Lower electrode structure of plasma device and plasma device

Abstract

The present disclosure provides a lower electrode structure of a plasma device and a plasma device. The lower electrode structure comprises: a lower electrode, an insulating layer and a base, wherein the insulating layer is arranged on the base, the lower electrode is arranged on the insulating layer, an exhaust channel is arranged on the base and at least one exhaust port is formed on the upper surface of the base, the lower electrode structure further comprises a rectifying structure, the rectifying structure is made of an insulating material and has a height exceeding the lower electrode, and the rectifying structure is located on a side of the exhaust port facing the lower electrode to slow down the exhaust flow rate of the lower electrode near the exhaust port. The lower electrode structure helps to improve the consistency of process results.

Description

Technical Field

[0001] The present disclosure belongs to the technical field of semiconductor equipment, and more specifically, relates to a lower electrode structure of a plasma equipment and a plasma equipment. Background Art

[0002] This section is intended to provide a background or context to the embodiments recited in the claims. No admission is made that the description herein is prior art by inclusion in this section.

[0003] Plasma equipment usually excites plasma by applying an electric field between the upper electrode and the lower electrode. Plasma can be used in semiconductor processes such as etching. In semiconductor processes, it is necessary to improve the consistency of process results as much as possible. For example, when plasma etches a metal layer to form the source and drain of a transistor, the higher the consistency of the spacing between the source and drain in transistors of the same specification, the better. Summary of the invention

[0004] The present disclosure provides a lower electrode structure of a plasma device and a plasma device.

[0005] The present disclosure provides the following scheme: a lower electrode structure of a plasma device, comprising: a lower electrode, an insulating layer and a base, wherein the insulating layer is arranged on the base, the lower electrode is arranged on the insulating layer, an exhaust channel is provided on the base and at least one exhaust port is formed on the upper surface of the base, the lower electrode structure also includes a rectifying structure, the rectifying structure is an insulating material and its height exceeds the lower electrode, the rectifying structure is located on the side of the exhaust port facing the lower electrode to slow down the exhaust flow rate of the lower electrode near the exhaust port area.

[0006] In some embodiments, the rectifying structure and an edge region of the lower electrode and / or an edge region of the insulating layer are arranged opposite to each other.

[0007] In some embodiments, the rectifying structure is in a plate shape, which is perpendicular or nearly perpendicular to the plane where the lower electrode is located.

[0008] In some embodiments, the lower electrode is rectangular, the exhaust port is arranged outside the four corners of the lower electrode, the rectifying structure includes four first plates and four second plates corresponding to each other, the first plates are spliced ​​with the corresponding second plates to form a right-angle dihedral angle, the extension direction of the first plates is the same as the extension direction of a group of opposite sides of the lower electrode, the extension direction of the second plates is the same as the extension direction of another group of opposite sides of the lower electrode, and the opening direction of the right-angle dihedral angle is toward the central area of ​​the lower electrode.

[0009] In some embodiments, the lower electrode is rectangular, the first plate and the long side of the rectangle have the same extension direction, the second plate and the short side of the rectangle have the same extension direction, and the size of the first plate along the extension direction of the long side of the rectangle is larger than the size of the second plate along the extension direction of the short side of the rectangle.

[0010] In some embodiments, the rectifying structure has through holes in the up-and-down directions, and a connecting member passes through the through holes to fix the rectifying structure on the insulating layer.

[0011] In some embodiments, the height of the rectifying structure beyond the lower electrode is in a range of 6 cm to 10 cm.

[0012] In some embodiments, a distance between the rectifying structure and the lower electrode in a horizontal direction is in a range of 1 cm to 2 cm.

[0013] In some embodiments, the material of the rectifying structure includes ceramic.

[0014] The present disclosure provides the following solution: a plasma device, comprising the above-mentioned lower electrode structure. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 It is a schematic structural diagram of the first flat plate in the lower electrode structure of an embodiment of the present disclosure.

[0016] Figure 2 It is a schematic structural diagram of the second flat plate in the lower electrode structure of an embodiment of the present disclosure.

[0017] Figure 3 yes Figure 1 The first plate shown Figure 2 Schematic diagram of the splicing state of the second flat plate shown.

[0018] Figure 4 is a top view of the lower electrode structure of an embodiment of the present disclosure.

[0019] Figure 5 yes Figure 4 A variation of the lower electrode structure shown.

[0020] Figure 6 It is a schematic structural diagram of a plasma device according to an embodiment of the present disclosure.

[0021] Among them, 1. base; 2. insulating layer; 3. lower electrode; 4. exhaust channel; 41. exhaust port; 5. rectification structure; 51. first plate; 52. second plate; 6. upper electrode; 61. crossbeam; 62. air inlet channel; 7. insulating layer; 8. chamber wall; H. through hole. DETAILED DESCRIPTION

[0022] The present disclosure is further described below in conjunction with the embodiments shown in the accompanying drawings.

[0023] Combination Figures 1 to 6 An embodiment of the present disclosure provides a lower electrode structure of a plasma device, comprising: a lower electrode 3, an insulating layer 2 and a base 1, wherein the insulating layer 2 is arranged on the base 1, the lower electrode 3 is arranged on the insulating layer 2, an exhaust channel 4 is provided on the base 1 and at least one exhaust port 41 is formed on the upper surface of the base 1, the lower electrode structure also includes a rectifying structure 5, the rectifying structure 5 is an insulating material and its height exceeds the lower electrode 3, the rectifying structure 5 is located on the side of the exhaust port 41 facing the lower electrode 3, so as to slow down the exhaust flow rate of the lower electrode 3 near the exhaust port 41.

[0024] The base 1 is, for example, a metal base 1. The insulating layer 2 is, for example, a ceramic insulating layer 2. In a plasma device, the lower electrode 3 is usually connected to a radio frequency power source (not shown).

[0025] After the reaction in the plasma device is finished, the residual reaction gas needs to be discharged from the exhaust port 41. The rectifying structure 5 has the function of blocking the airflow, so that the flow rate of the reaction gas flowing through the edge area of ​​the lower electrode 3 is slow and the flow rate is reduced. The reaction between the residual plasma in the reaction gas and the edge area of ​​the processed object (such as a wafer or a display substrate, etc.) above the lower electrode 3 is suppressed. This helps to improve the consistency of the process.

[0026] In some embodiments, the rectifying structure 5 is fixed on the insulating layer 2. In other embodiments, the rectifying structure 5 is fixed on the base 1.

[0027] In some embodiments, reference Figure 4 The rectifying structure 5 and the edge region of the insulating layer 2 are arranged opposite to each other.

[0028] In some other embodiments, reference Figure 5 The rectifying structure 5 and the edge region of the insulating layer 2 and the edge region of the lower electrode 3 are arranged opposite to each other.

[0029] In some other embodiments, the rectifying structure 5 and the edge region of the lower electrode 3 are arranged opposite to each other.

[0030] The orthographic projection of the lower electrode 3 on the insulating layer 2 is located inside the insulating layer 2. That is, the insulating layer 2 exceeds the lower electrode 3 in the horizontal direction.

[0031] In some embodiments, reference Figures 1 to 3 , the rectifying structure 5 is plate-shaped. The plate-shaped rectifying structure 5 is perpendicular or nearly perpendicular to the plane where the lower electrode 3 is located. In other words, the normal direction of each position of the plate-shaped rectifying structure 5 is parallel or nearly parallel to the plane where the lower electrode 3 is located.

[0032] The plate-shaped rectifying structure 5 is beneficial to blocking the exhaust gas flow.

[0033] In other embodiments, the rectifying structure 5 has other shapes, such as a convex structure with a curved surface disposed on the insulating layer 2 .

[0034] In some embodiments, reference Figure 3 , Figure 4 and Figure 5 The lower electrode 3 is rectangular, and the exhaust port 41 is arranged outside the four corners of the lower electrode 3. The rectifying structure 5 includes four first plates 51 and four second plates 52 corresponding to each other. The first plates 51 and the corresponding second plates 52 are spliced ​​into a right-angle dihedral angle. The first plates 51 and a group of opposite sides of the lower electrode 3 have the same extension direction, and the second plates 52 and another group of opposite sides of the lower electrode 3 have the same extension direction. The opening direction of the right-angle dihedral angle is toward the central area of ​​the lower electrode 3.

[0035] Specifically, a notch is formed on the cross section where the first plate 51 and the second plate 52 meet, so as to facilitate the fixation of the two.

[0036] In some other embodiments, the first plate 51 and the second plate 52 are integrally formed.

[0037] In some other embodiments, the rectifying structure 5 includes four curved plates, and the four curved plates are arranged one by one on the side of the four exhaust holes facing the lower electrode 3 .

[0038] Figure 4 and Figure 5 In the illustrated embodiment, the lower electrode 3 is rectangular, the first flat plate 51 and the long side of the rectangle have the same extension direction, the second flat plate 52 and the short side of the rectangle have the same extension direction, and the size of the first flat plate 51 along the extension direction of the long side of the rectangle is greater than the size of the second flat plate 52 along the extension direction of the short side of the rectangle.

[0039] This further helps to improve the consistency of the plasma process in the area near the long side and the short side of the lower electrode 3.

[0040] In some other embodiments, the dimension of the first flat plate 51 along the direction in which the long side of the rectangle extends is equal to the dimension of the second flat plate 52 along the direction in which the short side of the rectangle extends.

[0041] In some other embodiments, the lower electrode 3 is square or circular.

[0042] In some other embodiments, the exhaust port 41 is opposite to the long side or short side of the lower electrode 3. The rectifying structure 5 is located on the side of the exhaust port 41 facing the lower electrode 3, and the rectifying structure 5 is opposite to the long side or short side of the lower electrode 3.

[0043] refer to Figures 1 to 3 In some embodiments of the present disclosure, the rectifying structure 5 has a through hole H in the up-down direction, and a connecting member such as a bolt passes through the through hole H to fix the rectifying structure 5 on the insulating layer 2.

[0044] In some embodiments of the present disclosure, the height of the rectifying structure 5 beyond the lower electrode 3 is in the range of 6 cm to 10 cm. If the rectifying structure 5 is too high, it is easy to cause structural interference with other structures. If the rectifying structure 5 is too low, it is not conducive to slowing down the exhaust flow rate above the lower electrode 3.

[0045] In some embodiments, the distance between the rectifying structure 5 and the lower electrode 3 in the horizontal direction is in the range of 1 cm to 2 cm.

[0046] The area above the lower electrode 3 can be used to place a display substrate, for example. This design can avoid collision between the display substrate and the rectifying structure 5 .

[0047] In some embodiments, the material of the rectifying structure 5 includes ceramic.

[0048] The inventors of the present disclosure Figure 4 The plasma equipment shown is verified. The plasma equipment is specifically a plasma etching equipment, and is used to etch and form the source and drain patterns of the transistors on the display motherboard (which can be cut into multiple display substrates). The lateral spacing between the first plate 51 and the long side of the lower electrode 3 is 1.5 cm, and the lateral spacing between the second plate 52 and the short side of the lower electrode 3 is 1.5 cm. The display motherboard to be processed is placed on the lower electrode 3, and the spacing between the display motherboard and the rectifying structure 5 is about 0.8 cm. Such a setting will not affect the placement operation of the display motherboard, and can effectively slow down the exhaust airflow above the four corners of the display motherboard.

[0049] The process is as follows: first, photoresist is applied, followed by exposure. Then, the photoresist is etched using plasma equipment. Since the hardness and structural stability of different areas of the photoresist after exposure are different, a photoresist pattern is formed. Then, a wet etching process is used to remove the metal under the opening of the photoresist, thereby forming the source and drain pattern of the transistor.

[0050] The following table shows the photoresist thickness detection data in the comparative examples of the present disclosure, wherein some data points are missing.

[0051]

[0052] The following table shows the photoresist thickness detection data in the verification example of the present disclosure, wherein some data points are missing.

[0053]

[0054] In the comparative example, after the plasma etching of the photoresist is completed, the average photoresist thickness (PR Remain) is 13938 Å, the uniformity of the photoresist thickness is 20.69%, and the photoresist thickness at the corner of the display motherboard is 10000 Å to 10750 Å.

[0055] In the verification example, after completing the plasma etching of the photoresist, the average photoresist thickness is 14088A (basically consistent with the comparative example), the photoresist thickness uniformity is 11.61% (9.08% increase relative to the comparative example), and the photoresist thickness at the four corners of the display motherboard is between 12000A and 12500A (1600A to 2000A increase relative to the comparative example.

[0056] The following table shows the channel length detection data of the first type of transistors in the comparative example of the present disclosure.

[0057]

[0058] The following table shows the channel length detection data of the first type of transistors in the verification example of the present disclosure.

[0059]

[0060] In the present disclosure, the channel length (Channel FICD) refers to the distance between the source and drain of a transistor. The first type of transistor is a type of transistor having the same design parameters in a pixel region of a display substrate.

[0061] In the comparative example, the average channel length of the first type of transistors in the display motherboard is 3.97um, the channel length uniformity is 17.18%, and the channel length of the first type of transistors at the four corners of the display motherboard is 4.65um to 5.04um.

[0062] In the verification example, it is shown that the average channel length of the first type of transistors in the motherboard is 3.89um (basically consistent with the comparison example), the channel length uniformity of the first type of transistors is 10.49% (an increase of 6.69% compared with the comparison example), and the channel length of the first type of transistors at the four corners of the motherboard is 3.98um to 4.36um (a decrease of 0.52um to 0.68um compared with the comparison example).

[0063] The following table shows the channel length detection data of the second type of transistors in the comparative example of the present disclosure.

[0064]

[0065] The following table shows the channel length detection data of the second type of transistors in the verification example of the present disclosure.

[0066]

[0067] The second type of transistors are transistors that directly drive gate lines in a gate drive circuit (GOA) area of ​​the display substrate.

[0068] In the comparative example, the average channel length of the second type of transistors in the display motherboard is 3.94um, the channel length uniformity is 13.9%, and the channel length of the second type of transistors at the four corners of the display motherboard is 4.65um to 4.72um.

[0069] In the verification example, the average channel length of the second type of transistors in the display motherboard is 3.84um (basically consistent with the comparative example), and the uniformity of the channel length of the second type of transistors is 10.45% (3.45% higher than the comparative example). The channel length of the second type of transistors at the four corners of the display motherboard is 4.08um to 4.3um (0.42um to 0.62um lower than the comparative example.

[0070] The thinner the retained photoresist is, the more metal will be removed in the subsequent process, the smaller the size of the retained metal is, and the larger the channel length is. It can be determined from the above test data that before and after the installation of the rectifier structure 5, the channel length of the first type of transistors at the four corners of the display motherboard decreased by 0.52um to 0.68um, and its uniformity was improved by 6.69%, and the channel length of the second type of transistors decreased by 0.42um to 0.62um, and its uniformity was improved by 3.45%. Without affecting the characteristics of the transistors, the situation where the transistor performance test at the edge area of ​​the display motherboard fails can be effectively avoided. The embodiments of the present disclosure can improve the consistency of the plasma process and improve the consistency of the dimensional parameters of the processed devices.

[0071] The following table is the electrical properties test (EPM) data of the comparative examples and verification examples of the present disclosure. The first row of test data in the comparative examples and test examples is the test data of the first type of transistors, and the second row of test data in the comparative examples and test examples is the test data of the second type of transistors.

[0072]

[0073] Ion is the transistor on-current, in uA. Ioff (-8V) is the source-drain leakage current when the gate-source voltage is -8V and the source-drain voltage is 15V, in A. Vth is the transistor threshold voltage, in V. Mob is the transistor mobility, in cm 2 / V·s. Ioff(-20V) is the source-drain leakage current when the gate-source voltage is -20V and the source-drain voltage is 15V, and the unit is flat A. The unit of channel length is um. The Ion coefficient is defined as: Ion coefficient = Ion / (W / L), Ion is the measured value of the on-current in a darkroom environment, W is the transistor channel width, and L is the transistor channel length.

[0074] The above data show that after the plasma equipment is modified, the changes in the characteristics of the transistor are within an acceptable range.

[0075] Based on the same inventive concept, an embodiment of the present disclosure further provides a plasma device, comprising the aforementioned lower electrode structure.

[0076] The present disclosure does not limit the structure other than the lower electrode structure in the plasma device. Those skilled in the art can design it according to conventional design schemes.

[0077] The present disclosure does not limit the type of plasma equipment. For example, the plasma equipment is a plasma etching equipment.

[0078] Figure 6 : is a simplified structural diagram of a plasma device. The lower electrode structure provided in the embodiment of the present disclosure is arranged at the bottom of the inner side of the chamber wall 8. The chamber wall 8 is usually a metal structure. The crossbeam 61 is fixed on the inner top surface of the chamber wall 8. The crossbeam 61 is usually a metal structure. The upper electrode 6 is fixed on the crossbeam 61. A ring insulating layer 7 is arranged around the outer periphery of the upper electrode 6. The material of the insulating layer 7 is, for example, ceramic. The gas inlet channel 62 is used to input the reaction gas into the plasma chamber.

[0079] When the reaction is completed, the reaction gas is discharged from the exhaust channel 4, and the airflow above the edge area of ​​the lower electrode 3 is relatively slow, which suppresses the reaction of the edge area of ​​the wafer or display substrate above the lower electrode 3 and improves the consistency of the process.

[0080] The various embodiments in the present disclosure are described in a progressive manner, and the same or similar parts between the various embodiments can be referenced to each other, and each embodiment focuses on the differences from other embodiments.

[0081] The protection scope of the present disclosure is not limited to the above-mentioned embodiments. Obviously, those skilled in the art can make various changes and modifications to the present disclosure without departing from the scope and spirit of the present disclosure. If these changes and modifications fall within the scope of the claims of the present disclosure and their equivalents, the intention of the present disclosure also includes these changes and modifications.

Claims

1. A lower electrode structure of a plasma device, characterized in that: include: A lower electrode, an insulating layer and a base, wherein the insulating layer is disposed on the base, the lower electrode is disposed on the insulating layer, an exhaust channel is disposed on the base and at least one exhaust port is formed on the upper surface of the base, the lower electrode structure further comprises a rectifying structure, the rectifying structure is made of an insulating material and has a height exceeding the lower electrode, the rectifying structure is located on a side of the exhaust port facing the lower electrode, so as to slow down the exhaust flow rate of the lower electrode near the exhaust port; The rectifying structure is in a plate shape, which is perpendicular or nearly perpendicular to the plane where the lower electrode is located; The lower electrode is rectangular, and the exhaust port is arranged outside the four corners of the lower electrode. The rectifying structure includes four first plates and four second plates corresponding to each other. The first plates and the corresponding second plates are spliced ​​into a right-angle dihedral angle. The first plate and a group of opposite sides of the lower electrode have the same extension direction, and the second plate and another group of opposite sides of the lower electrode have the same extension direction. The opening direction of the right-angle dihedral angle is toward the central area of ​​the lower electrode.

2. The lower electrode structure according to claim 1, characterized in that: The rectifying structure and an edge region of the lower electrode and / or an edge region of the insulating layer are arranged opposite to each other.

3. The lower electrode structure according to claim 1, characterized in that: The lower electrode is rectangular, the first plate and the long side of the rectangle have the same extension direction, the second plate and the short side of the rectangle have the same extension direction, and the size of the first plate along the extension direction of the long side of the rectangle is greater than the size of the second plate along the extension direction of the short side of the rectangle.

4. The lower electrode structure according to claim 1, characterized in that: The rectifying structure has through holes in the up-and-down directions, and a connecting piece passes through the through holes to fix the rectifying structure on the insulating layer.

5. The lower electrode structure according to claim 1, characterized in that: The height of the rectifying structure beyond the lower electrode is in the range of 6 cm to 10 cm.

6. The lower electrode structure according to claim 1, characterized in that: The distance between the rectifying structure and the lower electrode in the horizontal direction is in the range of 1 cm to 2 cm.

7. The lower electrode structure according to claim 1, characterized in that: The material of the rectifying structure includes ceramics.

8. A plasma device, characterized in that: The invention comprises the lower electrode structure according to any one of claims 1 to 7.

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