Method of manufacturing a trench

Abstract

The application relates to the technical field of semiconductors, in particular to a trench preparation method. The trench preparation method comprises the following steps: providing a substrate, the substrate comprising a first etching area; forming a photoresist layer on the substrate, the photoresist layer covering the upper surface of the substrate; setting an Sbar mark at the position of the photoresist layer corresponding to the first etching area, the width of the Sbar mark being smaller than that of the first etching area; performing photoetching on the Sbar mark and the photoresist layer to obtain a patterned photoresist layer, the patterned photoresist layer being provided with a first opening in the position corresponding to the first etching area, and the first opening being provided with a residual photoresist layer with a preset thickness in the position corresponding to the Sbar mark; and etching the substrate based on the patterned photoresist layer to form a first trench in the substrate, the bottom of the first trench being in a stepped shape. The method sets the Sbar mark at the position of the photoresist layer corresponding to the first etching area, so that different etching depths are generated in the same trench.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of semiconductor technology, in particular to a trench preparation method. BACKGROUND

[0002] When the mask manufacturing pattern is shrunk to below the resolution capability of the photolithography machine, line width unevenness and line breakage problems will occur, so the industry generally adds Sbar (ScatterBar) to increase the resolution capability through the optical proximity correction (OPC) process. Optical proximity correction (OPC) is a process in which the pattern on the mask is projected onto the photoresist through an exposure system. Due to the imperfection of the optical system and the diffraction effect, the pattern on the photoresist and the pattern on the mask are not completely consistent. If these distortions are not corrected, they can greatly change the electrical properties of the circuit produced. Optical proximity effect correction (OPC) is a method of using calculation to correct the pattern on the mask to make the pattern projected onto the photoresist as consistent as possible with the design requirements.

[0003] In the full depletion type silicon-on-insulator (FDSOI) process technology, there is a special case where different etching depths need to be generated in the same trench in addition to increasing the resolution. The existing normal optical proximity correction (OPC) process can add Sbar to improve pattern flatness and error resistance for different main pattern line widths and pitches, but Sbar addition can only produce symmetrical patterns and cannot produce different etching depths in the same trench. SUMMARY

[0004] Therefore, it is necessary to provide a trench preparation method to solve the above technical problems.

[0005] The embodiment of the present application provides a trench preparation method, which comprises the following steps:

[0006] A substrate is provided, and the substrate comprises a first etching area;

[0007] A photoresist layer is formed on the substrate, and the photoresist layer covers the upper surface of the substrate;

[0008] An Sbar mark is arranged at a position corresponding to the first etching area on the photoresist layer, and the width of the Sbar mark is less than the width of the first etching area;

[0009] Photoetching is performed on the Sbar mark and the photoresist layer to obtain a patterned photoresist layer, a first opening is formed in a position corresponding to the first etching area in the patterned photoresist layer, and the first opening has a residual photoresist layer with a preset thickness at a position corresponding to the Sbar mark;

[0010] etching the substrate based on the patterned photoresist layer to form a first trench in the substrate, a bottom of the first trench being stepped.

[0011] In one of the embodiments, the photoetching the Sbar mark and the photoresist layer to obtain the patterned photoresist layer comprises:

[0012] providing a photomask, the photomask having a first light-transmissive pattern therein;

[0013] placing the photomask above the photoresist layer, a normal projection of the first light-transmissive pattern on the photoresist layer being coincident with the first etching region;

[0014] exposing and developing the Sbar mark and the photoresist layer based on the photomask to obtain the patterned photoresist layer.

[0015] In one of the embodiments, the substrate further comprises a second etching region to be etched, the second etching region to be etched being spaced apart from the first etching region to be etched; the Sbar mark is provided at a position of the photoresist layer corresponding to the first etching region to be etched; the Sbar mark is formed at a position of the photoresist layer corresponding to the second etching region to be etched; a residual photoresist layer is formed at a source region; and the substrate is etched based on the patterned photoresist layer to form a first trench in the substrate and a second trench in the substrate.

[0016] In one of the embodiments, the substrate comprises an active region, and the first etching region to be etched and the second etching region to be etched are both located in the active region.

[0017] In one of the embodiments, the material of the Sbar mark is photoresist.

[0018] In one of the embodiments, the thickness of the residual photoresist layer is 10% to 70% of the thickness of the photoresist layer.

[0019] In one of the embodiments, the etching the substrate based on the patterned photoresist layer to form a first trench in the substrate comprises:

[0020] first etching the substrate based on the patterned photoresist layer to remove the residual photoresist layer and form a preset trench in the substrate;

[0021] second etching the substrate based on the patterned photoresist layer to form the first trench in the substrate.

[0022] In one of the embodiments, after the etching the substrate based on the patterned photoresist layer to form a first trench in the substrate, the method further comprises:

[0023] removing the patterned photoresist layer.

[0024] In one embodiment, after the photoetching of the Sbar mark and the photoresist layer, further comprising:

[0025] proximity optical correction of the photoetched photoresist layer to obtain the patterned photoresist layer.

[0026] In one embodiment, before the Sbar mark is set at the position of the photoresist layer corresponding to the first etching area, further comprising:

[0027] forming an optical proximity correction mark on the photoresist layer.

[0028] The method for preparing the trench, providing a substrate, the substrate including a first etching area; forming a photoresist layer on the substrate, the photoresist layer covering the upper surface of the substrate; setting an Sbar mark at the position of the photoresist layer corresponding to the first etching area, the width of the Sbar mark being less than the width of the first etching area; photoetching the Sbar mark and the photoresist layer to obtain a patterned photoresist layer, the patterned photoresist layer having a first opening formed at the position corresponding to the first etching area, and the first opening having a residual photoresist layer of a preset thickness at the position corresponding to the Sbar mark; etching the substrate based on the patterned photoresist layer to form a first trench in the substrate, the bottom of the first trench being in a stepped shape. By setting the Sbar mark at the position of the photoresist layer corresponding to the first etching area, different etching depths in the same trench are achieved. The problem of needing two mask plates to achieve two etching depths in the prior art is solved, and two etching depths are achieved in one exposure and etching process, thus directly saving 50% of the cost. BRIEF DESCRIPTION OF DRAWINGS

[0029] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the drawings needed to be used in the embodiments or the prior art description will be briefly introduced. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative effort.

[0030] Figure 1 An application environment diagram of the trench preparation method in one embodiment;

[0031] Figure 2 A patterned photoresist layer diagram of the trench preparation method in one embodiment;

[0032] Figure 3 A preset trench diagram of the trench preparation method in one embodiment;

[0033] Figure 4 A first trench schematic diagram of a trench preparation method in an embodiment;

[0034] Figure 5 A flowchart schematic diagram of a trench preparation method in an embodiment;

[0035] Figure 6 A patterning photoresist layer flowchart schematic diagram of a trench preparation method in an embodiment;

[0036] Figure 7 A first trench flowchart schematic diagram of a trench preparation method in an embodiment. DETAILED DESCRIPTION

[0037] In order to facilitate the understanding of the present application, the present application will be described in more detail below with reference to the relevant drawings. The drawings show embodiments of the present application. However, the present application can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the disclosure of the present application more thorough and comprehensive.

[0038] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which the present application belongs. The terminology used in the specification of the present application is only for the purpose of describing specific embodiments and is not intended to limit the present application. The term "and / or" used herein includes any and all couplings of one or more relevant listed items.

[0039] It can be understood that the terms "first", "second", etc. used in the present application can be used herein to describe various elements, but these elements are not limited by these terms. These terms are only used to distinguish the first element from another element.

[0040] As Figures 1 to 5 shown, an embodiment of the present application provides a trench preparation method. Taking the trench preparation method applied to the trench preparation method in Figure 1 as an example for illustration, as shown in Figure 5 , the method comprises the following steps:

[0041] S202: providing a substrate 100, the substrate 100 comprising a first to-be-etched region.

[0042] Specifically, the trench preparation device provides a substrate 100 for etching, the substrate 100 is provided with a first to-be-etched region, and the trench preparation device is used to etch a trench in the first to-be-etched region.

[0043] S204: forming a photoresist layer 102 on the substrate 100, the photoresist layer 102 covering the upper surface of the substrate 100.

[0044] Specifically, the trench preparation device provides a substrate 100 for etching, and the substrate 100 is provided with a first etching area. A photoresist layer 102 is formed on the substrate 100, and the photoresist layer 102 covers the upper surface of the substrate 100. The photoresist, also known as a photoresist, is a resist that changes in solubility through irradiation or radiation of ultraviolet light, an electron beam, an ion beam, X-rays, etc., and is used in this embodiment to etch the substrate 100.

[0045] S206: An Sbar mark 104 is arranged on the photoresist layer 102 corresponding to the first etching area, and the width of the Sbar mark 104 is less than the width of the first etching area.

[0046] Specifically, the trench preparation device provides a substrate 100 for etching, and the substrate 100 is provided with a first etching area. A photoresist layer 102 is formed on the substrate 100, and the photoresist layer 102 covers the upper surface of the substrate 100. The trench preparation device arranges an Sbar mark 104 on the photoresist layer 102 corresponding to the first etching area, and the width of the Sbar mark 104 is less than the width of the first etching area.

[0047] S208: The Sbar mark 104 and the photoresist layer 102 are subjected to photolithography to obtain a patterned photoresist layer 102, and the patterned photoresist layer 102 has a first opening formed in the position corresponding to the first etching area. The first opening has a residual photoresist layer 102 with a preset thickness corresponding to the position of the Sbar mark 104.

[0048] Specifically, the trench preparation device arranges an Sbar mark 104 on the photoresist layer 102 corresponding to the first etching area, and the width of the Sbar mark 104 is less than the width of the first etching area. The trench preparation device subjects the Sbar mark 104 and the photoresist layer 102 to photolithography to obtain a patterned photoresist layer 102. The Sbar mark 104 and the photoresist layer 102 in the position corresponding to the first etching area of the patterned photoresist layer 102 are subjected to photolithography to form a first opening. In the first opening, the position corresponding to the Sbar mark 104 has a residual photoresist layer 102 with a preset thickness, because the trench preparation device only etches away the Sbar mark 104.

[0049] S210: The substrate 100 is etched based on the patterned photoresist layer 102 to form a first trench 108 in the substrate 100, and the bottom of the first trench 108 is stepped.

[0050] Specifically, the trench fabrication apparatus photolithographically forms a first opening at the Sbar mark 104 and the photoresist layer 102 within the patterned photoresist layer 102 at the location corresponding to the first etchable area. Within the first opening, at the location corresponding to the Sbar mark 104, since the trench fabrication apparatus only etched away the Sbar mark 104, a residual photoresist layer 102 of a predetermined thickness remains. Based on the patterned photoresist layer 102, the trench fabrication apparatus continues to etch the substrate 100 to form a first trench 108 within the substrate 100. Since the photoresist layer 102 remains at the location corresponding to the Sbar mark 104 within the first opening, the bottom of the first trench 108 is stepped.

[0051] The above-mentioned trench fabrication method involves providing a substrate 100, which includes a first etchable area; forming a photoresist layer 102 on the substrate 100, the photoresist layer 102 covering the upper surface of the substrate 100; setting an Sbar mark 104 at the position of the photoresist layer 102 corresponding to the first etchable area, the width of the Sbar mark 104 being smaller than the width of the first etchable area; performing photolithography on the Sbar mark 104 and the photoresist layer 102 to obtain a patterned photoresist layer 102, a first opening being formed in the patterned photoresist layer 102 at the position corresponding to the first etchable area, and a residual photoresist layer 102 of a predetermined thickness being formed in the first opening at the position corresponding to the Sbar mark 104; and etching the substrate 100 based on the patterned photoresist layer 102 to form a first trench 108 in the substrate 100, the bottom of the first trench 108 being stepped. This method achieves different etching depths within the same trench by setting Sbar markers 104 at the positions corresponding to the first etchable area on the photoresist layer 102. This solves the problem in existing technologies where two corresponding photomasks are required to achieve two etching depths. By achieving two etching depths in a single exposure etching process, it directly saves 50% of the cost.

[0052] like Figure 6 As shown, photolithography is performed on the Sbar mark 104 and the photoresist layer 102 to obtain a patterned photoresist layer 102, including:

[0053] S302: Provides a photomask having a first light-transmitting pattern.

[0054] Specifically, the trench fabrication apparatus provides a photomask containing a first light-transmitting pattern. The photomask, or simply mask, carries the first light-transmitting pattern, through which light transmits the design pattern onto the photoresist.

[0055] S304: Place the photomask above the photoresist layer 102, and the orthogonal projection of the first light-transmitting pattern on the photoresist layer 102 coincides with the first etched area.

[0056] Specifically, the trench preparation device provides a photomask having a first light-transmissive pattern, and places the photomask above the photoresist layer 102 so that the first light-transmissive pattern has a first light-transmissive pattern on the photoresist layer 102. When light is transmitted through the first light-transmissive pattern, the first light-transmissive pattern has a first etching area corresponding to the first light-transmissive pattern.

[0057] S306: Expose and develop the Sbar mark 104 and the photoresist layer 102 based on the photomask to obtain a patterned photoresist layer 102.

[0058] Specifically, the trench preparation device provides a photomask having a first light-transmissive pattern, and places the photomask above the photoresist layer 102 so that the first light-transmissive pattern has a first light-transmissive pattern on the photoresist layer 102. When light is transmitted through the first light-transmissive pattern, the first light-transmissive pattern has a first etching area corresponding to the first light-transmissive pattern.

[0059] In this embodiment, the trench preparation device places the photomask above the photoresist layer 102 so that the first light-transmissive pattern has a first light-transmissive pattern on the photoresist layer 102. Then, expose and develop the Sbar mark 104 and the photoresist layer 102 based on the photomask to obtain a patterned photoresist layer 102. By providing the Sbar mark 104, the photoresist layer 102 at the corresponding position of the Sbar mark 104 in the first etching area is reserved to obtain a patterned photoresist layer 102, and a first trench 108 with a stepped bottom is formed.

[0060] In one embodiment, the substrate 100 further includes a second etching area, and the second etching area has a spacing from the first etching area. The Sbar mark 104 is provided on the photoresist layer 102 corresponding to the first etching area, and the Sbar mark 104 is formed on the photoresist layer 102 corresponding to the second etching area. The patterned photoresist layer 102 further has a second opening, and the second opening has a residual photoresist layer 102 with a predetermined thickness. Based on the patterned photoresist layer 102, the substrate 100 is etched to form the first trench 108 and a second trench in the substrate 100.

[0061] Specifically, the substrate 100 further comprises a second to-be-etched region, and the second to-be-etched region is spaced apart from the first to-be-etched region. The trench preparation device forms the Sbar mark 104 in the photoresist layer 102 corresponding to the second to-be-etched region at the same time of forming the Sbar mark 104 in the photoresist layer 102 corresponding to the first to-be-etched region. The sizes of the two Sbar marks 104 can be the same or different, which is not limited here and can be set according to actual needs. The patterned photoresist layer 102 corresponding to the second to-be-etched region further has a second opening, and the photoresist layer 102 with a preset thickness remains in the second opening. The substrate 100 is etched based on the patterned photoresist layer 102, so as to form the first trench 108 in the substrate 100 and further form a second trench in the substrate 100.

[0062] In the above embodiment, the substrate 100 further comprises a second to-be-etched region, and the trench preparation device forms the Sbar mark 104 in the photoresist layer 102 corresponding to the second to-be-etched region at the same time of forming the Sbar mark 104 in the photoresist layer 102 corresponding to the first to-be-etched region. The trench preparation device uses one mask plate to form two openings at the same time, so as to form the first trench 108 in the substrate 100 and further form a second trench in the substrate 100, thereby improving the work efficiency and saving the cost of the mask plate.

[0063] In one of the embodiments, the substrate 100 comprises an active region, and the first to-be-etched region and the second to-be-etched region are both located in the active region.

[0064] Specifically, the substrate 100 comprises an active region and a field region, wherein the source region, the channel region and the drain region are collectively referred to as the active region, and the region outside the active region is defined as the field region. The sum of the active region and the field region is the entire surface of the substrate 100. In this embodiment, the first to-be-etched region and the second to-be-etched region are both located in the active region.

[0065] In this embodiment, the trench preparation device locates the first to-be-etched region and the second to-be-etched region in the active region to establish a transistor body and form the source, the drain and the gate in the source region. This can meet the special requirements of the full depletion type silicon-on-insulator (FDSOI) and produce different etching depths in the same trench.

[0066] In one of the embodiments, the material of the Sbar mark 104 is photoresist.

[0067] Specifically, the trench fabrication apparatus photolithographically forms a first opening at the Sbar mark 104 and the photoresist layer 102 within the patterned photoresist layer 102 corresponding to the first etchable area. Within the first opening, at the position corresponding to the Sbar mark 104, since the trench fabrication apparatus only etched away the Sbar mark 104, a residual photoresist layer 102 of a predetermined thickness remains. The material of the Sbar mark 104 is photoresist. Based on the patterned photoresist layer 102, the trench fabrication apparatus continues to etch the substrate 100 to form a first trench 108 within the substrate 100. Because a photoresist layer 102 remains at the position corresponding to the Sbar mark 104 within the first opening, the bottom of the first trench 108 is stepped.

[0068] In this embodiment, the trench fabrication apparatus sets an Sbar mark 104 at the position of the first etchable area corresponding to the photoresist layer 102, wherein the material of the Sbar mark 104 is photoresist. During the etching process, the trench fabrication apparatus leaves a photoresist layer 102 at the position corresponding to the Sbar mark 104, thus the bottom of the first trench 108 is stepped.

[0069] In one embodiment, the thickness of the residual photoresist layer 102 is 10% to 70% of the thickness of the photoresist layer 102.

[0070] Specifically, the trench fabrication apparatus sets an Sbar mark 104 at the position of the first etchable area corresponding to the photoresist layer 102. The trench fabrication apparatus forms a first opening at the Sbar mark 104 and the photoresist layer 102 at the position of the patterned photoresist layer 102 corresponding to the first etchable area. At the position of the Sbar mark 104 in the first opening, since the trench fabrication apparatus only etches away the Sbar mark 104, there is a residual photoresist layer 102 with a preset thickness. The thickness of the residual photoresist layer 102 is 10% to 70% of the thickness of the photoresist layer 102.

[0071] In this embodiment, the trench fabrication apparatus makes the thickness of the residual photoresist layer 102 10% to 70% of the thickness of the photoresist layer 102. The residual photoresist layer 102 with a thickness of 10% to 70% makes the bottom of the first trench 108 and the bottom of the second trench step-like.

[0072] like Figure 7 As shown, in one embodiment, etching of the substrate 100 based on the patterned photoresist layer 102 to form a first trench 108 within the substrate 100 includes:

[0073] S402: performing first etching on the substrate 100 based on the patterned photoresist layer 102 to remove the residual photoresist layer 102 and form the preset groove 106 in the substrate 100;

[0074] Specifically, the groove preparation device sets the Sbar mark 104 at the position of the first etching area of the photoresist layer 102, and the Sbar mark 104 and the photoresist layer 102 at the position of the first etching area of the patterned photoresist layer 102 are photoetched to form a first opening. In the first opening, the position of the Sbar mark 104 is etched only to obtain the patterned photoresist layer 102 with the residual photoresist layer 102 of the preset thickness. The groove preparation device performs first etching on the substrate 100 based on the patterned photoresist layer 102 to remove the residual photoresist layer 102 and form the preset groove 106 in the substrate 100 without the residual photoresist layer 102.

[0075] S404: performing second etching on the substrate 100 based on the patterned photoresist layer 102 to form the first groove 108 in the substrate 100.

[0076] Specifically, the groove preparation device performs first etching on the substrate 100 based on the patterned photoresist layer 102 to remove the residual photoresist layer 102 and form the preset groove 106 in the substrate 100 without the residual photoresist layer 102. The groove preparation device continues to perform second etching on the substrate 100 based on the patterned photoresist layer 102 to form the first groove 108 in the substrate 100.

[0077] In this embodiment, the groove preparation device performs first etching on the substrate 100 based on the patterned photoresist layer 102 to remove the residual photoresist layer 102, and then performs second etching on the substrate 100 based on the patterned photoresist layer 102 to form the first groove 108 with a stepped bottom in the substrate 100. This can meet the requirement of different etching depths in the same groove to satisfy the special case of full depletion type silicon-on-insulator (FDSOI).

[0078] In one of the embodiments, after the etching on the substrate 100 based on the patterned photoresist layer 102 to form the first groove 108 in the substrate 100, the patterned photoresist layer 102 is removed.

[0079] Specifically, the groove preparation device performs a first etching on the substrate 100 based on the patterned photoresist layer 102 to remove the residual photoresist layer 102, and then performs a second etching on the substrate 100 based on the patterned photoresist layer 102 to form the first groove 108 with a stepped bottom in the substrate 100. After the first groove 108 is formed in the substrate 100, the groove preparation device removes the patterned photoresist layer 102.

[0080] In this embodiment, after the first groove 108 is formed in the substrate 100, the groove preparation device removes the patterned photoresist layer 102 to ensure that the substrate 100 is clean for the next operation.

[0081] In one specific embodiment, after the photoresist layer 102 and the Sbar mark 104 are subjected to the photolithography, the method further includes: performing proximity optical correction on the photoresist layer 102 after the photolithography to obtain the patterned photoresist layer 102.

[0082] Specifically, the groove preparation device sets the Sbar mark 104 on the position of the first etching area corresponding to the photoresist layer 102, wherein the width of the Sbar mark 104 is smaller than the width of the first etching area. The groove preparation device performs photolithography on the Sbar mark 104 and the photoresist layer 102 to obtain the patterned photoresist layer 102. The proximity optical correction is performed on the photoresist layer 102 after the photolithography to obtain the patterned photoresist layer 102.

[0083] In this embodiment, the proximity optical correction is performed on the photoresist layer 102 after the photolithography, which effectively avoids the problem that the pattern on the mask is not completely consistent with the pattern on the photoresist due to the imperfection of the optical system and the diffraction effect, so as to obtain the patterned photoresist layer 102.

[0084] In one specific embodiment, before the Sbar mark 104 is set on the position of the first etching area corresponding to the photoresist layer 102, the method further includes: forming an optical proximity correction mark on the photoresist layer 102.

[0085] Specifically, the groove preparation device provides the substrate 100 for etching, and sets the first etching area on the substrate 100. The photoresist layer 102 is formed on the substrate 100, and covers the upper surface of the substrate 100. The optical proximity correction mark is formed on the photoresist layer 102.

[0086] In this embodiment, the groove preparation device forms the photoresist layer 102 on the substrate 100, and forms the optical proximity correction mark on the photoresist layer 102 before the Sbar mark 104 is set on the position of the first etching area corresponding to the photoresist layer 102, so that the position of the Sbar mark 104 is more accurate and the accuracy is improved.

[0087] It should be understood that, although steps of the methods of Figures 2-7 The steps in the flowcharts of the methods of Figures 2-7 At least some of the steps in the methods of

[0088] It should be understood that, although steps of the methods of

[0089] The technical features of the above embodiments can be coupled in any manner. To make the description concise, not all possible couplings of the technical features in the above embodiments are described, and as long as the coupling of the technical features does not exist contradictions, it should be considered that the coupling is within the scope of the description.

[0090] The above embodiments only express several implementation ways of the present application, and the description is more specific and detailed, but it should not be understood as a limitation to the patent scope of the application. It should be pointed out that for ordinary skilled in the art, without departing from the concept of the present application, several modifications and improvements can be made, which are all within the protection scope of the present application. Therefore, the protection scope of the patent of the present application should be subject to the appended claims.

Claims

1. A method of manufacturing a trench, characterized by, The trench preparation method comprises the following steps: providing a substrate, the substrate comprising a first etching area; forming a photoresist layer on the substrate, the photoresist layer covering the upper surface of the substrate; setting an Sbar mark at the position of the photoresist layer corresponding to the first etching area, the width of the Sbar mark being smaller than the width of the first etching area; photolithography of the Sbar mark and the photoresist layer to obtain a patterned photoresist layer, the patterned photoresist layer having a first opening formed in the position corresponding to the first etching area, the first opening having a residual photoresist layer with a preset thickness at the position corresponding to the Sbar mark; etching the substrate based on the patterned photoresist layer to form a first trench in the substrate, the bottom of the first trench being in a stepped shape; wherein the etching of the substrate based on the patterned photoresist layer to form a first trench in the substrate comprises: first etching of the substrate based on the patterned photoresist layer to remove the residual photoresist layer and form a preset trench in the substrate; second etching of the substrate based on the patterned photoresist layer to form the first trench in the substrate.

2. The method of claim 1, wherein The photolithography of the Sbar mark and the photoresist layer to obtain a patterned photoresist layer comprises: providing a photomask, the photomask having a first light-transmitting pattern; placing the photomask above the photoresist layer, the first light-transmitting pattern being in a front projection on the photoresist layer and coinciding with the first etching area; exposure and development of the Sbar mark and the photoresist layer based on the photomask to obtain the patterned photoresist layer.

3. The method of claim 1, wherein The substrate further comprises a second etching area, the second etching area having a spacing with the first etching area; the Sbar mark is set on the photoresist layer at the position corresponding to the first etching area at the same time; the Sbar mark is formed on the photoresist layer at the position corresponding to the second etching area; the patterned photoresist layer further has a second opening, the second opening having a residual photoresist layer with a preset thickness; etching the substrate based on the patterned photoresist layer to form a first trench in the substrate at the same time, and further forming a second trench in the substrate.

4. The method of making a trench according to claim 3, wherein, The substrate comprises an active area, the first etching area and the second etching area are both located in the active area.

5. The method of claim 1, wherein The material of the Sbar mark is photoresist.

6. The method of making a trench according to claim 1, wherein, The thickness of the residual photoresist layer is 10% to 70% of the thickness of the photoresist layer.

7. The method of making a trench according to claim 1, wherein, After the etching of the substrate based on the patterned photoresist layer to form a first trench in the substrate, the method further comprises: removing the patterned photoresist layer.

8. The method of producing a groove according to any one of claims 1 to 7, characterized by, After the photolithography of the Sbar mark and the photoresist layer, the method further comprises: proximity optical correction of the photoresist layer after photolithography to obtain the patterned photoresist layer.

9. The method of claim 8, wherein the trench is formed by a method comprising: Before the setting of the Sbar mark at the position of the photoresist layer corresponding to the first etching area, the method further comprises: forming an optical proximity correction mark on the photoresist layer.

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