Surface repairing process and surface repairing method

Abstract

The invention discloses a surface repairing process and a surface repairing method, and relates to the technical field of semiconductor manufacturing processes. The surface repairing technology comprises the steps that first gas is injected into a reaction cavity at a first flow rate, wherein the pressure intensity in the reaction cavity is set to be first pressure intensity, and the temperature in the reaction cavity is set to be first temperature; starting a radio frequency power source to generate free radicals, and maintaining for a first time, so that the free radicals are adsorbed with surface atoms of the to-be-repaired material layer; vacuumizing the reaction cavity, setting the temperature in the reaction cavity to be a second temperature, and maintaining the second temperature for a second time; and setting the pressure in the reaction cavity to be second pressure, injecting second gas into the reaction cavity, and maintaining for a third time. By implementing the surface repairing process and the surface repairing method disclosed by the embodiment of the invention, the free radicals generated in the reaction cavity are fully adsorbed to the rough surface of the wafer substrate with the defects, and are fully combined with the fine defects on the surface through adsorption, so that the reaction rate of the free radicals and the surface material of the substrate to be repaired is improved, and the repairing effect is further improved.

Description

Technical Field

[0001] This application relates to the technical field of semiconductor manufacturing processes, and particularly to a surface repair process and a surface repair method. Background Art

[0002] Dry etching is a key technology in semiconductor processes. Based on the requirements of the etching rate, high-energy plasmas are usually used for downward etching. However, after bombardment by high-energy plasmas, it is easy to cause damage to the wafer surface, resulting in a rough surface topography, affecting subsequent processes, and thus affecting the electrical performance of the product. Atomic layer etching, as a type of dry etching, uses a continuous self-limiting reaction for atomic-level etching, and usually uses a plasma with relatively low energy for surface treatment, but there is still a phenomenon of surface lattice damage. After multiple atomic layer etching processes, certain damage will accumulate on the wafer surface layer, destroying the surface flatness and affecting subsequent processes and product performance. Therefore, there is an urgent need for a surface repair process and a surface repair method to solve the above problems. Summary of the Invention

[0003] In order to solve the problems in the existing dry etching process, where plasma bombardment of the wafer causes damage to the wafer surface, destroys the surface flatness of the wafer, and affects subsequent processes and product performance. This application provides the following technical solutions:

[0004] In a first aspect, a surface repair process is provided, including:

[0005] Injecting a first gas into a reaction chamber with the chamber pressure set to a first pressure and the chamber temperature set to a first temperature at a first flow rate;

[0006] Starting a radio frequency power source to generate free radicals and maintaining for a first time to allow the free radicals to adsorb to the surface atoms of the material layer to be repaired.

[0007] Vacuuming the reaction chamber, setting the chamber temperature of the reaction chamber to a second temperature, and maintaining for a second time.

[0008] Setting the pressure in the reaction chamber to a second pressure, injecting a second gas into the reaction chamber, and maintaining for a third time.

[0009] Further, the first pressure is 10 mTorr - 10 Torr; the first temperature is 50 °C - 90 °C.

[0010] Further, the first gas is a fluorinated gas.

[0011] Further, the frequency of the radio frequency power source is any one of the following: 13.56 MHz, 27 MHz, 40 MHz, 60 MHz, 100 MHz, and 2.45 GHz;

[0012] The power of the radio frequency power source is 100W - 5000W.

[0013] Further, the first time is 3s - 10s.

[0014] Further, the second temperature is 200°C - 500°C;

[0015] The second pressure is 1 Torr - 10 Torr.

[0016] Further, the second time is 30s - 180s.

[0017] Further, the second gas is an inert gas.

[0018] Further, the third time is 60s - 180s.

[0019] In a second aspect, a surface repair method is provided, including:

[0020] Providing a substrate to be repaired to a reaction chamber, where a material layer to be repaired is attached to the surface of the substrate to be repaired.

[0021] Obtaining the number of surface repair times of the substrate to be repaired.

[0022] Performing a loop process until the number of surface repair times is equal to a preset number of repair times. The loop process includes:

[0023] Performing the surface repair process described in the first aspect.

[0024] Accumulating and updating the number of surface repair times.

[0025] The beneficial effects brought by the technical solutions provided in the embodiments of the present application are:

[0026] By implementing the surface repair process and the surface repair method disclosed in the embodiments of the present application, free radicals for repairing the surface of the wafer are generated in the reaction chamber. By maintaining the first time, the free radicals generated in the chamber are fully adsorbed on the rough surface of the defective wafer substrate. Since the free radicals are small in volume, they can be fully combined with the fine defects on the surface through adsorption, so as to increase the reaction rate of the free radicals with the surface material of the substrate to be repaired, and further improve the repair effect of the surface material of the substrate. Description of the Drawings

[0027] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following will briefly introduce the drawings required for the description of the embodiments. Obviously, the following drawings are only some embodiments of the present application. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0028] Figure 1It is a schematic diagram of a surface repair method provided by an embodiment of the present application;

[0029] Figure 2 It is a schematic diagram of a surface repair process provided by an embodiment of the present application;

[0030] Figure 3 It is a graph showing the relationship between the first pressure and the etching rate provided by an embodiment of the present application;

[0031] Figure 4 It is a graph showing the relationship between the first temperature and the etching rate provided by an embodiment of the present application;

[0032] Figure 5 It is a schematic diagram of the process equipment provided by an embodiment of the present application;

[0033] Figure 6 It is a schematic diagram of the change of surface atoms during the process provided by an embodiment of the present application;

[0034] Figure 7 It is a scanning electron microscope photograph of the surface of the material after repair provided by an embodiment of the present application;

[0035] Figure 8 It is a schematic diagram of the complete process of a surface repair method provided by an embodiment of the present application. Detailed implementation manners

[0036] To make the objectives, technical solutions, and advantages of the present application clearer, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present application. Apparently, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present application without creative efforts shall fall within the protection scope of the present application.

[0037] Unless otherwise defined, technical or scientific terms used in this disclosure shall have the ordinary meanings as understood by those of ordinary skill in the art to which this disclosure pertains. The terms "first", "second" and similar words used in this disclosure do not denote any order, quantity or importance, but are only used to distinguish different components. Similarly, words such as "a", "an" or "the" do not denote a limitation of quantity, but mean that there is at least one. The numbers in the accompanying drawings of the specification only represent the distinction of each functional component or module, and do not represent the logical relationship between the components or modules. Words such as "comprising" or "including" mean that the elements or objects appearing before this word cover the elements or objects listed after this word and their equivalents, without excluding other elements or objects. Words such as "connected" or "coupled" are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect. "Upper", "lower", "left", "right", etc. are only used to represent relative positional relationships, and when the absolute position of the object being described changes, the relative positional relationship may also change accordingly.

[0038] Next, various embodiments according to the present disclosure will be described in detail with reference to the accompanying drawings. It should be noted that in the drawings, the same reference numerals are assigned to components having substantially the same or similar structures and functions, and repeated descriptions thereof will be omitted.

[0039] During the dry etching process, it is inevitable to etch the substrate by means of plasma bombardment. As the substrate, the surface material of the wafer will be directly damaged under the bombardment of high-energy plasma, or cumulative damage will occur under the action of low-energy plasma, resulting in the destruction of the flatness of the surface material and affecting the subsequent production process and product performance. In order to overcome the manufacturing process and product performance problems caused by surface material damage, the embodiments of the present application provide the following surface repair methods.

[0040] In some embodiments, as Figure 1 shown, a surface repair method includes:

[0041] S100: Provide a substrate to be repaired to a reaction chamber, and a material layer to be repaired is attached to the surface of the substrate to be repaired.

[0042] S200: Obtain the number of surface repair times of the substrate to be repaired.

[0043] S300: Execute a loop process until the number of surface repair times is equal to a preset repair number. The loop process includes:

[0044] S310: Execute a surface repair process.

[0045] S320: Accumulate and update the number of surface repair times.

[0046] A reaction chamber refers to an entity device that performs a surface repair method on a substrate to be repaired. The structure of the reaction chamber will be introduced in detail below in combination with the surface repair method or surface repair process.

[0047] The substrate to be repaired refers to the base material with a layer of material to be repaired attached to its surface. Substrates referred to in the semiconductor manufacturing process include, but are not limited to: silicon wafers, silicon-on-insulator, and compound semiconductor materials. Among them, compound semiconductor materials include, but are not limited to: GaAs, GaN, and SiC, etc.

[0048] The layer of material to be repaired includes, but is not limited to: SiO2.

[0049] The number of surface repair times refers to the number of cycles that the substrate to be repaired undergoes during the execution of the current surface repair method. The initial value of the number of surface repair times is 0, and it is accumulated in steps of 1 for each execution of a cycle. If the manufacturing process involves multiple implementations of the surface repair method on different surface materials, then each time the surface repair method is implemented, the value of the number of surface repair times should be initialized to 0.

[0050] The preset number of repair times refers to the number of times that the surface repair method needs to be executed, which can be set artificially. After implementing the surface repair method with the preset number of repair times on the substrate to be repaired, the repair of the layer of material to be repaired in the substrate to be repaired is completed.

[0051] Optionally, the preset number of repair times is 2 - 10 times.

[0052] Specifically, the surface repair process, such as Figure 2 shown, includes:

[0053] S311: Inject a first gas into the reaction chamber with the chamber pressure set to a first pressure and the chamber temperature set to a first temperature at a first flow rate.

[0054] S312: Start the radio frequency power source to generate free radicals and maintain for a first period of time for the free radicals to adsorb to the surface atoms of the layer of material to be repaired.

[0055] The first gas refers to the working gas used to generate free radicals. For products that are fluorine free radicals, the first gas is a fluorinated gas; for products that are oxygen free radicals, the first gas is an oxidizing gas; for products that are chlorine free radicals, the first gas is a chlorinated gas.

[0056] The fluorinated gases include, but are not limited to, at least one of the following: SF6, NF3, CF4, C2F6, C4F8, C5F8, and C4F6.

[0057] The oxidizing gases include, but are not limited to, at least one of the following: O2 and O3.

[0058] The chlorinated gas includes but is not limited to at least one of the following: Cl2, BCl3, and SiCl4.

[0059] The first flow rate is the flow rate of injecting the first gas into the reaction chamber. Generally, the unit of the first flow rate is cubic centimeters per minute (CCM).

[0060] In some embodiments, the first gas is preferably a fluorinated gas; the first flow rate is preferably 200 CCM.

[0061] Preferably, when injecting the first gas at the first flow rate, the dilution gas is injected at the third flow rate.

[0062] The third flow rate is the flow rate of injecting the dilution gas into the reaction chamber.

[0063] The dilution gas usually uses an inert gas, including but not limited to at least one of the following: Ar, N2, and He.

[0064] In some embodiments, the dilution gas is preferably He; the third flow rate is preferably 300 CCM.

[0065] The first pressure is the pressure in the reaction chamber. In some embodiments, the first pressure is 10 mTorr - 10 Torr. Schematically, the first pressure is 10 mTorr, 30 mTorr, 60 mTorr, 100 mTorr, 300 mTorr, 600 mTorr, 1 Torr, 5 Torr, or 10 Torr. The specific value of the first pressure can be adjusted according to the actual process environment to select the optimal value corresponding to the process conditions. Figure 3 Shows the relationship curve between the first pressure and the etching amount; Figure 3 Also shows the relationship curve between the first pressure and the uniformity. Among them, the abscissa represents the first pressure, with the unit of mTorr; the left ordinate represents the etching amount, with the unit of The right ordinate represents the wafer surface uniformity, with the unit of %. As Figure 3 Shown, when the first pressure is 1500 mTorr, the etching effect is the best. However, considering that when the first pressure increases from 1350 mTorr to 1500 mTorr, the uniformity of the wafer surface deteriorates from 2.9% to 3.9%, and the deterioration of the uniformity is relatively obvious. Therefore, 1350 mTorr is used as the preferred first pressure.

[0066] It should be noted that the "uniformity" described in the embodiments of the present application is obtained by taking 49 points on the surface of a blanket wafer and measuring the range uniformity before and after etching. Among them, a blanket wafer refers to a semiconductor wafer uniformly coated with a certain material on the entire surface, and the certain material coated in the embodiments of the present application is the material layer to be repaired.

[0067] The first temperature is the temperature in the reaction chamber. In some embodiments, the first temperature is 50°C - 90°C. The specific value of the first temperature can be adjusted according to the actual process environment to select the optimal value corresponding to the process conditions. Figure 4 The relationship curve between the first temperature and the etching amount is shown. Among them, the abscissa represents the temperature, with the unit of °C; the ordinate represents the etching amount, with the unit of As Figure 4 shown, when the first temperature is 90°C, the etching effect is the best.

[0068] Preferably, the first temperature is 90°C.

[0069] The radio frequency power source is a device that converts the first gas into corresponding free radicals, and its frequency and power will affect the concentration of free radicals.

[0070] The frequency of the radio frequency power source includes but is not limited to any one of the following: 13.56 MHz, 27 MHz, 40 MHz, 60 MHz, 100 MHz, and 2.45 GHz.

[0071] The power of the radio frequency power source is 100 W - 5000 W. Schematically, the power of the radio frequency power source can be 100 W, 300 W, 600 W, 1000 W, 1500 W, 2000 W, 3000 W, or 5000 W. The specific power value can be adjusted according to the actual process environment to select the optimal value corresponding to the process conditions.

[0072] Here, a process equipment for implementing the surface repair process and the surface repair method is introduced. As Figure 5 shown, the process equipment may include: a reaction chamber, a filter assembly 30, a coil assembly 40, and a base 50. The reaction chamber includes an upper cavity 10 and a lower cavity 20.

[0073] The upper cavity 10 and the lower cavity 20 are in communication with each other, and the filtering component 30 is arranged between the upper cavity 10 and the lower cavity 20. The filtering component 30 covers the top of the lower cavity 20, the side wall of the upper cavity 10 is supported on the top surface of the filtering component 30, the upper cavity 10 and the lower cavity 20 are kept in communication through the small holes of the filtering component 30, and the working gas is injected from the top of the upper cavity 10. Among them, the working gas includes at least one of the following: fluorinated gas, oxidizing gas, and chlorinated gas. The coil assembly 40 is arranged around the side wall of the upper cavity 10 and is used to excite the working gas injected into the upper cavity 10 to form a mixture of plasma and free radicals.

[0074] When the coil assembly 40 is loaded with a radio frequency voltage, the coil assembly 40 will generate an alternating magnetic field in the upper cavity 10, which can ionize the working process gas in the upper cavity to form a mixture of plasma and free radicals.

[0075] The base 50 is arranged at the bottom of the lower cavity 20 and is used to carry the substrate to be repaired. A heating component can be arranged in the base 50 at the same time. The filtering component 30 is used to filter the plasma, so that the free radicals passing through the filtering component 30 enter the lower cavity 20. After a first period of time, the free radicals entering the lower cavity 20 are sufficiently adsorbed on the surface atoms of the layer of the material to be repaired attached to the surface of the substrate to be repaired. Compared with plasma etching, the reaction of free radicals is mild, and it will not cause lattice deformation on the surface of the material to be repaired due to strong bombardment, and it will not affect the original composition of the substrate to be repaired.

[0076] The coil assembly 40 may include at least two coils, and all the coils are arranged at intervals along the height direction of the upper cavity 10 and are independently powered by radio frequency. Figure 5 Taking the example that there are two coils, they are the first coil 41 and the second coil 42 respectively. Since the first coil 41 and the second coil 42 are independently powered, therefore, the first coil 41, the second coil 42 can be turned on according to needs, or the first coil 41 and the second coil 42 can be turned on simultaneously, so as to adjust the concentration and distribution range (boundary) of plasma and free radicals, and increase the process window of the repair device.

[0077] Preferably, the chamber of the upper cavity 10 is conical, and the coil is wound spirally along the side wall of the chamber (instead of planar winding). Since both the radial coverage area and the longitudinal height of the coil will affect the concentration distribution of plasma and free radicals, in this application, the coil is wound spirally along the side wall of the conical chamber, so as to take into account both the coverage area and the height factors at the same time, and combined with the independent power supply of multiple coils, a more uniform plasma can be adjusted to be formed, and a more uniform concentration of free radicals can also be obtained after being filtered by the filtering component 30, so as to improve the repair uniformity of the surface of the layer of the material to be repaired.

[0078] Schematically, all the coils are built into the side wall of the upper cavity 10, and the outer surface of the upper cavity 10 is provided with a magnetic shielding coating, which can prevent the magnetic field generated by the coils from interfering with the external circuit.

[0079] Preferably, the filtering component 30 includes at least two layers of filtering plates arranged at intervals, and the filtering holes between all the filtering plates are staggered. Figure 5 Taking the filtering component 30 including two layers of filtering plates as an example, they are the first filtering plate 31 and the second filtering plate 32 respectively. There is a gap 33 between the first filtering plate 31 and the second filtering plate 32. The filtering holes 311 of the first filtering plate 31 and the filtering holes 321 of the second filtering plate 32 are staggered. The plasma enters the gap 33 after being first filtered through the filtering holes 311 of the first filtering plate 31 from the upper cavity 10, and then is secondarily filtered through the filtering holes 321 of the second filtering plate 32 and then enters the lower cavity 20. Through multi-layer filtering, purer free radicals can be obtained. The filtering holes between all the filtering plates are staggered, which can increase the filtering path and further improve the purity of the obtained free radicals.

[0080] The first time is the time when the free radicals generated in the reaction chamber are adsorbed by the surface atoms of the material layer to be repaired. Within the first time, the free radicals form sufficient adsorption with the surface atoms of the material to be repaired. In some embodiments, the first time is 3s - 10s. The specific value of the first time can be adjusted according to the actual process environment to select the optimal value corresponding to the process conditions. If the first time lasts too short, it is difficult for the free radicals to form sufficient adsorption with the surface atoms of the material to be repaired, and it is difficult to achieve an ideal repair effect through subsequent processes; if the first time lasts too long, the free radicals have already formed sufficient adsorption with the surface atoms of the material to be repaired, and through subsequent processes, the improvement of the single repair effect is not obvious.

[0081] Preferably, the first time is 5s.

[0082] By performing step S311, free radicals that can be adsorbed on the surface atoms of the material layer to be repaired are generated, and the generated free radicals are sufficiently adsorbed with the surface atoms of the material layer to be repaired, as Figure 6 shown in part (b) of the figure, providing good prerequisites for the subsequent process. And Figure 6 part (a) of the figure represents the original state of the surface atoms of the material layer to be repaired.

[0083] S313: Evacuate the reaction chamber, set the temperature inside the reaction chamber to the second temperature, and maintain it for the second time.

[0084] The second temperature is the temperature inside the reaction chamber when the reaction chamber maintains a vacuum state during the surface repair process. In some embodiments, the second temperature is 200°C - 500°C. The specific value of the second temperature can be adjusted according to the actual process environment to select the optimal value corresponding to the process conditions.

[0085] The second time is the time for fully activating the free radicals. During the second time, the free radicals react sufficiently with the surface atoms of the material layer to be repaired. The free radicals react with the rough parts on the surface of the material layer to be repaired to generate volatile reactants. After removing the volatile reactants, the surface of the new material layer to be repaired tends to be flat. After several cycles are implemented, the surface of the material layer to be repaired becomes flat. In some embodiments, the second time is 30s - 180s. The specific value of the second time can be adjusted according to the actual process environment to select the optimal value corresponding to the process conditions.

[0086] By performing step S312, the free radicals adsorbed on the surface atoms of the material layer to be repaired are activated at high temperature and react sufficiently with the surface atoms of the material layer to be repaired to generate volatile reactants. The surface of the material layer to be repaired after the reaction tends to be flat, achieving the repair effect, as Figure 6 shown in (c) and Figure 6 part (d) in

[0087] Taking the repair of SiO2 with fluorine free radicals as an example, the chemical reaction that occurs is:

[0088] SiO2 + F· → SiF4 + O2

[0089] where F· represents fluorine free radicals.

[0090] S314: Set the pressure inside the reaction chamber to the second pressure, inject the second gas into the reaction chamber, and maintain for the third time.

[0091] The second pressure is the pressure inside the reaction chamber when injecting the second gas. Injecting the second gas at the second pressure can complete the purging of the volatile reactants generated in step S312, exposing the surface atoms of the new material layer to be repaired to the environment for the next cycle process. In some embodiments, the second pressure is 1 Torr - 10 Torr. The specific value of the second pressure can be adjusted according to the actual process environment to select the optimal value corresponding to the process conditions.

[0092] The flow rate of the second gas is usually determined after being adjusted according to the actual process environment, so that the surface atoms of the new material layer to be repaired are exposed to the environment after purging for the next cycle process.

[0093] The second gas is a purge gas used to remove the volatile reactants generated on the surface of the material layer to be repaired in step S312. To avoid the reaction between the purge gas and the surface atoms of the material layer to be repaired during the purging process, preferably, an inert gas is used as the purge gas.

[0094] Schematically, the second gas includes, but is not limited to, at least one of the following: Ar, N2, and He.

[0095] The third time is the duration for purging the volatile reactants by injecting the second gas into the reaction chamber. Through purging, the volatile reactants on the surface layer of the material layer to be repaired are removed, exposing the surface atoms of the new material layer to be repaired to the environment, so as to effectively carry out the next round of cycle process. In some embodiments, the third time is 60s - 180s. The specific value of the third time can be adjusted according to the actual process environment to select the optimal value corresponding to the process conditions.

[0096] By performing step S313, the second gas is used to purge the volatile reactants generated in step S312, exposing the surface of the reacted material layer to be repaired to the environment, providing a prerequisite for performing the next cycle process, as Figure 6 shown in part (e) of

[0097] By implementing the surface repair process and surface repair method disclosed in the embodiments of the present application, free radicals for repairing the surface of the wafer are generated in the reaction chamber, and the first time is maintained, so that the free radicals generated in the chamber are fully adsorbed on the rough surface of the defective wafer substrate; due to the small volume of the free radicals, they can be fully adsorbed and combined with the tiny defects on the surface through adsorption, so as to improve the reaction rate between the free radicals and the surface material of the substrate to be repaired, and further improve the repair effect of the surface material of the substrate. After high-temperature activation, the free radicals react fully with the surface material of the substrate to be repaired to generate volatile reactants. After being purged by the purge gas, the flattened new layer of the surface material of the substrate to be repaired is exposed to the environment for the next round of cycle process until the flatness of the surface material of the substrate to be repaired reaches the preset requirement.

[0098] Compared with the process of directly adsorbing with gas, the effect of using free radical repair is as follows: on the one hand, the free radicals have a smaller volume and are easily adsorbed on the atoms at the tiny defects on the surface layer of the material (for example, the surface defects with a stepped morphology), which is beneficial to repairing the tiny defects on the surface layer in the subsequent process and has a good repair effect; on the other hand, the volatility of the free radicals is relatively poor compared with that of the gas, and it is easy to adsorb on the surface atoms of the material, which is beneficial to improving the reaction rate between the free radicals and the surface atoms in the subsequent process and improving the flatness effect of the material surface.

[0099] The repair effect can repair the surface damage of the wafer caused by plasma etching compared with the direct plasma etching process; it will not accumulate charges on the wafer surface, and thus will not have an adverse impact on subsequent processes and product performance.

[0100] Any combination of the above optional technical solutions can form an optional embodiment of the present application, which will not be elaborated here one by one.

[0101] Embodiment 1

[0102] A surface repair process, as Figure 2 shown, includes:

[0103] S311: Inject a first gas into a reaction chamber whose chamber pressure is set to a first pressure and whose chamber temperature is set to a first temperature at a first flow rate.

[0104] S312: Start a radio frequency power source to generate free radicals and maintain for a first time to allow the free radicals to adsorb to the surface atoms of the material layer to be repaired.

[0105] S313: Evacuate the reaction chamber, set the chamber temperature of the reaction chamber to a second temperature, and maintain for a second time.

[0106] S314: Set the chamber pressure in the reaction chamber to a second pressure, inject a second gas into the reaction chamber, and maintain for a third time.

[0107] The first pressure is 1350 mTorr, the first temperature is 90 °C, the first gas is NF3, the frequency of the radio frequency power source is 13.56 MHz, the power of the radio frequency power source is 1000 W, and the first time is 5 s. Correspondingly, the generated free radicals are fluorine free radicals.

[0108] The material layer to be repaired is SiO2.

[0109] The second temperature is 200 °C - 500 °C, and the second time is 30 s - 180 s.

[0110] The second pressure is 1 Torr - 10 Torr, the second gas is He, and the third time is 60 s - 180 s.

[0111] Embodiment 2

[0112] A surface repair method, as Figure 1 shown, includes:

[0113] S100: Provide a substrate to be repaired to a reaction chamber, and a material layer to be repaired is attached to the surface of the substrate to be repaired.

[0114] S200: Obtain the number of surface repair times of the substrate to be repaired.

[0115] S300: Execute the loop process until the number of surface repair times is equal to the preset repair times. The loop process includes:

[0116] S310: Execute the surface repair process described in Embodiment 1.

[0117] S320: Accumulate and update the number of surface repair times.

[0118] The material layer to be repaired attached to the surface of the substrate to be repaired is SiO2.

[0119] A surface repair process, as Figure 2 shown, includes:

[0120] S311: Inject the first gas into the reaction chamber with the chamber pressure set to the first pressure and the chamber temperature set to the first temperature at the first flow rate;

[0121] S312: Start the RF power source to generate free radicals and maintain for the first time to allow the free radicals to adsorb to the surface atoms of the material layer to be repaired;

[0122] S313: Evacuate the reaction chamber, set the chamber temperature of the reaction chamber to the second temperature, and maintain for the second time;

[0123] S314: Set the pressure in the reaction chamber to the second pressure, inject the second gas into the reaction chamber, and maintain for the third time.

[0124] The substrate to be repaired is a Si wafer, and the material layer to be repaired is SiO2.

[0125] The first pressure is 1350 mTorr, the first temperature is 90 °C, the first gas is NF3, the frequency of the RF power source is 13.56 MHz, the power of the RF power source is 1000 W, and the first time is 5 s. Correspondingly, the generated free radicals are fluorine free radicals.

[0126] The second temperature is 200 °C - 500 °C, and the second time is 30 s - 180 s.

[0127] The second pressure is 1 Torr - 10 Torr, the second gas is He, and the third time is 60 s - 180 s.

[0128] The preset number of repair times is 2 - 10 times.

[0129] The surface of the material layer to be repaired after repair is as Figure 7 (a) The SEM photo shown in the part, Figure 7 The part (b) in it shows the SEM photo of the surface of the material layer to be repaired before being repaired by the surface repair method described in the embodiment of the present application. Compare Figure 7From the SEM photos of the surface of the material layer to be repaired before and after repair, it can be found that after the surface of the material layer to be repaired is repaired by the surface repair method described in the embodiments of the present application, the flatness of the surface of the material layer to be repaired is significantly improved.

[0130] Figure 8 Shows the complete process of a surface repair method as described in Embodiment 2.

[0131] The surface atoms of SiO2 are fully adsorbed by the fluorine radicals generated in the reaction chamber. Since the fluorine radicals are small in volume, they can be fully adsorbed and combined with the small defects (such as steps) on the surface of SiO2 to increase the reaction rate of the radicals with the surface material of the substrate to be repaired. After high-temperature activation, the fluorine radicals react with SiO2 to generate volatile reactants. After being purged by the purge gas, the surface material of the newly flattened substrate to be repaired is exposed to the environment for a new round of cycle process until the flatness of the surface material of the substrate to be repaired reaches the preset requirement.

[0132] Compared with the process of directly adsorbing with gas, on the one hand, the fluorine radicals have a smaller volume and are easily adsorbed by the atoms at the small defects on the material surface layer (for example, the surface defects with a step morphology), which is beneficial to repairing the small defects on the surface layer in the subsequent process and has a good repair effect; on the other hand, the volatility of the fluorine radicals is relatively poor compared with gas, and the adsorption rate with the surface atoms of the material is high, which is beneficial to increasing the reaction rate of the fluorine radicals with the surface atoms of SiO2 in the subsequent process and improving the flatness effect of the SiO2 material surface.

[0133] Compared with the plasma direct etching process, the repair effect can repair the surface damage of the wafer caused by plasma etching; no charge will accumulate on the wafer surface, and thus it will not have an adverse impact on the subsequent process and product performance.

[0134] Note that the above is only the preferred embodiment of the present invention and the technical principles applied. Those skilled in the art will understand that the present invention is not limited to the specific embodiments described here. Various obvious changes, re-adjustments and substitutions can be made by those skilled in the art without departing from the protection scope of the present invention. Therefore, although the present invention has been described in detail through the above embodiments, the present invention is not limited to the above embodiments. Without departing from the concept of the present invention, more other equivalent embodiments can be included, and the scope of the present invention is determined by the scope of the appended claims.

Claims

1. A surface repair process, characterized in that: include: Injecting a first gas at a first flow rate into a reaction chamber where the chamber pressure is set to a first pressure and the chamber temperature is set to a first temperature; Starting a radio frequency power source to generate free radicals, and maintaining the free radicals for a first time, so that the free radicals can be adsorbed to surface atoms of the material layer to be repaired; The reaction chamber is evacuated, and the temperature inside the reaction chamber is set to a second temperature, and maintained for a second time; The pressure in the reaction chamber is set to a second pressure, and a second gas is injected into the reaction chamber and maintained for a third time.

2. The surface repair process according to claim 1, characterized in that: The first pressure is 10 mTorr-10 Torr; the first temperature is 50°C-90°C.

3. The surface repair process according to claim 1, characterized in that: The first gas is a fluorinated gas.

4. The surface repair process according to claim 1, characterized in that: The frequency of the radio frequency power source is any one of the following: 13.56 MHz, 27 MHz, 40 MHz, 60 MHz, 100 MHz and 2.45 GHz; The power of the radio frequency power source is 100W-5000W.

5. The surface repair process according to claim 1, characterized in that: The first time is 3s-10s.

6. The surface repair process according to claim 1, characterized in that: The second temperature is 200°C-500°C; The second pressure is 1 Torr-10 Torr.

7. The surface repair process according to claim 1, characterized in that: The second time is 30s-180s.

8. The surface repair process according to claim 1, characterized in that: The second gas is an inert gas.

9. The surface repair process according to claim 1, characterized in that: The third time is 60s-180s.

10. A surface repair method, characterized in that: include: Providing a substrate to be repaired to the reaction chamber, wherein a layer of material to be repaired is attached to a surface of the substrate to be repaired; Obtain the number of surface repairs of the substrate to be repaired; Executing a cyclic process until the number of surface repairs is equal to a preset number of repairs, the cyclic process comprising: executing the surface repair process according to any one of claims 1 to 9; The surface repair times are accumulated and updated.

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