after the resist film 92 is exposed and developed, the contact patterns PP of the resist pattern 191p are exposed, and also the memory patterns MP are formed in the resist film 92 located in the recess pattern DPb. When the process film PF is processed via the resist patterns 191p and 192p, the memory patterns MP are transferred to the process film PF, together with the contact patterns PP.
As a result, contact holes CH having different reaching depths in the process film PF and memory holes MH having substantially the same reaching depths can be collectively formed. By employing such a method, the workload and the costs at the time of manufacturing the semiconductor device MDV can be reduced.
In addition to the above, the pattern forming method according to Modification 2 exhibits the same effects as those of Embodiment 1.
In addition, in Modification 2 described above, the resist pattern 191p is covered with the positive resist film 92 but may be covered with the negative resist film 94 as in Modification 1 described above. In this case, the subsequent exposure of the resist film 94 is performed on a region obtained by inverting the exposure region of the resist film 92.
Next, a semiconductor device manufacturing method according to Modification 3 of Embodiment 1 is described with reference to
As illustrated in
The dummy patterns DMd and DMs include convex patterns each having a convex shape. Further, the dummy patterns DMs are located respectively adjacent to the actual patterns AC between the plurality of actual patterns AC and sandwich the actual patterns AC together with the dummy patterns DM. The dummy patterns DMd are located between the dummy patterns DMs respectively adjacent to the plurality of actual patterns AC.
As illustrated in
As illustrated in
The recess patterns DPs are recess patterns to which the dummy patterns DMs are transferred and are adjacent to the contact patterns PP between the plurality of contact patterns PP. As a result, the plurality of contact patterns PP each are sandwiched by the recess patterns DP and DPs.
The recess pattern DPd are recess patterns to which the dummy pattern DMd is transferred and is located between the recess patterns DPs respectively adjacent to the plurality of contact patterns PP.
As illustrated in
As illustrated in
The light shielding film pattern 45p includes the plurality of openings 42op larger than the plurality of contact patterns PP at positions vertically overlapping with the plurality of contact patterns PP like the light shielding film pattern 42p described above.
Further, the light shielding film pattern 45p includes a plurality of openings 45op at positions vertically overlapping with the recess pattern DPd. The plurality of openings 45op are located in regions overlapping with the recess patterns DPd.
Further, the light shielding film pattern 45p includes a plurality of openings 46op at positions deviated from the recess patterns DPd and DPs, between the recess patterns DPd and DPs. That is, the plurality of openings 46op are located on the contact surface of the resist pattern 291p with the template 12 between the recess patterns DPd and DPs.
With photomask 40c facing the resist film 92, the resist film 92 is irradiated with the exposure light (such as ultraviolet light) passing through the openings 42op, 45op, and 46op of the photomask 40c. As a result, the portions of resist film 92 that cover the plurality of contact patterns PP and certain portions on the recess pattern DPd, and between the recess patterns DPd and DPs are exposed.
As illustrated in
As illustrated in
As a result, the upper surface of the process film PF in the bottom portions of the hole patterns CP as the deepest holes and the plurality of hole patterns LP are exposed. Further, the plurality of hole patterns SP are transferred to the contact surface of the resist pattern 291p. Further, the film thicknesses of the resist patterns 291p and 292p are reduced as a whole.
As illustrated in
As illustrated in
As a result, contact holes CH having different reaching depths in the process film PF, holes LH having substantially the same reaching depths in the process film PF, and holes SH having reaching depths shallower than the holes LH but substantially the same reaching depths in the process film PF are formed in the process film PF.
With the above, the pattern forming process using the template 12 is completed.
Thereafter, the pillars PL (see
With the above, the semiconductor device manufacturing method according to Modification 3 is completed.
In the pattern forming method according to Modification 3, when the resist film 92 is exposed and developed, the hole patterns LP are formed in the resist film 92 located in the plurality of recess patterns DPd, the hole patterns SP are formed in the resist film 92 located at positions deviated from the plurality of recess patterns DPd and DPs, a part of the contact surface of the resist pattern 291p between the plurality of recess patterns DPd and DPs is exposed, the hole pattern LP is transferred to the process film PF, and the hole patterns SP are transferred to the process film PF to be shallower than the hole patterns LP.
As a result, the holes LH and SH having different reaching depths in the process film PF can be collectively formed by exposing and developing the resist film 92 once. By employing such a method, a semiconductor device having various configurations in which reaching depths in the stacked body LM are respectively different can be efficiently manufactured, and the workload and the costs at the time of manufacturing can be further reduced.
In addition to the above, the pattern forming method according to Modification 3 exhibits the same effects as those of Embodiment 1.
In Modification 3, the resist pattern 291p is covered with the positive resist film 92 but in other examples may be covered with the negative resist film 94 as in Modification 1. In this case, the subsequent exposure of the resist film 94 would be performed on a region obtained by inverting the exposure region of the resist film 92.
Hereinafter, Embodiment 2 is described below with reference to the drawings. Embodiment 2 is different from Embodiment 1 in that the imprint process is performed by locating a resist material on the film to be processed (process film) by an inkjet method. In the following, the same reference symbols are given to those aspects that are the same as in Embodiment 1 already described above, and additional description thereof may be omitted.
The droplet dispensing device 87 is a device that dispenses a resist material onto the wafer 30 by an inkjet method. The inkjet head in the droplet dispensing device 87 includes a plurality of fine holes (nozzles) for ejecting droplets of the resist material and locates droplets of the resist material on the wafer 30.
The control unit 290 controls each unit of the imprint apparatus 2 including the droplet dispensing device 87. Further, the control unit 290 controls the wafer stage 82, moves the wafer 30 below the droplet dispensing device 87 when the resist material is dispensed onto the wafer 30, and moves the wafer 30 below the template 10 when the transfer process is performed on the wafer 30.
Next, an example of the imprint process in the imprint apparatus 2 described above is described with reference to
As illustrated in
The template 10 is caused to face the process film PF on which the droplets of the resist material 93 are located, so that the surface on which the columnar-shaped patterns CL are formed faces the process film PF.
As illustrated in
By maintaining this state for a predetermined period of time, the droplets of the resist material 93 are wet and spread on the surface of the process film PF in a film-like manner, and also penetrate between the columnar-shaped patterns CL of the template 10 and between the dummy patterns DM.
After spaces between the columnar-shaped patterns CL and the dummy patterns DM of the template 10 are filled with the resist material 93, the resist material 93 is irradiated with light such as ultraviolet light and cured while the template 10 is kept pressed.
As illustrated in
Thereafter, the process illustrated in
In addition, in the process illustrated in
In the pattern forming method according to Embodiment 2, the resist pattern 93p to which the columnar-shaped patterns CL and the dummy patterns DM of the template 10 are transferred is formed by dispensing droplets of the resin material onto the film to be processed (process film).
In an imprint process using an inkjet method, air bubbles may be easily trapped in a region where the pattern is sparse. However, even when the inkjet method is used, formation defects of the resist pattern 93p can be prevented by preventing the trapping of the air bubbles.
In addition, the pattern forming method according to Embodiment 2 exhibits the same effects as those of Embodiment 1.
Next, Modification 1 of Embodiment 2 is described with reference to
As illustrated in
The dummy patterns DMp are located on the mesa portion MS of the template 20 to sandwich each of the actual patterns AC. With these dummy patterns DMp, actual patterns AC are protected so that damage or the like to the actual patterns AC is prevented.
The dummy patterns DMt are located between the end portions of the mesa portion MS and the plurality of actual patterns AC. When the template 20 is pressed against the resist material 93 on the process film PF, the dummy patterns DMt prevent the bending of the template 20 and possible contact of the end portions or the central portion of the mesa portion MS with the process film PF.
It is generally desirable that a minimum number of dummy patterns DMp and DMt are located in the template 20 of Modification 1.
The plurality of droplets of the resist material 93 are located on the process film PF. However, the droplets of the resist material 93 are not located over the entire process film PF but are located only at positions that vertically overlap (correspond to) the actual pattern AC and the dummy patterns DMp and DMt of the template 20, respectively. Further, the number of droplets of the resist material 93 located at each position on the process film PF can be adjusted according to the sizes, and the uneven portion shapes and the like in the actual patterns AC and the dummy patterns DMp and DMt.
That is, when the sizes of predetermined patterns such as the actual patterns AC are the same, the amount of the resist material 93 required to transfer the patterns tends to increase as the number of uneven portions formed in the patterns increases. In other words, as the volume of the resist pattern after the transfer of the predetermined pattern increases, the amount of resist material 93 required to transfer the pattern tends to increase.
Here, it is assumed as an example that the amount of the resist material 93 required to transfer one actual pattern AC and its adjacent dummy patterns DMp is an amount corresponding to two droplets, which is the minimum dispensing amount of the resist material 93. In this case, two droplets are located at positions on the process film PF corresponding to the actual pattern AC and its adjacent dummy patterns DMp.
In addition, it is assumed in this example that the amount of the resist material 93 required to transfer one dummy pattern DMt is an amount corresponding to one droplet of the resist material 93. In this case, one droplet is located at a position on the process film PF corresponding to each dummy pattern DMt.
The amount of the resist material 93 located at a predetermined position on the process film PF can be adjusted only by adjusting the number of droplets in this example, and thus the minimum adjustable amount (increment) is a discrete value (corresponding to droplet size). For this reason, it is desirable that the sizes, and the uneven portion shapes and the like in the dummy patterns DMp and DMt be adjusted (designed) so that the discrete amount substantially matches the amount of the resist material 93 required to transfer the pattern to each dummy pattern DMp and DMt.
As illustrated in
By maintaining this state for a predetermined period of time, the droplets of the resist material 93 wet and spread in a film-like manner on the process film PF at positions overlapping with the actual pattern AC and the dummy patterns DMp and DMt. Further, droplets of the resist material 93 corresponding to the actual pattern AC and the dummy pattern DMp penetrate into the actual pattern AC and the dummy pattern DMp. Further, the droplets of the resist material 93 corresponding to the dummy pattern DMt penetrate into the dummy pattern DMt.
After the insides of the actual pattern AC and the dummy patterns DMp and DMt of the template 20 are filled with the resist material 93, while the template 20 is pressed, the resist material 93 is irradiated with light such as ultraviolet light and cured.
As illustrated in
In the resist patterns 193p, portions to which the actual patterns AC and the dummy patterns DMp are transferred and a portion to which a dummy pattern DM5 is transferred are spaced from each other and located on the process film PF. Further, these portions of the resist patterns 193p all have residual resist films 193r on the bottom surface.
Thereafter, the process of
In addition, in the process of
In the pattern forming method according to Modification 1 of Embodiment 2, the imprint process can be performed using the template 20 in which the number of dummy patterns DMp and DMt is reduced as much as possible.
By configuring the template 20 in this way, the number of processes required when the template 20 is manufactured is reduced, so that the template 20 can be manufactured in a shorter period of time at lower cost. Further, by reducing the number of different patterns in the template 20, the risk that these patterns may be damaged is reduced so as to extend the lifespan of the template 20.
According to the pattern forming method of Modification 1, droplets of the resist material 93 are located at positions overlapping with the actual patterns AC and the dummy patterns DMp and DMt in the vertical direction.
In this case, as compared with a case where droplets are located over the whole of the actual patterns AC and the dummy patterns DMp and DMt, the usage amount of the resist material 93 can be reduced to reduce the cost of the imprint process.
Furthermore, droplets of the resist material 93 are located only in regions corresponding to the actual patterns AC and the dummy patterns DMp and DMt to form the resist patterns 193p, and thus the trapping of air bubbles can be further prevented.
Here, in the imprint process, there is a problem that formation defect of the resist pattern easily occurs, because the resist material protrudes from a pattern forming region of the template when the template is pressed against the resist material.
As described above, in the template 20, in which the number of dummy patterns DMp and DMt is reduced as much as possible, there is concern that the resist material protrudes more easily.
In the pattern forming method according to Modification 1, when droplets of the resist material 93 are dispensed onto the process film PF, droplets corresponding to the volume of the resist patterns 193p after the transfer of the actual patterns AC and the dummy patterns DMp and DMt are dispensed. As a result, protrusion of the resist material 93 can be prevented, and formation defects of the resist patterns 193p can be prevented.
In addition to the above, the pattern forming method according to this Modification 1 exhibits the same effects as those of Embodiment 2 described above.
Next, Modification 2 of Embodiment 2 is described with reference to
A shot region STR illustrated in
As illustrated in
The sizes, shapes, and arrangement of the resist forming regions RR are adjusted to prevent the connection of the resist patterns 193p to each other between the resist forming regions RR and protrusion of the resist patterns 193p from the resist forming regions RR.
In order to form the resist patterns 193p in the resist forming regions RR, the sizes, the shapes, and the arrangement of the dummy patterns DMp and DMt in the template 20 and the shape and arrangement on the reference plane are also adjusted according to the sizes, the shapes, and the arrangement of the resist forming regions RR.
As illustrated in
That is, the droplet of the resist material 93 in each resist forming region RR is spaced from a droplet of another resist forming region RR. However, a plurality of droplets located in the same resist forming region RR may be or may not be in contact with each other.
Furthermore, the number of droplets of the resist material 93 in each resist forming region RR can be adjusted according to the sizes, and the uneven portion shapes and the like in the pattern of the template 20 transferred to the resist forming region RR. As a result, the protrusion of the resist pattern 193p and contact between the resist forming regions RR are prevented.
In this way, the process illustrated in
As illustrated in
In this way, the process illustrated in
As described above, since the sizes, the shapes, and the arrangement of the resist forming regions RR are adjusted, the contact of the resist pattern 193p in each resist forming region RR with the resist pattern 193p in another resist forming region RR is prevented. Further, in the example illustrated in
In the pattern forming method according to Modification 2, the sizes, the shapes, and the arrangement of the resist forming regions RR on the process film PF are optimized. As a result, the formation defect of the resist patterns 193p can be prevented by preventing the protrusion of the resist material 93. Accordingly, the connection of the resist patterns 193p to each other, which are respectively formed in the resist forming regions RR is prevented.
In addition to the above, the pattern forming method according to Modification 2 exhibits the same effects as those of Embodiment 2 described above.
Next, Modification 3 of Embodiment 2 is described with reference to
As illustrated in
These resist materials 93 and 95 are different types of resist materials, but each can be freely selected in terms of material, composition, or the like. As for the materials of the resist materials 93 and 95, the selection can be made so that one is a silicon-based material and the other is a non-silicon-based material. As for the composition of the resist materials 93 and 95, the composition ratio with a solvent, an additive, and the like can be varied. By varying the compositions of the resist materials 93 and 95, the viscosities of these resist materials 93 and 95 can be made different, for example.
The types of resist materials 93 and 95 can be selected, for example, according to the sizes, and the uneven portion shapes and the like in the actual patterns AC and the dummy patterns DMp and DMt in the template 20. For example, a resist material of a type that wets and spreads well can be selected for a pattern having a large size, and a resist material of a type that more easily penetrates into the pattern can be selected for a pattern having a fine (narrower) shape.
It is assumed in this example that the resist material 93 is a particularly suitable type of resist material for imprinting the actual patterns AC and the dummy patterns DMp. Thus, droplets of the resist material 93 can be located at positions corresponding to the actual patterns AC and the dummy patterns DMp.
It is assumed in this example that the resist material 95 is particularly suitable type of resist material for imprinting the dummy pattern DMt. Thus, droplets of the resist material 95 can be located at positions corresponding to the dummy patterns DMt.
In such a case, different types of resist materials (e.g., resist material 93 and resist material 95) can be located on the process film PF by an imprint apparatus including a plurality of droplet dispensing devices 87 (see
Furthermore, the number of droplets of the resist materials 93 and 95 may be adjusted according to the sizes, the shapes of the uneven portions, and the like of the corresponding pattern of the template 20.
As illustrated in
By maintaining this state for a predetermined period of time, the droplets of the resist materials 93 and 95 wet and spread in a film-like manner on the process film PF and penetrate into the actual patterns AC and the dummy patterns DMp and DMt.
When the insides of the actual patterns AC and the dummy patterns DMp and DMt of the template 20 are filled with the resist materials 93 and 95, the resist materials 93 and 95 are irradiated with light such as ultraviolet light and cured while being pressed against the template 20.
As illustrated in
The resist patterns 193p and the resist pattern 95p are spaced from each other and located on the process film PF. Further, the resist patterns 193p include the residual resist films 193r on the bottom surface, and the resist pattern 95p includes the residual resist films 95r on the bottom surface.
Thereafter, the process of
In the process of
In the pattern forming method according to Modification 3, droplets of the resist material 93 are dispensed at the positions corresponding to the actual patterns AC and the dummy patterns DMp, and droplets of the resist material 95 (of a different type from the resist material 93) are dispensed at the positions corresponding to the dummy patterns DMt.
As a result, appropriate types of the resist materials 93 and 95 can be used for each of the actual patterns AC and the dummy patterns DMp and DMt of the template 20. Therefore, the formation defects of the resist patterns 193p and 95p can be further prevented.
In addition to the above, the pattern forming method according to this Modification 3 exhibits the same effects as those of Embodiment 2 described above.
Next, Modification 4 of Embodiment 2 is described with reference to
Modification 4 is different from Modifications 2 and 3 in that the transfer process is performed a plurality of times (repeatedly) on the resist materials 93 and 95 on the process film PF.
As illustrated in
As in the case of the template 20 of Modification 1, the dummy patterns DMp protect the actual patterns AC. Further, when the template 21 is pressed against the resist materials 93 and 95 on the process film PF, the dummy patterns DMt prevent the bending (warping) of the template 21 and the contact of the end portions of the mesa portion MS with the process film PF.
In the example of
The droplets of the resist material 93 are located at the positions overlapping with the actual pattern AC and the dummy pattern DMp on the process film PF in the vertical direction. Droplets of the resist material 95 are located at the positions overlapping with the dummy patterns DMt in the vertical direction.
In Modification 4, the number of droplets of the resist materials 93 and 95 may be adjusted according to the sizes, the uneven portion shapes, and the like in the corresponding pattern of the template 21.
As illustrated in
Once the insides of the actual patterns AC and the dummy patterns DMp and DMt of the template 21 are filled with the resist materials 93 and 95, the resist materials 93 and 95 are irradiated with light such as ultraviolet light and cured while being pressed against the template 21.
As illustrated in
As illustrated in
The relative position between the template 21 and the process film PF is moved so that the droplets of the newly located resist materials 93 and 95 and the actual patterns AC and the dummy patterns DMp and DMt overlap with each other in the vertical direction.
As illustrated in
After the insides of the actual patterns AC and the dummy patterns DMp and DMt of the template 21 are filled with the resist materials 93 and 95, the resist materials 93 and 95 are irradiated with light such as ultraviolet light and cured while being pressed against the template 21.
As illustrated in
As a result, a resist pattern including the resist patterns 193p and 95p formed in the transfer process of the first time and the resist patterns 193p and 95p formed in the transfer process of a second time is formed.
Thereafter, the process of
In the process of
In some examples, in the pattern forming method of performing the transfer process performed twice according to Modification 4, instead of the different types of resist materials 93 and 95, the transfer process may be similarly performed with just one type of resist material.
According to the pattern forming method of Modification 4, the template 21 is pressed against one or more droplets of the resist material 93 located on the process film PF, the resist patterns 193p to which the actual patterns AC and the dummy patterns DMp are transferred are formed, the template 21 is pressed against one or more droplets of the resist material 93 located on the process film PF and one or more droplets of the resist materials 95 located on the process film PF, the resist patterns 193p to which the actual patterns AC and the dummy patterns DMp are transferred and the resist pattern 95p to which the dummy patterns DMt are transferred are formed.
In this way, by forming the resist pattern including the resist patterns 193p and 95p in a divided manner, it becomes more difficult for air bubbles to be trapped, and thus formation defects of the resist patterns can be further prevented.
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.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2022-099537 | Jun 2022 | JP | national |
