Method for processing the product layer

Abstract

A method for treating a product layer comprises: providing a substrate having a dielectric layer thereon; etching away a portion of the dielectric layer to form a product layer on top of the dielectric layer; and providing a dissolving solution, rinsing or soaking the product layer with the dissolving solution, so that the product layer dissolves in the dissolving solution to remove the product layer. The present invention helps improve the efficiency of removing the product layer.

Description

Technical Field

[0001] The present invention relates to the technical field of semiconductor manufacturing, and in particular to a method for processing a product layer. Background Art

[0002] Silicon oxide plays a crucial role in semiconductor manufacturing. Because the diffusion rate of impurity elements such as boron, phosphorus, arsenic, and antimony in silicon oxide is much slower than that in silicon, silicon oxide is often used as a mask for selective diffusion. Furthermore, silicon oxide grown on a silicon surface not only adheres well to the surface but also exhibits excellent electrical insulation and chemical stability. Consequently, silicon oxide is widely used in semiconductor device production.

[0003] During semiconductor device manufacturing, silicon oxide must be etched to ensure that its thickness meets process requirements. During the etching process, gas molecules typically react chemically with the silicon oxide to remove it. The chemical reaction products adsorb onto the surface of the remaining silicon oxide. After the etching process, the products must be cleaned to ensure that the silicon oxide surface meets cleanliness requirements, ensuring smooth processing of subsequent processes.

[0004] However, the existing methods for processing the product layer still need to be improved. Summary of the Invention

[0005] The problem solved by the present invention is to provide a method for treating a product layer, which can efficiently remove the product layer.

[0006] To solve the above problems, the present invention provides a method for processing a product layer, comprising: providing a substrate having a dielectric layer thereon; etching away a portion of the dielectric layer to form a product layer on top of the dielectric layer; providing a dissolving solution, rinsing or soaking the product layer with the dissolving solution, and dissolving the product layer in the dissolving solution to remove the product layer.

[0007] Optionally, the dissolving liquid is a mixture of ammonia water and hydrogen peroxide.

[0008] Optionally, the molar ratio of NH3, H2O2 and H2O in the dissolving solution is 1:2:100.

[0009] Optionally, the dissolving liquid is aqueous ammonia.

[0010] Optionally, the molar ratio of NH3 to H2O in the dissolving solution is 1:100.

[0011] Optionally, the dissolving liquid is a carbonic acid solution.

[0012] Optionally, the concentration of the carbonic acid solution is 0.033 mol / L.

[0013] Optionally, the time for rinsing or soaking the product layer with the dissolving liquid is 60s to 120s.

[0014] Optionally, the material of the dielectric layer is silicon oxide.

[0015] Optionally, a dry etching process is used to etch away a portion of the dielectric layer.

[0016] Optionally, the process gas of the dry etching process includes hydrogen fluoride and ammonia.

[0017] Optionally, the process gas also includes nitrogen or argon.

[0018] Optionally, when the process gas includes nitrogen, the flow rate of the nitrogen is 400 sccm to 1500 sccm.

[0019] Optionally, the chamber pressure of the dry etching process is 20 mTorr to 2000 mTorr.

[0020] Optionally, after removing the product layer, the method further includes: providing a cleaning liquid, and using the cleaning liquid to rinse or soak the dielectric layer.

[0021] Optionally, the cleaning fluid is isopropyl alcohol or acetone.

[0022] Optionally, the time for rinsing or soaking the dielectric layer with the cleaning liquid is 15 seconds to 40 seconds.

[0023] Compared with the prior art, the technical solution of the present invention has the following advantages:

[0024] A dissolving solution is provided, and the product layer is rinsed or soaked in the solution. The product layer, the substrate, and the dielectric layer have different solubilities in the solution. The product layer dissolves in the solution, while the substrate is insoluble or poorly soluble in the solution, and the dielectric layer is insoluble or poorly soluble in the solution. This allows the product layer on top of the dielectric layer to be removed. Dissolving the product layer in the solution to remove the product layer improves removal efficiency, eliminating the need to repeat the steps of removing a portion of the dielectric layer and removing the product layer, thereby shortening process time. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figures 1 to 4 It is a schematic structural diagram corresponding to each step in an embodiment of a method for processing a product layer of the present invention. DETAILED DESCRIPTION

[0026] A method for processing a product layer is now analyzed, including: providing a substrate having a dielectric layer thereon; etching away a portion of the dielectric layer to form a product layer on top of the dielectric layer; removing the product layer by sublimating the product layer; and repeating the process steps of etching away a portion of the dielectric layer and sublimating the product layer multiple times until the thickness of the dielectric layer reaches a predetermined value.

[0027] On the one hand, during the process of removing the product layer by sublimating it (hereinafter referred to as the PHT process), the chamber temperature must be maintained at 80°C to 120°C using a temperature regulator. On the other hand, the PHT process is performed when a portion of the dielectric layer is etched away to form a small amount of the product layer. Therefore, the etching and removal of the dielectric layer and the PHT process must be repeated multiple times. Taking these two aspects into consideration, the processing steps of the treatment method are complex, resulting in low efficiency in removing the product layer.

[0028] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, specific embodiments of the present invention are described in detail below with reference to the accompanying drawings.

[0029] Figures 1 to 4 A structural diagram of the process of processing a product layer provided by one embodiment of the present invention.

[0030] refer to Figure 1 , providing a substrate 100, wherein the substrate 100 has a dielectric layer 300 thereon.

[0031] The substrate 100 is made of silicon, germanium, silicon germanium, silicon carbide, gallium arsenide, or indium gallium. In this embodiment, the substrate 100 is a silicon substrate.

[0032] In this embodiment, the material of the dielectric layer 300 is silicon oxide.

[0033] In this embodiment, the substrate 100 further comprises a fin 200 protruding from the substrate 100, and the dielectric layer 300 covers the sidewalls of the fin 200. In other embodiments, the substrate may comprise only the dielectric layer.

[0034] In this embodiment, the material of the fin 200 is silicon. In other embodiments, the material of the fin may also be germanium, silicon germanium, silicon carbide, gallium arsenide, or indium gallium.

[0035] There are multiple fins 200. In this embodiment, the fins 200 are arranged at equal intervals on the substrate 100. In other embodiments, the intervals between adjacent fins may be unequal.

[0036] In this embodiment, the process steps for forming the substrate 100 and the fin 200 include: providing an initial substrate (not shown in the figure); forming a patterned fin mask dielectric layer (not shown in the figure) on the surface of the initial substrate; etching the initial substrate using the fin mask dielectric layer as a mask, and the etched initial substrate serves as the substrate 100, and the protrusions located on the surface of the substrate 100 serve as the fin 200.

[0037] In this embodiment, the top of the fin 200 is covered with a hard mask layer 220 , and the top of the dielectric layer 300 is flush with the top of the hard mask layer 220 .

[0038] The hard mask layer 220 can protect the top of the fin 200. When a portion of the dielectric layer 300 is subsequently removed by etching, the hard mask layer 220 can prevent the top surface of the fin 200 from being damaged.

[0039] The material of the hard mask layer 220 is silicon nitride, silicon oxynitride, silicon carbide, silicon carbonitride, or silicon carbonitride oxynitride. In this embodiment, the material of the hard mask layer 220 is silicon nitride.

[0040] In this embodiment, an insulating layer 210 is further provided between the top of the fin 200 and the hard mask layer 220. The insulating layer 210 covers the top surface of the fin 200, and the hard mask layer 220 covers the top surface of the insulating layer 210. In other embodiments, the hard mask layer may also directly cover the top surface of the fin.

[0041] The insulating layer 210 can prevent atomic dislocation between the hard mask layer 220 and the top surface of the fin 200 , thereby helping to improve the bonding strength between the hard mask layer 220 and the fin 200 .

[0042] In this embodiment, the insulating layer 210 is made of silicon oxide. In other embodiments, the insulating layer 210 may be made of germanium oxide.

[0043] In this embodiment, the process for forming the insulating layer 210, the hard mask layer 220, and the dielectric layer 300 includes: forming a first insulating film (not shown) on the substrate 100, the first insulating film covering the top of the fin 200; etching the first insulating film to form a first through hole (not shown) in the first insulating film, with the bottom of the first through hole exposing the top surface of the fin 200; forming the insulating layer 210 to fill the first through hole; forming a second insulating film (not shown) on top of the first insulating film and the insulating layer 210; etching the second insulating film to form a second through hole (not shown) in the second insulating film, with the bottom of the second through hole exposing the top surface of the insulating layer 210; and forming the hard mask layer 220 to fill the second through hole. The first insulating film and the second insulating film serve as the insulating layer 210.

[0044] refer to Figure 2 , etching away a portion of the dielectric layer 300 , and forming a product layer 400 on top of the dielectric layer 300 .

[0045] In this embodiment, a dry etching process is used to etch away a portion of the dielectric layer 300. In other embodiments, a wet etching process may be used to etch away a portion of the dielectric layer.

[0046] In this embodiment, the process gas of the dry etching process includes hydrogen fluoride and ammonia. Hydrogen fluoride and ammonia react chemically with the dielectric layer 300 to generate ammonium fluorosilicate ((NH4)2SiF6) and water. The reaction formula is:

[0047] SiO2+6HF+2NH3→(NH4)2SiF6+2H2O↑.

[0048] The ammonium fluorosilicate is deposited on the surface of the remaining dielectric layer 300 to serve as the product layer 400. Water, another product of the chemical reaction, is vaporized.

[0049] During the dry etching process, if the chamber pressure is too high, on the one hand, the oxygen in the chamber will easily react with the silicon substrate 100 to form silicon oxide, reducing the thickness of the substrate 100. On the other hand, the vaporization temperature of the resulting water is related to the chamber pressure. If the chamber pressure is too high, the vaporization temperature of the water will increase, so the chamber temperature must be maintained at a high temperature, which will easily promote the oxidation reaction of the silicon substrate 100. If the chamber pressure is too low, the heat conduction in the chamber will be slow, affecting the etching rate of the dielectric layer 300. In this embodiment, the chamber pressure is 20mTorr to 2000mTorr.

[0050] Specifically, in this embodiment, the chamber pressure is 1800 mTorr.

[0051] If the process temperature of the dry etching process is too high, the silicon substrate 100 is susceptible to oxidation, affecting the quality of the silicon substrate 100. If the process temperature of the dry etching process is too low, the reaction rate between the hydrogen fluoride and ammonia and the dielectric layer 300 is slow, or even difficult to trigger. In this embodiment, the process temperature of the dry etching process is 70°C to 75°C.

[0052] Specifically, in this embodiment, the process temperature of the dry etching process is 75°C.

[0053] The process gas of the dry etching process further includes nitrogen or argon. In this embodiment, during the dry etching process, nitrogen is continuously introduced into the chamber.

[0054] In this embodiment, nitrogen gas is continuously introduced into the chamber to form a nitrogen flow within the chamber. The flowing nitrogen gas acts as a flushing agent, blowing a portion of the product layer 400 off the surface of the dielectric layer 300. The product layer 400 blown off the surface of the dielectric layer 300 is then discharged from the chamber along with the nitrogen flow, thereby reducing the amount of the product layer 400 adsorbed on the dielectric layer 300.

[0055] If the nitrogen flow rate is too low, the nitrogen flow within the chamber will be slow, resulting in poor nitrogen flushing effect and difficulty in blowing part of the product layer 400 off the surface of the dielectric layer 300. If the nitrogen flow rate is too high, the chamber pressure will increase and decrease instantaneously, affecting the vaporization of the product water. In this embodiment, the nitrogen flow rate is 400 sccm to 1500 sccm.

[0056] The pressure of the nitrogen gas is 0.1 mTorr to 1 mTorr. In this embodiment, the pressure of the nitrogen gas is 0.2 mTorr.

[0057] In this embodiment, the dry etching process is terminated until the thickness of the remaining dielectric layer 300 reaches a predetermined value.

[0058] refer to Figure 3 and Figure 4 , providing a dissolving solution 500, using the dissolving solution 500 to rinse or soak the product layer 400, the product layer 400 is dissolved in the dissolving solution 500, so as to remove the product layer 400.

[0059] The solubility of the product layer 400 in the dissolving solution 500 is much greater than the solubility of the substrate 100 and the dielectric layer 300 in the dissolving solution 500. The product layer 400 is soluble in the dissolving solution 500. The substrate 100 is poorly soluble or insoluble in the dissolving solution 500. The dielectric layer 300 is poorly soluble or insoluble in the dissolving solution 500. By utilizing this difference in solubility, the product layer 400 on the surface of the dielectric layer 300 can be removed using the dissolving solution 500.

[0060] Removing the product layer 400 from the surface of the dielectric layer 300 with the dissolving solution 500, on the one hand, allows the entire product layer 400 on the surface of the dielectric layer 300 to be removed at once, eliminating the need to repeatedly etch away a portion of the dielectric layer 300 and dissolve the product layer 400 in the dissolving solution 500. On the other hand, dissolving the product layer 400 can be performed at a relatively low temperature, even at room temperature. Taking these two aspects into account, the treatment method has simple process steps, which helps improve the efficiency of removing the product layer 400.

[0061] In this embodiment, the product layer 400 is soaked in the dissolving liquid 500 .

[0062] In this embodiment, the fin 200, the insulating layer 210, and the hard mask layer 220 are also immersed in the dissolving solution 500. The fin 200, the insulating layer 210, and the hard mask layer 220 are hardly soluble or insoluble in the dissolving solution 500.

[0063] In this embodiment, the process of soaking the substrate 100, the dielectric layer 300, and the product layer 400 is performed in different chambers from the dry etching process. In other embodiments, the process of soaking the substrate, the dielectric layer, and the product layer to remove the product layer can also be performed in the same chamber after the dry etching process is completed.

[0064] In other embodiments, the product layer can also be rinsed with the dissolving liquid. The rinsing method can efficiently remove the product layer and make the surface of the dielectric layer cleaner.

[0065] In this embodiment, the dissolving solution 500 is a mixture of ammonia and hydrogen peroxide. If the solute concentration in the dissolving solution 500 is too low, the dissolution rate of the product layer 400 will be too slow, affecting the processing efficiency of the product layer 400. In this embodiment, the molar ratio of NH3, H2O2, and H2O in the dissolving solution 500 is 1:2:100.

[0066] In other embodiments, the dissolving liquid is aqueous ammonia, and the molar ratio of NH 3 to H 2 O in the dissolving liquid 500 is 1:100.

[0067] In another embodiment, the dissolving liquid is a carbonate solution, and the concentration of the carbonate solution is 0.033 mol / L.

[0068] If the rinsing or soaking time is too short, the product layer 400 will not fully dissolve in the dissolving solution 500, resulting in residual product layer 400 on the surface of the dielectric layer 300. If the substrate 100 and the dielectric layer 300 are still rinsed or soaked after the entire product layer 400 has dissolved in the dissolving solution 500, the process time will be unnecessarily extended. In this embodiment, the rinsing or soaking time for the product layer 400 in the dissolving solution 500 is 60 seconds to 120 seconds.

[0069] Specifically, in this embodiment, the time for soaking the product layer 400 in the dissolving liquid shower 500 is 60 seconds.

[0070] The dissolution rate of the product layer 400 is related to the temperature of the dissolving solution 500. If the temperature of the dissolving solution 500 is too low, the dissolution rate of the product layer 400 will be too slow, resulting in a prolonged processing time. If the temperature of the dissolving solution 500 is too high, the substrate 100 will easily undergo an oxidation reaction, resulting in the formation of a silicon oxide film layer on the surface of the substrate 100, affecting the formation quality of the substrate 100. In this embodiment, the temperature of the dissolving solution 500 is 20°C to 25°C.

[0071] In this embodiment, after removing the product layer 400 , the process further includes providing a cleaning liquid (not shown in the figure) and rinsing or soaking the dielectric layer 300 with the cleaning liquid.

[0072] The cleaning liquid can remove the residual dissolving liquid 500 on the surfaces of the dielectric layer 300 and the substrate 100 .

[0073] The cleaning liquid is a volatile solution. In this embodiment, the cleaning liquid is isopropyl alcohol. In other embodiments, the cleaning liquid is acetone.

[0074] The time for rinsing or soaking the dielectric layer 300 with the cleaning liquid is 15 seconds to 40 seconds. In this embodiment, the time for rinsing or soaking the dielectric layer 300 with the isopropyl alcohol is 15 seconds.

[0075] Although the present invention is disclosed as above, the present invention is not limited thereto. Any person skilled in the art can make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, the scope of protection of the present invention should be based on the scope defined by the claims.

Claims

1. A method for treating a product layer, characterized in that: include: A substrate is provided, wherein a dielectric layer is formed on the substrate, and a fin portion protruding from the substrate is also formed on the substrate, wherein the dielectric layer covers the sidewalls of the fin portion; a hard mask layer is formed on the top of the fin portion; a top of the dielectric layer is flush with a top of the hard mask layer; and an insulating layer is provided between the top of the fin portion and the hard mask layer; A dry etching process is used to remove a portion of the dielectric layer, wherein the gas used in the dry etching process reacts with the dielectric layer to form a product layer on top of the remaining dielectric layer; the dry etching process gas includes nitrogen, and the flowing nitrogen gas is used to blow a portion of the product layer away from the surface of the dielectric layer to reduce the content of the product layer adsorbed on the dielectric layer; Providing a dissolving solution, and using the dissolving solution to rinse or soak the product layer, the fin, the insulating layer, and the hard mask layer, wherein the product layer is dissolved in the dissolving solution, and the fin, the insulating layer, and the hard mask layer are hardly soluble or insoluble in the dissolving solution, so as to remove the product layer; After removing the product layer, the method further includes: providing a cleaning liquid, and using the cleaning liquid to rinse or soak the dielectric layer to remove residual dissolving liquid on the dielectric layer and the substrate surface.

2. The processing method according to claim 1, characterized in that The dissolving liquid is a mixture of ammonia water and hydrogen peroxide, and the molar ratio of NH3, H2O2 and H2O in the dissolving liquid is 1:2:

100.

3. The processing method according to claim 1, characterized in that When the dissolving liquid is aqueous ammonia, the molar ratio of NH3 to H2O in the dissolving liquid is 1:

100.

4. The processing method according to claim 1, wherein The dissolving liquid is a carbonic acid solution, and the concentration of the carbonic acid solution is 0.033 mol / L.

5. The processing method according to any one of claims 1 to 4, characterized in that: The time for rinsing or soaking the product layer with the dissolving solution is 60s to 120s.

6. The processing method according to claim 1, wherein The material of the dielectric layer is silicon oxide.

7. The processing method according to claim 1, characterized in that When the process gas includes nitrogen, the flow rate of the nitrogen is 400 sccm-1500 sccm.

8. The processing method according to claim 1, wherein The chamber pressure of the dry etching process is 20mTorr~2000mTorr.

9. The processing method according to claim 1, wherein: The cleaning liquid is isopropyl alcohol or acetone.

10. The processing method according to claim 1 or 9, characterized in that: The time for rinsing or soaking the dielectric layer with the cleaning liquid is 15s to 40s.

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