Semiconductor device manufacturing method

Abstract

To obtain a desired shape in a processed film.SOLUTION: A manufacturing method of an embodiment includes the steps of: forming a processed film above a substrate; forming a first film above the processed film; forming a first groove having a bottom and a columnar part which is formed in the bottom and whose end part protrudes from the first groove in the first film by pressing an original plate against the first film; forming a second film different from the first film on the first film; exposing the columnar part from the second film and forming a first hole by in the second film by removing the columnar part; forming a second hole in the processed film by processing the processed film via the first hole; and removing the second film, masking the first film, and processing the processed film to form a second groove in an upper part of the second hole.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] FIELD An embodiment of the present invention relates to a method for manufacturing a semiconductor device. [Background technology]

[0002] In the manufacturing process of a semiconductor device, a dual damascene method is sometimes used to simultaneously form vias connected to an underlying structure and upper-layer wiring connected to the vias. Also, an imprint method may be applied to the formation of vias and upper-layer wiring using the dual damascene method. In the imprint method, a resist is formed on a film to be processed, and a patterned template is pressed against the resist to transfer the template pattern onto the resist. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2010-219456 [Patent Document 2] Japanese Patent Application Publication No. 2018-014497 [Patent Document 3] Japanese Patent Application Laid-Open No. 2012-009686 Summary of the Invention [Problem to be solved by the invention]

[0004] However, when a film to be processed is processed by transferring holes that will become vias and trenches that will become upper layer wiring simultaneously onto a resist using, for example, an imprinting method, the desired shape may not be obtained due to an insufficient selectivity of the resist, etc.

[0005] An object of an embodiment of the present invention is to provide a method for manufacturing a semiconductor device that makes it easy to obtain a desired shape in a film to be processed. [Means for solving the problem]

[0006] A method for manufacturing a semiconductor device according to an embodiment includes forming a film to be processed above a substrate, forming a first film above the film to be processed, pressing a master against the first film to form a first groove having a bottom and a columnar portion formed at the bottom and having an end protruding from the first groove in the first film, forming a second film different from the first film on the first film, exposing the columnar portion from the second film, removing the columnar portion to form a first hole in the second film, processing the film to be processed through the first hole to form a second hole in the film to be processed, removing the second film, processing the film to be processed using the first film as a mask, and forming a second groove above the second hole. [Brief explanation of the drawings]

[0007] [Figure 1] FIG. 1 is a diagram illustrating an example of the configuration of a replica template according to an embodiment. [Figure 2] FIG. 2 is a cross-sectional view showing an example of a procedure of a method for manufacturing a semiconductor device according to an embodiment. [Figure 3] FIG. 3 is a cross-sectional view showing an example of a procedure of a method for manufacturing a semiconductor device according to an embodiment. [Figure 4] FIG. 4 is a cross-sectional view showing an example of a procedure of a method for manufacturing a semiconductor device according to an embodiment. [Figure 5] FIG. 5 is a cross-sectional view showing an example of a procedure of a method for manufacturing a semiconductor device according to an embodiment. [Figure 6] FIG. 6 is a cross-sectional view showing an example of a procedure for a method for manufacturing a semiconductor device according to an embodiment. [Figure 7] FIG. 7 is a diagram illustrating an example of the configuration of the master template according to the embodiment. [Figure 8] 8A to 8C are cross-sectional views illustrating an example of a procedure for a method for manufacturing a master template according to an embodiment. [Figure 9] FIG. 9 is a cross-sectional view illustrating an example of a procedure of a method for manufacturing a master template according to an embodiment. [Figure 10]10A to 10C are cross-sectional views showing an example of a procedure for a method for manufacturing a replica template according to an embodiment. [Figure 11] FIG. 11 is a cross-sectional view showing an example of a procedure of a method for manufacturing a replica template according to an embodiment. [Figure 12] 12A to 12C are cross-sectional views illustrating an example of a procedure for a method for manufacturing a replica template according to an embodiment. [Figure 13] FIG. 13 is a cross-sectional view showing an example of a procedure for a method for manufacturing a semiconductor device according to a comparative example. [Figure 14] FIG. 14 is a cross-sectional view showing an example of a procedure for a method for manufacturing a semiconductor device according to a comparative example. DETAILED DESCRIPTION OF THE INVENTION

[0008] The present invention will be described in detail below with reference to the drawings. Note that the present invention is not limited to the following embodiments. Furthermore, the components in the following embodiments include those that can be easily imagined by a person skilled in the art or that are substantially the same.

[0009] [Replica template configuration] 1A and 1B are diagrams showing an example of the configuration of a replica template 10 according to an embodiment, in which Fig. 1A is a cross-sectional view, Fig. 1B is a partially enlarged cross-sectional view, and Fig. 1C is a partially see-through perspective view.

[0010] The replica template 10 as an original is an imprint template that transfers a pattern 10p provided on the replica template 10 to a resist film on a film to be processed that will become part of a semiconductor device. The replica template 10 is mass-produced from a master template (described later) that has a pattern that is an inverse of the concaves and convexes of the pattern 10p provided on the replica template 10.

[0011] In this specification, the direction in which the patterned surfaces of the replica template 10 and the master template face is referred to as "upward," and the opposite direction is referred to as "downward." Therefore, in this specification, in the configuration of each pattern of the replica template 10 and the master template, the distance from a predetermined position to a certain position above may be referred to as "height," and the distance from the predetermined position to a certain position below may be referred to as "depth."

[0012] As shown in FIG. 1(a), the replica template 10 includes a base material 10b made of a transparent material such as glass or quartz. The base material 10b is, for example, flat. A mesa portion 10m protruding from the main surface 10s is disposed on the main surface 10s of the base material 10b. The mesa portion 10m is disposed, for example, in the center of the base material 10b. A counterbore 10c is provided on the other main surface 10e of the base material 10b, where a portion of the base material 10b is removed from the other main surface 10e side.

[0013] A pattern 10p is disposed on the top surface of the mesa portion 10m. The pattern 10p has, for example, a periodic structure in which predetermined unit structures 10u are periodically repeated. Figures 1(b) and 1(c) show extracted unit structures 10u of the pattern 10p.

[0014] 1(b) and 1(c), the unit feature 10u of the pattern 10p is disposed on a base surface 11, which serves as a first surface of the mesa portion 10m. The unit feature 10u includes, for example, a step portion 12 that protrudes from the base surface 11 to a predetermined height, and a hole portion 13 that is disposed on a step of the step portion 12.

[0015] The step portion 12 extends in a predetermined direction, for example, along the base surface 11, and has an upper surface 12t and a side surface 12w. The upper surface 12t, which is the step of the step portion 12, is, for example, rectangular and has a substantially flat surface. Side surfaces 12w are arranged at both ends of the width direction of the upper surface 12t, which is a direction intersecting the extension direction of the step portion 12. Each side surface 12w extends from both ends of the width direction of the upper surface 12t to the base surface 11. The two side surfaces 12w are substantially parallel to each other in the extension direction of the step portion 12. However, the distance between the two side surfaces 12w may increase as the step portion 12 extends from the upper surface 12t toward the base surface 11, thereby forming a tapered shape.

[0016] As will be described later, the shape of the step portion 12 is transferred to a film to be processed that will become part of the semiconductor device, for example, to form an upper layer wiring. Therefore, the step portion 12 does not need to extend in one direction or in a straight line as described above, but may bend in various directions or extend in a curved or cranked shape.

[0017] The hole 13 has an opening 13t on the upper surface 12t of the step 12 and extends to a predetermined depth within the mesa 10m of the substrate 10b. The hole 13 has a substantially flat bottom surface 13b at its bottom. The depth from the opening 13t to the bottom surface 13b of the hole 13 is greater than, for example, the height of the step 12, i.e., the amount of protrusion from the base surface 11. Therefore, the bottom surface 13b of the hole 13 is located deeper than, for example, the base surface 11.

[0018] As will be described later, the shape of hole 13 is transferred to a film to be processed that will become part of the semiconductor device, and will become, for example, a via that connects an upper layer wiring to a lower layer structure. Therefore, it is desirable that the cross section of hole 13 perpendicular to the depth direction be rounded, i.e., a shape without corners, such as a circle, an ellipse, or an oval. Also, the diameter of opening 13t of hole 13 may be larger than the diameter of bottom surface 13b, so that hole 13 has a tapered shape.

[0019] [Method of manufacturing a semiconductor device] Next, a method for manufacturing the semiconductor device 200 according to the embodiment will be described with reference to Figures 2 to 6. Figures 2 to 6 are cross-sectional views showing an example of the steps of the method for manufacturing the semiconductor device 200 according to the embodiment. In the method for manufacturing the semiconductor device 200, the above-mentioned replica template 10 is used, and a dual damascene method is applied in which the vias 223v and the upper layer wiring 222w (see Figure 6) are formed collectively in the insulating film 220 as the film to be processed.

[0020] In this specification, the up-down direction of the semiconductor device 200 is determined based on, for example, the via 223v and the upper layer wiring 222w. That is, the via 223v is located below the upper layer wiring 222w, and the upper layer wiring 222w is located above the via 223v. The above-mentioned lower layer structure is located further below the via 223v and the upper layer wiring 222w. Furthermore, when we say "above" something, it does not necessarily mean that certain structures in a vertical relationship are in contact with each other. The same applies to when we say "below".

[0021] FIG. 2 shows how a transistor TR is formed as an underlying structure connected to via 223v.

[0022] As shown in Fig. 2(a), a gate electrode GE is formed on a substrate 210, which is a semiconductor substrate such as a silicon substrate. As shown in Fig. 2(b), sidewall spacers SW are formed to cover the gate electrode GE. As shown in Fig. 2(c), a source and a drain SD are formed on the surface layer of the substrate 210 on both sides of the gate electrode GE by, for example, a self-aligned process.

[0023] In this way, a transistor TR including a gate electrode GE and a source and drain SD is formed. However, the method for forming the transistor TR is not limited to the above, and various methods may be used.

[0024] 2(d), the transistor TR is covered with an insulating film 220 such as a silicon oxide (TEOS) film. In addition, on the insulating film 220, a carbon (SOC: Spin On Carbon) film 230 is formed as a carbon-based film.

[0025] Next, the replica template 10 is used. Fig. 3 shows how the unit features 10u of the pattern 10p of the replica template 10 are pressed against the resist film 240 formed on the carbon film 230.

[0026] 3(a), a resist film 240 is formed as a first film on the carbon film 230 above the substrate 210. A pattern 10p of the replica template 10, which has a step portion 12, a hole portion 13, etc., is placed opposite the resist film 240.

[0027] The resist film 240 may be, for example, a photo-curable resist that is cured by being irradiated with light or a thermosetting resist that is cured by being heated. The resist film 240 is formed by being dropped onto a shot region that is an area to be processed in one imprint process, or by being applied to the entire substrate 210 by spin coating or the like.

[0028] 3(b), the pattern 10p of the replica template 10 is pressed against the resist film 240. Then, in this state, the resist film 240 is hardened by irradiating it with light if the resist film 240 is a photocurable resist, or by heating it if the resist film 240 is a thermosetting resist.

[0029] When the replica template 10 is pressed against the resist film 240, a slight distance is maintained between the replica template 10 and the underlying carbon film 230 in order to prevent contact with and damage to the substrate 210 or the like.

[0030] 3(c), after the resist film 240 is hardened, the replica template 10 is released. The resist film 240 becomes a resist pattern 240p to which the pattern 10p of the replica template 10 is transferred.

[0031] The resist pattern 240p has grooves 242 as first grooves to which the step portions 12 of the replica template 10 have been transferred, and pillars 243 as columnar portions to which the hole portions 13 of the replica template 10 have been transferred. The grooves 242 have a shape recessed in the film thickness direction of the resist pattern 240p, and the pillars 243 have a shape protruding from the bottom surface of the grooves 242. In this way, the resist pattern 240p has a pattern in which the concave and convex portions of the pattern 10p of the replica template 10 are inverted.

[0032] As described above, since the replica template 10 is pressed against the resist film 240 with a slight distance from the carbon film 230, the resist pattern 240p has a slight resist residual film 240r on the bottom surface of the groove 242.

[0033] Next, the pattern is transferred from the resist pattern 240p to the carbon film 230 and the insulating film 220. This process is shown in FIGS.

[0034] FIG. 4(a) shows the state after the imprint process shown in FIG. 3(c).

[0035] As shown in FIG. 4(b), the resist pattern 240p is etched back to remove the remaining resist film 240r.

[0036] 4(c), etching back is then performed on the carbon film 230. As a result, the carbon film 230 is etched from the portion where the resist residual film 240r has been removed, and a carbon film pattern 230p is formed, which has shallow grooves 232h recessed to a predetermined depth in the film thickness direction of the carbon film 230 and protruding portions 233p disposed in the shallow grooves 232h.

[0037] The resist pattern 240p and the carbon film 230 are made of similar materials containing a large amount of carbon. Therefore, the carbon film 230 can be etched under the same or similar etching conditions, for example, following the removal process of the remaining resist film 240r shown in FIG. 4(b).

[0038] In the process of FIG. 4(c), the carbon film 230 is half-etched to form the shallow grooves 232h, but at this stage, a through groove that penetrates the carbon film 230 in the film thickness direction may be formed.

[0039] 4(d), a reversal film 250 is formed as a second film covering the resist pattern 240p and the carbon film pattern 230p exposed from the resist pattern 240p. The reversal film 250 is made of a non-carbon material different from the resist pattern 240p and the carbon film pattern 230p, and is, for example, an oxide film such as a silicon oxide (SOG: Spin On Glass) film.

[0040] For example, as described above, by limiting the carbon film 230 to half etching, the height difference of the unevenness of the resist pattern 240p and the carbon film pattern 230p is suppressed, and it becomes easy to form the reversal film 250 flat.

[0041] 4(e), the reversal film 250 is etched back to expose a portion of the pillars 243 of the resist pattern 240p from the upper surface of the reversal film 250. At this time, the exposed amount of the pillars 243 can be adjusted as appropriate, as long as at least the tops of the pillars 243 are exposed from the upper surface of the reversal film 250.

[0042] Since the reversal film 250 is made of a non-carbon material different from the resist pattern 240p, the selectivity with respect to the resist pattern 240p can be increased to selectively etch the reversal film 250 and expose the pillars 243 of the resist pattern 240p.

[0043] 4(f), the pillars 243 exposed from the upper surface of the reversal film 250 are removed. At this time, by utilizing the difference in material between the reversal film 250 and the resist pattern 240p, processing conditions can be set to selectively etch the pillars 243 of the resist pattern 240p relative to the reversal film 250.

[0044] This forms a reversal film pattern 250p having holes 253 as first holes formed by removing the pillars 243. The holes 253 of the reversal film pattern 250p open above the protrusions 233p of the carbon film pattern 230p.

[0045] 5(a), the protrusions 233p of the carbon film pattern 230p are etched away through the holes 253 in the reversal film pattern 250p. At this time, too, by utilizing the difference in material between the reversal film pattern 250p and the carbon film pattern 230p, the carbon film pattern 230p can be selectively etched while ensuring a selectivity with respect to the reversal film pattern 250p.

[0046] As a result, holes 233 are formed that open to the bottom surfaces of the shallow grooves 232h of the carbon film pattern 230p.

[0047] In other words, by the processing up to this point, the pillars 243 formed in the grooves 242 of the resist pattern 240p have been converted into holes 233 that penetrate the carbon film pattern 230p in the depth direction. In this way, the reversal film 250 has the function of reversing the pattern of the resist pattern 240p.

[0048] As shown in FIG. 5(b), the insulating film 220, which is the film to be processed, is etched through the holes 253 in the reversal film pattern 250p and the holes 233 in the carbon film pattern 230p. In the example embodiment, the reversal film pattern 250p and the insulating film 220 are both silicon-based oxide films made of similar materials. For this reason, it is difficult to ensure a selectivity between the reversal film pattern 250p and the insulating film 220. However, by appropriately setting the film thickness of the reversal film 250 when forming the reversal film 250, the film thickness of the reversal film pattern 250p can be sufficiently maintained until etching of the insulating film 220 is complete.

[0049] As a result, through-holes 223t as second holes are formed in the insulating film 220. The through-holes 223t penetrate the insulating film 220 and reach the source and drain SD of the transistor TR formed in the substrate 210, for example.

[0050] As shown in FIG. 5(c), the remaining reversal film pattern 250p is selectively etched back and removed while ensuring a selectivity with respect to the resist pattern 240p.

[0051] 5(d), the shallow groove 232h of the carbon film pattern 230p is additionally etched to form a through groove 232 in the carbon film pattern 230p. At this time, the carbon film pattern 230p is selectively etched while ensuring a selectivity with respect to the insulating film 220.

[0052] The opening of the through hole 223t in the insulating film 220 is exposed at the bottom of the through groove 232 in the carbon film pattern 230p. As described above, by ensuring the selectivity between the insulating film 220 and the carbon film pattern 230p, etching of the edge of the opening of the through hole 223t, that is, the shoulder of the through hole 223t, is suppressed. This allows the shape of the bottom of the through groove 232 in the carbon film pattern 230p to be adjusted so that the shape of the bottom is flat.

[0053] 5(e), the insulating film 220 is etched using the resist pattern 240p and the carbon film pattern 230p as a mask. At this time, it is difficult to ensure a selectivity between the resist pattern 240p and the carbon film pattern 230p. However, even if the resist pattern 240p completely disappears, it is acceptable as long as the carbon film pattern 230p remains until the etching of the insulating film 220 is completed.

[0054] By the above etching, a wiring groove 222 is formed as a second groove of a predetermined depth in the upper part of the insulating film 220. As a result, the upper part of the through hole 223t in the insulating film 220 disappears, and a via hole 223 is formed, the upper part of which is connected to the wiring groove 222. Since the carbon film pattern 230p remains until the etching is completed, the edge part of the opening of the wiring groove 222, that is, the shoulder of the wiring groove 222, is protected.

[0055] As shown in FIG. 5(f), the carbon film pattern 230p is removed by etching while ensuring a selectivity with respect to the insulating film 220.

[0056] As a result of the above, via holes 223 connected to the upper portions of the wiring trenches 222 can be formed in the insulating film 220 in a single step from the resist pattern 240p in which the pillars 243 protrude from the bottom surfaces of the trenches 242.

[0057] Thereafter, the via holes 223 and the wiring grooves 222 in the insulating film 220 are filled with a metal material such as tungsten or copper. This state is shown in FIG.

[0058] As shown in FIG. 6, a semiconductor device 200 according to the embodiment is manufactured by applying the imprint method using the replica template 10 and the dual damascene method using a resist pattern 240p pattern-transferred by the imprint method.

[0059] The semiconductor device 200 includes a transistor TR, a via 223v, and an upper layer wiring 222w. The semiconductor device 200 may include a substrate 210. As described above, the transistor TR is disposed on the substrate 210. The lower end of the via 223v is connected to the source and drain SD of the transistor TR. The upper end of the via 223v is connected to the upper layer wiring 222w. The via 223v and the upper layer wiring 222w have a metal member 224 filled in the via hole 223 and the wiring groove 222 described above. This electrically connects the source and drain SD of the transistor TR to the upper layer wiring 222w.

[0060] 2 to 6, the vias 223v and the upper layer wiring 222w connected to the source and drain SD of the transistor TR are formed. However, the manufacturing method of the semiconductor device 200 according to the embodiment can also be applied to the case of forming the vias and the upper layer wiring connected to the gate GE of the transistor TR, for example.

[0061] 2 to 6, the lower layer structure is a transistor TR. However, the manufacturing method of the semiconductor device 200 according to the embodiment can also be applied to the case of forming a via and an (upper layer) wiring connected to the upper layer wiring 222w or a wiring further above the upper layer wiring 222w.

[0062] 2 to 6, the semiconductor device 200 is disposed on a substrate 210 such as a semiconductor substrate. However, the semiconductor device may be disposed on a substrate other than a semiconductor substrate, such as a ceramic substrate, a glass substrate, or a quartz substrate.

[0063] [Master template configuration] Next, the configuration of the master template 20 according to the embodiment will be described with reference to Fig. 7. Fig. 7 is a diagram showing an example of the configuration of the master template 20 according to the embodiment. Fig. 7(a) is a cross-sectional view, Fig. 7(b) is a partially enlarged cross-sectional view, and Fig. 7(c) is a partially see-through perspective view.

[0064] The master template 20 as an original is an imprint template that transfers a pattern 20p provided on the master template 20 to a resist film on a substrate 10b that will become the replica templates 10. Replica templates 10 are mass-produced from the master template 20 by processing the substrate 10b based on the pattern transferred to the resist film on the substrate 10b.

[0065] As shown in FIG. 7(a), the master template 20 includes a base material 20b made of a transparent material such as glass or quartz. The base material 20b is, for example, flat. A mesa portion 20m protruding from the main surface 20s is disposed on the main surface 20s of the base material 20b. The mesa portion 20m is disposed, for example, in the center of the base material 20b. A counterbore 20c is provided on the other main surface 20e of the base material 20b, where a portion of the base material 20b is removed from the other main surface 20e side.

[0066] A pattern 20p is disposed on the upper surface of the mesa portion 20m. The pattern 20p has, for example, a periodic structure in which predetermined unit structures 20u are periodically repeated. Figures 7(b) and 7(c) show extracted unit structures 20u of the pattern 20p.

[0067] 7(b) and 7(c), the unit feature 20u of the pattern 20p is disposed on the base surface 21, which serves as the first surface of the mesa portion 20m. The unit feature 20u includes, for example, a groove 22 having a bottom recessed to a predetermined depth from the base surface 21, and a pillar 23 disposed at the bottom of the groove 22.

[0068] The groove 22 extends in a predetermined direction, for example, along the base surface 21, and has a bottom surface 22b and side surfaces 22w. The bottom surface 22b, which is the bottom of the groove 22, is, for example, rectangular and has a substantially flat surface. Side surfaces 22w are arranged at both ends of the bottom surface 22b in the width direction, which is a direction intersecting the extension direction of the groove 22. Each side surface 22w extends from both ends of the bottom surface 22b in the width direction to the base surface 21. The two side surfaces 22w are substantially parallel to each other in the extension direction. However, the distance between the two side surfaces 22w may increase as it goes from the bottom surface 22b toward the base surface 21, so that the groove 22 has a tapered shape.

[0069] The grooves 22 do not necessarily extend in one direction or in a straight line as described above, but may bend in various directions, or may extend in a curved or cranked shape.

[0070] The pillars 23 serving as columnar portions have bases 23b on the bottom surfaces 22b of the grooves 22 and extend to a predetermined height from the bottom surfaces 22b of the grooves 22. The pillars 23 have substantially flat top surfaces 23t at their tops. The height from the bases 23b of the pillars 23 to the top surfaces 23t is greater than, for example, the depth of the grooves 22, i.e., the amount of depression from the base surface 21. Therefore, the top surfaces 23t of the pillars 23 are located higher than, for example, the base surface 21 and protrude from the base surface 21.

[0071] It is desirable that the cross section of pillar 23 perpendicular to the height direction be rounded, i.e., have no corners, such as a circle, an ellipse, or an oval. In addition, pillar 23 may have a tapered shape by making the diameter of base 23b of pillar 23 larger than the diameter of top surface 23t.

[0072] In this way, the master template 20 has a pattern 20p in which the protrusions and recesses of the replica template 10 are reversed.

[0073] [Master template manufacturing method] Next, a method for manufacturing the master template 20 according to the embodiment will be described with reference to Figures 8 and 9. Figures 8 and 9 are cross-sectional views showing an example of a procedure for the method for manufacturing the master template 20 according to the embodiment.

[0074] 8(a), a hard mask (HM) film 30, which is a film containing a metal such as chromium, molybdenum, or tantalum, or carbon, is formed on a substrate 20b made of a flat plate of glass, quartz, or the like. At this time, the HM film 30 is made thicker than usual in consideration of subsequent processing. In addition, a resist film 40, which is a resin film for electron beam (EB) writing, is formed on the HM film 30.

[0075] As shown in FIG. 8(b), the resist film 40 is processed by EB lithography to form pillars 43 made of the resist film 40.

[0076] 8(c), the HM film 30 is etched using the pillars 43 as a mask to form pillars 33 made of the HM film 30. As a result, the surface of the substrate 20b is exposed except for the portions where the pillars 43, 33 are formed.

[0077] 8(d), the exposed surface of the base material 20b is etched using the pillars 33 as a mask. As a result, a predetermined thickness of the surface of the base material 20b is removed, and the base material 20b has an etched surface. This etched surface becomes the base surface 21 of the master template 20.

[0078] This also forms protrusions 23p that protrude from the base surface 21 of the substrate 20b. At this time, the pillars 43 may disappear. However, because the HM film 30 is thickened, parts of the pillars 33 remain. In other words, in the process shown in FIG. 8(d), the thickness of the HM film 30 is set so that at least parts of the pillars 33 remain.

[0079] 8(e), a material member containing, for example, a metal such as chromium, molybdenum, or tantalum, or carbon, is sputtered onto the substrate 20b, including on the pillars 33 of the protrusions 23p. As a result, an HM film 50 of a predetermined thickness is formed on the base surface 21 of the substrate 20b, and pillars 53 made of the above material member are formed on the pillars 33. As a result, an HM pattern 50p including the HM film 50 and the pillars 33, 53 is formed.

[0080] Here, the material sputtered onto the substrate 20b may be the same as or different from the material constituting the HM film 30. Furthermore, the HM film 30 and the HM pattern 50p may have different characteristics, such as etching resistance. When the HM film 30 and the HM pattern 50p are made of the same material, their characteristics can be made different by, for example, varying the sputtering conditions. When the HM film 30 and the HM pattern 50p are made of different materials, their characteristics can be made different by selecting the respective materials.

[0081] At this time, when etching the base material 20b, it is preferable that the etching resistance of the HM film 30 is higher than the etching resistance of the HM pattern 50p. In other words, the pillars 33 made of the HM film 30 are required to have higher etching resistance.

[0082] As shown in FIG. 8(f), a resist film 60, which is a resin film for EB writing, is formed to cover the entire HM pattern 50p.

[0083] 9(a), the resist film 60 is processed by EB lithography to form a resist pattern 60p having a through groove 62 that reaches the HM pattern 50p, thereby exposing a part of the HM film 50 in the HM pattern 50p and all of the pillars 33 and 53.

[0084] 9(b), the HM pattern 50p is etched using the resist pattern 60p as a mask. As a result, a portion of the HM film 50 of the HM pattern 50p is removed, exposing a portion of the base surface 21 of the substrate 20b. Furthermore, the pillars 53 of the HM pattern 50p disappear because they have approximately the same film thickness as the HM film 50, exposing the top surfaces of the pillars 33.

[0085] As shown in FIG. 9(c), the substrate 20b is etched using the resist pattern 60p and the HM pattern 50p as a mask. As a result, grooves 22 are formed in the substrate 20b, digging down to a predetermined depth from the base surface 21. Pillars 23 having bases 23b are also formed on the bottom surfaces 22b of the grooves 22. At this time, at least a portion of the pillars 33 of the HM pattern 50p remains, and the top surfaces 23t of the pillars 23 are protected until etching is completed.

[0086] As shown in FIG. 9(d), the resist pattern 60p and the HM pattern 50p are removed.

[0087] In this way, the master template 20 of the embodiment is manufactured.

[0088] [Manufacturing method of replica template] Next, a method for manufacturing the replica template 10 according to the embodiment will be described with reference to Figures 10 to 12. Figures 10 to 12 are cross-sectional views showing an example of the procedure for the method for manufacturing the replica template 10 according to the embodiment.

[0089] 10(a), an HM film 130, which is a film containing a metal such as chromium, molybdenum, or tantalum, or carbon, is formed on a substrate 10b made of a flat plate of glass, quartz, or the like. In addition, a photo-curable or thermosetting resist film 140 is formed on the HM film 130.

[0090] It is not necessary to thicken the HM film 130. The resist film 140 is locally dropped onto a shot region of the base material 10b, or is applied to the entire base material 10b, similar to the resist film 240 used in manufacturing the semiconductor device 200 described above.

[0091] The pattern 20p of the master template 20, which has the grooves 22, pillars 23, etc., is placed opposite to the resist film 140 formed on the base material 10b.

[0092] 10(b), the pattern 20p of the master template 20 is pressed against the resist film 140. Then, in this state, the resist film 140 is irradiated with light or heated to harden the resist film 140.

[0093] 10(c), after the resist film 140 is hardened, the master template 20 is released. The resist film 140 becomes a resist pattern 140p to which the pattern 20p of the master template 20 is transferred.

[0094] The resist pattern 140p has step portions 142 to which the grooves 22 of the master template 20 have been transferred, and holes 143 to which the pillars 23 of the master template 20 have been transferred. The step portions 142 protrude from the upper surface of the resist pattern 140p, and the holes 143 have a shape that is recessed from the upper surface of the step portions 142 in the film thickness direction of the resist pattern 140p. The resist pattern 140p has a resist residual film 140r at the bottom of the holes 143.

[0095] FIG. 11(a) shows the state after the imprint process shown in FIG. 10(c).

[0096] As shown in FIG. 11(b), the resist pattern 140p is etched back to remove the remaining resist film 140r.

[0097] 11(c), the HM film 130 is etched using the resist pattern 140p as a mask, thereby forming an HM pattern 130p that is penetrated through the portions of the resist pattern 140p that correspond to the holes 143.

[0098] As shown in FIG. 11(d), etching is continued using the resist pattern 140p as a mask to etch the substrate 10b exposed from the through-portion of the HM pattern 130p. As a result, shallow holes 13h are formed in the substrate 10b. The shallow holes 13h have a configuration corresponding to the hole portions 13 of the replica template 10, but are shallower than the hole portions 13. The shallow holes 13h are subsequently etched to become the hole portions 13 of a predetermined depth.

[0099] 11(e), the resist pattern 140p is etched back, so that a step portion 142 having a hole 143 in the resist pattern 140p remains on the HM pattern 130p.

[0100] 11(f), the HM pattern 130p is etched using the step portion 142 of the resist pattern 140p as a mask, thereby leaving the step portion 142 of the resist pattern 140p and the HM pattern 130p below the step portion 142 on the base material 10b.

[0101] 12(a), the base material 10b is etched using the step portion 142 of the resist pattern 140p and the underlying HM pattern 130p as a mask. As a result, a predetermined thickness of the surface of the base material 10b is removed, and the base material 10b has an etched surface. This etched surface becomes the base surface 11 of the replica template 10.

[0102] This also causes the etched surface of the substrate 10b, i.e., the substrate 10b below the HM pattern 130p, to protrude relative to the base surface 11, forming a step portion 12. Furthermore, the shallow hole 13h is additionally etched to form a hole portion 13 of a predetermined depth.

[0103] As shown in FIG. 12(b), the HM pattern 130p is removed from the upper surface 12t of the step portion 12 of the base material 10b.

[0104] In this way, the replica template 10 of the embodiment is manufactured.

[0105] [Comparative Example] Next, a method for manufacturing a semiconductor device of a comparative example will be described with reference to FIGS.

[0106] As shown in FIG. 13(a), a replica template 10' of the comparative example has, for example, a step portion 12' and a pillar 13' protruding from the step portion 12'.

[0107] An insulating film 220′, a carbon film 230′, and a resist film are formed in this order on a substrate 210′, and the replica template 10′ is pressed against the substrate 210′ ​​to form a resist pattern 240′ having grooves and holes on the carbon film 230′ (FIG. 13(a)). The remaining resist film of the resist pattern 240′ is removed (FIG. 13(b)), and the holes in the resist pattern 240′ are transferred to the carbon film 230′ to form a carbon film pattern 230p′ (FIG. 13(c)). Furthermore, the grooves in the resist pattern 240′ are transferred to the carbon film pattern 230p′ (FIG. 13(d)). Next, the holes in the carbon film pattern 230p′ are transferred to the insulating film 220′ (FIG. 13(e)), and the grooves in the carbon film pattern 230p′ are transferred to the insulating film 220′ to form a via hole 223′ and a wiring groove 222′ (FIG. 13(f)).

[0108] However, the method for manufacturing a semiconductor device of the comparative example has various problems as shown in FIG.

[0109] 14(a), in the process of transferring the grooves of the resist pattern 240' to the carbon film pattern 230p', for example, the selectivity for the resist pattern 240' is reduced to penetrate the grooves of the resist pattern 240' and transfer them to the carbon film pattern 230p'. As a result, the shoulders of the grooves of the resist pattern 240', that is, the edges of the openings of the grooves, are easily etched away, and for example, as shown in FIG. 14(a'), the shoulders 242s' of the grooves may become rounded or the groove width may increase.

[0110] As shown in FIG. 14(b), in the process of transferring the grooves of the carbon film pattern 230p' to the insulating film 220', for example, the selectivity for the carbon film pattern 230p' is reduced to penetrate the grooves of the carbon film pattern 230p' and transfer them to the insulating film 220'. As a result, the shoulders of the holes in the carbon film pattern 230p' are likely to be etched away, and as shown in FIG. 14(b'), for example, the shoulders 233s' of the holes may become rounded or the hole diameter may increase. Furthermore, for example, because the penetration of the grooves of the carbon film pattern 230p' and the transfer to the insulating film 220' are performed simultaneously, the depth of the bottom surfaces of the grooves is unlikely to be uniform, and the flatness of the bottom surface is likely to be impaired. 14(a') is transferred to the grooves of the carbon film pattern 230p', and there is nothing to protect the shoulders of the grooves of the carbon film pattern 230p' when the grooves are transferred to the insulating film 220', so the shoulders 232s' of the grooves of the carbon film pattern 230p' tend to have a more rounded shape, and the width of the grooves may also increase.

[0111] As a result of the above, the insulating film 220' does not have the ideal shape shown in FIG. 14(c), and as shown in FIG. 14(c'), for example, the shoulders 222s' of the wiring grooves 222' and the shoulders 223s' of the via holes 223' may have rounded shapes. Also, the dimensional difference between the wiring grooves 222' and the via holes 223' may become large. Furthermore, the depths of the wiring grooves 222' may not be uniform, and the flatness of the bottom surfaces of the wiring grooves 222' may be impaired.

[0112] According to the manufacturing method of the semiconductor device 200 of the embodiment, the carbon film 230 and the resist film 240, each made of the same material, are used in combination with the inversion film 250, made of a different material. This allows various processes to be performed while ensuring the appropriate selectivity between them. This makes it easy to obtain a desired shape in the insulating film 220.

[0113] For example, in the process shown in Figure 5(a) above, in which the pillars 243 of the resist pattern 240p are inverted and transferred as holes 233 in the carbon film pattern 230p, the shoulders of the grooves 242 of the resist pattern 240p are protected by the inverted film pattern 250p, thereby allowing the shape of the grooves 242 to be maintained.

[0114] 4(d) to 5(b), the resist pattern 240p is protected by the reversal film pattern 250p. Therefore, the process shown in FIG. 5(d) for completely transferring the grooves 242 of the resist pattern 240p as the through grooves 232 of the carbon film pattern 230p can be performed with a sufficient film thickness of the resist pattern 240p remaining. This makes it easier to transfer the shape of the grooves 242 of the resist pattern 240p to the through grooves 232 of the carbon film pattern 230p with high accuracy.

[0115] According to the manufacturing method of the semiconductor device 200 of the embodiment, the dual damascene pattern is transferred stepwise to the insulating film 220. This also makes it easier to obtain a desired pattern in the insulating film 220.

[0116] 5(b) described above, the process of transferring the hole 233 of the carbon film pattern 230p to the insulating film 220 is performed in a state where the shoulder of the groove 242 of the resist pattern 240p and the entire shallow groove 232h of the carbon film pattern 230p are covered with the reverse film pattern 250p. This makes it possible to maintain the shapes of the groove 242 of the resist pattern 240p and the shallow groove 232h of the carbon film pattern 230p during the process of transferring the hole 233 of the carbon film pattern 230p to the insulating film 220.

[0117] 5(d) to the carbon film pattern 230p, and the process shown in FIG. 5(e) to transfer the through grooves 232 of the carbon film pattern 230p to the insulating film 220 are performed separately. That is, in the process shown in FIG. 5(d), the through grooves 232 are formed in the carbon film pattern 230p while ensuring a selectivity with respect to the insulating film 220, and the insulating film 220 functions as an etch stop film. This makes it easier to make the depths of the bottom surfaces 222b of the wiring grooves 222 formed in the insulating film 220 uniform, and also makes it easier to obtain flatness of the bottom surfaces 222b.

[0118] To make the bottom surface of the wiring trench uniform and flat, one possible method is to insert a stopper film to a predetermined depth in the insulating film and use this as the bottom surface of the wiring trench. However, this method may increase the parasitic capacitance (inter-wiring capacitance) of the insulating film, including the stopper film. By separately forming the through groove 232 of the carbon film pattern 230p and the wiring trench 222 of the insulating film 220, it is easier to obtain the desired shape of the wiring trench 222 without inserting a stopper film.

[0119] The replica template 10 of the embodiment includes a step portion 12 that protrudes from the base surface 11 to a predetermined height, and a hole portion 13 that extends from the upper surface 12t of the step portion 12 to a predetermined depth.

[0120] That is, the replica template 10 does not have protruding pillars 13' like the replica template 10' of the comparative example. This eliminates the risk of damage to the pillars 13', which have weak mechanical strength, in the replica template 10, which is used frequently, and allows the replica template 10 to have a longer life.

[0121] Furthermore, unlike the replica template 10' of the comparative example, which is composed only of convex shapes, the replica template 10 includes both convex and concave shapes as described above, and the height difference on its surface is relatively small. Therefore, pattern transfer is possible without making the resist film 240 thick.

[0122] Furthermore, as long as there is a slight difference in height between the pillars 243 of the resist pattern 240p and the other surface of the resist pattern 240p, the pillars 243 can be exposed from the reversal film 250, which makes it possible to keep the aspect ratio of the holes 13 of the replica template 10 low and further reduce the difference in height on the surface of the replica template 10. This also makes it easy to manufacture such a replica template 10.

[0123] According to the replica template 10 of the embodiment, the method for manufacturing the semiconductor device 200 of the embodiment is realized, and the effects of the method for manufacturing the semiconductor device 200 of the embodiment described above are created.

[0124] The master template 20 of the embodiment includes grooves 22 recessed to a predetermined depth from a base surface 21, and pillars 23 protruding from bottom surfaces 22b of the grooves 22 to a position higher than the base surface 21. The master template 20 having such a shape enables the manufacture of the replica template 10 of the embodiment, and produces the effects of the method for manufacturing the semiconductor device 200 of the embodiment described above.

[0125] According to the manufacturing method of the master template 20 of the embodiment, the pattern 20p is formed in two stages: forming the protrusions 23p and forming the grooves 22. This allows the pillars 23 protruding from the bottom surfaces 22b of the grooves 22 to be formed.

[0126] According to the manufacturing method of the master template 20 of the embodiment, the positions where the protrusions 23p are formed and the positions where the grooves 22 are formed are aligned by EB lithography. This allows the grooves 22 to be aligned with the positions of the pillars 23 with high accuracy.

[0127] According to the manufacturing method of the master template 20 of this embodiment, a sputtered material member that will become the HM pattern 50p when forming the grooves 22 is formed over the entire surface of the substrate 20b, with the pillars 33 of the HM film 30 remaining on the protrusions 23p. This allows the pillars 33, 53 on the protrusions 23p to be thicker than the HM film 50 on the base surface 21 of the substrate 20b. Therefore, when opening the HM film 50 to form the grooves 22, at least the pillars 33 can be left on the protrusions 23p. Because the pillars 33 protect the protrusions 23p when forming the grooves 22, the height of the protrusions 23p is maintained, and therefore the aspect ratio of the pillars 23 can be maintained.

[0128] Although several embodiments of the present invention have been described, these embodiments are presented as examples and are not intended to limit the scope of the invention. These novel embodiments can be embodied in various other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and their modifications are included within the scope and spirit of the invention, and are also included in the scope of the invention and its equivalents as defined in the claims. [Explanation of symbols]

[0129] 10...replica template, 10b...substrate, 10p...pattern, 11...base surface, 12...step portion, 13...hole portion, 20...master template, 20b...substrate, 20p...pattern, 21...base surface, 22...groove, 23...pillar, 200...semiconductor device, 210...substrate, 220...insulating film, 230...carbon film, 240...resist film, 250...inversion film, 222...wiring groove, 222w...upper layer wiring, 223...via hole, 223v...via.

Claims

1. forming a film to be processed above a substrate, and forming a first film above the film to be processed; pressing an original against the first film to form a first groove having a bottom and a columnar portion formed at the bottom and having an end protruding from the first groove in the first film; forming a second film different from the first film on the first film; exposing the columnar portion from the second film and removing the columnar portion to form a first hole in the second film; processing the processing target film through the first hole to form a second hole in the processing target film; removing the second film, and processing the film to be processed using the first film as a mask to form a second groove above the second hole; A method for manufacturing a semiconductor device.

2. further comprising filling the second groove and the second hole with a metal member. The method for manufacturing a semiconductor device according to claim 1 .

3. the first film is a resist film, and the processed film is an insulating film; 3. The method for manufacturing a semiconductor device according to claim 1.

4. the second film is an oxide film containing silicon; The method for manufacturing a semiconductor device according to any one of claims 1 to 3.

5. A transistor is formed on the substrate. The method for manufacturing a semiconductor device according to any one of claims 1 to 4.

6. The method further includes the step of forming a carbon film between the film to be processed and the first film. The method for manufacturing a semiconductor device according to any one of claims 1 to 5.

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