A small line width circular or elliptical device with controllable shape and a method for manufacturing the same
By employing a two-stage etching process and a vertical cross-sidewall technique, the linewidth of small-sized patterns is controlled, solving the problems of pattern uniformity and integrity in photolithography and enabling the fabrication of small-sized devices.
Patent Information
- Application Number
- CN202111452105.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2021-12-01
- Publication Date
- 2026-01-06
- Estimated Expiration
- 2041-12-01
AI Technical Summary
In existing photolithography technology, it is difficult to effectively control the linewidth of small-sized patterns while maintaining the uniformity and integrity of the patterns in subsequent processes, especially without increasing the cost of wafer fabrication.
Two perpendicularly intersecting sidewalls are used as hard masks. Through two etching processes, small-linewidth circular or elliptical devices are formed. Polysilicon is used as an auxiliary patterning layer, and the shape and position of the device are controlled by adjusting the width and position of the sidewalls.
It achieves uniformity and integrity of small linewidth patterns, avoids dependence on overlay accuracy, and meets the process requirements of small-sized devices.
Smart Images
Figure CN114420546B_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of integrated circuit semiconductor manufacturing technology, and in particular to a method for fabricating small-sized patterned devices. Background Technology
[0002] With the development of the integrated circuit industry and the continuous shrinking of process dimensions, the demand for even smaller devices and patterns (tens of nanometers or even smaller) is increasing. This places increasingly higher demands on lithography machines. Whether it's immersion lithography machines or ASML's latest lithography machines, the cost of lithography machines is very high, which in turn increases the tape-out cost of small-linewidth device patterns. Therefore, being able to produce small-sized patterns and devices without increasing existing tape-out costs is a very meaningful endeavor.
[0003] This has also led to many ideas for solving this problem. For example, some methods use the overlay precision of the lithography machine to achieve small linewidths. However, this method requires very high overlay precision from the lithography machine, and the overlay precision cannot reach 100%, which affects the uniformity of the target pattern. Other methods involve separating the pattern into two patterns and fabricating them through a double exposure + double etching (LELE) process or by using photolithography freeze followed by photolithography etching (LPLE). However, this method also requires high overlay precision, which will affect the symmetry and uniformity of the pattern.
[0004] Therefore, under the current conditions of photolithography technology, how to directly and effectively control the linewidth of small-sized patterns while maintaining the uniformity and integrity of the patterns in subsequent processes is a problem faced by many small-sized pattern designers. Summary of the Invention
[0005] To overcome the above problems, the present invention aims to provide a method for fabricating small linewidth devices that can effectively control the shape, and the fabrication method can maintain the uniformity and integrity of the pattern in subsequent processes.
[0006] To achieve the above objectives, the present invention provides a method for fabricating a small-linewidth circular or elliptical device with controllable shape, comprising the following steps:
[0007] A substrate material layer is provided, and a layer of the required material is epitaxially formed on the surface of the substrate material layer as the target layer to be etched.
[0008] The first etching process is performed on the target layer to form the first target layer:
[0009] An auxiliary pattern layer is deposited on the target layer to be etched, and the excess portion of the auxiliary pattern layer is removed by photolithography to form the first auxiliary pattern layer.
[0010] A first barrier layer is deposited on the surface of the first auxiliary patterning layer and the target layer to be etched that is not covered by the first auxiliary patterning layer;
[0011] The first barrier layer in the horizontal direction is removed by an etching process, leaving only the first barrier layer in the vertical direction on both sides of the first auxiliary pattern layer.
[0012] The first auxiliary graphic layer is removed by erosion, leaving the first barrier layers in the vertical direction on both sides as the first sidewall layers;
[0013] Using the first sidewall layer as a hard mask, etching is performed to remove excess target layers to be etched on the substrate, leaving only the target layers to be etched below the first sidewall layer.
[0014] The first sidewall layer is etched away, and the target layer to be etched left on the substrate is used as the first target layer;
[0015] The first target layer is etched a second time to form the second target layer:
[0016] A second auxiliary pattern layer is formed by redepositing an auxiliary pattern layer on the surface of the substrate material layer and the first target layer, and then removing the excess portion of the auxiliary pattern layer by photolithography.
[0017] A second barrier layer is deposited on the surface of the second auxiliary patterning layer and the surface of the first target layer not covered by the second auxiliary patterning layer;
[0018] The excess second barrier layer in the horizontal direction is removed by an etching process, leaving only the second barrier layer in the vertical direction on both sides of the second auxiliary pattern layer.
[0019] The second auxiliary graphic layer is removed by erosion, leaving the second barrier layers in the vertical direction on both sides as the second sidewall layers;
[0020] The second sidewall layer is used as a hard mask for etching to remove the excess first target layer on the substrate, leaving only the first target layer below the second sidewall layer.
[0021] The second sidewall layer is etched away, leaving the first target layer on the substrate as the second target layer;
[0022] After the secondary etching process, the second target layer on the substrate is etched to remove excess edges and corners, ultimately forming a small linewidth circular or elliptical device.
[0023] As a further preferred option, the target layer to be etched is a metallic material.
[0024] As a further preferred option, both the first and second auxiliary patterning layers are polycrystalline silicon.
[0025] As a further preferred option, the first and second barrier layers may be silicon oxide or silicon nitride.
[0026] As a further preferred option, the organic base used to etch the first and second auxiliary pattern layers is a tetramethylammonium hydroxide solution.
[0027] As a further preferred embodiment, the formed second auxiliary graphic layer and the second sidewall layer are both perpendicular to the first target layer and form a 90° angle with each other.
[0028] As a further preferred embodiment, the formed second sidewall layer is perpendicular to the first target layer, forming a 90° angle.
[0029] As a further preferred option, the solution used to corrode the first and second sidewall layers is a KOH solution.
[0030] As a further preferred option, the size, shape, and position of the final small-linewidth circular or elliptical device can be controlled by adjusting the width and position of the first and second sidewall layers.
[0031] As a further preferred embodiment, the width and position of the first and second sidewall layers can be controlled by adjusting the shape of the first and second auxiliary graphic layers and the thickness of the barrier layer deposited on their surfaces.
[0032] The controllable shape small linewidth circular or elliptical device is prepared by the method described above.
[0033] This invention employs two perpendicularly intersecting sidewalls as a hard mask, and through a two-stage etching process, ultimately obtains a small-linewidth circular or elliptical device after subsequent processing. The resulting pattern exhibits good uniformity and high integrity, is not limited by overlay precision, and allows for control of the circular or elliptical linewidth shape by varying the dimensions of different sidewalls. Furthermore, this method largely meets the process requirements of most manufacturers producing small-sized devices and is therefore worthy of widespread adoption. Attached Figure Description
[0034] Figure 1 These are the front view (left) and top view (right) after the first auxiliary graphic layer is formed;
[0035] Figure 2 These are front view (left) and top view (right) schematic diagrams after the formation of the first barrier layer;
[0036] Figure 3 These are the front view (left) and top view (right) after the first sidewall layer has been formed;
[0037] Figure 4 These are the front view (left) and top view (right) after removing the first auxiliary graphic layer;
[0038] Figure 5 These are the front view (left) and top view (right) after the first target layer is formed;
[0039] Figure 6 These are the front view (left) and top view (right) after removing the first side wall layer;
[0040] Figure 7 These are the front view (left) and top view (right) after the auxiliary graphics have been regrown;
[0041] Figure 8 These are the left view (left) and top view (right) after the second auxiliary graphic layer is formed;
[0042] Figure 9 These are the front view (left) and top view (right) after the second barrier layer has been formed;
[0043] Figure 10 These are the front view (left) and top view (right) after the second side wall layer has been formed;
[0044] Figure 11 These are the front view (left) and top view (right) after removing the second auxiliary graphic layer;
[0045] Figure 12 These are the front view (left) and top view (right) after the second target layer is formed;
[0046] Figure 13 These are the front view (left) and top view (right) after removing the second side wall layer;
[0047] Figure 14 This is a schematic diagram of the device morphology after post-processing.
[0048] In the figure, 1 - substrate material layer, 2 - target layer to be etched, 21 - first target layer, 22 - second target layer, 3 - auxiliary pattern layer to be etched, 31 - first auxiliary pattern layer, 32 - second auxiliary pattern layer, 41 - first barrier layer, 42 - second barrier layer, 411 - first sidewall layer, 421 - second sidewall layer. Detailed Implementation
[0049] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings.
[0050] In the description of this invention, it should be understood that the terms "upper", "lower", "front", "rear", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.
[0051] The terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. Specific Implementation Example 1
[0053] A layer of the required material is epitaxially formed on the surface of the provided substrate material layer 1 as the target layer to be etched. Specifically, in this embodiment, the target layer to be etched is a metal material.
[0054] The target layer is subjected to the first etching process to form the first target layer 21:
[0055] An auxiliary patterning layer is deposited on the target layer 2 to be etched. The material used for the auxiliary patterning layer is polycrystalline silicon.
[0056] Combination Figure 1 As shown, the auxiliary pattern layer is photolithographically removed using a tetramethylammonium hydroxide solution, leaving the required portion of the auxiliary pattern layer as the first auxiliary pattern layer 31. The shape of the first auxiliary pattern layer 31 is then adjusted.
[0057] Combination Figure 2 As shown, a first barrier layer 41 is deposited on the surface of the first auxiliary patterning layer 31 and the surface of the target layer 2 to be etched that is not covered by the first auxiliary patterning layer 31. The material used for the first barrier layer 41 can be silicon oxide or silicon nitride.
[0058] Combination Figure 3 As shown, a dry etching process is used to remove the first auxiliary pattern layer 31 in the horizontal direction and the first barrier layer 41 on the surface of the target layer 2 to be etched that is not covered by the first auxiliary pattern layer 31, leaving only the first barrier layer 41 in the vertical direction on both sides of the first auxiliary pattern layer 31.
[0059] Combination Figure 4 As shown, the first auxiliary pattern layer 31 is etched away with an organic base tetramethylammonium hydroxide solution, leaving the first barrier layer 41 in the vertical direction on both sides as the first sidewall layer 411; the tetramethylammonium hydroxide solution used in this process only etches the auxiliary pattern layer, and does not etch the first barrier layer 41 in the vertical direction.
[0060] Combination Figure 5 As shown, the first sidewall layer 411 is used as a hard mask for etching to remove the excess target layer 2 to be etched on the substrate, leaving only the target layer 2 to be etched below the first sidewall layer 411.
[0061] Combination Figure 6As shown, the first sidewall layer 411 is removed by etching with alkaline liquid KOH solution, leaving the target layer 2 to be etched on the substrate as the first target layer 21. Since the sidewall layer and the target layer materials have high selectivity to KOH solution, only the first sidewall layer 411 will be etched in this etching process, and the first target layer 21 will not be etched at the same time.
[0062] During the first etching process, the position of the first target layer 21 on the substrate material layer can be controlled by adjusting the shape and position of the first auxiliary pattern layer 31; the width of the first target layer 21 can be controlled by adjusting the thickness of the deposited first barrier layer 41.
[0063] The first target layer 21 is etched a second time to form the second target layer 22:
[0064] Combination Figure 7 As shown, a new auxiliary patterning layer 3 to be etched is deposited on the surface of the substrate material layer 1 and the first target layer 21. The material of the auxiliary patterning layer to be etched is also polycrystalline silicon.
[0065] Combination Figure 8 As shown, the excess portion of the auxiliary pattern layer is removed by photolithography using tetramethylammonium hydroxide solution to form a second auxiliary pattern layer; the second auxiliary pattern layer 32 formed in this process is perpendicular to the first target layer 21 formed after the first etching process, forming a 90° angle.
[0066] Combination Figure 9 As shown, a second barrier layer 42 is deposited on the surface of the second auxiliary patterning layer 32 and the surface of the first target layer 21 not covered by the second auxiliary patterning layer 32. The material used for the second barrier layer can be silicon oxide or silicon nitride.
[0067] Combination Figure 10 As shown, a dry etching process is used to remove the excess second auxiliary pattern layer 32 in the horizontal direction, leaving only the second barrier layer 42 in the vertical direction on both sides of the second auxiliary pattern layer 31.
[0068] Combination Figure 11 As shown, the second auxiliary pattern layer 32 is etched away with an organic base tetramethylammonium hydroxide solution, leaving two vertically oriented second barrier layers 42 as the second sidewall layers 421. The tetramethylammonium hydroxide solution used in this process only etches the auxiliary pattern layer and does not etch the vertically oriented second barrier layer 42. The formed second sidewall layer 42 forms a 90° angle with the first target layer 21.
[0069] Combination Figure 12 As shown, the second sidewall layer 421 is used as a hard mask for etching to remove the excess first target layer 21 on the substrate, leaving only the first target layer 21 below the second sidewall layer 421.
[0070] Combination Figure 13 As shown, the second sidewall layer 421 is removed by etching with an alkaline liquid KOH solution, leaving a first target layer 21 below the second sidewall layer 421 on the substrate, which serves as the second target layer 22. Since the sidewall layer and target layer materials have a high selectivity ratio to KOH solution, only the second sidewall layer 421 will be etched away during this etching process, and the second target layer 22 will not be etched away at the same time.
[0071] During the second etching process, the position of the second target layer 22 on the substrate material layer can be controlled by adjusting the shape and position of the second auxiliary pattern layer 32; the shape of the second target layer 22 can be controlled by adjusting the thickness of the deposited second barrier layer 42.
[0072] After the aforementioned secondary etching process, combined Figure 14 As shown, the second target layer 22 on the substrate is etched to remove excess edges and corners, ultimately forming a small linewidth circle or ellipse device.
[0073] The above are merely preferred embodiments of the present invention and are not intended to limit the implementation methods and protection scope of the present invention. Those skilled in the art should recognize that any equivalent substitutions and obvious changes made based on the description and illustrations of the present invention should be included within the protection scope of the present invention.
Claims
1. A method for fabricating a controllable shape small line width circular or elliptical device, characterized by, The preparation method comprises the following steps: providing a substrate material layer, epitaxially forming a layer of a material required to be prepared on the surface of the substrate material layer as a target layer to be etched; performing a first etching treatment on the target layer to be etched to form a first target layer; depositing a first auxiliary pattern layer on the target layer to be etched and the surface of the first target layer not covered by the first auxiliary pattern layer, and performing photolithography on the first auxiliary pattern layer to remove the excess part of the first auxiliary pattern layer to form a first auxiliary pattern layer; depositing a first blocking layer on the first auxiliary pattern layer and the surface of the target layer to be etched not covered by the first auxiliary pattern layer; removing the horizontal first blocking layer by etching process, and only keeping the vertical first blocking layer on both sides of the first auxiliary pattern layer; eroding the first auxiliary pattern layer to leave the vertical first blocking layer on both sides as a first side wall layer; performing etching with the first side wall layer as a hard mask to remove the excess target layer to be etched on the substrate, and only keeping the target layer to be etched under the first side wall layer; eroding the first side wall layer to leave the target layer to be etched on the substrate as the first target layer; performing a second etching treatment on the first target layer to form a second target layer; redepositing a target layer to be etched on the surface of the substrate material layer and the first target layer, performing photolithography on the auxiliary pattern layer to remove the excess part of the auxiliary pattern layer to form a second auxiliary pattern layer; depositing a second blocking layer on the second auxiliary pattern layer and the surface of the first target layer not covered by the second auxiliary pattern layer; removing the excess horizontal second blocking layer by etching process, and only keeping the vertical second blocking layer on both sides of the second auxiliary pattern layer; eroding the second auxiliary pattern layer to leave the vertical second blocking layer on both sides as a second side wall layer; performing etching with the second side wall layer as a hard mask to remove the excess first target layer on the substrate, and only keeping the first target layer under the second side wall layer; eroding the second side wall layer to leave the first target layer on the substrate as the second target layer; after the second etching treatment, performing etching on the second target layer on the substrate to remove the excess corner, and finally forming a small-line-width circular or elliptical device; wherein the second side wall layer and the first side wall layer are perpendicularly crossed, and the intersection part of the first side wall layer and the second side wall layer forms the second target layer.
2. The production method according to claim 1, wherein The target layer to be etched is a metal material.
3. The production method according to claim 1, wherein The first auxiliary pattern layer and the second auxiliary pattern layer are polysilicon.
4. The production method according to claim 1, wherein The first blocking layer and the second blocking layer are silicon oxide or silicon nitride.
5. The production method according to claim 1, wherein The organic base used for etching the first auxiliary pattern layer and the second auxiliary pattern layer is tetramethylammonium hydroxide solution.
6. The production method according to claim 1, wherein The second auxiliary pattern layer and the second side wall layer formed are both perpendicular to the first target layer to form a 90° included angle.
7. The production method according to claim 1, wherein The KOH solution is used for etching the first side wall layer and the second side wall layer.
8. The production method according to claim 1, wherein The size, shape and position of the finally formed small-line-width circular or elliptical device are controlled by adjusting the width and position of the first side wall layer and the second side wall layer.
9. The production method according to claim 8, wherein The width and position of the first and second sidewall layers are controlled by adjusting the shape of the first and second auxiliary patterned layers and the thickness of the barrier layer deposited on their surfaces.
10. A shape-controllable small-line-width round or elliptical device, characterized by, Prepared by the process of any one of claims 1 to 9.
Citation Information
Patent Citations
Forming method of multigraph
CN104022022A