Substrate processing method, substrate and plasma processing equipment

Abstract

The invention discloses a substrate processing method, a substrate and plasma processing device.The substrate processing method comprises the following steps that a reaction cavity is provided, and a base is arranged in the reaction cavity; a substrate is placed on the base; the substrate comprises a functional area located in the middle of the substrate and an edge area located on the edge of the substrate, and the functional area is used for containing circuit elements; a deposition step: introducing deposition gas to form a first deposition layer only covering the edge region; etching gas is introduced, only the first deposition layer is etched, a second deposition layer is formed, and the thickness uniformity of the second deposition layer is better than that of the first deposition layer.

Description

Technical Field

[0001] The present invention relates to the field of semiconductors, and particularly to a substrate processing method, a substrate, and a plasma processing apparatus. Background Art

[0002] In the semiconductor manufacturing process, complex interactions such as lithography, etching, and chemical mechanical polishing will form various unstable thin films at the wafer edge. These thin films may peel off or transfer to the device area in subsequent process steps, resulting in defects and semiconductor device failures. Currently, edge etching is generally used to remove the film stack to reduce the impact of defects, but this will cause problems such as over-etching on the wafer edge, forming edge defects. Subsequently, arc and surface charge-discharge problems that may occur on the back-end of line (BEOL) wafers cannot be removed by etching with severely damaged edge defects. Or by pre-depositing an etch stop layer to avoid over-etching at the edge, however, this increases the process complexity.

[0003] Therefore, there is currently a solution to use an edge etching device to deposit a proprietary protective film on the edge to solve these common problems that may affect the semiconductor quality.

[0004] However, for the protective film deposited by the edge etching device, the protective film near the center of the substrate is thinner, and the protective film near the edge of the substrate is thicker. The thickness of the protective film at the edge of the substrate may even reach more than 10 times the thickness of the protective film near the center of the substrate. The film thickness of the protective film is large and unevenly distributed, and it is easy to peel off from the substrate in subsequent processes, causing contamination or failure. And, as Figure 1 shown, the protective film stacked on the edge of the substrate shortens the distance between the substrate A, the upper electrode B, and the upper ground ring C, and arc discharge D is likely to occur at the gap between the protective film and the upper electrode B or the upper ground ring C. Summary of the Invention

[0005] The object of the present invention is to provide a method capable of depositing a deposition layer with better uniformity on a substrate.

[0006] To achieve the above object, the present invention provides a substrate processing method, including the following steps:

[0007] Providing a reaction chamber, wherein a susceptor is provided in the reaction chamber;

[0008] Placing a substrate on the susceptor; the substrate includes a functional area located in the middle of the substrate and an edge area located at the edge of the substrate, and the functional area is used to accommodate circuit elements;

[0009] Deposition step: introducing a deposition gas to form a first deposition layer covering only the edge area;

[0010] Etching step: Introduce an etching gas to etch only the first deposited layer to form a second deposited layer, and the thickness uniformity of the second deposited layer is better than that of the first deposited layer.

[0011] Optionally, the radius of the substrate is R, and the edge region is at least 0.98R away from the center of the substrate.

[0012] Optionally, the thickness of the first deposited layer increases from the junction of the functional region and the edge region to the edge of the substrate.

[0013] Optionally, the difference in thickness at each part of the second deposited layer is not greater than

[0014] Optionally, in the deposition step, the deposition rate increases from the junction of the functional region and the edge region to the edge of the substrate.

[0015] Optionally, in the etching step, the etching rate increases from the junction of the functional region and the edge region to the edge of the substrate.

[0016] Optionally, the surface of the edge region of the substrate has a thin film layer, and both the first deposited layer and the second deposited layer completely cover the surface of the thin film layer.

[0017] Optionally, the first deposited layer directly covers the surface of the edge region of the substrate.

[0018] Optionally, the first deposited layer wraps the edge of the substrate; the coverage area of the second deposited layer is smaller than that of the first deposited layer.

[0019] Optionally, the deposition gas includes CH x F y or C n F m at least one of them; wherein, 0 < x ≤ 3, y = 4 - x; 0 < n ≤ 4, 0 < m ≤ 8.

[0020] Optionally, in the deposition step, the pressure in the reaction chamber is 5 Torr - 10 Torr, the temperature in the reaction chamber is 20 - 90 °C, the deposition time is 200 s - 400 s, and the deposition power is 500 - 1500 W.

[0021] Optionally, the deposition gas is at least one of hydrocarbons or carbon oxides, and the first deposited layer is amorphous carbon.

[0022] Optionally, the pressure in the reaction chamber is 1 Torr - 8 Torr, the temperature in the reaction chamber is 20°C - 70°C, the deposition time is 30 s - 100 s, and the deposition power is 500 W - 1000 W.

[0023] Optionally, the deposition gas is a metal gas, and the first deposition layer is a metal layer.

[0024] Optionally, the etching gas is at least one of O2 or N2.

[0025] Optionally, the pressure in the reaction chamber is 1 Torr - 4 Torr, the temperature in the reaction chamber is 20°C - 70°C, the etching time is 30 s - 100 s, and the etching power is 100 W - 500 W.

[0026] Optionally, the reaction chamber further includes:

[0027] An upper electrode, disposed opposite to the base, for delivering deposition gas and etching gas into the reaction chamber;

[0028] An upper edge ring, disposed around the upper electrode;

[0029] Adjust the radius of the upper edge ring and / or the distance between the upper electrode and the substrate so that the plasma aggregation range is concentrated in the edge region.

[0030] The present invention also provides a substrate obtained after being processed by the above-mentioned substrate processing method.

[0031] The present invention also provides a plasma processing device, including:

[0032] A plasma reaction chamber;

[0033] A base, located in the plasma reaction chamber, for carrying a substrate;

[0034] A radio frequency source, for exciting the gas in the plasma reaction chamber into plasma;

[0035] A controller, configured to execute the above-mentioned substrate processing method.

[0036] Compared with the prior art, the beneficial effects of the present invention at least include:

[0037] (1) The substrate processing method provided by the present invention further includes an etching step after the deposition step. An etching gas is introduced to etch the first deposition layer to form a second deposition layer with a thinner thickness. Compared with the first deposition layer, the gap between the surface of the second deposition layer and the upper electrode or the upper ground ring is larger, reducing the possibility of arc discharge at the gap. The etching amount of the first deposition layer at the junction of the functional area and the edge area is the smallest, and the etching amount at the outermost edge of the substrate is the largest, that is, the etching amount is small in the area where the first deposition layer is thinner and large in the area where the first deposition layer is thicker, making the thickness uniformity of the second deposition layer better than that of the first deposition layer. Compared with the first deposition layer, the second deposition layer has better thickness uniformity, better stability and more uniform thermal stress performance, avoiding the problem that the first deposition layer is likely to fall off from the edge due to uneven deposition thickness at the edge of the substrate.

[0038] (2) The substrate processing method provided by the present invention can be carried out before the semiconductor production process. First, use the substrate processing method provided by the present invention to directly cover the surface of the edge area of the substrate with the first deposition layer to protect the surface of the edge area of the substrate and prevent damage to the substrate by subsequent processing techniques; it can also be carried out during the semiconductor production process, so that the second deposition layer completely covers and wraps the loose thin film layer formed on the surface of the substrate, preventing the thin film layer from falling off the substrate and not overly shortening the distance between the substrate and the upper electrode and the upper ground ring.

[0039] (3) In order to make the deposition gas and the etching gas only lead to the edge area of the substrate, the present invention also provides two ways to adjust the plasma aggregation range. One is to roughly adjust the plasma aggregation range by adjusting the radius of the upper edge ring, and the other is to finely adjust the plasma aggregation range by adjusting the distance between the upper electrode and the substrate. By controlling whether the contact area between the plasma and the substrate surface is the same or different, a second deposition layer with better uniformity can be obtained. Description of the Drawings

[0040] Figure 1 Schematic diagram of arc discharge generated in the reaction chamber for the substrate processed by the prior art.

[0041] Figure 2 Schematic flow chart of the substrate processing method provided by the present invention.

[0042] Figure 3 Schematic diagram of the substrate processed by the substrate processing method of the present invention.

[0043] Figure 4 Schematic diagram of the reaction chamber structure provided by the present invention.

[0044] Figure 5 Deposition thickness curves of Example 1, Example 2 and the comparative example. Detailed implementation manners

[0045] The technical solutions of the present invention will be clearly and completely described below in conjunction with the accompanying drawings. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0046] As Figure 2 shown, the present invention provides a substrate processing method, including the following steps:

[0047] Step S1: Provide a reaction chamber, and a pedestal is provided in the reaction chamber. Place the substrate on the pedestal; the substrate includes a functional area located in the middle of the substrate and an edge area located at the edge of the substrate, and the functional area is used to accommodate circuit elements. It can be understood that the edge area is the corner area on the substrate where circuit elements cannot be formed.

[0048] In some embodiments, the radius of the substrate is R, and the edge area is at least 0.98R away from the center of the substrate, so as to ensure the effective utilization rate of the substrate. Taking the substrate with a radius of 150 mm as an example, the functional area falls within the area from the center of the substrate to 147 mm away from the center of the substrate. The functional area is a circle with a radius of 147 mm; the edge area is the area from 147 mm away from the center of the substrate to 150 mm away from the center of the substrate, and the edge area is an annular ring with an annular width of 3 mm.

[0049] Step S2: Deposition step: Introduce deposition gas to form a first deposition layer covering only the edge area.

[0050] As Figure 3 (a) shown, in the deposition step, the deposition gas is led to the edge area of the substrate 1 to form a first deposition layer 2 covering the edge area of the substrate 1. When the deposition gas is led to the substrate, the deposition rate increases from the junction of the functional area and the edge area to the edge of the substrate. We found that whether it is edge etching or edge deposition, as Figure 1 shown, the plasma E is located outside the circumference of the substrate, and the reaction intensity decreases sharply from the outside to the inside in the radial direction. When depositing, a first deposition layer 2 with a thickness increasing from the junction of the functional area and the edge area to the edge of the substrate is formed.

[0051] In some embodiments, the deposition gas includes CH x F y or C n F mat least one of them; wherein, 0 < x ≤ 3, y = 4 - x; 0 < n ≤ 4, 0 < m ≤ 8. The pressure in the reaction chamber is 5 Torr - 10 Torr, the temperature in the reaction chamber is 20 - 90 °C, the deposition time is 200 s - 400 s, and the deposition power is 500 - 1500 W. The first deposition layer is a carbon fluoride or carbon hydrogen fluoride material layer to inhibit the shedding of the deposited layer particles already formed at the edge of the substrate or to protect the exposed substrate material.

[0052] In some embodiments, the deposition gas is at least one of hydrocarbons or carbon oxides, the pressure in the reaction chamber is 1 Torr - 8 Torr, the temperature in the reaction chamber is 20 °C - 70 °C, the deposition time is 30 s - 100 s, and the deposition power is 500 W - 1000 W. The first deposition layer is amorphous carbon, and the etching selectivity of the amorphous carbon relative to the commonly used silicon oxide and silicon nitride materials in the functional area is high and it is not easily etched away, which is beneficial to the protection of the edge in the etching process.

[0053] In some embodiments, the deposition gas is a metal-containing organic compound gas, and the first deposition layer is a metal layer.

[0054] Step S3: Etching step: Introduce an etching gas to etch only the first deposition layer to form a second deposition layer, and the thickness uniformity of the second deposition layer is better than that of the first deposition layer.

[0055] The first deposition layer and the second deposition layer of the present invention can be a passivation layer or a protection layer.

[0056] After the deposition step of the present invention, an etching step is further provided. Thus, by etching and trimming the first deposition layer, the problem that the first deposition layer piled up from the junction of the functional area and the edge area to the substrate edge is likely to fall off and cause pollution and increase the risk of arc discharge is overcome.

[0057] Specifically, without replacing the reaction chamber, the same edge etching equipment can be continuously used to introduce an etching gas to etch the first deposition layer to form a second deposition layer with a thinner thickness. Compared with the first deposition layer, the gap between the surface of the second deposition layer and the upper electrode or the upper grounding ring is larger, reducing the possibility of arc discharge at the gap.

[0058] Similarly, just as the deposition gas has different deposition rates at various locations in the edge region of the substrate, by controlling the plasma around the circumference of the substrate, the reaction intensity decreases sharply from the outside to the inside in the radial direction. When the etching gas reaches the substrate, the etching rate increases from the junction of the functional region and the edge region to the edge of the substrate. Therefore, the etching amount of the first deposition layer at the junction of the functional region and the edge region is the smallest, and the etching amount at the outermost edge of the substrate is the largest. That is, the etching amount is small in the region where the first deposition layer is thinner, and the etching amount is large in the region where the first deposition layer is thicker. Moreover, for the same etching machine, the rates of introducing the deposition gas and the etching gas to the same position are basically the same. As Figure 3 shown in (b) of Figure 3 , finally, the first deposition layer can be etched into a second deposition layer 3 with better thickness uniformity than the first deposition layer. After the etching step, the first deposition layer is modified into a second deposition layer 3 with smaller thickness differences at various locations. Compared with the first deposition layer, the second deposition layer 3 has better layer thickness uniformity, better stability, and more uniform thermal stress performance, avoiding the problem that the first deposition layer is likely to fall off from the edge due to uneven deposition thickness at the edge of the substrate.

[0059] The first deposition layer covers at least the outermost edge of the substrate. The substrate includes a back surface facing the pedestal and a front surface opposite to the back surface. In some embodiments, the first deposition layer also wraps the edge of the substrate, that is, the first deposition layer also covers the junction of the front surface and the back surface of the substrate, and even covers the back surface of the substrate.

[0060] In some embodiments, the coverage area of the second deposition layer is smaller than that of the first deposition layer. However, the second deposition layer still covers at least the outermost edge of the substrate. Viewing the substrate in the direction perpendicular to the plane of the substrate, the first deposition layer is an annular shape with a width r1, and the second deposition layer is an annular shape with a width r2, where r1 ≥ r2.

[0061] It should be emphasized that the main purpose of the etching step of the present invention is to reduce the coverage thickness of the first deposition layer and improve its thickness uniformity and density, rather than significantly reducing the coverage area of the first deposition layer. In particular, in the present invention, the second deposition layer still covers at least the outermost edge of the substrate, and will not completely remove the deposition layer at the outermost edge of the substrate, thereby forming a dense passivation layer / protective layer to inhibit the deposition of residues in the subsequent process on the second deposition layer, and can wrap the residues inside and prevent them from falling off. It can be understood that the density of the first deposition layer deposited at one time decreases from the bottom layer to the surface layer, and the surface layer is relatively loose, which is not conducive to the stability of the deposition layer and increases the risk of falling off and particulate pollution. Through the thickness trimming of the etching step, the loose part on the surface is removed, the dense part at the bottom is retained, and due to the plasma bombardment extrusion effect, the second deposition layer becomes more dense.

[0062] In some embodiments, the difference in thickness at various locations of the second deposition layer is not greater than To improve the stability of the second deposition layer and the more uniform thermal stress performance.

[0063] In some embodiments, the etching gas is at least one of O2 or N2. The pressure in the reaction chamber is 1 Torr - 4 Torr, the temperature in the reaction chamber is 20°C - 70°C, the etching time is 30 s - 100 s, and the etching power is 100 W - 500 W.

[0064] The substrate processing method provided by the present invention can be carried out before the semiconductor production process, that is, before processing technologies such as depositing, lithography, etching, or chemical mechanical polishing of the substrate. At this time, the surface of the substrate edge region is untreated and there is no impurity accumulation. However, each processing technology in the semiconductor production process will damage the edge region of the substrate. For example, it will cause the thickness of the substrate edge region to thin or the surface structure to change. In particular, the edge of the substrate is etched, resulting in a reduction in the substrate size. When the reduced substrate is transferred into the next reaction chamber, it may cause a program error, and the entire substrate can only be scrapped. Therefore, before the semiconductor production process starts, first use the substrate processing method provided by the present invention to directly cover the first deposition layer on the surface of the edge region of the substrate, so as to protect the surface of the substrate edge region and prevent subsequent processing technologies from damaging the substrate.

[0065] The substrate processing method provided by the present invention can also be carried out during the semiconductor production process. When the substrate has undergone all or part of the processing technologies such as deposition, lithography, etching, or chemical mechanical polishing, a thin film layer will gradually accumulate in the edge region of the substrate. The compactness of the thin film layer is poor, and it is easy to fall off and contaminate the reaction chamber. It will also shorten the distance between the substrate and the upper electrode and the upper grounding ring, and arc discharge is likely to occur at the gap between the thin film layer and the upper electrode or the upper grounding ring. During the semiconductor production process, when the thin film layer is generated or the thin film layer reaches a certain thickness and has a negative impact on the semiconductor production process, use the substrate processing method provided by this application. In the deposition step, the first deposition layer completely covers the surface of the thin film layer. The thin film layer is composed of various impurities and is loose inside, while the compactness of the first deposition layer is higher than that of the thin film layer. The first deposition layer covers the thin film layer inside, so that the thin film layer cannot fall off from the substrate. The first deposition layer will further increase the overall thickness of the substrate and shorten the distance between the substrate and the upper electrode and the upper grounding ring. However, since the etching step is included after the deposition step of the present invention, in the etching step, the thickness of the first deposition layer is thinned to form a second deposition layer, and the second deposition layer also completely covers the surface of the thin film layer. Although the second deposition layer still has a certain thickness, compared with the substrate thickness without setting the second deposition layer, the increase in this thickness is small and will not overly shorten the distance between the substrate and the upper electrode and the upper grounding ring.

[0066] In some embodiments, such as Figure 4As shown in the figure, the reaction chamber of the present invention further includes: an upper electrode 4, which is disposed opposite to the base 5 and is used to transport deposition gas and etching gas into the reaction chamber; an upper edge ring 6, which is disposed around the upper electrode 4; by adjusting the radius of the upper edge ring 6, and / or the distance between the upper electrode and the substrate, the deposition gas and the etching gas are led to the edge area.

[0067] In order to make the deposition gas and the etching gas only lead to the edge area of the substrate, the present invention provides two ways to adjust the plasma aggregation range. One is to roughly adjust the plasma aggregation range by adjusting the radius of the upper edge ring 6, and the adjustment accuracy is 1 mm. Taking the formation of the first deposition layer by introducing deposition gas as an example, the larger the radius of the upper edge ring 6, the smaller the area of the plasma covering the edge area of the substrate 1. Viewing the substrate 1 from the direction perpendicular to the plane of the substrate, the first deposition layer is annular, and the first deposition layer wraps the edge of the substrate 1; the larger the radius of the upper edge ring 6, the smaller the width of the annular first deposition layer. If the radius of the substrate 1 is R and the radius of the upper edge ring 6 is r, then the observed width of the annular first deposition layer is (R - r). The other is to finely adjust the plasma aggregation range by adjusting the distance between the upper electrode 4 and the substrate 1, the adjustment accuracy is 0.05 mm, and the adjustment range does not exceed 1 mm. The smaller the distance between the upper electrode 4 and the substrate 1, the smaller the area of the plasma covering the edge area of the substrate 1, and the smaller the width of the annular first deposition layer. In order to ensure that in the etching step, the etching gas only etches the first deposition layer, the radius of the upper edge ring 6 in the etching step is not less than the radius of the upper edge ring 6 in the deposition step.

[0068] The present invention also provides a plasma processing device, including: a plasma reaction chamber; a base, which is located in the plasma reaction chamber and is used to carry a substrate; a radio frequency source, which is used to excite the gas in the plasma reaction chamber into plasma; a controller, which is configured to execute the above-mentioned substrate processing method.

[0069] Embodiment 1

[0070] This embodiment provides a substrate processing method, including the following steps:

[0071] Step S1.1: Provide a reaction chamber, and a base is provided in the reaction chamber.

[0072] Place the substrate on the base; the substrate includes a functional area located in the middle of the substrate and an edge area located at the edge of the substrate, and the functional area is used to accommodate circuit elements. The substrate in this embodiment is a 12-inch polysilicon substrate.

[0073] The reaction chamber further includes an upper electrode disposed opposite to the base, which is used to transport deposition gas and etching gas into the reaction chamber; and an upper edge ring disposed around the upper electrode.

[0074] Step S1.2: Deposition step: Introduce deposition gas to form a first deposition layer that only covers the edge region.

[0075] Adjust the radius of the upper edge ring of the reaction chamber to 148 mm, and the distance between the upper electrode and the substrate is 0.45 mm. The deposition gas is led to the edge region of the substrate to form a first deposition layer covering the edge region of the substrate. The deposition gas is at least one of CH4, CO, or CO2. For example, CO can be selected, or a combination of CH4, CO, or CO2, etc. The pressure in the reaction chamber is 4 Torr, the temperature in the reaction chamber is 50 °C, the deposition time is 60 s, and the deposition power is 300 W. The first deposition layer is amorphous carbon.

[0076] Step S1.3: Etching step: Introduce etching gas to etch only the first deposition layer to form a second deposition layer, and the thickness uniformity of the second deposition layer is better than that of the first deposition layer.

[0077] The etching gas is at least one of O2 or N2. The pressure in the reaction chamber is 2 Torr, the temperature in the reaction chamber is 50 °C, the etching time is 60 s, and the etching power is 300 W.

[0078] Example 2

[0079] This example provides a substrate processing method. Among them, steps S2.1 - S2.2 are the same as steps S1.1 - S1.2 of Example 1.

[0080] Step S2.3: Etching step: Introduce etching gas to etch only the first deposition layer to form a second deposition layer, and the thickness uniformity of the second deposition layer is better than that of the first deposition layer.

[0081] Adjust the radius of the upper edge ring of the reaction chamber to 149 mm, and the distance between the upper electrode and the substrate is 0.55 mm. The etching gas is at least one of O2 or N2. For example, the etching gas is O2. The pressure in the reaction chamber is 2 Torr, the temperature in the reaction chamber is 50 °C, the etching time is 60 s, and the etching power is 300 W.

[0082] In the deposition step and etching step of Example 1, the radius of the upper edge ring of the reaction chamber is the same as the distance between the upper electrode and the substrate, and the regions where the deposition gas and the etching gas are led to the substrate surface are also the same.

[0083] Compared with Example 1, the etching step of Example 2 adjusts the radius of the upper edge ring and the distance between the upper electrode and the substrate. After adjustment, the region where the etching gas is led to the substrate surface is smaller than the region where the deposition gas is led to the substrate surface.

[0084] Example 3

[0085] This embodiment provides a substrate processing method. Among them, step S3.1 is the same as step S1.1 of Embodiment 1.

[0086] Step S3.2: Deposition step: Introduce deposition gas to form a first deposition layer that only covers the edge region.

[0087] Adjust the radius of the upper edge ring of the reaction chamber to 148 mm, and the distance between the upper electrode and the substrate is 0.45 mm. The deposition gas is directed to the edge region of the substrate to form a first deposition layer covering the edge region of the substrate. The deposition gas includes CH x F y or C n F m wherein at least one of them; where 0 < x ≤ 3, y = 4 - x; 0 < n ≤ 4, 0 < m ≤ 8. For example, the deposition gas includes C4F8. The pressure in the reaction chamber is 8 Torr, the temperature in the reaction chamber is 100 °C, the deposition time is 300 s, and the deposition power is 1500 W. The first deposition layer is a carbon fluoride or carbon hydrogen fluoride material layer.

[0088] Step S3.3: Etching step: Introduce etching gas to only etch the first deposition layer to form a second deposition layer, and the thickness uniformity of the second deposition layer is better than that of the first deposition layer.

[0089] The etching gas is at least one of O2 or N2. The pressure in the reaction chamber is 2 Torr, the temperature in the reaction chamber is 50 °C, the etching time is 60 s, and the etching power is 300 W.

[0090] Comparative example

[0091] The comparative example also provides a substrate processing method. Compared with Embodiment 1, the substrate processing method of the comparative example does not include an etching step, that is, after forming the first deposition layer, the processing method ends.

[0092] Slice the wafers of Embodiment 1, Embodiment 2 and the comparative example, and observe and measure the thickness of the deposition layer under SEM (scanning electron microscope). Draw a curve as Figure 5 shown. The abscissa of this curve is the substrate radius, and the ordinate is the thickness of the deposition layer. According to Figure 5 , the thickness of the first deposition layer of the comparative example exceeds the second deposition layers of Embodiment 1 and Embodiment 2, and the difference in thickness at each place does not exceed Compared with the first deposition layer of the comparative example, after the etching step in Example 1 and Example 2, the formed second deposition layer has better thickness uniformity. The ranges of the deposition gas and the etching gas reaching the substrate surface in Example 1 are the same; compared with Example 1, in the etching step of Example 2, the radius of the upper edge ring and the distance between the upper electrode and the substrate are also adjusted, so that the range of the etching gas reaching the substrate surface in Example 2 is smaller than that of the deposition gas. It is equivalent to that the etching gas in Example 1 etches and modifies all parts of the surface of the first deposition layer, while the etching gas in Example 2 does not etch and modify the thinner part of the first deposition layer, but only etches and modifies the thicker part of the first deposition layer. The thickness uniformity of the second deposition layer in Example 2 is better than that in Example 1.

[0093] In summary, the present invention provides a substrate processing method, in which an etching step is further provided after the deposition step. Without replacing the reaction chamber, the same etching machine is continued to be used, and an etching gas is introduced to etch the first deposition layer to form a second deposition layer with a thinner thickness. Compared with the first deposition layer, the gap between the surface of the second deposition layer and the upper electrode or the upper grounding ring is larger, reducing the possibility of arc discharge at the gap. The etching amount of the first deposition layer at the junction of the functional area and the edge area is the smallest, and the etching amount at the outermost edge of the substrate is the largest, that is, the etching amount of the thinner area of the first deposition layer is small, and the etching amount of the thicker area of the first deposition layer is large, so that the thickness uniformity of the second deposition layer is better than that of the first deposition layer. Compared with the first deposition layer, the surface of the second deposition layer is closer to the horizontal plane, avoiding the problem that the first deposition layer is likely to fall off from the edge due to uneven deposition thickness at the edge of the substrate. It should be noted that the deposition step and the etching step of the present invention can be completed once or alternately cycled multiple times to form a protective deposition layer with uniform thickness and density and the expected thickness.

[0094] Although the content of the present invention has been introduced in detail through the above preferred embodiments, it should be recognized that the above description should not be considered as a limitation of the present invention. After those skilled in the art read the above content, various modifications and substitutions to the present invention will be obvious. Therefore, the protection scope of the present invention should be defined by the appended claims.

Claims

1. A substrate processing method, characterized in that, Comprising the following steps: Providing a reaction chamber, wherein a pedestal is arranged in the reaction chamber; Placing a substrate on the pedestal; the substrate includes a functional area located in the middle of the substrate and an edge area located at the edge of the substrate, and the functional area is used to accommodate circuit elements; Deposition step: Introducing deposition gas to form a first deposition layer that only covers the edge area; Etching step: Introducing etching gas to only etch the first deposition layer to form a second deposition layer, and the thickness uniformity of the second deposition layer is better than that of the first deposition layer.

2. The substrate processing method according to claim 1, characterized in that, The radius of the substrate is R, and the edge area is at least 0.98R away from the center of the substrate.

3. The substrate processing method according to claim 1, characterized in that, The thickness of the first deposition layer increases from the junction of the functional area and the edge area to the edge of the substrate.

4. The substrate processing method according to claim 1, characterized in that, The difference in thickness at each location of the second deposition layer is not greater than 5. The substrate processing method according to claim 1, characterized in that, In the deposition step, the deposition rate increases from the junction of the functional area and the edge area to the edge of the substrate.

6. The substrate processing method according to claim 5, characterized in that, In the etching step, the etching rate increases from the junction of the functional area and the edge area to the edge of the substrate.

7. The substrate processing method according to claim 1, characterized in that, The surface of the edge area of the substrate has a thin film layer, and both the first deposition layer and the second deposition layer completely cover the surface of the thin film layer.

8. The substrate processing method according to claim 1, characterized in that, The first deposition layer directly covers the surface of the edge area of the substrate.

9. The substrate processing method according to claim 1, characterized in that, The first deposition layer wraps the edge of the substrate; the coverage area of the second deposition layer is smaller than that of the first deposition layer.

10. The substrate processing method according to claim 1, characterized in that, The deposition gas includes CH x F y or C n F m wherein at least one of them; where 0 < x ≤ 3, y = 4 - x; 0 < n ≤ 4, 0 < m ≤ 8.

11. The substrate processing method according to claim 10, characterized in that, In the deposition step, the pressure in the reaction chamber is 5 Torr - 10 Torr, the temperature in the reaction chamber is 20 - 90 °C, the deposition time is 200 s - 400 s, and the deposition power is 500 - 1500 W.

12. The substrate processing method according to claim 1, characterized in that, The deposition gas is at least one of hydrocarbon or carbon oxide, and the first deposition layer is amorphous carbon.

13. The substrate processing method according to claim 12, characterized in that, The pressure in the reaction chamber is 1 Torr - 8 Torr, the temperature in the reaction chamber is 20 °C - 70 °C, the deposition time is 30 s - 100 s, and the deposition power is 500 W - 1000 W.

14. The substrate processing method according to claim 1, characterized in that, The deposition gas is a metal gas, and the first deposition layer is a metal layer.

15. The substrate processing method according to claim 1, characterized in that, The etching gas is at least one of O2 or N2.

16. The substrate processing method according to claim 15, characterized in that, The pressure in the reaction chamber is 1 Torr - 4 Torr, the temperature in the reaction chamber is 20 °C - 70 °C, the etching time is 30 s - 100 s, and the etching power is 100 W - 500 W.

17. The substrate processing method according to claim 1, characterized in that, The reaction chamber further includes: an upper electrode, which is arranged opposite to the pedestal and is used to transport deposition gas and etching gas into the reaction chamber; An upper edge ring, which is arranged around the upper electrode; Adjusting the radius of the upper edge ring and / or the distance between the upper electrode and the substrate to make the plasma aggregation range concentrate on the edge area.

18. A substrate obtained by processing with the substrate processing method according to any one of claims 1-17.

19. A plasma processing apparatus, characterized in that Including: A plasma reaction chamber; A pedestal, which is located in the plasma reaction chamber and is used to carry the substrate; A radio frequency source, which is used to excite the gas in the plasma reaction chamber into plasma; A controller, which is configured to execute the substrate processing method according to any one of claims 1 - 17.

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