Electrode coating process optimization method and electrode structure

Abstract

The invention provides an electrode coating process optimization method and an electrode structure, a titanium layer is manufactured on a substrate, oxidation treatment is performed on the titanium layer, a titanium oxide film is formed on the titanium layer, then a gold layer is manufactured on the titanium oxide film, an electrode of a titanium structure is obtained, and finally an annealing process is performed on the electrode of the titanium structure, the titanium oxide film is used for separating the titanium layer from the gold layer and inhibiting mutual diffusion between the titanium layer and the gold layer, and the annealing process is used for completing lattice matching of the titanium layer and the gold layer, so that the adhesive force between the gold layer and the titanium layer is improved. According to the electrode coating process optimization method provided by the invention, a set of complete metal precipitation process can be saved, and the cost of a platinum layer and the process cost are saved. And moreover, the platinum layer with relatively high resistivity is reduced, so that the square resistance of the electrode structure is relatively low, and the performance is relatively excellent.

Description

Technical Field

[0001] This invention relates to the field of electrode technology, and in particular to an optimized method for electrode coating process and an electrode structure. Background Technology

[0002] like Figure 1 As shown, in the existing fabrication process of thermally tunable etalon electrodes for external cavity tunable lasers (ITLA), the transport electrode used for ohmic contact is typically a titanium-platinum-gold three-layer system. The platinum layer is positioned between the gold and titanium layers, with the titanium layer serving as an interlayer between the substrate and the metal layers, and the platinum layer acting as an interlayer between the gold and titanium layers. During the annealing process, the substrate, titanium layer, platinum layer, and gold layer achieve lattice matching, thereby improving the adhesion between the layers. Platinum is relatively stable and acts as a barrier layer between the titanium and gold layers, inhibiting diffusion from both. Therefore, the platinum layer, as an interlayer between the gold and titanium layers, not only reduces the diffusion between them, preventing an increase in the resistance of the titanium-gold electrode and affecting power transmission, but also improves the adhesion between the substrate, titanium layer, platinum layer, and gold layer, enhancing the stability of the film structure.

[0003] However, setting a platinum layer between the titanium and gold layers requires an additional complete metal deposition process to create the platinum layer, resulting in a lengthy process flow and increased costs for both the platinum layer itself and the process. Therefore, a simpler process or structure is needed for optimization.

[0004] Therefore, overcoming the shortcomings of the existing technology is an urgent problem to be solved in this technical field. Summary of the Invention

[0005] The technical problem to be solved by this invention is how to reduce the process flow and cost in the titanium-gold coating process while suppressing the mutual diffusion between the titanium layer and the gold layer and ensuring good adhesion between the titanium layer and the gold layer.

[0006] Firstly, a method for optimizing an electrode coating process is provided, including:

[0007] A titanium layer 2 is formed on substrate 1;

[0008] The titanium layer 2 is oxidized to form a titanium oxide film 3 on the titanium layer 2, and the titanium oxide film 3 is used to suppress the upward diffusion of the titanium layer 2.

[0009] A gold layer 4 is formed on the titanium oxide thin film 3 to obtain a titanium-gold structure electrode.

[0010] The electrode is subjected to an annealing process, which is used to improve the adhesion between the gold layer 4 and the titanium layer 2.

[0011] Preferably, forming the titanium layer 2 on the substrate 1 specifically includes:

[0012] The pattern of the titanium layer 2 is photolithographically etched on the substrate 1;

[0013] Titanium metal is sputtered onto the substrate 1;

[0014] The titanium metal outside the pattern obtained by photolithography is stripped off to complete the coating of the titanium layer 2.

[0015] Preferably, the process parameters for forming the titanium layer 2 on the substrate 1 are as follows:

[0016] The vacuum level is below 1.5E-4Pa, the gas pressure range is 0.18Pa-0.22Pa, the argon flow rate is 18±0.1sccm, the sputtering power is 600±5w, the film thickness is 43nm-52nm, and the process temperature is 19.5℃-21.5℃.

[0017] Preferably, the oxidation treatment of the titanium layer 2 to form a titanium oxide thin film 3 on the titanium layer 2 specifically includes:

[0018] Under preset temperature and humidity conditions, the titanium layer 2 is naturally oxidized to form the titanium oxide film 3 on the surface of the titanium layer 2;

[0019] The preset temperature is 22±1℃, and the preset humidity is 50±1%.

[0020] Preferably, the oxidation treatment of the titanium layer 2 to form a titanium oxide thin film 3 on the titanium layer 2 further includes:

[0021] The titanium oxide film 3 is subjected to a backsplashing process, which is used to improve the adhesion of the titanium oxide film 3.

[0022] Preferably, the relevant parameters of the anti-sputtering process are:

[0023] The vacuum level is below 1.5E-5Pa, the gas pressure range is 5Pa-10Pa, the argon flow rate range is 30±0.1sccm, the sputtering power range is 200±5W, and the working time is 120±1s.

[0024] Preferably, the formation of the gold layer 4 on the titanium oxide thin film 3 specifically includes:

[0025] The pattern of the gold layer 4 is photolithographically etched on the titanium oxide thin film 3;

[0026] Gold is sputtered onto the titanium oxide thin film 3;

[0027] The gold layer 4 is coated by stripping away the gold outside the pattern obtained by photolithography.

[0028] Preferably, the gold layer 4 is formed on the titanium oxide thin film 3, and the corresponding process parameters are as follows:

[0029] The vacuum level is below 1.5E-4Pa; the gas pressure range is 0.7±0.1Pa; the argon flow rate is 30±0.1sccm; the sputtering power is 130±5W; the film thickness is 498nm-512nm; and the process temperature is 19.5℃-21.5℃.

[0030] Preferably, the relevant parameters of the annealing process are:

[0031] The heating rate was 0.62±0.01℃ / s, the holding time after the temperature reached 400±1℃ was 30±0.01min, the annealing nitrogen flow rate was 2000±0.1sccm, and the cooling time was 1200±1s.

[0032] Secondly, an electrode structure is provided, fabricated by the aforementioned optimized electrode coating process, characterized in that it comprises: a substrate 1, a titanium layer 2, a titanium oxide thin film 3, and a gold layer 4, wherein:

[0033] The titanium layer 2 is located on the substrate 1, the titanium oxide thin film 3 is located on the titanium layer 2, and the gold layer 4 is located on the titanium oxide thin film 3.

[0034] This invention provides an optimized electrode coating process and electrode structure. A titanium layer 2 is fabricated on a substrate 1 and then oxidized to form a titanium oxide thin film 3. A gold layer 4 is then fabricated on the titanium oxide thin film 3 to obtain a titanium-gold structure electrode. Finally, the titanium-gold structure electrode undergoes an annealing process. The titanium oxide thin film 3 serves to isolate the titanium layer 2 and the gold layer 4, suppressing mutual diffusion between them. The annealing process completes the lattice matching of the titanium layer 2 and the gold layer 4, thereby improving the adhesion between them. The optimized electrode coating process provided by this invention can save a complete metal deposition process, reducing the cost of the platinum layer and overall process costs. Furthermore, by reducing the high resistivity of the platinum layer, the sheet resistance of the electrode structure is lower, resulting in superior performance. Attached Figure Description

[0035] To more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for use in the embodiments of the present invention. Obviously, the drawings described below are only some embodiments of the present invention. Those skilled in the art can also derive other drawings based on these drawings without inventive effort.

[0036] Figure 1 This is a schematic diagram of the existing titanium-platinum-gold three-layer architecture provided in an embodiment of the present invention;

[0037] Figure 2 This is a schematic diagram of an electrode structure provided in an embodiment of the present invention;

[0038] Figure 3 This is a schematic diagram of another electrode structure provided in an embodiment of the present invention;

[0039] Figure 4 This is a flowchart of an electrode coating process optimization method provided in an embodiment of the present invention;

[0040] Figure 5 This is a flowchart of a titanium layer coating method for an electrode coating process optimization method provided in an embodiment of the present invention;

[0041] Figure 6 This is a flowchart of an oxidation treatment method for an electrode coating process optimization method provided in an embodiment of the present invention;

[0042] Figure 7 This is a flowchart of another electrode coating process optimization method provided in an embodiment of the present invention;

[0043] Figure 8 This is a flowchart of a titanium layer coating method for another electrode coating process optimization method provided in this embodiment of the invention;

[0044] Figure 9 This is a flowchart of an oxidation treatment method for another electrode coating process optimization method provided in this embodiment of the invention;

[0045] Figure 10 This is a gold layer surface diffusion diagram of Group A process in a comparative experiment of an electrode coating process optimization method provided in an embodiment of the present invention.

[0046] Figure 11 This is a gold layer surface diffusion diagram of Group B process in a comparative experiment of an electrode coating process optimization method provided in an embodiment of the present invention.

[0047] Figure 12 This is a gold layer surface diffusion diagram of the C group process in a comparative experiment of an electrode coating process optimization method provided in an embodiment of the present invention.

[0048] Figure 13 This is a gold layer surface diffusion diagram of the D group process in a comparative experiment of an electrode coating process optimization method provided in an embodiment of the present invention.

[0049] Figure 14This is a gold layer surface diffusion diagram of the E group process in a comparative experiment of an electrode coating process optimization method provided in an embodiment of the present invention.

[0050] Figure 15 This is a schematic diagram of an electrode structure provided in an embodiment of the present invention;

[0051] Figure 16 This is a top view of an electrode structure provided in an embodiment of the present invention;

[0052] Figure 17 This is a schematic diagram of another electrode structure provided in an embodiment of the present invention;

[0053] The diagram numbers are as follows:

[0054] Substrate 1; Titanium layer 2; Titanium oxide thin film 3; Gold layer 4; Platinum layer 5; Heating electrode 6; Transport electrode 7; Second titanium layer 8. Detailed Implementation

[0055] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0056] In the description of this invention, the terms "inner", "outer", "longitudinal", "lateral", "upper", "lower", "top", "bottom", 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 do not require that this invention must be constructed and operated in a specific orientation. Therefore, they should not be construed as limiting this invention.

[0057] In this invention, the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Therefore, a feature defined with "first," "second," etc., may explicitly or implicitly include one or more of that feature. In the description of this invention, unless otherwise stated, "a plurality of" means two or more.

[0058] In this invention, unless otherwise explicitly specified and limited, the term "connection" should be interpreted broadly. For example, "connection" can be a fixed connection, a detachable connection, or an integral part; it can be a direct connection or an indirect connection through an intermediate medium. Furthermore, the term "coupled" can refer to an electrical connection method for achieving signal transmission.

[0059] Furthermore, the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0060] Embodiment 1:

[0061] Combination Figure 1 The existing titanium-platinum-gold three-layer system for thermally tunable etalon electrodes in external cavity tunable lasers has at least the following technical problems:

[0062] (1) Figure 1 The electrode structure shown includes a heating electrode and a transfer electrode. Transfer electrodes are disposed on both sides of the heating electrode. The heating electrode includes a titanium layer and a platinum layer, and the transfer electrode includes a titanium layer, a platinum layer, and a gold layer. Although both the heating electrode and the transfer electrode include a platinum layer, the thickness of the platinum layer of the heating electrode is greater than that of the platinum layer of the transfer electrode. Therefore, the platinum layer of the heating electrode and the platinum layer of the transfer electrode require two different coating processes, which increases the number of process steps in the entire process and also increases the cost of the platinum layer itself and the process cost.

[0063] (2) Because the platinum layer in the transmission electrode is thin, when the platinum layer and the gold layer use the same photolithography pattern, the platinum layer may melt after being powered on.

[0064] To address the aforementioned issues, this embodiment provides an electrode coating process optimization method, primarily optimizing the process of the transfer electrode 7. Similar to existing technologies, the transfer electrode 7 is located on both sides of the heating electrode 6, with at least one transfer electrode 7 disposed on each side of the heating electrode 6. The transfer electrode 7 can be used for ohmic contact, and the heating electrode 6 primarily utilizes the thermal stability of the platinum layer and the thermal effect of the current for thermo-optical tuning.

[0065] like Figure 3 and Figure 4 As shown, the method flow of the electrode coating process optimization method includes:

[0066] In step 101, a titanium layer 2 is formed on the substrate 1.

[0067] In this embodiment, the substrate 1 can be silicon dioxide.

[0068] In step 102, the titanium layer 2 is oxidized to form a titanium oxide film 3 on the titanium layer 2. The titanium oxide film 3 is used to suppress the upward diffusion of the titanium layer 2.

[0069] In this embodiment, the oxidation treatment needs to be carried out after the coating process of titanium layer 2 is completed. The titanium oxide film 3 is used as an isolation layer between titanium layer 2 and gold layer 4 which needs to be coated later. It is used to reduce the degree of diffusion between titanium layer 2 and gold layer 4, and to avoid the increase of resistance between titanium layer 2 and gold layer 4, which would affect the power transmission efficiency.

[0070] In step 103, a gold layer 4 is formed on the titanium oxide thin film 3 to obtain an electrode with a titanium-gold structure.

[0071] In this embodiment, since the gold layer 4 has excellent conductivity and corrosion resistance, it is an ideal ohmic contact material, so the gold layer 4 is placed on the top layer.

[0072] The titanium oxide film 3 is obtained by oxidizing the titanium layer 2, and the titanium oxide film 3 is relatively thin. The specific process parameters for forming the titanium oxide film 3 are described below.

[0073] In step 104, the electrode is subjected to an annealing process, which is used to improve the adhesion between the gold layer 4 and the titanium layer 2.

[0074] In this embodiment, after the gold layer 4 is coated, the entire electrode is then annealed. The annealing process eliminates film stress and structural defects, and completes lattice matching, thereby improving the adhesion between the titanium layer 2 and the gold layer 4.

[0075] This invention provides an optimized electrode coating process and electrode structure. The process involves depositing a titanium layer 2 on a substrate 1, followed by oxidation of the titanium layer 2 to form a titanium oxide thin film 3. A gold layer 4 is then deposited on the titanium oxide thin film 3. Finally, the electrode undergoes an annealing process. The titanium oxide thin film 3 isolates the titanium layer 2 and the gold layer 4, suppressing mutual diffusion between them. The annealing process ensures lattice matching between the titanium layer 2 and the gold layer 4, thereby improving their adhesion. This optimized electrode coating process utilizes a more stable and lower-cost process flow instead of a complex one, saving on a complete metal deposition process, reducing the cost of the platinum layer, and lowering overall process costs. Furthermore, by reducing the high resistivity of the platinum layer, the sheet resistance of the electrode structure is lower, reducing device power consumption and improving performance.

[0076] like Figure 3 and Figure 5 As shown, the process of depositing titanium layer 2 on substrate 1 includes:

[0077] In step 201, a pattern of titanium layer 2 is photolithographically etched on the substrate 1.

[0078] Photoresist is coated on substrate 1, and the designated locations on the photoresist are exposed and developed according to the pattern of titanium layer 2 to define the pattern of titanium layer 2. The photoresist can be either positive or negative, depending on the specific circumstances.

[0079] In this embodiment, the pattern of the titanium layer 2 is set by those skilled in the art according to the actual situation. For different chip structures, the required pattern of the titanium layer 2 is also different.

[0080] In step 202, titanium metal is sputtered onto the substrate 1.

[0081] Of the sputtered titanium metal, one part is located on substrate 1 and the other part is located on photoresist.

[0082] In step 203, the titanium metal outside the pattern obtained by photolithography is stripped off to complete the coating of the titanium layer 2.

[0083] The photoresist is stripped, and the titanium metal on the photoresist is also stripped at the same time. However, the titanium metal sputtered on the substrate 1 is not stripped. The remaining unstripped titanium metal is the titanium layer 2.

[0084] In this embodiment, the titanium layer 2 can be grown using an MS200-1 / EXW type metal thin film and deposited using a physical vapor deposition (PVD) device. The vacuum level of the device can be controlled below 1.5E-4Pa, the gas pressure range can be 0.18Pa-0.22Pa, the argon flow rate can be 18±0.1sccm, the sputtering power can be 600±5W, the film thickness of the titanium layer 2 can be 43nm-52nm, and the process temperature can be 19.5℃-21.5℃.

[0085] In this embodiment, the oxidation treatment method is as follows:

[0086] The oxidation treatment of the titanium layer 2 to form a titanium oxide thin film 3 on the titanium layer 2 specifically includes:

[0087] Under preset temperature and humidity conditions, the titanium layer 2 is naturally oxidized to form the titanium oxide film 3 on the surface of the titanium layer 2.

[0088] It should be noted that during the oxidation process, the structure with the titanium layer 2 coating completed needs to be placed in an ultra-clean environment under normal pressure. The preset temperature and preset humidity can be set by those skilled in the art. The preset temperature can be 22±1℃, the preset humidity can be 50±1%, and the oxidation time can be 120±0.1min. Alternatively, natural oxidation can be carried out under normal pressure.

[0089] like Figure 3 and Figure 6 As shown, the process of depositing the gold layer 4 on the titanium oxide thin film 3 includes:

[0090] In step 301, the pattern of the gold layer 4 is photolithographically etched on the titanium oxide thin film 3.

[0091] Photoresist is coated on the titanium oxide thin film 3, and the designated positions on the photoresist are exposed and developed according to the pattern of the gold layer 4 to define the pattern of the gold layer 4.

[0092] In this embodiment, the pattern of the gold layer 4 is set by those skilled in the art according to the actual situation. For different chip structures, the required pattern of the gold layer 4 is also different.

[0093] In step 302, gold is sputtered onto the titanium oxide film 3.

[0094] Of the sputtered gold, one part is located on the titanium oxide thin film 3, and the other part is located on the photoresist.

[0095] In step 303, the gold outside the pattern obtained by photolithography is stripped off to complete the coating of the gold layer 4.

[0096] The photoresist is stripped, and the gold on the photoresist is also stripped at the same time. However, the gold sputtered on the substrate 1 is not stripped. The remaining unstripped gold is the gold layer 4.

[0097] In this embodiment, the gold layer 4 can be grown using an MS200-1 / EXW type metal thin film and deposited using a PVD device. The vacuum level of the device can be controlled below 1.5E-4Pa, the gas pressure range for preparing the gold layer 4 can be 0.7±0.1Pa, the argon flow rate can be 30±0.1sccm, the sputtering power can be 130±5W, the thickness of the titanium layer 2 can be 498nm-512nm, and the process temperature can be 19.5℃-21.5℃.

[0098] In this embodiment, the corresponding application parameters for the annealing process can be: heating rate of 0.62±0.01℃ / s, holding time of 30±0.01min after the temperature reaches 400±1℃, annealing nitrogen flow rate of 2000±0.1sccm, and cooling time of 1200±1s.

[0099] Example 2:

[0100] Example 2 further optimizes the electrode coating process based on Example 1, providing an optimized electrode coating process method. Unlike Example 1, this example, after oxidizing the titanium layer 2, also performs a back-sputtering treatment on the titanium oxide film 3 to increase the adhesion of the titanium oxide film 3. Figure 3 and Figure 7 As shown, the method flow is as follows:

[0101] In step 401, a titanium layer 2 is deposited on the substrate 1.

[0102] In this embodiment, the corresponding structure provided can be used in an electrode structure for ohmic contact, and further, it can be applied to the wire bonding structure of the electrode structure. The substrate 1 can be silicon dioxide.

[0103] In step 402, the titanium layer 2 is oxidized to form a titanium oxide film 3 on the titanium layer 2. The titanium oxide film 3 is used to reduce the upward diffusion of the titanium layer 2.

[0104] In this embodiment, the oxidation treatment needs to be carried out after the coating process of titanium layer 2 is completed. Titanium layer 2 is used as an isolation layer between titanium layer 2 and gold layer 4 which needs to be coated later. It is used to reduce the degree of diffusion between titanium layer 2 and gold layer 4, and avoid the increase in resistance of titanium layer 2 and gold layer 4 due to diffusion, which would affect the power transmission efficiency.

[0105] In step 403, the titanium oxide film 3 is subjected to a backsplashing process, which is used to improve the adhesion of the titanium oxide film 3.

[0106] By performing a backsputtering process on the titanium oxide film 3, the surface contact angle of the titanium oxide film 3 is reduced, thereby improving the film activity, which in turn improves the adhesion of the titanium oxide film 3 and enhances the stability of the subsequent adhesion between the gold layer 4 and the titanium oxide film 3.

[0107] In step 404, a gold layer 4 is deposited on the titanium oxide thin film 3 to obtain an electrode with a titanium-gold structure.

[0108] In this embodiment, since the gold layer 4 has excellent conductivity and corrosion resistance, it is an ideal ohmic contact material. Therefore, the gold layer 4 is placed on the top layer, and the electrode of the titanium-gold structure is the electrode after the gold layer 4 has been deposited on the titanium oxide thin film 3. It should be noted that after completing the backsputtering process, the gold layer 4 can be deposited after cooling to room temperature under vacuum.

[0109] In step 405, the electrode is subjected to an annealing process, which is used to improve the adhesion between the gold layer 4 and the titanium layer 2.

[0110] In this embodiment, after the gold layer 4 is coated, the entire electrode is then annealed. The annealing process eliminates film stress and structural defects, and completes lattice matching, thereby improving the adhesion between the titanium layer 2 and the gold layer 4.

[0111] This embodiment involves depositing a titanium layer 2 on a substrate 1, followed by oxidation of the titanium layer 2 to form a titanium oxide thin film 3. A backsputtering process is then performed on the titanium layer 2 and the titanium oxide thin film 3. Subsequently, a gold layer 4 is deposited on the titanium oxide thin film 3. Finally, the electrode is annealed. The titanium oxide thin film 3 serves to isolate the titanium layer 2 and the gold layer 4, reducing the degree of mutual diffusion between them. The backsputtering process reduces the surface contact angle between the titanium layer 2 and the titanium oxide thin film 3, thereby improving film activity and thus enhancing the adhesion between the titanium layer 2 and the titanium oxide. The annealing process completes the lattice matching between the titanium layer 2 and the gold layer 4, thereby improving the adhesion between the gold layer 4 and the titanium layer 2. This embodiment further improves the adhesion between the titanium layer 2, titanium oxide, and gold layer 4 by performing a backsputtering process before depositing the gold layer 4.

[0112] like Figure 3 and Figure 8 As shown, the process of depositing titanium layer 2 on substrate 1 includes:

[0113] In step 501, a pattern of titanium layer 2 is photolithographically etched on the substrate 1.

[0114] Photoresist is coated on substrate 1, and the designated positions on the photoresist are exposed and developed according to the pattern of titanium layer 2 to define the pattern of titanium layer 2.

[0115] In this embodiment, the pattern of the titanium layer 2 is set by those skilled in the art according to the actual situation. For different chip structures, the required pattern of the titanium layer 2 is also different.

[0116] In step 502, titanium metal is sputtered onto the substrate 1.

[0117] Of the sputtered titanium metal, one part is located on substrate 1 and the other part is located on photoresist.

[0118] In step 503, the titanium metal outside the pattern obtained by photolithography is stripped off to complete the coating of the titanium layer 2.

[0119] The photoresist is stripped, and the titanium metal on the photoresist is also stripped at the same time. However, the titanium metal sputtered on the substrate 1 is not stripped. The remaining unstripped titanium metal is the titanium layer 2.

[0120] In this embodiment, the titanium layer 2 can be grown using an MS200-1 / EXW type metal thin film and deposited using a PVD device. The vacuum level of the device can be controlled below 1.5E-4Pa, the gas pressure range for preparing the titanium layer 2 can be 0.18Pa-0.22Pa, the argon flow rate can be 18±0.1sccm, the sputtering power can be 600±5W, the film thickness of the titanium layer 2 can be 43nm-52nm, and the process temperature can be 19.5℃-21.5℃.

[0121] In this embodiment, the oxidation treatment method is as follows:

[0122] The oxidation treatment of the titanium layer 2 to form a titanium oxide thin film 3 on the titanium layer 2 specifically includes:

[0123] The structure after titanium layer 2 coating is placed under preset temperature and preset humidity for natural curing to form the titanium oxide thin film 3.

[0124] It should be noted that during the oxidation process, the structure with the titanium layer 2 coating completed needs to be placed in an ultra-clean environment under normal pressure. The preset temperature and preset humidity can be set by those skilled in the art. The preset temperature can be 22±1℃, the preset humidity can be 50±1%, and the oxidation time can be 120±0.1min.

[0125] For the back-sputtering process of the titanium layer 2 and the titanium oxide thin film 3, this embodiment provides a preferred process parameter as follows:

[0126] In this embodiment, the vacuum degree of the backsplashing process can be below 1.5E-5Pa, the gas pressure range is 5Pa-10Pa, the argon flow rate range is 30±0.1sccm, the sputtering power range is 200±5w, and the working time is 120±1s.

[0127] The gold layer 4 is deposited on the titanium oxide thin film 3, such as... Figure 3 and Figure 9 As shown, the method flow includes:

[0128] In step 601, the pattern of the gold layer 4 is photolithographically etched on the titanium oxide thin film 3.

[0129] Photoresist is coated on the titanium oxide thin film 3, and the designated positions on the photoresist are exposed and developed according to the pattern of the gold layer 4 to define the pattern of the gold layer 4.

[0130] In this embodiment, the pattern of the gold layer 4 is set by those skilled in the art according to the actual situation. For different chip structures, the required pattern of the gold layer 4 is also different.

[0131] In step 602, gold is sputtered onto the titanium oxide film 3.

[0132] Of the sputtered gold, one part is located on the titanium oxide thin film 3, and the other part is located on the photoresist.

[0133] In step 603, the gold outside the pattern obtained by photolithography is stripped off to complete the coating of the gold layer 4.

[0134] The photoresist is stripped, and the gold on the photoresist is also stripped at the same time. However, the gold sputtered on the substrate 1 is not stripped. The remaining unstripped gold is the gold layer 4.

[0135] In this embodiment, the gold layer 4 can be grown using an MS200-1 / EXW type metal thin film and deposited using a PVD device. The vacuum level of the device can be controlled below 1.5E-4Pa, the gas pressure range for preparing the gold layer 4 can be 0.7±0.1Pa, the argon flow rate can be 30±0.1sccm, the sputtering power can be 130±5W, the thickness of the titanium layer 2 can be 498nm-512nm, and the process temperature can be 19.5℃-21.5℃.

[0136] In this embodiment, the corresponding application parameters for the annealing process can be: heating rate of 0.62±0.01℃ / s, holding time of 30±0.01min after the temperature reaches 400±1℃, annealing nitrogen flow rate of 2000±0.1sccm, and cooling time of 1200±1s.

[0137] Example 3:

[0138] Example 3, based on Examples 1 and 2, compares the diffusion degree and adhesion of electrode structures formed by five different titanium-gold coating processes, thereby demonstrating the superiority of Examples 1 and 2 over existing processes.

[0139] Five different titanium-gold coating processes are included in Group A, Group B, Group C, Group D, and Group E.

[0140] In Group A, the process employs a standard titanium-gold process, which omits the platinum layer 5 deposition between the titanium layer 2 and the gold layer 4, avoids oxidation treatment to generate a titanium oxide thin film 3, and also omits the corresponding back-sponging and annealing processes. In this embodiment, the process parameters used in Group A can be:

[0141] The titanium layer 2 can be grown using an MS200-1 / EXW type metal thin film and deposited using a PVD device. The vacuum level of the device can be controlled below 1.5E-4Pa, the working pressure range for preparing the titanium layer 2 can be 0.18Pa-0.22Pa, the argon flow rate can be 18±0.1sccm, the sputtering power can be 600±5W, the film thickness of the titanium layer 2 can be 43nm-52nm, and the process temperature can be 19.5℃-21.5℃.

[0142] The gold layer 4 can be grown using an MS200-1 / EXW type metal thin film and deposited using a PVD device. The vacuum level of the device can be controlled below 1.5E-4Pa. The working pressure range for the preparation of the gold layer 4 can be 0.7±0.1Pa, the argon flow rate can be 30±0.1sccm, the sputtering power can be 130±5W, the thickness of the titanium layer 2 can be 498nm-512nm, and the process temperature can be 19.5℃-21.5℃.

[0143] After depositing titanium layer 2, process group B oxidizes titanium layer 2 to form titanium oxide film 3, and then deposits gold layer 4 on titanium oxide film 3. The process parameters for depositing gold layer 4 and titanium layer 2 in process group B are the same as those in process group A, and will not be repeated here. The process parameters used for oxidation treatment in process group B can be:

[0144] During the oxidation process, the structure with the titanium layer 2 coating completed needs to be placed in an ultra-clean environment under normal pressure. The temperature during the oxidation process can be 22±1℃, the humidity can be 50±1%, and the time can be 120±0.1min.

[0145] In Group C, after oxidation treatment and before gold layer 4 deposition, a back-sputtering process is performed on titanium layer 2 and titanium oxide film 3. The process parameters for gold layer 4 deposition, oxidation treatment, and titanium layer 2 deposition in Group C are the same as those in Group B, and will not be repeated here. The process parameters used for the back-sputtering process in Group C can be:

[0146] The vacuum degree of the backsplashing process can be below 1.5E-5Pa, the gas pressure range is 5Pa-10Pa, the argon flow rate range is 30±0.1sccm, the sputtering power range is 200±5w, and the working time is 120±1s.

[0147] In Group D, the titanium layer 2 coating, oxidation treatment, and back-sputtering process are performed sequentially. After the gold layer 4 coating, the resulting electrode structure undergoes an annealing process. The process parameters for the titanium layer 2 coating, oxidation treatment, back-sputtering process, and gold layer 4 coating in Group D are the same as those in Group C, and will not be repeated here. The process parameters used for the annealing process in Group D can be as follows:

[0148] The corresponding application parameters for the annealing process can be: heating rate of 0.62±0.01℃ / s, holding time of 30±0.01min after reaching 400±1℃, annealing nitrogen flow rate of 2000±0.1sccm, and cooling time of 1200±1s.

[0149] Group E processes are the existing titanium-platinum-gold processes that use platinum as an intermediate layer.

[0150] The table below shows the test data for front and rear resistance and adhesion after the AD group process is completed:

[0151] Group A Group B Group C Group D Group E Titanium Surface State Oxidation-free Oxidation Oxidation Oxidation Oxidation-free Platinum transition layer thickness (nm) 0 0 0 0 13.9-15.5 Splashing state none none have have none Annealed state none none none have none ASTM D3359 Adhesion Test 0B 0B 3B 5B 4B Average sheet resistance (Ω / □) 0.06447 0.06497 0.06282 0.05587 0.06354 Shear resistance consistency (%) 2.279 2.457 1.984 2.12 2.317 Adhesion test after aging 5B 5B 5B 5B 5B Average sheet resistance after aging (Ω / □) 0.3267 0.11737 0.05487 0.05627 0.06531 Sheet resistance consistency after aging (%) 3.065 8.051 2.734 3.491 1.505

[0152] like Figures 10-14 As shown, Figures 10-14 The images shown are, in order, images of the gold layer 4 surface corresponding to processes A through E, combined with the table above and... Figures 10-14 The following conclusions can be drawn:

[0153] Figure 10 In the corresponding Group A process, obvious white textures appeared on the surface of gold layer 4, which is a manifestation of titanium diffusion upward. Compared with other processes, the diffusion degree of Group A process is the largest, while the adhesion is 0B.

[0154] Figure 11 In the corresponding Group B process, the white texture on the surface of the gold layer 4 was significantly reduced. This is because the titanium oxide film 3 in the Group B process acts as an isolation layer, reducing the degree of diffusion between the titanium layer 2 and the gold layer 4. However, the adhesion is also 0B, and the film bonding is weak. It is speculated that the titanium-gold film separation was caused by stress during the aging test, and the resistance defects formed during the aging process affected the current transmission.

[0155] Figure 12 In the corresponding Group C process, the white texture on the surface of the gold layer 4 basically disappeared. Compared with Group A and Group B, the diffusion between the titanium layer 2 and the gold layer 4 was further reduced. At the same time, the adhesion was improved to 3B. The resistance value was significantly reduced after the aging test, but the front and back resistance test results showed large fluctuations.

[0156] Figure 13In the corresponding D group process, the white texture on the surface of the gold layer 4 completely disappeared, which relatively stably suppressed the diffusion between the titanium layer 2 and the gold layer 4. At the same time, the adhesion was the maximum. Furthermore, since the D group reduced the platinum layer with high resistivity in the structure, the average sheet resistance was smaller than that of the E group. After the aging test, the sheet resistance changed little, and the film state basically reached a stable state.

[0157] Figure 14 In the corresponding E group process, the white texture on the surface of gold layer 4 completely disappears, which is basically the same as the D group process, and most of the values ​​in the table are basically consistent with the D group process.

[0158] As shown in the table above, the differences in the measured data of groups A to E before and after aging are significant. Among them, the average adhesion and sheet resistance of groups A to C changed considerably after aging, while the average adhesion and sheet resistance of groups D and E did not change much after aging. This proves the stability of the parameters of the structure produced by the electrode coating process optimization method provided in this embodiment, and that the changes in various parameters are still small even after aging. As for the sheet resistance consistency, in this embodiment, it is acceptable as long as it does not exceed 5%.

[0159] Based on the above comparison, it can be seen that after oxidation treatment, anti-sputtering process and annealing process, the D group process can stably suppress the mutual diffusion between titanium layer 2 and gold layer 4, while improving the adhesion between titanium layer 2, gold layer 4 and substrate 1, and improving the stability of the overall structure. The beneficial effects are basically the same as the existing titanium-platinum-gold coating process. Therefore, under the premise of meeting the above beneficial effects, the D group process eliminates the platinum layer 5 coating process, speeds up the overall manufacturing process, and also saves the material cost of platinum layer 5.

[0160] Example 4:

[0161] Example 4 provides an electrode structure based on Examples 1 and 2, such as... Figures 15-17 As shown, it includes: a substrate 1, a titanium layer 2, a titanium oxide thin film 3, and a gold layer 4, wherein:

[0162] The titanium layer 2 is located on the substrate 1, the titanium oxide thin film 3 is located on the titanium layer 2, and the gold layer 4 is located on the titanium oxide thin film 3.

[0163] In this embodiment, the electrode structure is applied to the ohmic contact transmission electrode 7, as shown below. Figure 15 and Figure 16 As shown, a heating electrode 6 is also disposed on the substrate 1, wherein at least three transmission electrodes 7 are disposed on both sides of the heating electrode 6, and the three transmission electrodes 7 on each side are arranged side by side on the substrate 1; as Figure 17As shown, the heating electrode 6 includes a second titanium layer 8 and a platinum layer 5, the second titanium layer 8 being disposed on the substrate 1, and the platinum layer 5 being disposed on the second titanium layer 8.

[0164] For details on the specific production method, please refer to the aforementioned Examples 1 and 2, which will not be repeated here.

[0165] In this embodiment, a titanium layer 2 is fabricated on a substrate 1 and then oxidized to form a titanium oxide thin film 3. A gold layer 4 is then fabricated on the titanium oxide thin film 3 to obtain a titanium-gold structure electrode. Finally, the titanium-gold structure electrode undergoes an annealing process. The titanium oxide thin film 3 serves to isolate the titanium layer 2 and the gold layer 4, suppressing mutual diffusion between them. The annealing process completes the lattice matching of the titanium layer 2 and the gold layer 4, thereby improving the adhesion between them. The electrode coating process optimization method provided by this invention can save a complete metal deposition process, reducing the cost of the platinum layer and overall process costs. Furthermore, by reducing the high resistivity of the platinum layer, the sheet resistance of the electrode structure is lower, resulting in superior performance.

[0166] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for optimizing an electrode coating process, characterized in that, include: A titanium layer (2) is formed on a substrate (1); The titanium layer (2) is oxidized to form a titanium oxide film (3) on the titanium layer (2), the titanium oxide film (3) being used to suppress the upward diffusion of the titanium layer (2); A gold layer (4) is formed on the titanium oxide thin film (3) to obtain an electrode with a titanium-gold structure; The electrode is subjected to an annealing process, which is used to improve the adhesion between the gold layer (4) and the titanium layer (2).

2. The electrode coating process optimization method according to claim 1, characterized in that, The formation of a titanium layer (2) on the substrate (1) specifically includes: A pattern of titanium layer (2) is photolithographically etched on the substrate (1); Titanium metal is sputtered onto the substrate (1); The titanium metal outside the pattern obtained by photolithography is stripped off to complete the coating of the titanium layer (2).

3. The electrode coating process optimization method according to claim 2, characterized in that, The titanium layer (2) is formed on the substrate (1), and the corresponding process parameters are as follows: The vacuum level is below 1.5E-4Pa, the gas pressure range is 0.18Pa-0.22Pa, the argon flow rate is 18±0.1sccm, the sputtering power is 600±5w, the film thickness is 43nm-52nm, and the process temperature is 19.5℃-21.5℃.

4. The electrode coating process optimization method according to claim 1, characterized in that, The oxidation treatment of the titanium layer (2) to form a titanium oxide thin film (3) on the titanium layer (2) specifically includes: Under preset temperature and humidity conditions, the titanium layer (2) is naturally oxidized to form the titanium oxide film (3) on the surface of the titanium layer (2); The preset temperature is 22±1℃, and the preset humidity is 50±1%.

5. The electrode coating process optimization method according to claim 1, characterized in that, The oxidation treatment of the titanium layer (2) to form a titanium oxide film (3) on the titanium layer (2) further includes: The titanium oxide film (3) is subjected to a backsplashing process, which is used to improve the adhesion of the titanium oxide film (3).

6. The electrode coating process optimization method according to claim 5, characterized in that, The relevant parameters for the backsplashing process are: The vacuum level is below 1.5E-5Pa, the gas pressure range is 5Pa-10Pa, the argon flow rate range is 30±0.1sccm, the sputtering power range is 200±5W, and the working time is 120±1s.

7. The electrode coating process optimization method according to claim 1, characterized in that, The formation of a gold layer (4) on the titanium oxide thin film (3) specifically includes: The pattern of the gold layer (4) is photolithographically etched on the titanium oxide thin film (3); Gold is sputtered onto the titanium oxide thin film (3); The gold layer (4) is completed by stripping away the gold outside the pattern obtained by photolithography.

8. The electrode coating process optimization method according to claim 7, characterized in that, The gold layer (4) is formed on the titanium oxide thin film (3), and the corresponding process parameters are as follows: The vacuum level is below 1.5E-4Pa; the gas pressure range is 0.7±0.1Pa; the argon flow rate is 30±0.1sccm; the sputtering power is 130±5W; the film thickness is 498nm-512nm; and the process temperature is 19.5℃-21.5℃.

9. The method for optimizing electrode coating process according to any one of claims 1-8, characterized in that, The relevant parameters for the annealing process are as follows: The heating rate was 0.62±0.01℃ / s, the holding time after the temperature reached 400±1℃ was 30±0.01min, the annealing nitrogen flow rate was 2000±0.1sccm, and the cooling time was 1200±1s.

10. An electrode structure, manufactured by the optimized electrode coating process method according to any one of claims 1-9, characterized in that, include: Substrate (1), titanium layer (2), titanium oxide thin film (3), and gold layer (4), wherein: The titanium layer (2) is located on the substrate (1), the titanium oxide film (3) is located on the titanium layer (2), and the gold layer (4) is located on the titanium oxide film (3).

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