Dry type photoresist removing method after capacitor dielectric layer etching

Abstract

The invention discloses a dry photoresist removing method after capacitor dielectric layer etching, which belongs to the technical field of semiconductor manufacturing, and comprises the following steps: S1, putting an IPD capacitor product with a polymer formed on the surface into a reaction chamber for photoresist removing; s2, argon is introduced into the reaction chamber, and radio frequency power is applied at the same time, so that the argon in the reaction chamber forms plasma; s3, after argon introduction is stopped, nitrogen is introduced into the reaction chamber for multiple times; s4, repeating the step S2 and the step S3 for 3-6 times; s5, after nitrogen introduction is stopped, oxygen is introduced into the reaction chamber, and radio frequency power is applied at the same time, so that oxygen in the reaction chamber forms plasma; and S6, after stopping introducing the oxygen, continuing to vacuumize the reaction chamber to recover the pressure of the chamber to an initial state, then slowly introducing inert gas to recover the pressure of the chamber to normal pressure, and taking out the IPD capacitor product. According to the invention, the photoresist and the polymer on the IPD capacitor product can be efficiently removed, and the photoresist removing efficiency and quality are greatly improved.

Description

Technical Field

[0001] The invention belongs to the technical field of semiconductor manufacturing, and in particular relates to a dry-type de-bonding method after etching a capacitor dielectric layer. Background Art

[0002] In the semiconductor industry's IPD capacitor manufacturing process, the RIE process is often used to etch the SiNx capacitor dielectric layer using gases such as CF4 and CHF3 (etching stops at the TaN layer). However, during the etching process, Ta, C, and F ions react with the photoresist to form fluorocarbon polymers (CF bonds) and non-volatile tantalum fluoride.

[0003] In IPD capacitor manufacturing, the presence of fluorocarbon polymers (CF bonds) and tantalum fluoride polymers produced after RIE (Reinforced Electron Electrode) etching of SiN using F-based gases severely impacts the subsequent dry stripping process. Conventional O2 plasma stripping methods are ineffective in removing these polymers, resulting in residual polymer and photoresist residues and significantly reducing product appearance and electrical performance yields. Wet stripping, on the other hand, introduces additional chemicals and corrodes the AlCu in the electrodes, creating environmental issues such as wastewater disposal. It can also introduce new impurity contamination and damage delicate structures. Therefore, a dry stripping method for capacitor dielectric layer etching is urgently needed. Summary of the Invention

[0004] The present invention overcomes the deficiencies of the prior art and provides a dry-type desmearing method after etching a capacitor dielectric layer, so as to solve the problems existing in the prior art.

[0005] To achieve the above object, the present invention adopts a technical solution: a dry descaling method after etching a capacitor dielectric layer, comprising the following steps:

[0006] S1. Place the IPD capacitor product with polymer formed on the surface into a degumming reaction chamber and perform vacuum treatment on the reaction chamber;

[0007] S2, introducing argon gas into the reaction chamber and applying radio frequency power to form plasma in the argon gas in the reaction chamber;

[0008] S3, after stopping the introduction of argon gas, nitrogen gas is introduced into the reaction chamber multiple times, and the small molecules and particles in the reaction chamber are sucked out of the reaction chamber along with the nitrogen gas;

[0009] S4, repeat step S2 and step S3 3-6 times;

[0010] S5. After the nitrogen is stopped, oxygen is introduced into the reaction chamber while applying radio frequency power to form a plasma of oxygen in the reaction chamber. The oxygen plasma reacts chemically with the residual photoresist on the IPD capacitor product, oxidizing it into carbon dioxide and water.

[0011] S6. After stopping the introduction of oxygen, continue to evacuate the reaction chamber to restore the chamber pressure to the initial state, then slowly introduce inert gas to restore the chamber pressure to normal pressure, and remove the IPD capacitor product.

[0012] In a preferred embodiment of the present invention, in step S1, the reaction chamber is vacuumed to a pressure of 5×10 -5 Pa to 1×10 -3 Pa.

[0013] In a preferred embodiment of the present invention, in step S2, the flow rate of argon gas introduced into the reaction chamber is 30 sccm-80 sccm, and the applied RF power ranges from 150 W to 400 W.

[0014] In a preferred embodiment of the present invention, in step S3, the flow rate of nitrogen gas introduced into the reaction chamber each time is 80 sccm-200 sccm, and the number of times of introduction is 4-10 times.

[0015] In a preferred embodiment of the present invention, in step S5, the flow rate of oxygen introduced into the reaction chamber is 50 sccm-150 sccm, and the applied radio frequency power is 200W-500W.

[0016] In a preferred embodiment of the present invention, before taking out the IPD capacitor product from the reaction chamber, nitrogen is introduced into the reaction chamber to remove trace volatile substances remaining in the reaction chamber.

[0017] The present invention solves the defects existing in the background technology and has the following beneficial effects:

[0018] 1. The dry degumming method of the present invention can efficiently remove photoresist and polymer on IPD capacitor products. Through the cyclic operation of argon plasma bombardment and nitrogen circulation purification, most of the polymer is effectively destroyed and removed. Combined with oxygen plasma degumming, the residual polymer and photoresist can be completely removed, greatly improving the degumming efficiency and quality.

[0019] 2. The present invention adopts dry degumming without using chemical reagents, thus avoiding the wastewater treatment and environmental pollution problems caused by wet degumming, while reducing production costs, and realizing the automation of the degumming process, thereby improving production efficiency and consistency of product quality, and reducing the influence of human factors on the degumming effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] The present invention will be further described below with reference to the accompanying drawings and examples;

[0021] Figure 1 A flowchart of a preferred embodiment of the present invention; DETAILED DESCRIPTION

[0022] The following drawings illustrate various embodiments of the present invention. For clarity, many physical details will be included in the following description. However, it should be understood that these physical details are not intended to limit the present invention. In other words, in some embodiments of the present invention, these physical details are not essential. Furthermore, to simplify the drawings, some commonly used structures and components are depicted in simplified schematic form.

[0023] In addition, in the present invention, descriptions such as "first" and "second" are only used for descriptive purposes and do not specifically refer to the order or sequence, nor are they used to limit the present invention. They are only used to distinguish components or operations described with the same technical terms, and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one such feature. In addition, the technical solutions between the various embodiments can be combined with each other, but they must be based on the ability of ordinary technicians in this field to implement them. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such a combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

[0024] This embodiment provides a dry stripping method after etching the capacitor dielectric layer. This dry stripping method can efficiently remove photoresist and polymer on IPD capacitor products. Through the cyclic operation of argon plasma bombardment and nitrogen circulation purification, most polymers are effectively destroyed and removed. Combined with oxygen plasma stripping, the residual polymer and photoresist can be completely removed, greatly improving the stripping efficiency and quality.

[0025] Before degumming the IPD capacitor product, place the product in a Teflon container in a water tank and rinse it with a spray for 5-10 minutes and then with nitrogen bubbling for 5-10 minutes. After rinsing, place the product in a spin dryer and set the speed to 1000-2000 rpm for 120 seconds.

[0026] Place the product into the PVD sputtering TaN / AlCu / TaN bottom electrode, set the power to 300-600W, and the argon flow rate to 50-200sccm;

[0027] Place the product into the PECVD deposition medium layer SiN, set the power to 80-300W, SiH4 flow rate to 50-200sccm, NH3 flow rate to 50-200sccm, pressure to 50-150Pa, and power to 50-200W;

[0028] Place the product into the PVD sputtering TaN / AlCu / TaN top electrode, set the power to 300-600W, and the argon flow rate to 50-200sccm;

[0029] Perform photolithography on the front of the product. When using 5214 resist for coating, set the rotation speed to 3000-5000 rpm for 20-40 seconds. Use 90-120°C for pre-baking and bake for 80-120 seconds. Set the exposure energy to 10-30 joules and use a specific mask for exposure for 5-25 seconds. Post-exposure bake for 40-60 seconds at 80-100°C. Use negative resist for development for 30-50 seconds and cure at 325-375°C.

[0030] Place the product in the RIE machine for dry etching, using a Cl2 flow rate of 50-100 sccm, a BCl3 flow rate of 50-100 sccm, a pressure of 50-200 mTorr, a power of 500-1000 W, and an etching time of 60-90 s;

[0031] After etching, dry stripping is performed with an O2 flow rate of 2500-3500sccm, a H2O flow rate of 300-500sccm, a N2 flow rate of 500-800sccm, a power of 1000-3000W, a pressure of 1-2Torr, a temperature of 200-280°C, and a stripping time of 30-90S;

[0032] Perform photolithography on the front of the product. When using 5214 resist for coating, set the rotation speed to 3000-5000 rpm for 20-40 seconds. Use 90-120°C for pre-baking and bake for 80-120 seconds. Set the exposure energy to 10-30 joules and use a specific mask for exposure for 5-25 seconds. Post-exposure bake for 40-60 seconds at 80-100°C. Use negative resist for development for 30-50 seconds and cure at 325-375°C.

[0033] The product is placed in the RIE machine for dry etching, with a CF4 flow rate of 50-100sccm, a CHF3 flow rate of 50-100sccm, a pressure of 50-300mTorr, a power of 500-1000W, and an etching time of 90-120s, forming an IPD capacitor product with photoresist and polymer on the surface. The photoresist and polymer on the surface of the IPD capacitor product are processed as follows.

[0034] This embodiment provides a dry stripping method for a capacitor dielectric layer after etching, the dry stripping method comprising the following steps:

[0035] S1. Place the IPD capacitor product with polymer formed on the surface into the degumming reaction chamber, and evacuate the reaction chamber to make the pressure in the reaction chamber reach 5×10 -5 Pa to 1×10 -3 Pa, which can effectively reduce the interference of residual gas on the subsequent degumming process;

[0036] S2, argon gas is introduced into the reaction chamber, and radio frequency power is applied simultaneously to form plasma in the reaction chamber. The argon gas flow rate introduced into the reaction chamber is 30 sccm-80 sccm, and the range of the applied radio frequency power is 150W-400W. The high-energy ions in the argon plasma can bombard the polymer on the surface of the photoresist, destroying the structure of the polymer by physical sputtering, and decomposing it into smaller particles or molecular fragments. The bombardment time is determined according to the thickness and density of the polymer, generally 60s-300s;

[0037] S3, after stopping the introduction of argon gas, nitrogen is introduced into the reaction chamber for many times, and the small molecules and particles in the reaction chamber are extracted from the reaction chamber along with the nitrogen suction. The nitrogen flow rate introduced into the reaction chamber at each time is 80sccm-200sccm, and the number of introductions is 4-10 times. When nitrogen is introduced into the reaction chamber, a vacuum pump is synchronously opened to pump air, so that the small molecules and particles produced by the argon plasma bombardment in the reaction chamber are extracted from the chamber along with the nitrogen. Multiple air intake and pumping operations are circulated, with each air intake time of 8s-25s, and the pumping time of 15s-60s. The number of cycles is 4 to 10 times, to ensure the preliminary removal of polymer decomposition products on the surface of the photoresist and in the reaction chamber;

[0038] S4, repeat step S2 and step S3 3-6 times;

[0039] S5. After stopping the nitrogen flow, oxygen is introduced into the reaction chamber while applying radio frequency power to form a plasma of the oxygen in the reaction chamber. The oxygen plasma reacts chemically with the residual photoresist on the IPD capacitor product to oxidize it into carbon dioxide and water. The oxygen flow rate into the reaction chamber is 50 sccm-150 sccm, the applied radio frequency power is 200 W-500 W, and the oxygen introduction time is 90 s-360 s.

[0040] S6. After stopping the introduction of oxygen, continue to evacuate the reaction chamber to restore the chamber pressure to the initial state, then slowly introduce inert gas to restore the chamber pressure to normal pressure, and remove the IPD capacitor product.

[0041] In this embodiment, before taking out the IPD capacitor product from the reaction chamber, nitrogen gas is introduced into the reaction chamber to remove trace volatile substances remaining in the reaction chamber.

[0042] Although the present invention has been described above with reference to various embodiments, it will be understood that many changes and modifications may be made without departing from the scope of the present invention. That is, the methods, systems, or devices discussed above are examples. Various configurations may omit, replace, or add various processes or components as appropriate. For example, in alternative configurations, the methods may be performed in an order different from that described, and / or various stages may be added, omitted, and / or combined. Moreover, features described with respect to certain configurations may be combined in various other configurations. Different aspects and elements of the configurations may be combined in a similar manner. Furthermore, as technology advances, many elements are merely examples and do not limit the scope of this disclosure or the claims.

[0043] Specific details are given in the specification to provide a thorough understanding of the exemplary configurations including implementations. However, the configurations can be practiced without these specific details. For example, well-known circuits, processes, algorithms, structures, and techniques have been shown without unnecessary detail to avoid obscuring the configurations. This description provides only example configurations and does not limit the scope, applicability, or configurations of the claims. On the contrary, the foregoing description of the configurations will provide those skilled in the art with an enabling description for implementing the described techniques. Various changes may be made to the functions and arrangements of the elements without departing from the spirit or scope of this disclosure.

[0044] Furthermore, although each operation may be described as a sequential process, many operations may be performed in parallel or simultaneously. Furthermore, the order of the operations may be rearranged. A process may have additional steps. Furthermore, examples of the methods may be implemented in hardware, software, firmware, middleware, code, hardware description languages, or any combination thereof. When implemented in software, firmware, middleware, or code, the program code or code segments for performing the necessary tasks may be stored in a non-transitory computer-readable medium such as a storage medium, and the described tasks may be performed by a processor.

[0045] In summary, it is intended that the above detailed description is considered to be exemplary and not restrictive, and it should be understood that the claims (including all equivalents) are intended to limit the spirit and scope of the present invention. These embodiments should be understood to be merely for illustrating the present invention and not for limiting the scope of protection of the present invention. After reading the content of the record of the present invention, the technician can make various changes or modifications to the present invention, and these equivalent variations and modifications fall into the scope limited by the claims of the present invention equally.

Claims

1. A dry stripping method after etching a capacitor dielectric layer, characterized in that: The following steps are involved: S1. Place the IPD capacitor product with polymer formed on the surface into a degumming reaction chamber and perform vacuum treatment on the reaction chamber; S2, introducing argon gas into the reaction chamber and applying radio frequency power to form plasma in the argon gas in the reaction chamber; S3, after stopping the introduction of argon gas, nitrogen gas is introduced into the reaction chamber multiple times, and the small molecules and particles in the reaction chamber are sucked out of the reaction chamber along with the nitrogen gas; S4, repeat step S2 and step S3 3-6 times; S5. After the nitrogen is stopped, oxygen is introduced into the reaction chamber while applying radio frequency power to form a plasma of oxygen in the reaction chamber. The oxygen plasma reacts chemically with the residual photoresist on the IPD capacitor product, oxidizing it into carbon dioxide and water. S6. After stopping the introduction of oxygen, continue to evacuate the reaction chamber to restore the chamber pressure to the initial state, then slowly introduce inert gas to restore the chamber pressure to normal pressure, and remove the IPD capacitor product.

2. The dry stripping method after etching of a capacitor dielectric layer according to claim 1, characterized in that: In step S1, the reaction chamber is vacuumed to a pressure of 5×10 -5 Pa to 1×10 -3 Pa.

3. The dry stripping method after etching of a capacitor dielectric layer according to claim 1, characterized in that: In step S2, the flow rate of argon gas into the reaction chamber is 30 sccm-80 sccm, and the applied radio frequency power ranges from 150 W to 400 W.

4. The dry stripping method after etching of a capacitor dielectric layer according to claim 1, characterized in that: In step S3, the flow rate of nitrogen gas introduced into the reaction chamber is 80 sccm-200 sccm each time, and the number of times of introduction is 4-10 times.

5. The dry stripping method after etching of a capacitor dielectric layer according to claim 1, characterized in that: In step S5, the flow rate of oxygen introduced into the reaction chamber is 50 sccm-150 sccm, and the applied radio frequency power is 200 W-500 W.

6. The dry stripping method after etching of a capacitor dielectric layer according to claim 1, characterized in that: Before taking out the IPD capacitor product from the reaction chamber, nitrogen is introduced into the reaction chamber to remove trace volatile substances remaining in the reaction chamber.

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