MANUFACTURING METHOD FOR GRAPHITE SLIDER ARRAYS

Abstract

Provided is a manufacturing method for graphite slider arrays in batches. In this method, a grain structures examination step is added to a process of manufacturing graphite slider arrays, and a subsequent etching step is controlled so that only one horizontal grain boundary exists inside the graphite mesas, and when cleaved, the sliders slide away on the only grain boundary. The slider arrays prepared by this method have uniform easy-slip surfaces and thickness with good consistency.

Claims

1. A manufacturing method for graphite slider array, comprising: in step 1: covering at least photoresist on highly oriented pyrolytic graphite (HOPG); in step 2: patterning the photoresist and retaining a plurality of photoresist mesas; in step 3: etching the HOPG and removing part of the HOPG that is not protected by the photoresist, so as to form a plurality of graphite mesas; and in step 4: removing residual photoresist to obtain the graphite slider array; before the step 1, performing examination on three-dimensional grain structures near surfaces of the HOPG to obtain grain information of polycrystalline structures near the surfaces of the HOPG; and in the step 3, based on the grain information of the polycrystalline structures, controlling the etching process so that each of the plurality of graphite mesas made through the etching process comprise only one horizontal grain boundary layer.

2. The manufacturing method of claim 1, wherein in the step 1, the HOPG is covered by the photoresist with spin-coating.

3. The manufacturing method of claim 1, wherein in the step 2, the average size of each of the plurality of photoresist mesas is 1 m to 30 m, and the average interval between the plurality of photoresist mesas is 1 m to 100 m.

4. The manufacturing method of claim 1, wherein in the step 3, the etching is reactive ion etching (RIE).

5. The manufacturing method of claim 1, wherein the examination is electron backscatter diffraction (EBSD), X-ray scattering, and/or ellipsometry.

6. The manufacturing method of claim 1, wherein the grain information includes a grain thickness, a grain length and a grain width.

7. The manufacturing method of claim 6, wherein etching time is controlled to make an etching depth greater than the thickness of the grain of the outermost layer of graphite and less than a distance from the outermost layer of the graphite to a bottom of a second grain of the graphite.

8. The manufacturing method of claim 1, wherein each of the plurality of graphite mesas is covered by a connection layer (9) on a top of the each graphite mesa.

9. The manufacturing method of claim 8, wherein the connection layer (8) is deposited on the HOPG by a plasma chemical vapor deposition (CVD) method to form the connection layer (9) on the top of the each graphite mesa.

10. The manufacturing method of claim 9, wherein a material of the connection layer (8) is SiO2, and a thickness of the connection layer (8) is 50 nm to 500 nm.

11. A manufacturing method for graphite slider array, comprising: in step 1: covering at least photoresist on graphite; in step 2: patterning the photoresist and retaining a plurality of photoresist mesas; in step 3: etching the graphite and removing part of the graphite that is not protected by the photoresist, so as to form a plurality of graphite mesas; and in step 4: removing residual photoresist to obtain the graphite slider array; before the step 1, growing a single crystal graphite or a poly crystal graphite on a substrate, in a case where the single crystal graphite is grown on the substrate, performing examination on the single crystal graphite to detect a flatness of the single crystal graphite; in a case where the poly crystal graphite is grown on the substrate, performing examination on three-dimensional grain structures near surfaces of the poly crystal graphite to obtain grain information of polycrystalline structures near the surfaces of the poly crystal graphite; and in the step 3, based on the grain information of the polycrystalline structures, controlling the etching process so that each of the plurality of graphite mesas comprises only one horizontal grain boundary layer.

12. The manufacturing method of claim 11, wherein in the step 1, the substrate is covered by the photoresist with spin-coating.

13. The manufacturing method of claim 11, wherein in the step 2, the average size of each of the plurality of photoresist mesas is 1 m to 30 m, and the average interval between the plurality of photoresist mesas is 1 m to 100 m.

14. The manufacturing method of claim 11, wherein in the step 3, the etching is reactive ion etching (RIE).

15. The manufacturing method of claim 11, wherein the examination is electron backscatter diffraction (EBSD), X-ray scattering, and/or ellipsometry.

16. The manufacturing method of claim 11, wherein the grain information includes a grain thickness, a grain length and a grain width.

17. The manufacturing method of claim 16, wherein etching time is controlled to make an etching depth greater than the thickness of the grain of an outermost layer of graphite and less than the distance from the outermost layer of the graphite to a bottom of a second grain of the graphite.

18. The manufacturing method of claim 11, wherein each of the plurality of graphite mesas is covered by a connection layer (9) on a top of the each graphite mesa.

19. The manufacturing method of claim 18, wherein the connection layer (8) is deposited on the HOPG by a plasma chemical vapor deposition (CVD) method to form the connection layer (9) on the top of the each graphite mesa.

20. A manufacturing method for graphite slider array, comprising: in step 1: covering at least photoresist on a single crystal graphite with large size; in step 2: patterning the photoresist and retaining a plurality of photoresist mesas; in step 3: etching the single crystal graphite and removing part of the single crystal graphite that is not protected by the photoresist, so as to form a plurality of graphite mesas; and in step 4: removing residual photoresist to obtain the graphite slider array; before the step 1, performing examination on three-dimensional grain structures near surfaces of the single crystal graphite to obtain grain information of polycrystalline structures near the surfaces of the single crystal graphite; and in the step 3, based on the grain information of the polycrystalline structures, controlling the etching process so that each of a plurality of graphite mesas comprise only one horizontal grain boundary layer.

Description

BRIEF DESCRIPTION OF DRAWINGS

[0026] FIG. 1 is a schematic diagram of typical expected results for non-destructive three-dimensional examination of HOPG according to the present disclosure;

[0027] FIG. 2 is a schematic diagram of a sample after the photoresist is spin-coated and patterned according to the present disclosure;

[0028] FIG. 3 is a schematic diagram of a sample after a substrate is etched so as to form a graphite mesa array according to the present disclosure;

[0029] FIG. 4 is a schematic diagram illustrating that after residual photoresist is removed, a graphite slider array in a finished sample has uniform easy-slip surfaces and thickness according to the present disclosure;

[0030] FIG. 5 is a schematic diagram of a sample with a connection layer after the photoresist is spin-coated and patterned according to the present disclosure;

[0031] FIG. 6 is a schematic diagram of a sample after the connection layer and the substrate are etched so as to form a graphite mesa array according to the present disclosure;

[0032] FIG. 7 is a schematic diagram of a finished sample with a connection layer according to the present disclosure.

REFERENCE LIST

[0033] 1 longitudinal grain boundaries extending from the graphite surfaces to the interior [0034] 2 horizontal grain boundaries inside the graphite [0035] 3 single crystal region with a relative large area [0036] 4 patterned photoresist [0037] 5 slip interface in the graphite mesa [0038] 6 graphite mesa substrate [0039] 7 graphite slider [0040] 8 connection layer [0041] 9 connection layer on the top of the graphite mesa

DETAILED DESCRIPTION

[0042] A manufacturing method for graphite sliders in the present disclosure is described in detail below with reference to the drawings.

[0043] In the step 1, a HOPG is selected which has relatively flat surfaces and layered structures and has single crystal grains with a large size and a large thickness.

[0044] Optionally, the single crystal graphite or the poly crystal graphite with a relatively high flatness may also be selected. The single crystal graphite or the poly crystal graphite is self-grown and is non-standardized.

[0045] In the step 2, through non-destructive examination on three-dimensional grain structures near surfaces of the HOPG, information of polycrystalline structures near the surfaces of the HOPG is obtained. The non-destructive examination method could be, for example, EBSD, X-ray scattering, ellipsometry, and the like. An example of expected measurement results is shown in FIG. 1. Highly oriented graphite has polycrystalline mosaic-like structures similar to bricks and includes several longitudinal grain boundaries 1 extending from graphite surfaces to the interior and several horizontal grain boundaries 2 inside the graphite. Positions of these grain boundaries could be accurately measured. According to grain structure information provided by the examination, a single crystal region 3 with a relatively large area could be accurately selected on the surfaces of the HOPG.

[0046] In the step 3, the HOPG is covered by the photoresist. Optionally, the HOPG is covered by the photoresist with spin-coating.

[0047] In the step 4, the photoresist is patterned and multiple photoresist mesas are retained in the patterned photoresist. The step of patterning the photoresist determines the layout of the graphite mesas formed in the subsequent steps. The photoresist could be patterned by electron beam etching method. The average size of the formed photoresist mesas (square or circular) could be 1 m to 30 m, and the average interval between the photoresist mesas could be 1 m to 100 m. The etched graphite mesas have corresponding average size and average intervals as shown in FIG. 2.

[0048] In the step 5, the substrate is etched and part of the substrate that is not protected by the photoresist is removed, so as to form multiple graphite mesas. The etching method could be, for example, RIE. Based on the measurement data in the step 2, especially the grain thickness data in the region where the mesa structures are located, the etching time of RIE is strictly controlled during the etching process so that the etching depth is greater than the thickness of the grain of the outermost layer of the graphite and less than the distance from the outermost layer of the graphite to the bottom of the second grain as shown in FIG. 3.

[0049] In the step 6, residual photoresist is removed and the processing is completed so as to obtain a batch of graphite slider arrays. The horizontal grain boundaries in the HOPG now become uniform easy-slip interfaces of the graphite slider arrays as shown in FIG. 4. Different graphite mesas in the same batch of arrays will be cleaved at the same height, so a good consistency of the graphite slider arrays is ensured.

[0050] In particular, each graphite slider could also have a connection layer, such as SiO.sub.2. A specific manufacturing method is described below.

[0051] In step 1, a HOPG is selected which has relatively flat surfaces and layered structures and has single crystal grains with a large size and a large thickness.

[0052] In step 2, through non-destructive examination on three-dimensional grain structures near surfaces of the HOPGs, information of polycrystalline structures near the surfaces of the HOPG is obtained, as shown in FIG. 1. A single crystal region 3 with a relatively large area could be accurately selected on the surfaces of the HOPG.

[0053] In step 3, a connection layer is deposited on the HOPG and then the photoresist is coated on the connection layer, where the connection layer may be SiO.sub.2, the thickness of the connection layer may be, for example, 50 nm to 500 nm, and the SiO.sub.2 connection layer may be deposited by plasma CVD. Covering of the photoresist may be performed by spin-coating.

[0054] In step 4, the photoresist is patterned and multiple photoresist mesas are retained in the patterned photoresist. The photoresist could be patterned by electron beam etching method. The average size of the formed photoresist mesas could be 1 m to 30 m, and the average interval between the photoresist mesas is 1 m to 100 m. The etched graphite mesa structures have corresponding average size and average intervals. A sample after the photoresist is patterned is shown in FIG. 5.

[0055] In step 5, the connection layer and the graphite substrate are sequentially etched, so as to remove the connection layer and part of the graphite that are not protected by the photoresist, thereby forming multiple graphite mesa structures with connection layers. Each connection layer is located on the top side of the corresponding graphite mesa and may be described as a connection layer on top of the graphite mesa, the connection layer may be SiO.sub.2 and is used to improve the connection effect between the graphite substrate and the other structure. The etching could be, for example, RIE. When the graphite substrate is etched, the etching time of RIE is strictly controlled, and based on the measurement data in the step 2, the etching depth is greater than the thickness of the grain of the outermost layer of graphite and less than the distance from the outermost layer of the graphite to the bottom of the second grain as shown in FIG. 6.

[0056] In step 6, residual photoresist is removed and the processing is completed so as to obtain a batch of graphite slider arrays with connection layers and uniform easy-slip surfaces as shown in FIG. 7.

INDUSTRIAL APPLICABILITY

[0057] The above are only preferred embodiments of the present disclosure. Any equivalent variations or modifications made according to the scope of the claims in the present disclosure should belong to the coverage scope of the claims in the present disclosure.