CN103367224A - Method for forming groove in substrate - Google Patents

Abstract

A method of forming a trench in a substrate is disclosed. First, a first patterned mask layer is formed on a substrate, wherein the first patterned mask layer has a first trench. Then, a material layer is formed on the substrate, and the material layer is formed along the first trench conformally. Then, a second patterned mask layer is formed on the material layer to fill the first trench. Then, part of the material layer is removed, and the material layer between the second patterned mask layer and the substrate is remained to form a second trench. Finally, an etching manufacturing process is carried out by taking the first patterning mask layer and the second patterning mask layer as masks.

Description

Method of forming a trench in a substrate

technical field

The present invention relates to a method of forming a trench in a substrate, in particular, to a method of forming an extremely narrow trench in a substrate.

Background technique

In the semiconductor manufacturing process, in order to smoothly transfer the pattern of integrated circuits (integrated circuits) to the semiconductor chip, the circuit pattern must first be designed on a photomask layout, and then the light output according to the photomask layout A photomask pattern is used to make a photomask, and the pattern on the photomask is transferred to the semiconductor chip in a certain proportion, which is commonly known as lithography.

With the rapid increase of the integration level of semiconductor circuits, the current photolithography technology has encountered a bottleneck and cannot cope with the ever-shrinking component sizes. For example, the damascene process for forming metal wires must first form trench patterns in the hard mask, then transfer the trench patterns to the dielectric layer, and then fill the trenches in the dielectric layer with metal. to form metal wires. However, limited by the current semiconductor technology, the existing photolithography technology cannot form a narrow trench pattern in the mask layer, which also limits the size of the overall metallization interconnection system.

Therefore, there is also a need for a novel semiconductor manufacturing process that can form trenches with narrower widths in the substrate.

Contents of the invention

It is an object of the present invention to provide a method for forming trenches in a substrate capable of forming extremely narrow trenches.

In order to achieve the above object, according to an embodiment of the present invention, a method for forming a groove in a substrate provided by the present invention includes first forming a first patterned mask layer on a substrate, the first patterned mask The layer has a first trench. Then, a material layer is formed on the entire surface of the substrate, and the material layer is conformally formed along the first groove. Then a second patterned mask layer is formed on the material layer to fill up the first trench. Then part of the substance layer is removed, and the substance layer located between the second patterned mask layer and the substrate remains, so as to form a second groove. Finally, an etching process is performed using the first patterned mask layer and the second patterned mask layer as masks.

According to another embodiment of the present invention, the present invention provides a method for forming a groove in a substrate. Firstly, a first patterned mask layer is formed on a substrate, which has a first groove. Then a substance layer is formed on the sidewall of the first trench. Then a second patterned mask layer is formed to fill up the first trench. Then all the material layer on the substrate is removed to form a second groove. Finally, an etching process is performed using the first patterned mask layer and the second patterned mask layer as masks.

The method for forming trenches proposed by the present invention is characterized in that a material layer is conformally formed in the first trench, and then the first trench is filled with a second patterned mask layer, and finally the sidewall of the first trench is removed. The upper material layer, the width of the formed second trench is substantially equal to the thickness of the material layer. Utilizing the method provided by the invention, a trench with extremely narrow width can be obtained in the substrate.

Description of drawings

1 to 7 are schematic diagrams of a first embodiment of a method for forming a trench in a substrate according to the present invention;

8 is a schematic diagram of a second embodiment of a method for forming a trench in a substrate according to the present invention;

9 to 10 are schematic diagrams of a third embodiment of a method for forming a trench in a substrate according to the present invention;

11 to 12 are schematic diagrams of another embodiment of a method for forming a groove in a substrate according to the present invention;

13 to 17 are schematic diagrams of a fourth embodiment of a method for forming a trench in a substrate according to the present invention;

18 to 20 are schematic diagrams of a fifth embodiment of a method for forming a trench in a substrate according to the present invention.

Description of main component symbols

300 Substrate 310 Second groove

302 first patterned mask layer 312 third mask layer

302a bottom first patterned mask layer 312a bottom third mask layer

302b top first patterned mask layer 312b top third mask layer

304 first trench 313 third patterned mask layer

304a Bottom surface 314 Second gap wall (side wall)

304b Sidewall 315 Linear Pattern

306 Substance Layer 316 Third Groove

308 second mask layer 318 fourth groove

309 second patterned mask layer 320 fifth trench

Detailed ways

In order to enable those who are familiar with the technical field of the present invention to further understand the present invention, several preferred embodiments of the present invention are listed below, together with the accompanying drawings, the content of the composition of the present invention and the intended achievement are described in detail. effect.

Please refer to FIG. 1 to FIG. 7 , which are schematic diagrams of a first embodiment of a method for forming a trench in a substrate according to the present invention. As shown in FIG. 1, a substrate 300 is firstly provided. The substrate 300 can be various semiconductor substrates, such as silicon substrate, epitaxial silicon substrate, silicon germanium substrate, silicon carbide The substrate (siliconcarbide substrate) or silicon-on-insulator (SOI) substrate may also include a substrate having a non-semiconductor material, such as a glass substrate, to form a thin-film transistor (thin- film-transistor), or a fused quartz block (fused quartz) to form a photomask thereon. In another embodiment of the present invention, the substrate 300 may include one or more low dielectric constant layers to form a metal interconnection system having a dual damascene structure thereon. For example, the substrate 300 may include different doped regions, one or more layers of low-k dielectric layers, or a multi-layer metal interconnection system. , and have one or more microelectronic elements disposed therein, such as complementary metal oxide semiconductor (CMOS) or photo-diode. Next, a first patterned mask layer 302 is formed on the substrate 300 . In an embodiment of the present invention, the first patterned mask layer 302 has a first trench 304, the first trench 304 has a bottom surface 304a and a side wall 304b, wherein the bottom surface 304a of the first trench 304 The substrate 300 will be exposed. The first patterned mask layer 302 may include various materials suitable as a hard mask, such as silicon nitride, silicon oxynitride, silicon carbide or materials provided by Applied Materials. Advanced patterned film (advanced pattern film, APF). In another embodiment, the first patterned mask layer 304 may comprise a multi-layer film structure, such as a phosphor-silicate glass (PSG) layer plus silicon nitride thereon. layer. In another embodiment, the first patterned mask layer 302 may also ^{include an organic polymer, such as spin-on-glass or SiLK™ polymer} .

Next, as shown in FIG. 2 , a material layer 306 is formed on the entire substrate 300 . Wherein the substance layer 306 will be formed on the top surface of the first patterned mask layer 302 and conformally (conformally) along the bottom surface 304a and sidewall 304b of a trench 304, but will not fill the first trench groove 304 . The method of forming the material layer 306 includes chemical vapor deposition (chemical vapor deposition, CVD) process, such as atomic layer deposition (atomic layer deposition, ALD) process, etc., but not limited thereto. In an embodiment of the present invention, the material layer 306 is, for example, boronphosphor-silicate glass (boronphosphor-silicate glass, BPSG) or an advanced patterned film (advanced pattern film, APF) provided by Applied Materials, and the material layer 306 It has a thickness T generally between 10 nanometers and 200 nanometers.

As shown in FIG. 3 , a second mask layer 308 is fully formed on the substrate 300 , wherein the second mask layer 308 is formed on the substance layer 306 and fills up the first trench 304 . The material of the second mask layer 308 can be the same as or different from that of the first patterned mask layer 302, and it includes various materials suitable as a mask layer, such as silicon nitride, silicon oxynitride, silicon carbide or applied materials. The advanced patterned thin film provided by the company must have an etching selectivity ratio with the substance layer 306, that is, have a different etching rate for an etchant. In another embodiment of the present invention, the second mask layer 308 can also be polysilicon (poly-silicon) or organic polymer such as spin-on-glass (spin-on-glass) or photoresist layer .

As shown in FIG. 4 , a planarization process, such as an etch-back process, a chemical mechanical polish (CMP) process, or a combination of both, is performed to remove the first trench 304 Except for the second mask layer 308 , only the second mask layer 308 in the first trench 304 is reserved to form a second patterned mask layer 309 . The planarization process is based on the principle that the material layer 306 on the first patterned mask layer 302 can be exposed. Preferably, the planarization process will be carried out until the second mask layer 308 is flush with the first patterned mask Layer 306 of matter on layer 302 . In a preferred embodiment of the present invention, the planarization process is an etch-back process, and since there is an etching selectivity ratio between the second mask layer 308 and the material layer 306, the material layer 306 in this planarization process will not be removed.

As shown in FIG. 5, a dry etching and/or wet etching process is performed to remove the substance layer 306 on the sidewall 304b of the first trench 304 and the first patterned mask layer 302, while the substrate 300 and Substance layer 306 between second patterned mask layers 309 . In a preferred embodiment of the present invention, a dry etching process is performed using the first patterned material layer 302 and the second patterned material layer 309 as masks to remove part of the material layer 306, so that the remaining material layer 306 can be substantially aligned with the second patterned mask layer 309 on the vertical plane. At this time, a second groove 310 is formed between the first patterned mask layer 302 and the second patterned mask layer 309 , and the width of the second groove 310 is substantially the same as the thickness T of the substance layer 306 .

As shown in FIG. 6 , a dry etching process is performed using the first patterned mask layer 302 and the second patterned mask layer 309 as masks to deepen the depth of the second trench 310 into the substrate 300 . Finally, as shown in FIG. 7 , the first patterned mask layer 302 , the second patterned mask layer 309 and the substance layer 306 on the substrate 300 are all removed, so that a first patterned mask layer 302 can be formed in the substrate 300 There are three grooves 316 , and the width of the third groove 316 is substantially equal to the thickness T of the material layer 306 . Using the method of the present invention, an extremely narrow third trench 316 can be formed in the substrate 300 . In one embodiment, if the substrate 300 is a semiconductor substrate, the method of the present invention can be applied to, for example, shallow trench isolation (shallow trench isolation, STI), non-planar transistors such as fin transistors (Fin-FET) or multi-gate transistors. (multigate FET), etc.; in another embodiment, if the substrate 300 includes a low dielectric constant layer, the third trench 316 can be used to form a metal interconnection system such as dual damascene and other manufacturing processes, but not with The above is limited.

Please refer to FIG. 8 , which is a schematic diagram of a second embodiment of a method for forming a trench in a substrate according to the present invention. After performing the manufacturing process in FIG. 5, as shown in FIG. A fourth trench 318 is formed in the second trench 310 . Subsequently, an etching process is performed to transfer the pattern of the fourth trench 318 to the substrate 300 to form a narrower trench pattern.

Please refer to FIG. 9 and FIG. 10 , which are schematic diagrams of a third embodiment of a method for forming trenches in a substrate according to the present invention. As shown in FIG. 9, the difference between this embodiment and the first embodiment is that, before forming the first patterned mask layer 302, a third mask layer 312 can also be fully formed on the substrate 300, and then as shown in FIG. 10 As shown, the pattern of the second groove 310 is transferred into the third mask layer 312 to form a third patterned mask layer 313 . In detail, in FIG. 9, a dry etching process is performed first, and the first patterned mask layer 302 and the second patterned mask layer 309 are used as masks to deepen the depth of the second trench 310 to the third mask. In the mold layer 312 , a fifth groove 320 is formed in the third mask layer 312 , and then the first patterned mask layer 302 , the second patterned mask layer 309 and the substance layer 306 are removed. Finally, an etching process is performed using the third patterned mask layer 313 as a mask to etch the substrate 300 , and the structure with the third groove 316 in the substrate 300 as shown in FIG. 7 can also be obtained.

It should be noted that the third patterned mask layer 313 may include various hard mask materials, such as silicon nitride, silicon oxynitride, silicon carbide, or advanced patterned films provided by Applied Materials. In an embodiment of the present invention, the third patterned mask layer 313 may have the same multi-layer structure as the first patterned mask layer 302, such as a phosphosilicate glass layer plus silicon nitride on it. layer. If the third patterned mask layer 313 is a single-layer film structure, preferably, there will be a layer between the third patterned mask layer 313 and the first patterned mask layer 302 and the second patterned mask layer 309. Etching selectivity, wherein the materials of the first patterned mask layer 302 and the second patterned mask layer 309 can be the same or different. In an embodiment of the present invention, the third patterned mask layer 313 is, for example, an advanced patterned film, the first patterned mask layer 302 is, for example, a silicon nitride layer, and the second patterned mask layer 309 is, for example, A photoresist layer, and the substance layer 306 is, for example, a borophosphosilicate glass layer.

In another embodiment of the present invention, this embodiment can also be combined with the steps of the second embodiment. As shown in FIG. A narrower trench structure is formed in the substrate 300 . Alternatively, in another embodiment of the present invention, after FIG. 11 , the third patterned mask layer 313 can also be removed to keep the second spacer 314, and then etching is performed using the second spacer 314 as a mask. The fabrication process removes part of the substrate 300 . In this way, a very narrow line pattern (line pattern) 315 can be formed in the substrate 300 . The linear pattern 315 can be used to form a gate of a planar transistor or a fin structure of a non-planar transistor.

Please refer to FIG. 13 to FIG. 17 , which are schematic diagrams of a fourth embodiment of a method for forming a trench in a substrate according to the present invention. The characteristic of the fourth embodiment is that the mask layer is multi-layered, which can better ensure the accuracy of the etching process. As shown in Figure 13, the first patterned mask layer 302 includes a bottom first patterned mask layer 302a and a top first patterned mask layer 302b; the third mask layer 312 includes a bottom third mask layer 312a and a third mask layer 312b. In an embodiment of the present invention, the bottom first patterned mask layer 302a and the bottom third mask layer 312a comprise the same material, such as a silicon oxide layer; and the top first patterned mask layer 302b and the top third mask layer The mask layer 312b includes the same material, such as silicon nitride; the second mask layer 308 is, for example, a photoresist layer or an organic molecular layer; the material layer 306 is, for example, a borophosphosilicate glass layer.

Next, as shown in FIG. 14 , a planarization process, such as an etch-back process, is performed to remove the second mask layer 308 outside the first trench 304, leaving only the second mask layer in the first trench 304. mold layer 308 to form a second patterned mask layer 309 . Due to the etching selectivity between the second mask layer 308 and the substance layer 306 , the etching process will not remove the substance layer 306 . In one embodiment, if the material of the second mask layer 308 is a photoresist layer or an organic molecular layer, the etching back may use an etching gas containing CHF ₃ /O ₂ .

As shown in FIG. 15, a dry etching process is performed using the top first patterned mask layer 302b and the second patterned mask layer 309 as a mask to remove the sidewall 304b of the first trench 304 and the first trench 304. The substance layer 306 on the mask layer 302 is patterned, while the substance layer 306 between the substrate 300 and the second patterned mask layer 309 remains. In one embodiment, if the material layer 306 is a borophosphosilicate glass layer, the dry etching process may use a gas containing CF ₄ /O ₂ or C ₄ F ₈ /O ₂ .

As shown in FIG. 16 , a dry etching process is performed using the second patterned mask layer 309 as a mask to remove the top first patterned mask layer 302 b and part of the top third mask layer 312 b. Since the top first patterned mask layer 302b and the top third mask layer 312b use the same material, such as silicon nitride, and the bottom first patterned mask layer 302a and the bottom third mask layer 312a use the same material, For example, it is a silicon oxide layer, and there is an etching selectivity between the two, so the etching process will use the bottom first patterned mask layer 302a and the bottom third mask layer 312a as the etching stop layer. In one embodiment, the etching process may use a gas comprising CF ₄ /O ₂ or C ₄ F ₈ /O ₂ .

As shown in FIG. 17 , an etching process is performed using the second patterned mask layer 309 as a mask to remove the bottom first patterned mask layer 302 a and part of the bottom third mask layer 312 a . Since the bottom first patterned mask layer 302 a and the bottom third mask layer 312 a are made of the same material, the etching process will stop on the top third mask layer 312 b and the substrate 300 . In one embodiment, the etching process may use a gas including CH ₃ F/O ₂ or CH ₂ F ₂ /O ₂ .

Finally, the substrate 300 is etched using the top third mask layer 312b and the second patterned mask layer 309 as masks, and the trench structure as shown in FIG. 7 can also be formed. In an embodiment of the present invention, if the substrate 300 is a silicon substrate, the etching process may use a gas comprising Cl ₂ /He, HBr/He or Cl ₂ /HBr/He. In this embodiment, due to the use of a multi-layer mask layer structure, the etching selectivity between different materials can be utilized during etching, and the bottom first patterned mask layer 302a and the bottom third mask layer 312a As an etching stop layer, the accuracy of the etching process can be increased. Likewise, the fourth embodiment can be combined with the implementation aspects of the aforementioned second embodiment to the third embodiment, which will not be repeated here.

Please refer to FIG. 18 to FIG. 20 , which are schematic diagrams of a fifth embodiment of a method for forming a trench in a substrate according to the present invention. The preceding steps of the fifth embodiment are the same as those shown in Fig. 1 and Fig. 2 in the first embodiment, and will not be repeated here. After forming the substance layer 306 as shown in FIG. 2 , as shown in FIG. 18 , a dry etching process is performed to remove the substance layer 306 on the first patterned mask layer 302 and the bottom surface 304 a of the first trench 304 , and Only the substance layer 306 of the sidewall 304b of the first trench 304 remains.

Next, as shown in FIG. 19 , a second patterned mask layer 309 is formed to at least fill up the first trench 304 . The method for forming the second patterned mask layer 309 is, for example, to firstly form a second mask layer (not shown) on the substrate 300, and then perform an etch-back process or a planarization process, so that the first trench A second patterned mask layer 309 is formed in the groove 304 , wherein the second patterned mask layer 309 may be equal to or slightly lower than the first patterned mask layer 302 , so as to expose the top surface of the substance layer 306 as a principle.

Finally, as shown in FIG. 20 , all the substance layer 306 on the substrate 300 is removed, so that a second groove 310 is formed between the first patterned mask layer 302 and the second patterned mask layer 309 , and the second groove The width of 310 is substantially equal to the thickness T of the layer of substance 306 . Subsequently, according to the steps of the first embodiment, a dry etching process can be performed using the first patterned mask layer 302 and the second patterned mask layer 309 as masks to form an extremely narrow third Groove 316, as shown in FIG. 7 . This embodiment can also form a spacer in the second trench 310 as in the second embodiment, so as to form a narrower trench structure in the substrate 300 . Alternatively, as in the steps of the third embodiment, a third mask layer 312 is first formed between the first patterned mask layer 302 and the substrate 300, and then the pattern of the second groove 310 is transferred to the third mask layer 312 , an etching process is performed using the third patterned mask layer 313 as a mask, and the pattern of the third patterned mask layer 313 is transferred to the substrate 300 . Next, the fabrication process shown in FIG. 11 and FIG. 12 can be used to form a very narrow linear pattern structure in the substrate 300 by using the spacer as a mask.

It should be noted that in this embodiment, the first patterned mask layer 302 and the material layer 306 must have an etch selectivity ratio, while the first patterned mask layer 302 and the second patterned mask layer 309 The materials may be the same or different. In one embodiment, the third patterned mask layer 313 is, for example, an advanced patterned film, the first patterned mask layer 302 is, for example, a silicon nitride layer, and the second patterned mask layer 309 is, for example, a photoresist etchant layer, and the substance layer 306 is, for example, a borophosphosilicate glass layer.

In summary, the method for forming trenches proposed by the present invention is characterized in that a material layer is conformally formed in the first trench, and then the first trench is filled with a second patterned mask layer, and finally the first trench is removed. The material layer on the sidewall of the first groove forms a second groove whose width is substantially equal to the thickness of the material layer. Utilizing the method provided by the invention, a trench with extremely narrow width can be obtained in the substrate.

The above descriptions are only preferred embodiments of the present invention, and all equivalent changes and modifications made according to the claims of the present invention shall fall within the scope of the present invention.

Claims (26)

1. method that forms groove in substrate comprises:

One substrate is provided;

Form one first patterned mask layer at this substrate, this first patterned mask layer has one first groove;

Form a material layer on this substrate, this material layer conformally forms along a bottom surface and at least one sidewall of this first groove comprehensively;

Form one second patterned mask layer at this material layer, this second patterned mask layer is filled up this first groove;

Remove this material layer of part, and keep this material layer between this second patterned mask layer and this substrate, so that form at least one the second groove between this first patterned mask layer and this second patterned mask layer; And

After forming this second groove, carry out an etching process take this first patterned mask layer and this second patterned mask layer as mask.

2. the method that forms groove in substrate as claimed in claim 1, wherein this etching process is to remove this substrate that the second groove exposes, to form one the 3rd groove in this substrate.

3. the method that in substrate, forms groove as claimed in claim 1, form this second groove after, also comprise:

Sidewall at this second groove forms at least one the second clearance wall, to form one the 4th groove in the second groove; And

Remove this substrate that the 4th groove exposes.

4. the method that forms groove in substrate as claimed in claim 1 wherein has etching selectivity between this second patterned mask layer and this material layer.

5. the method that forms groove in substrate as claimed in claim 1 wherein before forming this first patterned mask layer, also comprises: form one the 3rd mask layer on this substrate comprehensively.

6. the method that in substrate, forms groove as claimed in claim 5, wherein this etching process can remove the 3rd mask layer that this second groove exposes, and forming one the 3rd patterned mask layer, and the 3rd patterned mask layer has one the 5th groove.

7. the method that in substrate, forms groove as claimed in claim 6, form the 3rd patterned mask layer after, also comprise: take the 3rd patterned mask layer as mask, this substrate that is exposed to remove the 5th groove.

8. the method that in substrate, forms groove as claimed in claim 6, form the 3rd patterned mask layer after, also comprise:

At least one sidewall at the 5th groove forms one the 5th clearance wall, to form one the 6th groove in the 5th groove.

9. the method that forms groove in substrate as claimed in claim 8 also comprises and removes this substrate that the 6th groove exposes.

10. the method that forms groove in substrate as claimed in claim 8 also comprises:

Remove the 3rd patterned mask layer; And

Come the etching substrate take the 5th clearance wall as mask.

11. the method that forms groove in substrate as claimed in claim 6 wherein has etching selectivity between the 3rd patterned mask layer and this first patterned mask layer and this second patterned mask layer.

12. the method that forms groove in substrate as claimed in claim 1, the step that wherein forms this second patterned mask layer comprises:

Form one second mask layer on this material layer, this second mask layer can fill up this first groove comprehensively; And

Remove this second mask layer that is positioned at beyond this first groove, to form this second patterned mask layer.

13. the method that forms groove in substrate as claimed in claim 1, wherein this first patterned mask layer is identical with the material of this second patterned mask layer.

14. a method that forms groove in substrate comprises:

One substrate is provided;

Form one first patterned mask layer at this substrate, this first patterned mask layer has one first groove, and this first groove has a bottom surface and at least one sidewall;

This sidewall at this first groove forms a material layer;

Form one second patterned mask layer, to fill up this first groove;

Remove this whole material layer on this substrate, so that form one second groove between this first patterned mask layer and this second patterned mask layer; And

After forming this second groove, carry out an etching process take this first patterned mask layer and this second patterned mask layer as mask.

15. the method that forms groove in substrate as claimed in claim 14, wherein this etching process is to remove this substrate that the second groove exposes, to form one the 3rd groove in this substrate.

16. the method that in substrate, forms groove as claimed in claim 14, form this second groove after, also comprise:

This sidewall at this second groove forms one second clearance wall, to form one the 4th groove in the second groove; And

Remove this substrate that the 4th groove exposes.

17. the method that forms groove in substrate as claimed in claim 14 wherein has etching selectivity between this first patterned mask layer and this material layer.

18. the method that forms groove in substrate as claimed in claim 14 wherein before forming this first patterned mask layer, also comprises: on this substrate, form one the 3rd mask layer comprehensively.

19. the method that forms groove in substrate as claimed in claim 18, wherein this etching process can remove the 3rd mask layer that this second groove exposes, and to form one the 3rd patterned mask layer, the 3rd patterned mask layer has one the 5th groove.

20. the method that in substrate, forms groove as claimed in claim 19, form the 3rd patterned mask layer after, also comprise: take the 3rd patterned mask layer as mask, this substrate that is exposed to remove the 5th groove.

21. the method that in substrate, forms groove as claimed in claim 19, form the 3rd patterned mask layer after, also comprise:

This sidewall at the 5th groove forms one the 5th clearance wall, to form one the 6th groove in the 5th groove.

22. the method that forms groove in substrate as claimed in claim 21 also comprises and removes this substrate that the 6th groove exposes.

23. the method that forms groove in substrate as claimed in claim 21 also comprises:

Remove the 3rd patterned mask layer; And

Come the etching substrate take the 5th clearance wall as mask.

24. the method that forms groove in substrate as claimed in claim 19 wherein has etching selectivity between the 3rd patterned mask layer and this first patterned mask layer and this second patterned mask layer.

25. the method that forms groove in substrate as claimed in claim 14 wherein comprises in the step that this sidewall of this first groove forms this material layer:

Form a material layer on this substrate, this material layer conformally forms along a bottom surface and at least one sidewall of this first groove comprehensively; And

Remove this material layer of part, and only keep this material layer on this sidewall that is positioned at this first groove.

26. the method that forms groove in substrate as claimed in claim 14, wherein this first patterned mask layer is identical with the material of this second patterned mask layer.

Images