Semiconductor device etching method, radio frequency module and etching machine

Abstract

The invention relates to the technical field of semiconductors, and discloses a semiconductor device etching method, a radio frequency module and an etching machine, and the method comprises the steps: employing a first etching gas to etch a silicon nitride layer on a first semiconductor device, so as to enable the thickness of the silicon nitride layer of the first semiconductor device to be different from the thickness of a silicon nitride layer of a second semiconductor device; obtaining a second etching gas, and controlling the etching rate of the second etching gas according to the thickness of the residual silicon nitride layer on the first semiconductor device and the thickness of the silicon nitride layer of the second semiconductor device; and etching the residual silicon nitride layer on the first semiconductor device and the silicon nitride layer on the second semiconductor device by using second etching gas based on the etching rate so as to form different side walls on the side surface of the first semiconductor device and the side surface of the second semiconductor device, thereby forming different side walls on the side surfaces of different semiconductor devices. The performance of different semiconductor devices is effectively balanced, and the overall performance of the radio frequency module formed by different semiconductor devices is improved.

Description

Technical Field

[0001] The present invention relates to the field of semiconductor technology, and particularly to a method for etching semiconductor devices, a radio frequency module, and an etching machine. Background Art

[0002] A radio frequency module integrates discrete semiconductor devices with two or more functions, such as radio frequency switches, low-noise amplifiers, filters, duplexers, power amplifiers, etc. into a module, thereby improving integration and performance and miniaturizing the volume.

[0003] Currently, sidewalls of different semiconductor devices in a radio frequency module are etched through non-selective area etching, so that the sidewall morphologies formed by different semiconductor devices are the same. For semiconductor devices that are sensitive to sidewall morphology, such as radio frequency switches and low-noise amplifiers, the same sidewall morphology will result in poor performance of these different semiconductor devices, and thus reduce the overall performance of the radio frequency module.

[0004] The above content is only used to assist in understanding the technical solution of the present invention, and does not represent an admission that the above content is prior art. Summary of the Invention

[0005] The main objective of the present invention is to provide a method for etching semiconductor devices, a radio frequency module, and an etching machine, aiming to solve the technical problem that in the prior art, non-selective area etching is used, resulting in the same sidewall morphology formed by different semiconductor devices, leading to poor performance of different semiconductor devices, and thus reducing the overall performance of the radio frequency module.

[0006] To achieve the above objective, the present invention provides a method for etching semiconductor devices, which is applied to a structure provided with a first semiconductor device and a second semiconductor device, and side surfaces of the first semiconductor device and the second semiconductor device are both covered with silicon nitride layers having the same thickness;

[0007] The method for etching semiconductor devices includes:

[0008] Etching the silicon nitride layer on the first semiconductor device with a first etching gas, so that the thickness of the silicon nitride layer of the first semiconductor device is different from that of the silicon nitride layer of the second semiconductor device;

[0009] Obtaining a second etching gas, and controlling the etching rate of the second etching gas according to the remaining thickness of the silicon nitride layer on the first semiconductor device and the thickness of the silicon nitride layer of the second semiconductor device;

[0010] Etching the remaining silicon nitride layer on the first semiconductor device and the silicon nitride layer on the second semiconductor device with the second etching gas based on the etching rate, so as to form different sidewalls on the side surfaces of the first semiconductor device and the second semiconductor device.

[0011] Optionally, the step of etching the silicon nitride layer on the first semiconductor device with the first etching gas to make the thickness of the silicon nitride layer of the first semiconductor device different from that of the second semiconductor device includes:

[0012] Coat photoresist on the silicon nitride layer of the second semiconductor device;

[0013] Simultaneously etch the first semiconductor device and the second semiconductor device with the first etching gas to remove a part of the silicon nitride layer on the first semiconductor device;

[0014] When the etching of the first semiconductor device is completed, remove the photoresist with the third etching gas to make the thickness of the silicon nitride layer of the first semiconductor device different from that of the second semiconductor device.

[0015] Optionally, a first oxide layer is provided between the side surface of the first semiconductor device and the silicon nitride layer covering the first semiconductor device, and a second oxide layer is provided between the side surface of the second semiconductor device and the silicon nitride layer covering the second semiconductor device;

[0016] The step of simultaneously etching the first semiconductor device and the second semiconductor device with the first etching gas to remove a part of the silicon nitride layer on the first semiconductor device includes:

[0017] Control the selectivity ratio of the first etching gas to be greater than a first preset threshold, where the selectivity ratio is the ratio of the reaction rate of the first etching gas etching the silicon nitride layer to the reaction rate of etching the oxide layer;

[0018] Simultaneously etch the first semiconductor device and the second semiconductor device with the first etching gas based on the selectivity ratio of the first etching gas to remove a part of the silicon nitride layer on the first semiconductor device.

[0019] Optionally, the step of controlling the etching rate of the second etching gas according to the remaining thickness of the silicon nitride layer on the first semiconductor device and the thickness of the silicon nitride layer of the second semiconductor device includes:

[0020] Determine a second preset threshold of the second etching gas according to the remaining thickness of the silicon nitride layer on the first semiconductor device and the thickness of the silicon nitride layer of the second semiconductor device;

[0021] Control the selectivity ratio of the second etching gas to reach the second preset threshold, and use the selectivity ratio reaching the second preset threshold as the etching rate of the second etching gas.

[0022] Optionally, the step of etching the remaining silicon nitride layers on the first semiconductor device and the silicon nitride layer on the second semiconductor device based on the etching rate using the second etching gas to form different sidewalls on the sides of the first semiconductor device and the second semiconductor device includes:

[0023] Etching the first semiconductor device and the second semiconductor device based on the selectivity of the second etching gas using the second etching gas;

[0024] During the etching process, etching the remaining silicon nitride layer on the first semiconductor device, retaining a part of the oxide layer on the side of the first semiconductor device, etching the silicon nitride layer on the top of the second semiconductor device, and retaining a part of the silicon nitride layer on the side of the second semiconductor device to form different sidewalls on the sides of the first semiconductor device and the second semiconductor device.

[0025] Optionally, after the step of, during the etching process, etching the remaining silicon nitride layer on the first semiconductor device, retaining a part of the oxide layer on the side of the first semiconductor device, etching the silicon nitride layer on the top of the second semiconductor device, and retaining a part of the silicon nitride layer on the side of the second semiconductor device to form different sidewalls on the sides of the first semiconductor device and the second semiconductor device, further includes:

[0026] Etching the first semiconductor device and the second semiconductor device with different sidewalls formed thereon simultaneously based on the selectivity of the first etching gas using the first etching gas to remove the remaining silicon nitride layers on the first semiconductor device and the second semiconductor device;

[0027] When removing the remaining silicon nitride layer on the second semiconductor device, adjusting the thickness of the sidewall of the second semiconductor device.

[0028] In addition, to achieve the above object, the present invention further provides a radio frequency module, which includes a first semiconductor device and a second semiconductor device;

[0029] The first semiconductor device and the second semiconductor device are on the same substrate;

[0030] The sidewalls of the first semiconductor device and the second semiconductor device are different.

[0031] Optionally, the radio frequency module further includes: a first oxide layer, a second oxide layer, and a first silicon nitride layer;

[0032] The first oxide layer covers the gate of the first semiconductor device;

[0033] The second oxide layer covers the gate of the second semiconductor device, and the first silicon nitride layer covers the second oxide layer on the side of the second semiconductor device;

[0034] Wherein, the first oxide layer on the side of the first semiconductor device forms the sidewall of the first semiconductor device, the second oxide layer on the side of the second semiconductor device and the first silicon nitride layer form the sidewall of the second semiconductor device, and the sidewall thickness of the second semiconductor device is greater than that of the first semiconductor device.

[0035] Optionally, the radio frequency module further includes: a second silicon nitride layer and a third silicon nitride layer;

[0036] The second silicon nitride layer is disposed in the first oxide layer on the side of the first semiconductor device;

[0037] The third silicon nitride layer is disposed between the gate of the second semiconductor device and the second oxide layer.

[0038] In addition, to achieve the above object, the present invention also provides an etching machine for implementing the semiconductor device etching method as described above.

[0039] The present invention provides a semiconductor device etching method, a radio frequency module and an etching machine. The method is applied to a structure provided with a first semiconductor device and a second semiconductor device, and the sides of the first semiconductor device and the second semiconductor device are both covered with silicon nitride layers of the same thickness; the method etches the silicon nitride layer on the first semiconductor device by using a first etching gas, so that the thickness of the silicon nitride layer of the first semiconductor device is different from that of the second semiconductor device; a second etching gas is obtained, and the etching rate of the second etching gas is controlled according to the remaining thickness of the silicon nitride layer on the first semiconductor device and the thickness of the silicon nitride layer of the second semiconductor device; the remaining silicon nitride layer on the first semiconductor device and the silicon nitride layer on the second semiconductor device are etched by using the second etching gas based on the etching rate, so as to form different sidewalls on the sides of the first semiconductor device and the second semiconductor device. By first etching the silicon nitride layer on the first semiconductor device, and then adjusting the etching rate of the second etching gas according to the thickness of the silicon nitride layers of different semiconductor devices, and using the etching rate of the second etching gas to etch the silicon nitride layers on different semiconductor devices, compared with the prior art by non-selective area etching, the above method of the present invention realizes the formation of different sidewalls on the sides of different semiconductor devices, effectively balances the performance of different semiconductor devices, and further improves the overall performance of the radio frequency module composed of different semiconductor devices. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] Figure 1 It is a schematic flowchart of the first embodiment of the semiconductor device etching method of the present invention;

[0041] Figure 2 Schematic diagram of etching of the first etching gas in the first embodiment of the semiconductor device etching method of the present invention;

[0042] Figure 3 Schematic diagram of the sidewall topography of different semiconductor devices in the first embodiment of the semiconductor device etching method of the present invention;

[0043] Figure 4 Flow chart of the second embodiment of the semiconductor device etching method of the present invention;

[0044] Figure 5 Schematic diagram of photoresist coating in the second embodiment of the semiconductor device etching method of the present invention;

[0045] Figure 6 Schematic diagram of etching of the first etching gas in the second embodiment of the semiconductor device etching method of the present invention;

[0046] Figure 7 Schematic diagram of photoresist removal in the second embodiment of the semiconductor device etching method of the present invention;

[0047] Figure 8 Flow chart of the third embodiment of the semiconductor device etching method of the present invention;

[0048] Figure 9 Schematic diagram of the sidewall topography of different semiconductor devices in the third embodiment of the semiconductor device etching method of the present invention;

[0049] Figure 10 Schematic diagram of the structure of the radio frequency module embodiment of the present invention.

[0050] Explanation of the reference numerals in the drawings:

[0051] Reference numeral Name Reference numeral Name 10 First semiconductor device 20 Second semiconductor device 30 Silicon nitride layer 40 Photoresist 101 First oxide layer 201 Second oxide layer 301 First silicon nitride layer 302 Second silicon nitride layer 303 Third silicon nitride layer 50 Substrate

[0052] The realization, functional features and advantages of the object of the present invention will be further described with reference to the embodiments and the accompanying drawings. Detailed implementation manners

[0053] It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0054] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts belong to the scope of protection of the present invention.

[0055] It should be noted that in the embodiments of the present invention, the descriptions involving "first", "second", etc. are only for descriptive purposes, and cannot be construed as indicating or implying their relative importance or implicitly specifying the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include at least one such feature. Additionally, the technical solutions between various embodiments may be combined with each other, but it must be based on the fact that those skilled in the art can implement them. When the combination of technical solutions results in contradictions or cannot be implemented, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

[0056] Refer to Figure 1 , Figure 1 which is a schematic flowchart of the first embodiment of the semiconductor device etching method of the present invention.

[0057] As Figure 1 shown, in this embodiment, the method is applied to a structure provided with a first semiconductor device 10 and a second semiconductor device 20, and the sides of the first semiconductor device 10 and the second semiconductor device 20 are both covered by silicon nitride layers 30 with the same thickness.

[0058] The semiconductor device etching method includes:

[0059] Step S10: Etch the silicon nitride layer on the first semiconductor device using a first etching gas to make the thickness of the silicon nitride layer of the first semiconductor device different from that of the second semiconductor device.

[0060] It should be noted that both the above-mentioned first semiconductor device 10 and the second semiconductor device 20 can be devices that are sensitive to the sidewall thickness. Among them, the above-mentioned first semiconductor device 10 can be a radio frequency switch in a radio frequency module, and the second semiconductor device 20 can be a low noise amplifier in a radio frequency module.

[0061] It can be understood that the above-mentioned first etching gas can be a gas for etching the silicon nitride layer 30 on the first semiconductor device 10. The first etching gas may include a main etching gas and other etching gases. Among them, the main etching gas can be the core gas participating in the reaction during the etching process, such as SF6, and the other etching gases are auxiliary gases, such as O2 and HBR, etc.

[0062] In a specific implementation, refer to Figure 2 , Figure 2 which is an etching schematic diagram of the first etching gas in the first embodiment of the semiconductor device etching method of the present invention. Figure 2In [the above situation], a protective layer can be covered on the outer side of the second semiconductor device 20, and then the first semiconductor device 10 and the second semiconductor device 20 can be etched simultaneously with the first etching gas. Due to the function of the protective layer, the silicon nitride layer 30 on the first semiconductor device 20 can be protected from being etched away. At the same time, the reaction rate of the first etching gas can be controlled to ensure that the first etching gas does not etch all the silicon nitride layer 30 on the first semiconductor device 10, but leaves a part of the silicon nitride layer, so that the thickness of the silicon nitride layer 30 on the first semiconductor device 10 is different from that of the silicon nitride layer 30 on the second semiconductor device 20. Then, the protective layer on the second semiconductor device 20 is removed to form as Figure 2 the structure shown.

[0063] Step S20: Obtain a second etching gas, and control the etching rate of the second etching gas according to the thickness of the remaining silicon nitride layer on the first semiconductor device and the thickness of the silicon nitride layer of the second semiconductor device.

[0064] It should be noted that the above second etching gas is the gas for simultaneously etching the first semiconductor device 10 and the second semiconductor device 20. The second etching gas may also include a main etching gas and other etching gases. The main etching gas is such as CHxFy (where x > 0, y > 0), and the other etching gases may be a protective gas HE and O2 that play a protective role, etc.

[0065] In a specific implementation, since the thickness of the silicon nitride layer of the first semiconductor device 10 is already different from that of the silicon nitride layer of the second semiconductor device 20, if etched simultaneously, there will be a situation where the silicon nitride layer 30 on the first semiconductor device 10 has been completely etched, while the silicon nitride layer 30 on the second semiconductor device 20 has not reached the requirement and needs to be etched further. During the further etching process, the gate inside the first semiconductor device 10 will be etched, resulting in the destruction of the structure of the first semiconductor device 10. Therefore, after obtaining the second etching gas, the etching rate of the second etching gas can be controlled according to the thickness of the remaining silicon nitride layer on the first semiconductor device 10 and the current thickness of the silicon nitride layer of the second semiconductor device 20, to ensure that when the silicon nitride layer on the second semiconductor device 20 is etched to meet the requirement, the internal structure of the first semiconductor device 10 is not damaged.

[0066] Step S30: Use the second etching gas to etch the remaining silicon nitride layer on the first semiconductor device and the silicon nitride layer on the second semiconductor device based on the etching rate, so as to form different sidewalls on the side surfaces of the first semiconductor device and the second semiconductor device.

[0067] In a specific implementation, referring to Figure 3 , Figure 3 is a schematic diagram of the sidewall morphologies of different semiconductor devices in the first embodiment of the semiconductor device etching method of the present invention.Figure 3 In this case, the above-mentioned second etching gas can be used to etch the first semiconductor device 10 and the second semiconductor device 20 simultaneously based on the controlled etching rate, etching away the remaining silicon nitride layer 30 on the first semiconductor device 10, as well as the silicon nitride layer 30 above and on the sides of the second semiconductor device 20.

[0068] As Figure 2 shown, after etching at the above etching rate of the second etching gas, the entire silicon nitride layer 30 on the first semiconductor device 10 is etched away. At the same time, the structure of the first semiconductor device 10 is not damaged, and a part of the silicon nitride layer 20 is retained on the side of the second semiconductor device 20. Thus, sidewalls with different morphologies and different thicknesses are formed on the sides of the first semiconductor device 10 and the second semiconductor device 20, which can adjust the distance between the drain region and the gate in the first semiconductor device 10 and the second semiconductor device 20, effectively balancing the performance of the first semiconductor device 10 and the second semiconductor device 20, and further improving the overall performance of the RF module.

[0069] It should be understood that in addition to the RF switch and the low-noise amplifier that can be etched in the above manner, other devices in the RF module can also be etched in the above manner to form sidewalls with different morphologies. This embodiment does not limit this.

[0070] This embodiment is applied to a structure provided with a first semiconductor device and a second semiconductor device, and the sides of the first semiconductor device and the second semiconductor device are both covered with silicon nitride layers of the same thickness; this method etches the silicon nitride layer on the first semiconductor device by using a first etching gas so that the thickness of the silicon nitride layer of the first semiconductor device is different from that of the silicon nitride layer of the second semiconductor device; obtains a second etching gas, and controls the etching rate of the second etching gas according to the thickness of the remaining silicon nitride layer on the first semiconductor device and the thickness of the silicon nitride layer of the second semiconductor device; uses the second etching gas to etch the remaining silicon nitride layer on the first semiconductor device and the silicon nitride layer on the second semiconductor device based on the etching rate, so as to form different sidewalls on the sides of the first semiconductor device and the second semiconductor device. By first etching the silicon nitride layer on the first semiconductor device, then adjusting the etching rate of the second etching gas according to the thickness of the silicon nitride layers of different semiconductor devices, and using the etching rate of the second etching gas to etch the silicon nitride layers on different semiconductor devices, compared with the prior art method of etching without a selective area, the above method of this embodiment realizes the formation of different sidewalls on the sides of different semiconductor devices, effectively balancing the performance of different semiconductor devices, and further improving the overall performance of the RF module composed of different semiconductor devices.

[0071] Refer to Figure 4 , Figure 4Schematic flowchart of the second embodiment of the semiconductor device etching method of the present invention.

[0072] Based on the above first embodiment, in this embodiment, the step S10 includes:

[0073] Step S101: Coat a photoresist on the silicon nitride layer of the second semiconductor device.

[0074] In a specific implementation, referring to Figure 5 , Figure 5 is a schematic diagram of photoresist coating in the second embodiment of the semiconductor device etching method of the present invention. Figure 5 in, a photoresist 40 can be coated on the silicon nitride layer 30 of the above-mentioned second semiconductor device 20 to protect the silicon nitride layer 30 under the photoresist 40 from being etched away.

[0075] Step S102: Use a first etching gas to etch the first semiconductor device and the second semiconductor device simultaneously, and remove a part of the silicon nitride layer on the first semiconductor device.

[0076] In a specific implementation, the above-mentioned first semiconductor device 10 and the above-mentioned second semiconductor device 20 can be etched simultaneously using the above-mentioned first etching other. Since the second semiconductor device 20 is covered with a photoresist 40, when removing a part of the silicon nitride layer 30 on the first semiconductor device 10, the silicon nitride layer 30 under the photoresist 40 on the second semiconductor device will not be etched.

[0077] Furthermore, in this embodiment, a first oxide layer 101 is provided between the side surface of the first semiconductor device 10 and the silicon nitride layer 30 covering the first semiconductor device 10, and a second oxide layer 201 is provided between the side surface of the second semiconductor device 20 and the silicon nitride layer 30 covering the second semiconductor device 20.

[0078] The step of using the first etching gas to etch the first semiconductor device and the second semiconductor device simultaneously and removing a part of the silicon nitride layer on the first semiconductor device includes:

[0079] Step S1021: Control the selectivity ratio of the first etching gas to be greater than a first preset threshold, where the selectivity ratio is the ratio of the reaction rate of the first etching gas for etching the silicon nitride layer to the reaction rate for etching the oxide layer.

[0080] It should be noted that referring to Figure 6 , Figure 6 is a schematic diagram of the etching of the first etching gas in the second embodiment of the semiconductor device etching method of the present invention. Figure 6In the above, a first oxide layer 101 is provided between the side surface of the first semiconductor device 10 and the silicon nitride layer 30 covering the first semiconductor device 10, and a second oxide layer 201 is provided between the side surface of the second semiconductor device 20 and the silicon nitride layer 30 covering the second semiconductor device 20.

[0081] It can be understood that the above first preset threshold can be a threshold to ensure that the first etching gas does not etch the oxide layer when etching the silicon nitride layer 30. For example, if the first preset threshold is 100, that is, the selectivity of the first etching gas is greater than 100, it means that when the first etching gas etches 100 nm of the silicon nitride layer, 1 nm of the oxide layer is consumed, so as to ensure that the oxide layer is not etched as much as possible.

[0082] In a specific implementation, the selectivity of the first etching gas can be controlled to be greater than the above first preset threshold to ensure that the first etching gas etches a part of the silicon nitride layer 30 on the first semiconductor device 10 without etching to the first oxide layer 101.

[0083] Step S1022: Use the first etching gas to etch the first semiconductor device 10 and the second semiconductor device simultaneously based on the selectivity of the first etching gas to remove a part of the silicon nitride layer on the first semiconductor device.

[0084] It should be understood that in addition to controlling the selectivity of the first etching gas to reach the above first preset threshold, the source power, bias voltage power, and pressure of the etching can also be controlled to ensure the etching accuracy. For example, the source power can be 400 - 1000 W, the bias voltage power can be 0 W, and the pressure can be 40 - 100 mT.

[0085] In a specific implementation, referring to Figure 6 , the first semiconductor device 10 and the second semiconductor device 20 can be etched simultaneously using the first etching gas based on the selectivity of the first etching gas to etch a part of the silicon nitride layer 30 between the first semiconductor device 101 and the photoresist 40. At the same time, protected by the photoresist 40, the silicon nitride layer 30 under the photoresist 40 on the second semiconductor device 20 is not etched.

[0086] Step S103: When the etching of the first semiconductor device is completed, use a third etching gas to remove the photoresist so that the thickness of the silicon nitride layer of the first semiconductor device is different from that of the second semiconductor device.

[0087] It should be noted that the above third etching gas is a gas used to remove the photoresist 40, such as O2.

[0088] In a specific implementation, referring to Figure 7 , Figure 7This is a schematic diagram of photoresist removal in the second embodiment of the etching method for semiconductor devices of the present invention. Figure 7 After the etching of the first semiconductor device 10 is completed, the photoresist 40 on the second semiconductor device 10 can be removed using a third etching gas, so that the thickness of the silicon nitride layer 30 on the first semiconductor device 10 is different from that of the silicon nitride layer 30 on the second semiconductor device 20, thereby obtaining the first semiconductor device 10 and the second semiconductor device 20 with different silicon nitride layer thicknesses.

[0089] In this embodiment, a photoresist is coated on the silicon nitride layer of the second semiconductor device; the first semiconductor device and the second semiconductor device are etched simultaneously using a first etching gas to remove a part of the silicon nitride layer on the first semiconductor device; when the etching of the first semiconductor device is completed, the photoresist is removed using a third etching gas so that the thickness of the silicon nitride layer of the first semiconductor device is different from that of the silicon nitride layer of the second semiconductor device. When etching the first semiconductor device and the second semiconductor device using the first etching gas in this embodiment, the photoresist is used to protect the silicon nitride layer on the second semiconductor device from etching, so that a part of the silicon nitride layer 30 on the first semiconductor device 10 can be removed more accurately, effectively improving the etching accuracy.

[0090] Reference Figure 8 , Figure 8 This is a schematic flowchart of the third embodiment of the etching method for semiconductor devices of the present invention.

[0091] Based on the above embodiments, in this embodiment, the step of controlling the etching rate of the second etching gas according to the remaining thickness of the silicon nitride layer on the first semiconductor device and the thickness of the silicon nitride layer of the second semiconductor device includes:

[0092] Step S201: Determine a second preset threshold of the second etching gas according to the remaining thickness of the silicon nitride layer on the first semiconductor device and the thickness of the silicon nitride layer of the second semiconductor device.

[0093] It should be noted that the above second preset threshold can be a selectivity threshold for ensuring that when the second etching gas etches the silicon nitride layers 30 of the first semiconductor device 10 and the second semiconductor device 20, a part of the oxide layer is retained. For example, if the second preset threshold is 5, that is, the selectivity of the second etching gas is greater than 5, it means that when the first etching gas etches 5 nm of the silicon nitride layer, 1 nm of the oxide layer is consumed, so that the oxide layer can be ensured not to be etched while the silicon nitride layer 30 is etched as much as possible.

[0094] In a specific implementation, the above-mentioned first oxide layer 101 coats the gate of the first semiconductor device 10, and the second oxide layer 201 coats the gate of the second semiconductor device 20. After etching with the first etching gas, the thickness of a part of the silicon nitride layer 30 on the first semiconductor device 10 is relatively thin. To ensure that the second etching gas does not etch away the first oxide layer 101 of the first semiconductor device 10, the second preset threshold of the second etching gas can be determined according to the remaining thickness of the silicon nitride layer on the first semiconductor device 10 and the thickness of the silicon nitride layer of the second semiconductor device 20.

[0095] Step S202: Control the selectivity of the second etching gas to reach the second preset threshold, and use the selectivity that reaches the second preset threshold as the etching rate of the second etching gas.

[0096] In a specific implementation, the selectivity of the above-mentioned second etching gas can be controlled to reach the above-mentioned second preset threshold, and then the selectivity that reaches the second preset threshold is used as the etching rate of the second etching gas.

[0097] Further, in this embodiment, the step S30 includes:

[0098] Step S301: Use the second etching gas to etch the first semiconductor device and the second semiconductor device based on the selectivity of the second etching gas.

[0099] In a specific implementation, the above-mentioned second etching gas can be used to simultaneously etch the above-mentioned first semiconductor device 10 and the second semiconductor device 20 based on the selectivity of the second etching gas, ensuring that when the remaining silicon nitride layer 30 of the second semiconductor device 20 meets the requirements, the first oxide layer 101 on the first semiconductor device 10 still remains and is not completely etched.

[0100] It should be understood that in addition to controlling the selectivity of the second etching gas to reach the above-mentioned second preset threshold, the source power, bias voltage power, and pressure of the etching can also be controlled to ensure the etching accuracy. For example, the source power can be 200 - 600 W, the bias voltage power can be 100 - 400 W, and the pressure can be 0 - 50 mT.

[0101] Step S302: During the etching process, etch the remaining silicon nitride layer on the first semiconductor device, retain a part of the oxide layer on the side of the first semiconductor device, etch the silicon nitride layer on the top of the second semiconductor device, and retain a part of the silicon nitride layer on the side of the second semiconductor device, so as to form different sidewalls on the sides of the first semiconductor device and the second semiconductor device.

[0102] In a specific implementation, refer to Figure 9 , Figure 9Schematic diagram of the sidewall morphologies of different semiconductor devices in the third embodiment of the etching method for the semiconductor device of the present invention. Figure 9 In this case, during the etching process, the remaining silicon nitride layer 300 on the first semiconductor device 10 can be etched, the first oxide layer 101 on the side of the first semiconductor device 10 can be retained, and in the region where the thickness of the silicon nitride of the first semiconductor device 10 is lower than that of the second semiconductor device 20 before the second etching gas is etched, part of the first oxide layer 101 is also retained. At the same time, the silicon nitride layer 30 on the top of the second semiconductor device 20 obtained above is etched, and part of the silicon nitride layer 30 on the side of the second semiconductor device 20 is retained, so as to form different sidewalls on the side of the first semiconductor device 10 and the side of the second semiconductor device 20.

[0103] Among them, as Figure 9 described, the sidewall of the first semiconductor device 10 is composed of the first oxide layer 101, and the sidewall of the second semiconductor device 20 is composed of the silicon nitride layer 30 and the second oxide layer 201, forming sidewalls with different morphologies, and the width of the sidewall of the first semiconductor device 10 is smaller than the width of the sidewall of the second semiconductor device 20.

[0104] Furthermore, in this embodiment, after the step S302, the following is further included:

[0105] Step S303: Using the first etching gas, based on the selectivity of the first etching gas, simultaneously etch the first semiconductor device and the second semiconductor device with different sidewalls formed thereon to remove the remaining silicon nitride layer on the first semiconductor device and the second semiconductor device.

[0106] In a specific implementation, the above-mentioned first etching gas can be used again to simultaneously etch the first semiconductor device 10 and the second semiconductor device 20 with different sidewalls formed thereon based on the selectivity of the first etching gas, so as to remove the remaining silicon nitride layer on the first semiconductor device 10 and the second semiconductor device 20 and ensure the etching accuracy.

[0107] Step S304: When removing the remaining silicon nitride on the second semiconductor device, adjust the sidewall thickness of the second semiconductor device.

[0108] In a specific implementation, the source power, bias voltage power, and pressure of the etching can be set. For example, the source power is 400 - 1000W, the bias voltage power is 0W, and the pressure is 40 - 100mT. When removing the remaining silicon nitride layer 30 on the second semiconductor device 20, use the set selectivity, source power, bias voltage power, and pressure of the first etching gas to further etch the silicon nitride layers 30 on both sides of the second semiconductor device 20 to adjust the sidewall thickness of the second semiconductor device to meet the accuracy requirements.

[0109] In this embodiment, a second preset threshold of the second etching gas is determined according to the thickness of the remaining silicon nitride layer on the first semiconductor device and the thickness of the silicon nitride layer of the second semiconductor device; the selection ratio of the second etching gas is controlled to reach the second preset threshold, and the selection ratio reaching the second preset threshold is used as the etching rate of the second etching gas. The first semiconductor device and the second semiconductor device are etched by using the second etching gas based on the selection ratio of the second etching gas; during the etching process, the remaining silicon nitride layer on the first semiconductor device is etched, a part of the oxide layer on the side of the first semiconductor device is retained, the silicon nitride layer on the top of the second semiconductor device is etched, and a part of the silicon nitride layer on the side of the second semiconductor device is retained, so as to form different sidewalls on the sides of the first semiconductor device and the second semiconductor device. In this embodiment, the etching rate of the second etching gas is adjusted according to the thickness of the silicon nitride layer of different semiconductor devices, so as to improve the precision of forming different-shaped sidewalls of the first semiconductor device and the second semiconductor device.

[0110] In addition, an embodiment of the present invention further provides a radio frequency module, refer to Figure 10 , Figure 10 which is a schematic structural diagram of an embodiment of the radio frequency module of the present invention. In this embodiment, the radio frequency module includes a first semiconductor device 10 and a second semiconductor device 20.

[0111] The first semiconductor device 10 and the second semiconductor device 20 are on the same substrate 50; the sidewalls of the first semiconductor device 10 and the second semiconductor device 20 are different.

[0112] In a specific implementation, the above-mentioned first semiconductor device 10 and second semiconductor device 20 are on the same substrate 50, and the sidewalls of the first semiconductor device 10 and the second semiconductor device 20 are different, that is, the sidewall morphologies are different, so as to balance the performance of the first semiconductor device 10 and the second semiconductor device 20, and further improve the overall performance of the radio frequency module.

[0113] Furthermore, in this embodiment, the radio frequency module further includes: a first oxide layer 101, a second oxide layer 201, and a first silicon nitride layer 301.

[0114] The first oxide layer 101 covers the gate 11 of the first semiconductor device; the second oxide layer 201 covers the gate 21 of the second semiconductor device, and the first silicon nitride layer 301 covers the second oxide layer 201 on the side of the second semiconductor device 20.

[0115] Among them, the first oxide layer 101 on the side of the first semiconductor device forms the sidewall of the first semiconductor device 10, the second oxide layer 201 on the side of the second semiconductor device and the first silicon nitride layer 301 form the sidewall of the second semiconductor device 20, and the sidewall thickness of the second semiconductor device 20 is greater than that of the first semiconductor device 10.

[0116] In a specific implementation, the gate 11 of the first semiconductor device is covered by the first oxide layer 101, and the first oxide layer 101 on its side forms the sidewall of the first semiconductor device 10. The gate 21 of the second semiconductor device is covered by the second oxide layer 201, and the second oxide layer 201 on its side and the first silicon nitride layer 301 form the sidewall of the second semiconductor device 20, and the sidewall thickness of the second semiconductor device 20 is greater than that of the first semiconductor device 10.

[0117] In addition, the second silicon nitride layer 301 is located on the side of the second oxide layer 201 and covers the second oxide layer 201 on the side.

[0118] It should be understood that in the region of the connection between the first semiconductor device 10 and the second semiconductor device 20, the thickness of the oxide layer near the first semiconductor device 10 is lower than that near the second semiconductor device 20.

[0119] Furthermore, in this embodiment, the RF module further includes: a second silicon nitride layer 302 and a third silicon nitride layer 303.

[0120] The second silicon nitride layer 302 is disposed in the first oxide layer 101 on the side of the first semiconductor device; the third silicon nitride layer 303 is disposed between the gate 21 of the second semiconductor device and the second oxide layer 201.

[0121] In a specific implementation, the second silicon nitride layer 302 can be covered in the first oxide layer 101, and the second silicon nitride layer 302 does not contact the gate 11 of the first semiconductor device. At the same time, a third silicon nitride layer 303 is disposed between the gate 21 of the second semiconductor device and the oxide layer 201, and the third silicon nitride layer 303 does not contact the gate 21 of the second semiconductor device, thereby effectively improving the performance and structural stability of the first semiconductor device 10 and the second semiconductor device 20.

[0122] In addition, an embodiment of the present invention also proposes an etching machine, and the etching machine includes the steps of the semiconductor device etching method described in the above embodiment.

[0123] It should be noted that, in this document, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, such that a process, method, article or system comprising a series of elements not only includes those elements but also includes other elements not expressly listed, or further includes elements inherent to such process, method, article or system. Without further limitation, an element defined by the statement "comprising one..." does not exclude the presence of additional identical elements in the process, method, article or system comprising such element.

[0124] The serial numbers of the embodiments of the present invention described above are for description only and do not represent the superiority or inferiority of the embodiments.

[0125] The above are only the preferred embodiments of the present invention and do not limit the patent scope of the present invention. Any equivalent structure or equivalent process transformation made by using the content of the specification and drawings of the present invention, or directly or indirectly applied in other related technical fields, shall be equally included in the patent protection scope of the present invention.

Claims

1. A semiconductor device etching method, characterized in that The method is applied to a structure provided with a first semiconductor device and a second semiconductor device, and the sides of the first semiconductor device and the second semiconductor device are both covered with silicon nitride layers having the same thickness; The semiconductor device etching method includes: Etching the silicon nitride layer on the first semiconductor device with a first etching gas to make the thickness of the silicon nitride layer of the first semiconductor device different from that of the silicon nitride layer of the second semiconductor device; Obtaining a second etching gas and controlling the etching rate of the second etching gas according to the remaining thickness of the silicon nitride layer on the first semiconductor device and the thickness of the silicon nitride layer of the second semiconductor device; Etching the remaining silicon nitride layer on the first semiconductor device and the silicon nitride layer on the second semiconductor device with the second etching gas based on the etching rate to form different sidewalls on the sides of the first semiconductor device and the second semiconductor device.

2. The semiconductor device etching method according to claim 1, characterized in that, The step of etching the silicon nitride layer on the first semiconductor device with a first etching gas to make the thickness of the silicon nitride layer of the first semiconductor device different from that of the silicon nitride layer of the second semiconductor device includes: Coating a photoresist on the silicon nitride layer of the second semiconductor device; Simultaneously etching the first semiconductor device and the second semiconductor device with a first etching gas to remove a part of the silicon nitride layer on the first semiconductor device; When the etching of the first semiconductor device is completed, removing the photoresist with a third etching gas to make the thickness of the silicon nitride layer of the first semiconductor device different from that of the silicon nitride layer of the second semiconductor device.

3. The semiconductor device etching method according to claim 2, wherein, A first oxide layer is provided between the side of the first semiconductor device and the silicon nitride layer covering the first semiconductor device, and a second oxide layer is provided between the side of the second semiconductor device and the silicon nitride layer covering the second semiconductor device; The step of simultaneously etching the first semiconductor device and the second semiconductor device with a first etching gas to remove a part of the silicon nitride layer on the first semiconductor device includes: Controlling the selectivity ratio of the first etching gas to be greater than a first preset threshold, where the selectivity ratio is the ratio of the reaction rate of the first etching gas for etching the silicon nitride layer to the reaction rate for etching the oxide layer; Simultaneously etching the first semiconductor device and the second semiconductor device with the first etching gas based on the selectivity ratio of the first etching gas to remove a part of the silicon nitride layer on the first semiconductor device.

4. The semiconductor device etching method according to claim 3, wherein, The step of controlling the etching rate of the second etching gas according to the remaining thickness of the silicon nitride layer on the first semiconductor device and the thickness of the silicon nitride layer of the second semiconductor device includes: Determining a second preset threshold of the second etching gas according to the remaining thickness of the silicon nitride layer on the first semiconductor device and the thickness of the silicon nitride layer of the second semiconductor device; Controlling the selectivity ratio of the second etching gas to reach the second preset threshold and taking the selectivity ratio reaching the second preset threshold as the etching rate of the second etching gas.

5. The semiconductor device etching method according to claim 4, wherein The step of etching the remaining silicon nitride layer on the first semiconductor device and the silicon nitride layer on the second semiconductor device based on the etching rate by using the second etching gas, so as to form different sidewalls on the sides of the first semiconductor device and the second semiconductor device, includes: Etching the first semiconductor device and the second semiconductor device based on the selectivity of the second etching gas by using the second etching gas; During the etching process, etching the remaining silicon nitride layer on the first semiconductor device, retaining a part of the oxide layer on the side of the first semiconductor device, etching the silicon nitride layer on the top of the second semiconductor device, and retaining a part of the silicon nitride layer on the side of the second semiconductor device, so as to form different sidewalls on the sides of the first semiconductor device and the second semiconductor device.

6. The semiconductor device etching method according to claim 5, wherein, After the step of, during the etching process, etching the remaining silicon nitride layer on the first semiconductor device, retaining a part of the oxide layer on the side of the first semiconductor device, etching the silicon nitride layer on the top of the second semiconductor device, and retaining a part of the silicon nitride layer on the side of the second semiconductor device, so as to form different sidewalls on the sides of the first semiconductor device and the second semiconductor device, further includes: Simultaneously etching the first semiconductor device and the second semiconductor device with different sidewalls formed by using the first etching gas based on the selectivity of the first etching gas to remove the remaining silicon nitride layer on the first semiconductor device and the second semiconductor device; When removing the remaining silicon nitride layer on the second semiconductor device, adjusting the thickness of the sidewall of the second semiconductor device.

7. A radio frequency module, characterized in that, The radio frequency module includes a first semiconductor device and a second semiconductor device; The first semiconductor device and the second semiconductor device are on the same substrate; The sidewalls of the first semiconductor device and the second semiconductor device are different.

8. The RF module according to claim 7, wherein, The radio frequency module further includes: a first oxide layer, a second oxide layer, and a first silicon nitride layer; The first oxide layer covers the gate of the first semiconductor device; The second oxide layer covers the gate of the second semiconductor device, and the first silicon nitride layer covers the second oxide layer on the side of the second semiconductor device; Wherein, the first oxide layer on the side of the first semiconductor device constitutes the sidewall of the first semiconductor device, the second oxide layer on the side of the second semiconductor device and the first silicon nitride layer constitute the sidewall of the second semiconductor device, and the thickness of the sidewall of the second semiconductor device is greater than the thickness of the sidewall of the first semiconductor device.

9. The radio frequency module according to claim 8, wherein The radio frequency module further includes: a second silicon nitride layer and a third silicon nitride layer; The second silicon nitride layer is disposed in the first oxide layer on the side of the first semiconductor device; The third silicon nitride layer is disposed between the gate of the second semiconductor device and the second oxide layer.

10. An etching machine, characterized in that, The etching machine is used to implement the semiconductor device etching method according to any one of claims 1 to 6.

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