Flow uniformizing structure, semiconductor process equipment and photoresist opening morphology adjusting method

Abstract

The invention discloses a flow uniformizing structure, semiconductor process equipment and a photoresist opening morphology adjusting method. The flow uniformizing structure comprises a first flow uniformizing piece, a second flow uniformizing piece and a driving part, the first flow uniformizing piece comprises a plurality of through holes; the second flow uniformizing piece is movably arranged above the first flow uniformizing piece, and a gap is formed between the second flow uniformizing piece and the first flow uniformizing piece in the vertical direction; the driving part is connected with the second flow uniformizing piece and is used for driving the second flow uniformizing piece to move to a first position above the central area of the first flow uniformizing piece or a second position far away from the central area of the first flow uniformizing piece; according to the flow uniformizing structure provided by the invention, the semiconductor process equipment can be compatible with two types of processes that only the remote plasma source above is turned on and the upper radio frequency source and the lower radio frequency source are turned on, a plurality of processes for adjusting the photoresist opening morphology can be executed through one set of semiconductor process equipment, and the technological process for adjusting the photoresist opening morphology is simplified.

Description

Technical Field

[0001] This application relates to the field of semiconductor process technology, specifically to a uniform flow structure, semiconductor process equipment, and a method for adjusting the opening morphology of photoresist. Background Technology

[0002] Photoresist (PR), also known as photoresist, is a photosensitive material whose properties change upon exposure to light. It is one of the key materials for micro-patterning in microelectronics technology, mainly used in the electronics and printing industries. Photoresists are classified as positive or negative: positive photoresists, after exposure to light, become more easily dissolved in the exposed areas, and after development, they dissolve completely, leaving only the unexposed areas to form the pattern; negative photoresists, on the other hand, become less easily dissolved in the exposed areas after exposure to light, and after development, the exposed areas remain to form the pattern.

[0003] As the thickness and aspect ratio of photoresist increase, the light received at the bottom of the photoresist is significantly reduced. This reduced light reception at the bottom means that the acid generated by the light exposure is insufficient to completely deprotect the acid-insecure groups of the polymer resin. Consequently, the solubility of the photoresist at the bottom does not change after exposure, leading to problems such as footing or scumming after development. Therefore, solving the morphology issues of thick photoresists or high aspect ratio photoresists has become one of the key technologies in semiconductor manufacturing.

[0004] Existing technologies generally achieve photoresist morphology control by adjusting the photoresist composition and changing the photolithography and development processes. However, these control schemes often suffer from problems such as process complexity. Summary of the Invention

[0005] In view of this, this application provides a uniform flow structure, semiconductor process equipment, and a method for adjusting the opening morphology of photoresist to solve the problem of complex processes in traditional photoresist morphology adjustment schemes.

[0006] This application provides a flow equalization structure, which includes a first flow equalization element, a second flow equalization element, and a driving unit;

[0007] The first flow equalizer includes multiple through holes;

[0008] The second flow equalizer is movably disposed above the first flow equalizer, and there is a gap between them in the vertical direction;

[0009] The driving unit is connected to the second flow equalizer and is used to drive the second flow equalizer to a first position above the central region of the first flow equalizer or a second position away from the central region of the first flow equalizer.

[0010] Optionally, the gap between the second flow equalizer and the first flow equalizer is less than twice the thickness of the plasma sheath, or the gap between the second flow equalizer and the first flow equalizer is 1-2 mm.

[0011] Optionally, the first flow equalizer is a circular plate; the diameter of the first flow equalizer is 310-350 mm; or, the diameter of the first flow equalizer is 1-1.2 times the diameter of the wafer to be processed.

[0012] Optionally, the second flow equalizer is a circular plate; the diameter of the second flow equalizer is 180-220 mm; or, the diameter of the second flow equalizer is 0.6-0.7 times the diameter of the wafer to be processed.

[0013] Optionally, the second flow equalizer includes at least two sub-flow equalizers. When the second flow equalizer is in the first position, the at least two sub-flow equalizers are spliced ​​together as a whole. The driving unit includes at least two sub-driving units, each of which is respectively disposed corresponding to each of the sub-flow equalizers, for driving the corresponding sub-flow equalizers to move closer to or further away from each other.

[0014] Optionally, the sub-drive unit includes a cylinder and a piston rod. The cylinder drives the piston rod to move, and the piston rod connects the cylinder and the corresponding sub-flow equalizer plate, and drives the sub-flow equalizer plate to move between the first position and the second position.

[0015] Optionally, the sub-drive unit includes a linear motor and a support rod. The linear motor drives the support rod to move, and the support rod connects the cylinder and the corresponding sub-flow equalizer, and drives the sub-flow equalizer to move between the first position and the second position.

[0016] This application also provides a semiconductor process apparatus, which includes a remote plasma source, a lower radio frequency source, a process chamber, and a uniform flow structure as described in any of the above embodiments;

[0017] The flow equalization structure is used to equalize the flow of gas entering the process chamber from the remote plasma source;

[0018] The process chamber includes a wafer carrier, and the lower radio frequency source is used to apply radio frequency power to the bias electrodes within the wafer carrier.

[0019] Optionally, the process chamber includes a reaction chamber and a flow equalization chamber located above the reaction chamber, and the first flow equalization element of the flow equalization structure is disposed between the reaction chamber and the flow equalization chamber; the side wall of the flow equalization chamber is also provided with a receiving cavity for accommodating the second flow equalization element when the second flow equalization element moves to the second position.

[0020] Optionally, the semiconductor process equipment further includes a controller; the controller is configured to control the drive unit to drive the second current equalizer to the first position when the remote plasma source is turned on, and to control the drive unit to drive the second current equalizer to the second position when the remote plasma source and the lower radio frequency source are turned on simultaneously.

[0021] This application also provides a method for adjusting the opening morphology of a photoresist, wherein the photoresist includes a plurality of openings, and the opening morphology adjustment method is applied to any of the above-mentioned semiconductor process equipment, comprising:

[0022] Turn on the remote plasma source and the lower radio frequency source to perform the first etching on the photoresist;

[0023] Determine whether the roughness of the opening sidewall of the photoresist exceeds a predetermined threshold;

[0024] When the roughness exceeds a predetermined threshold, the remote plasma source is turned on and the lower radio frequency source is turned off to perform a second etching on the photoresist.

[0025] Optionally, the first etching process includes: obtaining the opening shape; and controlling the remote plasma source to introduce a corresponding first etching gas according to the opening shape.

[0026] Optionally, the opening shape includes a trapezoid, and the first etching gas includes an oxygen-containing gas and a chemical etching gas.

[0027] Optionally, the opening shape includes an inverted trapezoid, and the first etching gas includes an oxygen-containing gas and a physical etching gas.

[0028] Optionally, the gas used for the second etching includes oxygen-containing gas and chemical etching gas.

[0029] The above-mentioned uniform flow structure, semiconductor process equipment, and photoresist opening morphology adjustment method of this application achieves an adjustable single / double-layer uniform flow mode by setting a first uniform flow element and a second uniform flow element. When using a remote plasma source, such as a microwave plasma source, with the plasma generation cavity located directly above the wafer to be processed, and both the remote plasma source and the lower radio frequency source are on, the driving unit drives the second uniform flow element to move to a second position away from the center region of the first uniform flow element, so that the incoming plasma passes through the first uniform flow element, which can improve the etching rate of the central region and ensure the overall uniformity of the plasma etching process; when only the aforementioned remote plasma source is on, the second uniform flow element is moved to a second position away from the center region of the first uniform flow element. When the plasma source is activated, the driving unit drives the second uniform flow element to a first position above the central region of the first uniform flow element. This can block at least part of the plasma flowing into the central region, reduce the etching rate in the central region, and make the etching rate of the plasma at the center and edge of the wafer to be processed tend to be consistent, thereby improving the etching uniformity. In this way, the corresponding semiconductor process equipment can be compatible with both processes where only the upper remote plasma source is turned on and both the upper and lower radio frequency sources are turned on. Multiple processes for adjusting the opening morphology of photoresist can be executed through a single semiconductor process equipment, simplifying the process of adjusting the opening morphology of photoresist.

[0030] Furthermore, the above-mentioned method for adjusting the opening morphology of photoresist involves reading the opening shape of the photoresist, determining the etching gas corresponding to the opening shape, and introducing the etching gas into a remote plasma source to etch the photoresist. This allows the first etching gas to be adjusted in a targeted manner according to the opening shape, which can further simplify the process. Attached Figure Description

[0031] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0032] Figure 1 and Figure 2 This is a schematic diagram of a semiconductor process apparatus according to an embodiment of this application;

[0033] Figure 3 This is a schematic diagram of the first flow equalization element according to an embodiment of this application;

[0034] Figure 4 This is a schematic diagram of the second flow equalizer according to an embodiment of this application;

[0035] Figure 5 This is a schematic diagram illustrating the etching uniformity analysis of the process chamber under a single-layer uniform flow configuration.

[0036] Figure 6This is a schematic diagram illustrating the etching uniformity analysis of the process chamber under a double-layer uniform flow configuration.

[0037] Figure 7 This is a schematic flowchart of a method for adjusting the opening morphology of photoresist according to an embodiment of this application;

[0038] Figure 8 and Figure 9 This is a schematic diagram of the openings in the photoresist;

[0039] Figure 10 and Figure 11 This is a schematic diagram of a semiconductor process apparatus according to another embodiment of this application;

[0040] Figure 12 This is a schematic flowchart of a method for adjusting the opening morphology of photoresist according to another embodiment of this application;

[0041] Figure 13 This is a schematic diagram comparing the inverted trapezoidal opening shape before and after adjustment according to an embodiment of this application;

[0042] Figure 14 This is a schematic diagram comparing the shape of the trapezoidal opening before and after adjustment according to an embodiment of this application;

[0043] Figure 15 This is a schematic diagram showing the difference between before and after the improvement of the roughness of the opening sidewall in an embodiment of this application. Detailed Implementation

[0044] The technical solutions in the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of them. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application. In the absence of conflict, the following embodiments and their technical features can be combined with each other.

[0045] Photoresist typically requires several openings to function as a mask. During the formation of these openings, as the photoresist thickness and aspect ratio increase, the light reaching the bottom of the photoresist is significantly reduced. This reduced light reception at the bottom can make it difficult for the acid generated by the light to completely deprotect the unstable acid groups in the polymer resin. This results in the photoresist's solubility remaining unchanged after exposure, leading to bottom footing or scumming after development. Consequently, the resulting openings contain scumming and / or have morphological distortion. Some solutions employ remote plasma sources to dissociate the etching gas and further refine the opening morphology. The plasma is generated outside the process chamber. High-energy ions and hot electrons in the plasma are absorbed and filtered out before entering the process chamber. The plasma entering the process chamber is predominantly free radicals with fewer charged ions, resulting in weak bombardment and minimal damage to the photoresist. This approach, while adjusting the morphology and / or improving roughness, avoids damage to other structures of the photoresist.

[0046] The inventors of this application discovered that the plasma generation cavity of remote plasma sources such as microwave plasma sources (MW sources) is often located directly above the wafer being etched. When only this type of upper remote plasma source is turned on, the etching rate at the center of the wafer is easily faster, while the etching rate at the edges is slower, resulting in uniformity deviations. To address this type of process where the etching rate at the center is too fast, the aperture distribution of the upper electrode showerhead can be optimized to reduce the aperture density in the central region of the upper electrode showerhead. However, when both the upper remote plasma source and the lower radio frequency (BRF) source are turned on, the lower RF source forms a bias voltage on the chuck surface, attracting positive ions to bombard the wafer. At this time, the lower RF source plays a dominant role in the electric field, and the electric field intensity at the edges is stronger. If the central aperture of the upper electrode showerhead is blocked, the etching gas concentration in the central region decreases, easily leading to a slower etching rate in the central region and a faster etching rate at the edges, resulting in poor overall uniformity of the etching process. Therefore, current semiconductor process equipment requires different flow uniformity structures to perform the above two types of processes, making the process of adjusting the opening morphology of the photoresist more complicated.

[0047] In view of the above problems, the first aspect of this application provides a flow uniform structure, with reference to Figure 1 and Figure 2 As shown, the uniform flow structure 100 is disposed between the remote plasma source (not shown in the figure) and the process chamber 210, and is used to uniformly flow the plasma generated by the remote plasma source.

[0048] Specifically, the flow equalization structure 100 includes a first flow equalization element 110, a second flow equalization element 120, and a driving unit 130. The first flow equalization element 110 includes a plurality of through holes for the flow of process gas. The second flow equalization element 220 is movably disposed above the first flow equalization element 110 and has a vertical gap with the first flow equalization element 110. The driving unit 130 is connected to the second flow equalization element 120 and is used to drive the second flow equalization element 120 to a first position above the central region of the first flow equalization element 110 or a second position away from the central region of the first flow equalization element 110 (e.g., ...). Figure 2 (As shown).

[0049] The central region of the first flow equalizer 110 can be a circular region centered on the center of the first flow equalizer 110. This region is the area where airflow obstruction is required to ensure etching uniformity when only a remote plasma source is used. (Refer to...) Figure 1 As shown, when the second flow equalizer 120 is located at a first position above the central region of the first flow equalizer 110, it can block at least part of the process gas. The second position can be located on the side of the first flow equalizer 110. When the second flow equalizer 120 is located at the second position, the process gas enters the process chamber 210 through the through holes of the first flow equalizer 110.

[0050] By setting the first uniform flow element 110 and the second uniform flow element 120, a remote plasma source, such as a microwave plasma source, is used, with the plasma generation cavity located directly above the wafer to be processed. When both the remote plasma source and the lower radio frequency source are on, the driving unit 130 drives the second uniform flow element 120 to move to the second position, so that the incoming plasma passes through the first uniform flow element 110, increasing the etching rate in the central region and ensuring the overall uniformity of the plasma etching process. When only the remote plasma source is on, the driving unit 130 drives the second uniform flow element 120 to move to the first position, blocking at least part of the plasma, reducing the etching rate in the central region, and making the etching rate of the plasma in the center and edge of the wafer to be processed tend to be consistent, thereby improving the etching uniformity. In this way, the corresponding semiconductor process equipment can be compatible with both processes where only the upper remote plasma source is on and both the upper and lower radio frequency sources are on. Multiple processes for adjusting the photoresist opening morphology can be executed through one semiconductor process equipment, simplifying the process of adjusting the photoresist opening morphology.

[0051] Optionally, the gap between the first flow equalizer 110 and the second flow equalizer 120 is less than twice the thickness of the plasma sheath; or, the gap between the first flow equalizer 110 and the second flow equalizer 120 is 1-2 mm; the gaps in the above ranges can prevent plasma from entering the gap space between the first flow equalizer 110 and the second flow equalizer 120.

[0052] Optionally, the first flow equalizer 110, also referred to as the lower flow equalizer plate, can be a circular plate. The diameter of this circular plate is 310-350 mm; or, the diameter of this circular plate is 1-1.2 times the diameter of the wafer to be processed. The aforementioned circular plate diameter allows the process gas passing through the first flow equalizer 110 to fully contact the wafer to be processed. Optionally, the first flow equalizer 110 has the same structure as the original single-layer flow equalizer plate in the process chamber. For example, the material of the first flow equalizer is aluminum, and the surface pore size distribution is as follows: Figure 3 As shown, the thickness is 3mm, the diameter is 330mm, etc.

[0053] Optionally, the second flow equalizer is a circular plate; the diameter of the circular plate is 180-220 mm; or, the diameter of the circular plate is 0.6-0.7 times the diameter of the wafer to be processed. Optionally, the second flow equalizer 120 can also be called an upper flow equalizer plate. The second flow equalizer 120 has no through holes to enhance gas barrier capability; its material can be aluminum, and its thickness can be 3 mm. Preferably, the diameter of the circular second flow equalizer 120 is 200 mm to be suitable for most semiconductor process equipment.

[0054] In some embodiments, the second flow equalizer 120 includes at least two sub-flow equalizers, and when the second flow equalizer is in the first position, the at least two sub-flow equalizers are spliced ​​together as a whole. The driving unit includes at least two sub-driving units, each sub-driving unit being respectively disposed corresponding to each sub-flow equalizer, for driving the corresponding sub-flow equalizers to move closer to or further away from each other.

[0055] The number of the aforementioned sub-fluid equalizers can be set according to specific application requirements. For example, refer to... Figure 4 As shown in Figure a, there are three sub-fluid levelers, which can be joined together at the first position to form a circular fluid leveler or other integral fluid leveler. For example, see reference... Figure 4 As shown in Figure b, there are two sub-fluid levelers, which can be joined together at the first position to form a circular fluid leveler or other integral fluid levelers.

[0056] In some examples, the sub-drive unit includes a cylinder and a piston rod, for example Figure 1 and Figure 2 The diagram shows a cylinder 131 and a piston rod 132 in one of the sub-drive units. The cylinder 131 can be located on the side wall of the chamber where the second flow equalizer 120 is located, and is used to drive the piston rod 132 to move. The piston rod 132 is used to connect the cylinder 131 and the corresponding sub-flow equalizer, and to drive the corresponding sub-flow equalizer to move between a first position and a second position.

[0057] In some examples, the sub-drive unit includes a linear motor and a support rod (not shown in the figure). The linear motor drives the support rod to move, and the support rod connects the cylinder and the corresponding sub-flow equalizer, and drives the sub-flow equalizer to move between a first position and a second position.

[0058] The above-mentioned uniform flow structure 100 achieves an adjustable single / double-layer uniform flow mode by setting a first uniform flow element 110 and a second uniform flow element 120. When using a remote plasma source, such as a microwave plasma source, with the plasma generation cavity located directly above the wafer to be processed, and both the remote plasma source and the lower radio frequency source are on, the driving unit 130 drives the second uniform flow element 120 to move to a second position away from the central region of the first uniform flow element 110, so that the incoming plasma passes through the first uniform flow element 110, which can improve the etching rate in the central region and ensure the overall uniformity of the plasma etching process; when only the above-mentioned remote plasma source is on... At that time, the driving unit 130 drives the second uniform flow member 120 to move to a first position above the central region of the first uniform flow member 110, which can block at least part of the plasma flowing into the central region, reduce the etching rate of the central region, and make the etching rate of the plasma at the center and edge of the wafer to be processed tend to be consistent, thereby improving the etching uniformity. In this way, the corresponding semiconductor process equipment can be compatible with both processes that only turn on the upper remote plasma source and those that turn on both the upper and lower radio frequency sources. Multiple processes for adjusting the opening morphology of photoresist can be executed through a set of semiconductor process equipment, simplifying the process of adjusting the opening morphology of photoresist.

[0059] A second aspect of this application provides a semiconductor process apparatus, such as... Figure 1 and Figure 2 As shown, the semiconductor process equipment includes a remote plasma source (not shown), a lower radio frequency source (not shown), a process chamber 210, and a flow equalization structure 100 as described in any of the above embodiments. The flow equalization structure 100 is used to equalize the gas entering the process chamber 210 from the remote plasma source. The flow equalization structure 100 can provide single-layer and double-layer flow equalization methods to equalize the plasma generated by the remote plasma source, enabling the semiconductor process equipment to be compatible with various semiconductor processes with different flow equalization requirements. The process chamber 210 includes a wafer carrier 211, and the lower radio frequency source is used to apply radio frequency power to the bias electrodes within the wafer carrier 211.

[0060] Furthermore, such as Figure 1 and Figure 2As shown, the process chamber 210 includes a reaction chamber (not shown in the figure) and a flow equalization chamber 220 located above the reaction chamber. The first flow equalization element 110 of the flow equalization structure 100 is disposed between the reaction chamber and the flow equalization chamber 220. The flow equalization chamber 220 can be, for example, frustum-shaped; the upper diameter of the flow equalization chamber 220 is smaller for communication with the microwave generating tube of the remote plasma source, and the lower diameter is larger for communication with the reaction chamber. The sidewall of the flow equalization chamber 220 is also provided with a receiving cavity 221. For example, the receiving cavity 221 can be integrally formed with the sidewall of the flow equalization chamber 220, forming an outwardly protruding cavity above the first flow equalization element 110. The receiving cavity 221 is used to accommodate the second flow equalization element 120 when it moves to the second position. Specifically, the second flow equalization element 120 includes multiple sub-flow equalization plates, and the receiving cavity 221 includes sub-receiving cavities corresponding to each sub-flow equalization plate. The sub-receiving cavities are used to accommodate the corresponding sub-flow equalization plates, for example... Figure 2 As shown.

[0061] In some embodiments, the semiconductor process equipment further includes a controller (not shown). The controller controls the remote plasma source, the lower radio frequency source, and the drive unit 130 respectively. When the remote plasma source is turned on, the controller controls the drive unit 130 to drive the second current equalizer 120 to a first position. When the remote plasma source and the lower radio frequency source are turned on simultaneously, the controller controls the drive unit 130 to drive the second current equalizer 120 to a second position.

[0062] In some examples, the inventors have compared and analyzed the conventional single-layer flow uniformity scheme and the double-layer flow uniformity scheme provided in this application. In the conventional single-layer flow uniformity configuration, only the upper remote plasma source (such as...) is activated. Figure 5 At the MW (millimeters shown), the process uniformity is 25.4%. The etching depth distribution map can be referenced. Figure 5 As shown by the solid line, the upper remote plasma source and the lower radio frequency source are simultaneously turned on (e.g., Figure 5 When the BRF (Bio-Frequency Retrieval Process) is shown, the process uniformity is 6.1%. The etching depth distribution map can be referenced. Figure 5 As shown by the dashed line; Figure 5 In the diagram, the horizontal axis represents the position on the wafer to be processed, with 0 representing the center position, positive positions representing the right position, and negative positions representing the left position. The larger the absolute value of the coordinate, the closer the corresponding position is to the edge. Figure 5 This demonstrates that when only the upper remote plasma source is activated for plasma etching, a significant phenomenon occurs: the etching rate is high at the center and slow at the edges. Using the uniform flow structure 100 provided in this application, only the upper remote plasma source (such as...) is activated... Figure 6 When the MW is shown, the drive unit 130 drives the second flow equalizer 120 to the first position, corresponding to a process uniformity of 7.3%. The etching depth distribution diagram can be referenced. Figure 6 As shown by the solid line, the remote plasma source and the lower radio frequency source are simultaneously turned on (e.g., Figure 6When the BRF (Bio-Fluidized Retrieval Process) is shown, the driving unit 130 drives the second flow equalizer 120 to the second position, corresponding to a process uniformity of 4.6%. The etching depth distribution diagram can be referenced. Figure 6 As shown by the dashed line; Figure 6 In the diagram, the horizontal axis represents the position on the wafer to be processed, with 0 representing the center position, positive positions representing the right position, and negative positions representing the left position. The larger the absolute value of the coordinate, the closer the corresponding position is to the edge. Figure 6 It can be shown that by using the uniform flow structure 100 provided in this application to perform corresponding uniform flow treatment on plasma in various etching processes, the etching depth of the wafer center and edge is relatively similar in various etching processes, and the difference in etching depth at different locations is small. It can be seen that the uniform flow structure 100 provided in this application can optimize the etching uniformity of various etching processes.

[0063] The above semiconductor process equipment, including the uniform flow structure 100 described in any of the above embodiments, has all the beneficial effects of the uniform flow structure 100 described in any of the above embodiments, and will not be repeated here.

[0064] A third aspect of this application provides a method for adjusting the opening morphology of photoresist, wherein the photoresist includes a plurality of openings, and the opening morphology adjustment method is applied to the semiconductor process equipment described in any of the above embodiments. In the above-described semiconductor process equipment, the plasma from the remote plasma source is generated outside the process chamber. High-energy ions and hot electrons in the plasma are absorbed and filtered out before entering the process chamber. The plasma entering the process chamber is mainly composed of free radicals with fewer charged ions, resulting in weak bombardment and minimal damage to the photoresist. By adjusting the opening morphology during the etching process, damage to other structures of the photoresist can be avoided.

[0065] refer to Figure 7 As shown, the above-mentioned morphology adjustment method includes the following steps S310 to S330.

[0066] S310, turn on the remote plasma source and the lower radio frequency source, the driving part in the flow uniform structure drives the second flow uniform member to move to a second position away from the center region of the first flow uniform member, and the corresponding etching gas is uniformly flowed by the first flow uniform member to perform the first etching on the photoresist.

[0067] In some examples, the first etching process includes: obtaining the opening shape; controlling a remote plasma source to introduce a corresponding first etching gas according to the opening shape; and adjusting the opening morphology in a targeted manner according to the opening shape.

[0068] Specifically, the opening shape includes an inverted trapezoid, where the angle between the sidewall and bottom of the inverted trapezoidal opening is greater than 90°, and its top is wider than its bottom, such as... Figure 8As shown. For this type of opening, the first etching gas includes an oxygen-containing gas and a physical etching gas. The oxygen-containing gas may include gases such as O2 (oxygen). The physical etching gas can enhance the physical bombardment effect of the first etching gas, enabling it to effectively reduce the sharp corners at the top and bottom of the inverted trapezoidal opening, widen the top of the inverted trapezoidal opening, and optimize the bottom angle, making the morphology of this type of opening more consistent with the desired morphology. Optionally, the physical etching gas may include at least one of Ar (argon), He (helium), and N2 (nitrogen). Preferably, the physical etching gas is Ar, to make the physical bombardment effect of the first etching gas stronger.

[0069] Specifically, the opening shape includes a regular trapezoid, where the angle between the sidewall and the base of the trapezoidal opening is less than 90°, and its top is narrower than its bottom, such as... Figure 9 As shown. For this type of opening, the first etching gas includes an oxygen-containing gas (such as O2) and a chemical etching gas. The chemical etching gas can lower the activation energy of the reaction between oxygen free radicals and the photoresist when the first etching gas bombards the photoresist, promoting the chemical reaction and enhancing the chemical etching ability of the first etching gas. This allows the first etching gas to produce over-etching at the bottom of the opening, solving the problem of residue at the bottom of the trapezoidal opening and achieving the purpose of improving the morphology of this type of opening. Optionally, the chemical etching gas includes a fluorine-based gas; the fluorine-based gas can be a fluorocarbon gas, such as CF4 (carbon tetrafluoride), or other fluorine-containing gases that can enhance the chemical etching effect, such as SF6 (sulfur hexafluoride).

[0070] In some examples, the first etching can be performed at room temperature (e.g., within the temperature range of 20-25°C). In this case, the etching rate of the first etching gas relative to the photoresist is relatively low, typically less than 1 μm / min. This allows for morphological modification of the photoresist, and the overall etching depth can be controlled within 2 μm. The thickness and dimensional loss (CD loss) of the photoresist are small, and the original morphology is not damaged, which can further protect other structures of the photoresist. Optionally, the process parameters for the first etching include: a pressure range of 0.1T-0.8T in the process chamber, a power range of 500-2500W for the remote plasma source, and a power range of 100-500W for the lower radio frequency source; a flow rate range of 100-1500 sccm for the first etching gas; when the first etching gas uses both oxygen-containing gas and physical etching gas, the flow rate range of the oxygen-containing gas is 100-1500 sccm, and the flow rate range of the physical etching gas is 100-1000 sccm; when the first etching gas uses both oxygen-containing gas and chemical etching gas, the flow rate range of the oxygen-containing gas is 100-1500 sccm, and the flow rate range of the chemical etching gas is 100-300 sccm. Preferably, the pressure in the process chamber is 0.3T, the power of the remote plasma source is 500W, the power of the lower radio frequency source is 300W, the flow rate of the oxygen-containing gas is 500sccm, the flow rate of the physical etching gas is 200sccm, and the flow rate of the chemical etching gas is 200sccm.

[0071] Optionally, the number of etching operations in the first etching process can be set according to factors such as the size to be removed or expanded, and the size consumed in one etching operation. The duration of the first etching operation can be set based on the number of etching operations and the duration required for one etching operation. Preferably, the number of etching operations in the first etching process is 5, and the duration of each etching operation is 30 seconds.

[0072] S320, determine whether the roughness of the opening sidewall of the photoresist exceeds a predetermined threshold; wherein the predetermined threshold can be set according to the roughness requirements of the opening sidewall, and can usually be set to a relatively small roughness.

[0073] S330, when the roughness of the opening sidewall of the photoresist exceeds a predetermined threshold, the remote plasma source is turned on and the lower radio frequency source is turned off. The driving part in the uniform flow structure drives the second uniform flow element to move to the second position above the central region of the first uniform flow element. The corresponding etching gas is uniformly flowed through the double-layer uniform flow structure formed by the first and second uniform flow elements to perform the second etching on the photoresist.

[0074] The aforementioned S330 shuts off the RF power, resulting in a relatively low etching rate of the second etching gas during the second etching process. This effectively improves the roughness of the opening sidewall and avoids damage to other structures of the photoresist.

[0075] Optionally, the second etching gas used in the second etching process includes an oxygen-containing gas and a chemical etching gas. The oxygen-containing gas may include gases such as O2, and the chemical etching gas may include fluorine-based gases such as CF4. The roughness on the opening sidewall is usually caused by protrusions (also known as undulations or striations). The second etching gas, including fluorine-based gases and other chemical etching gases, can enhance the chemical etching ability of the second etching gas. More area is exposed to the second etching gas at the tip of the protrusion, while the bottom surface is exposed to a relatively smaller area. Therefore, the etching rate is faster at the tip and slower at the bottom. Through this chemical etching, the tip can be gradually smoothed, thereby improving the roughness of the opening sidewall.

[0076] Optionally, the etching duration of the second etching is determined based on the roughness of the sidewall of the opening before the second etching; the greater the roughness, the longer the etching duration. Preferably, the second etching duration is 60 seconds.

[0077] Specifically, the second etching can employ a room-temperature plasma etching process, with the following process parameters: a process chamber pressure range of 0.1T-0.8T, a remote plasma source power range of 500-2500W, a lower radio frequency source power of 0W, an oxygen-containing gas flow rate range of 100-1500 sccm, and a chemical etching gas flow rate range of 100-300 sccm. Preferably, the process chamber pressure is 0.3T, the remote plasma source power is 800W, the lower radio frequency source power is 0W, the oxygen-containing gas flow rate is 500 sccm, the chemical etching gas flow rate is 200 sccm, and the etching duration is 60s.

[0078] In some examples, for a trapezoidal opening, the first etching gas includes an oxygen-containing gas and a chemical etching gas. After etching the photoresist with the first etching gas, the roughness of the opening sidewall is relatively low. In order to improve process efficiency, for an inverted trapezoidal opening, an oxygen-containing gas and a physical etching gas can be used as the first etching gas to etch the photoresist. After etching with the first etching gas, the roughness of the opening sidewall is detected, and then steps S320 and S330 are executed.

[0079] The above-mentioned method for adjusting the opening morphology of photoresist can perform the opening morphology correction process and the roughness improvement process of photoresist sequentially in the same process chamber. It provides a comprehensive method for the morphology correction and roughness improvement of photoresist, and the process can be programmed and controlled in the controller of the corresponding semiconductor process equipment, which can improve the automation level of the machine.

[0080] In some examples, taking a microwave plasma source as an example, the method for adjusting the opening morphology of photoresist in semiconductor process equipment is analyzed and explained; the semiconductor process equipment can be referenced. Figure 10 and Figure 11 As shown in the figure, this diagram illustrates two sub-fluid leveling plates, fluid leveling plate 2-1 and fluid leveling plate 2-2. Fluid leveling plate 2-1 corresponds to support rod 1 and cylinder 1, while fluid leveling plate 2-2 corresponds to support rod 2 and cylinder 2. Support rods 1 and 2 can be piston rods. Furthermore, fluid leveling plate 1 represents the first fluid leveling element. Above fluid leveling plate 1, a microwave generating tube and a corresponding etching gas are shown. The etching gas forms a corresponding plasma through the microwave generating tube. Above fluid leveling plate 1, a lower radio frequency source, a chuck (i.e., a wafer carrier), and a wafer are shown. Figure 10 In the process, the flow equalizer 2-1 and the flow equalizer 2-2 move to a second position away from the center region of the flow equalizer 1, and the etching gas can flow into the process chamber through the flow equalizer 1. Figure 11 In this process, flow equalizers 2-1 and 2-2 move to a first position above the central region of flow equalizer 1, blocking the etching gas flowing into the central region. In this example, the first etching gas corresponding to the inverted trapezoidal opening uses O2 and Ar, the first etching gas corresponding to the regular trapezoidal opening uses O2 and CF4, and the second etching gas uses O2 and CF4. The above-mentioned opening morphology adjustment method can be referred to... Figure 12 As shown, it includes steps S201 to S206.

[0081] S201 identifies whether the opening of the photoresist is an inverted trapezoidal opening or a regular trapezoidal opening.

[0082] S202, if the opening is an inverted trapezoid, then O2 and Ar are introduced, the MW source and BRF source are turned on, and the second flow equalizer is driven to move to the second position to introduce the first etching gas into the process chamber; the corresponding process formula can be referred to Table 1, and then step S204 is executed.

[0083] Table 1

[0084] air pressure MW power BRF power Chuck temperature Ar traffic <![CDATA[O2 flow rate]]> time 0.3T 500W 300W 20℃ 200sccm 500sccm 30s

[0085] S203, if the opening is a trapezoidal shape, then O2 and CF4 are introduced, the MW source and BRF source are turned on, and the second flow equalizer is driven to move to the second position to introduce the first etching gas into the process chamber; the corresponding process formula can be referred to Table 2, and then step S204 is executed.

[0086] Table 2

[0087] air pressure MW power BRF power Chuck temperature <![CDATA[CF4 flow rate]]> <![CDATA[O2 flow rate]]> time 0.3T 500W 300W 20℃ 200sccm 500sccm 30s

[0088] S204 involves etching the photoresist five times with a first etching gas to create over-etching at the top of the inverted trapezoidal opening or at the bottom of the regular trapezoidal opening. For a detailed comparison of the inverted trapezoidal opening morphology before and after adjustment, please refer to [reference needed]. Figure 13 As shown, Figure 13In the image, 'a' represents the photoresist before morphology adjustment, and 'b' represents the photoresist after morphology adjustment. The comparison shows that after morphology adjustment, the top of the opening is significantly expanded. For photoresist with an inverted trapezoidal opening, when this layer of photoresist is used as an etching mask, morphological issues such as the presence of substrates at the bottom will severely affect the subsequent etching morphology. For example, it can easily lead to rough sidewalls and difficulty in obtaining a smooth sidewall etching morphology. This example can expand the top of the inverted trapezoidal opening and the substrates at the bottom, thereby improving the subsequent etching effect when using the corresponding photoresist as an etching mask. A comparison image of the trapezoidal opening before and after morphology adjustment can be found in the image. Figure 14 As shown, Figure 14 In the image, 'a' represents the photoresist before morphology adjustment, and 'b' represents the photoresist after morphology adjustment. The comparison shows that the morphology at the bottom of the opening is corrected after morphology adjustment. For photoresist with a trapezoidal opening, when metal is subsequently filled into the photoresist opening, the metal size on the side closer to the wafer will be larger than the size on the side farther from the wafer. After the photoresist is removed, the morphology of the metal layer, which is smaller at the top and larger at the bottom, will adhere more stably to the wafer, thereby ensuring the reliability of the device.

[0089] S205, Determine if the sidewall of the opening is rough.

[0090] S206, if the opening sidewall is rough, such as exceeding a predetermined threshold, then O2 and CF4 are introduced, the MW source is loaded and the BRF source is turned off. The corresponding process formulation can be found in Table 3. The second flow equalizer is driven to move to the first position to introduce the second etching gas into the process chamber, thereby improving the roughness of the opening sidewall. Specifically, the roughness improvement comparison diagram can be found in Table 3. Figure 15 As shown, Figure 15 In the image, 'a' represents the photoresist before roughness improvement, and 'b' represents the photoresist after roughness improvement. The comparison shows that the roughness of the opening sidewalls is significantly improved after roughness improvement. If a photoresist with rough opening sidewalls is used as an etching mask, the rough sidewalls may transfer to the wafer, causing anomalies such as striations. Improving the roughness of the opening sidewalls can avoid this, thus enhancing the etching effect when using the corresponding photoresist as an etching mask.

[0091] Table 3

[0092] air pressure MW power BRF power Chuck temperature <![CDATA[CF4 flow rate]]> <![CDATA[O2 flow rate]]> time 0.3T 800W 0 20℃ 200sccm 500sccm 60s

[0093] In addition to using microwave equipment, the above-mentioned method for adjusting the opening morphology of the photoresist can also be performed on other semiconductor process equipment for the RF top electrode. Taking the use of O2 and Ar as an example for the first etching body when targeting an inverted trapezoidal opening, the process parameters can be described as follows: the pressure range of the process chamber is 1mT-20mT, the upper RF power range is 100-1000W, the lower RF power range is 5-500W, the O2 flow rate range is 10-1000sccm, and the Ar flow rate range is 10-100sccm. The inventors tested and analyzed the inverted trapezoidal opening morphology adjustment process using the process formulation shown in Table 4. After the morphology adjustment, the top of the inverted trapezoidal opening was expanded to a certain extent.

[0094] Table 4

[0095]

[0096] The above-described method for adjusting the opening morphology of photoresist, when applied to the semiconductor process equipment described in any of the above embodiments, possesses all the beneficial effects of the semiconductor process equipment described in any of the above embodiments, and will not be elaborated further here. Furthermore, this opening morphology adjustment method also determines the first etching gas corresponding to the opening shape by reading the opening shape of the photoresist, and generates the first etching gas to etch the photoresist. This allows the first etching gas to widen the top of the inverted trapezoidal opening, reduce the bottom feet, and generate over-etching at the bottom of the regular trapezoidal opening. It also avoids loss of other photoresist structures, achieving the goal of improving the opening morphology of various types of photoresist openings using a simple process. The above-described opening morphology adjustment method can also sequentially execute the opening morphology correction process and the roughness improvement process within the same process chamber, providing a comprehensive method for photoresist morphology correction and roughness improvement. Moreover, the process can be programmed and controlled in the controller of the corresponding semiconductor process equipment, improving the automation level of the machine.

[0097] Although this application has been shown and described with respect to one or more implementations, equivalent variations and modifications will occur to those skilled in the art based on a reading and understanding of this specification and drawings. This application includes all such modifications and variations and is limited only by the scope of the appended claims. In particular, with respect to the various functions performed by the aforementioned components, the terminology used to describe such components is intended to correspond to any component (unless otherwise indicated) that performs the specified function of said component (e.g., is functionally equivalent to it), even if structurally not equivalent to the disclosed structure performing the functions in the exemplary implementations of this specification shown herein.

[0098] That is, the above description is only an embodiment of this application and does not limit the patent scope of this application. Any equivalent structural or procedural changes made using the content of this application’s specification and drawings, such as the combination of technical features between different embodiments, or direct or indirect application in other related technical fields, are similarly included within the patent protection scope of this application.

[0099] Furthermore, it should be understood that in the description of this application, the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicating the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application. Additionally, for structural elements with the same or similar characteristics, this application may use the same or different reference numerals for identification. Moreover, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, features defined with "first" and "second" may explicitly or implicitly include one or more features. In the description of this application, "multiple" means two or more, unless otherwise explicitly specified.

[0100] In this application, the term "exemplary" is used to mean "serving as an example, illustration, or description." Any embodiment described as "exemplary" in this application is not necessarily to be construed as more preferred or advantageous than other embodiments. This application has been provided above to enable any person skilled in the art to implement and use it. Various details have been set forth in the above description for purposes of explanation. It should be understood that those skilled in the art will recognize that this application can be implemented without using these specific details. In other embodiments, well-known structures and processes will not be described in detail to avoid obscuring the description of this application with unnecessary detail. Therefore, this application is not intended to be limited to the embodiments shown, but is consistent with the broadest scope of the principles and features disclosed herein.

Claims

1. A uniform flow structure for semiconductor process equipment, characterized in that, The flow equalization structure includes a first flow equalization element, a second flow equalization element, and a driving unit; The first flow equalizer includes multiple through holes; The second flow equalizer is movably disposed above the first flow equalizer, and there is a gap between them in the vertical direction; The driving unit is connected to the second flow equalizer and is used to drive the second flow equalizer to a first position above the central region of the first flow equalizer or a second position away from the central region of the first flow equalizer.

2. The uniform flow structure according to claim 1, characterized in that, The gap between the second flow equalizer and the first flow equalizer is less than twice the thickness of the plasma sheath, or the gap between the second flow equalizer and the first flow equalizer is 1-2 mm.

3. The uniform flow structure according to claim 1, characterized in that, The first flow equalizer is a circular plate; The diameter of the first flow equalizer is 310-350 mm; or, the diameter of the first flow equalizer is 1-1.2 times the diameter of the wafer to be processed.

4. The uniform flow structure according to claim 1, characterized in that, The second flow equalizer is a circular plate; The diameter of the second flow equalizer is 180-220 mm; or, the diameter of the second flow equalizer is 0.6-0.7 times the diameter of the wafer to be processed.

5. The uniform flow structure according to any one of claims 1-4, characterized in that, The second flow equalizer includes at least two sub-flow equalizers. When the second flow equalizer is in the first position, the at least two sub-flow equalizers are spliced ​​together as a whole. The driving unit includes at least two sub-driving units, each of which is respectively disposed corresponding to each of the sub-flow equalizers, and is used to drive the corresponding sub-flow equalizers to move closer to each other or further away from each other.

6. The uniform flow structure according to claim 5, characterized in that, The sub-drive unit includes a cylinder and a piston rod. The cylinder is used to drive the piston rod to move. The piston rod is used to connect the cylinder and the corresponding sub-flow equalizer plate, and to drive the sub-flow equalizer plate to move between the first position and the second position. Alternatively, the sub-drive unit includes a linear motor and a support rod. The linear motor drives the support rod to move, and the support rod connects the cylinder and the corresponding sub-flow equalizer plate, and drives the sub-flow equalizer plate to move between the first position and the second position.

7. A semiconductor process apparatus, characterized in that, The semiconductor process equipment includes a remote plasma source, a lower radio frequency source, a process chamber, and a flow uniform structure as described in any one of claims 1 to 6; The flow equalization structure is used to equalize the flow of gas entering the process chamber from the remote plasma source; The process chamber includes a wafer carrier, and the lower radio frequency source is used to apply radio frequency power to the bias electrodes within the wafer carrier.

8. The semiconductor process equipment according to claim 7, characterized in that, The process chamber includes a reaction chamber and a flow equalization chamber located above the reaction chamber, and the first flow equalization element of the flow equalization structure is disposed between the reaction chamber and the flow equalization chamber; The side wall of the flow equalization cavity is also provided with a receiving cavity for accommodating the second flow equalization component when the second flow equalization component moves to the second position.

9. The semiconductor process equipment according to claim 7, characterized in that, The semiconductor process equipment also includes a controller; The controller is used to control the driving unit to drive the second flow equalizer to the first position when the remote plasma source is turned on, and to control the driving unit to drive the second flow equalizer to the second position when the remote plasma source and the lower radio frequency source are turned on simultaneously.

10. A method for adjusting the opening morphology of photoresist, characterized in that, The photoresist includes a plurality of openings, and the opening morphology adjustment method is applied to the semiconductor process equipment according to any one of claims 7 to 9, comprising: Turn on the remote plasma source and the lower radio frequency source to perform the first etching on the photoresist; Determine whether the roughness of the opening sidewall of the photoresist exceeds a predetermined threshold; When the roughness exceeds a predetermined threshold, the remote plasma source is turned on and the lower radio frequency source is turned off to perform a second etching on the photoresist.

11. The method for adjusting the opening morphology according to claim 10, characterized in that, The first etching process includes: Get the shape of the opening; Based on the shape of the opening, the remote plasma source is controlled to introduce the corresponding first etching gas.

12. The method for adjusting the opening morphology according to claim 11, characterized in that, The opening shape includes a trapezoid, and the first etching gas includes an oxygen-containing gas and a chemical etching gas; Alternatively, the opening shape may include an inverted trapezoid, and the first etching gas may include an oxygen-containing gas and a physical etching gas.

13. The method for adjusting the opening morphology according to claim 10, characterized in that, The second etching process uses gases including oxygen-containing gases and chemical etching gases.

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