Method for etching thin-film resistor on aluminum wire etching machine

Abstract

The invention discloses a method for etching a thin-film resistor on an aluminum wire etching machine. The method comprises the following steps: sequentially forming a SiON dielectric layer, a TiN mask and a SiCr dielectric layer on a semiconductor substrate; etching each layer on the semiconductor substrate according to the gate pattern to be formed; when the silicon-chromium dielectric layer is etched, a bias radio frequency power source is added, and the flow of introduced gas and the etching time are adjusted. On the basis of an existing manufacturing method, the bias power is increased, the gas flow and the etching time are adjusted, the adjusted reaction steps meet the process requirements, O2 is introduced in the etching process to form a compound of CrO2Cl2, so that the Cr / Cl2-containing polymer is easy to remove, and the product quality is further improved.

Description

Technical Field

[0001] The present invention relates to the field of semiconductor technology, and in particular to a method for etching a thin film resistor on an aluminum wire etching machine. Background Art

[0002] Existing aluminum wire etching tools (AMAT-DPS) cannot etch thin film resistors (TFRs) using existing etching procedures, which cannot cut through the TFRs and therefore cannot meet process requirements. Furthermore, the SiCr etching process produces Cr / Cl₂ polymers that adhere to the sidewalls and are difficult to remove.

[0003] In view of this, the existing technology should be improved to solve the above-mentioned technical problems existing in the existing technology. Summary of the Invention

[0004] In order to solve the existing technical problems, the present invention proposes a method for etching thin-film resistors in an aluminum wire etching machine. Based on the existing production method, the original method is adjusted to increase the bias power, adjust the gas flow rate and etching time. The adjusted reaction steps meet the process requirements, and O2 is introduced during the etching process to form a chromyl chloride (CrO2Cl2) compound, which makes it easy to remove the Cr / Cl2 polymer, thereby improving product quality.

[0005] According to one aspect of the present invention, a method for etching a thin film resistor in an aluminum wire etching machine is provided, comprising the following steps:

[0006] forming a SiON dielectric layer, a TiN mask and a SiCr dielectric layer in sequence on a semiconductor substrate;

[0007] Etching each layer on the semiconductor substrate according to the gate pattern to be formed;

[0008] When etching the silicon chromium dielectric layer, the bias RF power source is increased and the flow rate of the introduced gas and the etching time are adjusted.

[0009] According to one embodiment of the present invention, the introducing of gas includes: first introducing Cl2, then introducing BCl3, and finally introducing O2.

[0010] According to one embodiment of the present invention, the flow rate of Cl 2 is in the range of 70 to 90 sccm.

[0011] According to one embodiment of the present invention, the flow rate of BCl 3 is in the range of 50 to 70 sccm.

[0012] According to one embodiment of the present invention, the flow rate of O2 is in the range of 10 to 30 sccm.

[0013] According to one embodiment of the present invention, the power range of the bias RF power source is 140-160W.

[0014] According to one embodiment of the present invention, the etching time ranges from 30 to 50 seconds.

[0015] According to one embodiment of the present invention, the etching is wet etching.

[0016] According to one embodiment of the present invention, the method further comprises a plasma radio frequency power source.

[0017] According to one embodiment of the present invention, the power of the plasma radio frequency power source is 1000W.

[0018] Due to the adoption of the above technical solution, the present invention has the following advantages compared with the prior art: on the basis of the existing manufacturing method, the original method is adjusted to add a bias RF power source, adjust the gas flow rate and etching time, the adjusted reaction steps meet the process requirements, and O2 is introduced during the etching process to form a compound such as chromyl chloride (CrO2Cl2), which makes it easy to remove the Cr / Cl2 polymer. Removing the chromium-containing compound can expose a more active surface, which helps to improve the adhesion and bonding strength, thereby improving the product quality. In some applications, such as electronic devices or conductor materials, electrical conductivity is very important. Chromium-containing compounds often affect electrical conductivity. By removing these compounds, electrical conductivity can be improved, which is crucial to ensuring the reliability and performance of the device. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for use in the embodiments. Obviously, the drawings described below are only some implementation cases of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0020] Figure 1 A schematic flow chart of a method for etching a thin film resistor on an aluminum wire etching machine according to an exemplary embodiment of the present invention is shown;

[0021] Figure 2 A schematic diagram showing the inability to open TFR in the prior art is shown;

[0022] Figure 3 A diagram showing an improved effect of a method for etching a thin film resistor in an aluminum wire etching machine according to an exemplary embodiment of the present invention is shown;

[0023] Figure 4 A schematic diagram of producing a Cr / Cl2-containing polymer in the prior art is shown;

[0024] Figure 5 FIG. 4 shows an improved effect of removing Cr / Cl 2 -containing compounds from the sidewall according to an exemplary embodiment of the present invention. DETAILED DESCRIPTION

[0025] In order to make the objectives, technical solutions and advantages of the present invention more clearly understood, the embodiments of the present invention are further described in detail below in conjunction with specific embodiments and with reference to the accompanying drawings.

[0026] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise" and the like to indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

[0027] like Figure 1 As shown, the present invention provides a method for etching a thin film resistor in an aluminum wire etching machine, which may specifically include the following steps:

[0028] forming a SiON dielectric layer, a TiN mask and a SiCr dielectric layer in sequence on a semiconductor substrate;

[0029] Etching each layer on the semiconductor substrate according to the gate pattern to be formed;

[0030] When etching the silicon chromium dielectric layer, the bias RF power source is increased and the flow rate of the introduced gas and the etching time are adjusted.

[0031] In some specific embodiments, the introducing of gas includes: first introducing Cl2, then introducing BCl3, and finally introducing O2.

[0032] During the etching process, Cl2 can react with aluminum to form aluminum chloride, which helps to remove the natural oxide layer on the aluminum surface and allow the etching process to continue; on the other hand, chlorine can react with BCl3 to form BCl3 + , the ions can bombard the silicon wafer surface vertically to achieve anisotropic etching.

[0033] In addition, BCl3 can reduce the natural oxide layer on the aluminum surface, preventing aluminum oxide from hindering further etching. At the same time, BCl3 also easily reacts with oxygen and water, absorbing water vapor and oxygen in the reaction chamber, thereby reducing the formation rate of aluminum oxide.

[0034] Introducing oxygen during the etching process helps form a uniform oxide layer, making the etching process more controllable. Furthermore, the introduction of O2 during the etching process forms a compound called chromyl chloride (CrO2Cl2), which has a low saturated vapor pressure and is easy to remove. This also solves the problem of Cr / Cl2 polymers adhering to the sidewalls and being difficult to remove. Chromium-containing compounds are often corrosive, and long-term contact with the material can cause corrosion. Removing chromium-containing compounds can avoid corrosion problems caused by contact with the material, thereby extending the material's service life.

[0035] The experimental results show a relationship between the etching gas flow rate and the sample etching efficiency. Increasing the etching gas flow rate during the experiment resulted in a continuous increase in the concentration of the reactive gas, which in turn resulted in more effective chemical and physical reactions on the silicon dioxide surface during the etching process, significantly improving the overall etching efficiency of the sample.

[0036] When the gas flow rate approaches saturation, the amount of gas that actually participates in chemical and physical reactions is very limited, which greatly limits the etching efficiency of the sample during the etching process. If the gas flow rate continues to increase after the gas reaches saturation, the collisions between the reacting ions will become more intense. The ion collisions will consume a certain amount of their own energy, which will greatly weaken the physical interaction of the ions, resulting in a significant reduction in the etching efficiency of the sample during the experiment. Therefore, a gas flow rate close to saturation is the optimal process condition and plays an important role in improving etching efficiency and saving gas resources.

[0037] It is important to note that the effect of gas flow on etching efficiency may vary under different process conditions. Therefore, in actual operation, it is necessary to reasonably control the gas flow according to specific needs and process conditions. At the same time, it is also necessary to pay attention to the purity and quality of the gas to ensure the etching effect and product quality.

[0038] Therefore, to ensure the maximum efficiency of the gas flow rate, without wasting resources and achieving the desired experimental results, different etching processes have different gas flow requirements. Different types of etching equipment have different gas flow processing capabilities. Different gases have different physical and chemical properties, which also require different gas flow rates. The temperature and pressure during the etching process also affect the gas flow requirements. The appropriate gas flow rate needs to be determined through experiments based on the actual temperature and pressure conditions.

[0039] After many experiments, based on the above embodiments, the flow rate range of Cl2 is 70 to 90 sccm.

[0040] Based on the above embodiment, the flow rate range of BCl3 is 50-70 sccm.

[0041] Based on the above embodiment, the flow rate range of O2 is 10 to 30 sccm.

[0042] Based on the above embodiment, in order to ensure that the gas flow rate is within the appropriate range, a high-precision gas flow meter is installed on the aluminum wire etching machine to ensure the accuracy of the measurement results. The accuracy of the gas flow meter is crucial to determining and monitoring the appropriate gas flow rate.

[0043] Setting a biased RF power source can control the energy of the ions bombarding the surface of the silicon wafer, allowing the entire device to separate and control the energy and concentration of the ions. This is critical for precise control of the etching process and can better control the etching rate and selectivity. The biased RF power source can more accurately control the ion density and ion energy, thereby saving energy and improving etching efficiency. However, in general, the higher the output power, the better the etching effect, but it also increases the cost and energy consumption of the equipment. Therefore, it is necessary to make a trade-off based on actual needs and select a biased RF power source with appropriate output power according to the requirements of the etching process.

[0044] Based on the above embodiment, the power range of the bias RF power source is 140-160W.

[0045] In some specific embodiments, the waveform of the bias RF power source includes a pulse waveform and a continuous waveform.

[0046] The bias RF power source needs to be used in conjunction with the etching machine and other related equipment. Therefore, it is necessary to select a bias RF power source with good compatibility to ensure that it works well with existing equipment.

[0047] Generally speaking, the wet etching time is between several seconds and several minutes. Taking into account the etching depth and the hardness of the etching material of the present application, based on the above embodiment, the etching time ranges from 30 to 50 seconds.

[0048] Based on the above embodiment, the etching is wet etching. Wet etching uses relatively simple equipment and materials, has low manufacturing costs, can selectively etch materials, and has small etching differences between different materials. It can process a large number of materials simultaneously and is suitable for mass production.

[0049] In some specific embodiments, the method further includes a plasma RF power source. This RF power source can generate a high-density plasma. Active species in this plasma can chemically react with the material surface, significantly increasing the etching rate. By controlling the plasma density and the energy of the active species during the process, anisotropic etching can be achieved, i.e., etching with strong directionality, which facilitates the formation of precise patterns and shapes.

[0050] In some specific embodiments, the power of the plasma RF power source is 1000W. In actual operation, the optimal power range can be determined through experiments, and then an appropriate power value can be selected within this range. The power can be adjusted by controlling the input voltage or current of the RF power source to achieve the best treatment effect. At the same time, attention should also be paid to equipment safety protection to avoid equipment damage or safety accidents caused by excessive power.

[0051] like Figure 2 As shown, when the aluminum wire etching tool (AMAT-DPS) runs the thin film resistor (TFR) etching step, the existing etching program cannot cut through the TFR and cannot meet the process requirements.

[0052] The inability to eat through TFR means that the existing etching process cannot meet the TFR requirements in the process.

[0053] Specifically, the following situations may exist:

[0054] 1. Insufficient etching depth: Existing etching procedures cannot etch the material to a sufficient depth, resulting in the inability to form deep trenches or channels that meet process requirements.

[0055] 2. Insufficient etching accuracy: Due to the limitation of control accuracy, the existing etching process may not be able to accurately control the shape, size and position of the channel, resulting in failure to meet the process's TFR accuracy requirements.

[0056] 3. Insufficient etching uniformity: During the etching process, etching results may vary between different areas or batches, resulting in inconsistent TFR. Existing etching procedures may not achieve uniform etching results, thus failing to meet the process's requirements for TFR consistency.

[0057] like Figure 3 As shown, the present invention not only adds a bias RF power source but also optimizes etching time and gas flow. This optimization allows for the TFR to be opened while maintaining a neat appearance. Optimizing the reaction steps during etching has multiple beneficial effects, including improving surface quality, preventing corrosion, enhancing conductivity, increasing surface activity, and complying with environmental and safety requirements.

[0058] like Figure 4 As shown, in the prior art, Cr / Cl2 polymers are generated during the SiCr etching process, which adhere to the sidewalls and are difficult to remove.

[0059] like Figure 5As shown, by adding an appropriate O2 flow rate to the etching process, Cr / Cl2 compounds on the sidewalls can be effectively removed. Chromium compounds often form deposits or films on the surface, which can affect surface smoothness. Removing chromium compounds can significantly improve surface smoothness, making subsequent processing or application smoother. Chromium compounds are also often corrosive, and long-term contact with materials can cause corrosion. Removing chromium compounds can avoid corrosion problems caused by contact with materials, thereby extending the service life of the material.

[0060] In the method for etching thin-film resistors in an aluminum wire etching machine according to an embodiment of the present invention, the etching step of the present application adjusts the original method to increase the bias power, adjust the gas flow rate and etching time on the basis of the existing manufacturing method. The adjusted reaction steps meet the process requirements, and O2 is introduced during the etching process to form a compound such as chromyl chloride (CrO2Cl2), which makes it easy to remove the Cr / Cl2 polymer, thereby improving the product quality.

[0061] Those skilled in the art should understand that the discussion of any of the above embodiments is merely illustrative and is not intended to imply that the scope of the disclosure of the embodiments of the present invention (including the claims) is limited to these examples. Within the spirit of the embodiments of the present invention, the technical features of the above embodiments or different embodiments may be combined, and there are many other variations of different aspects of the above embodiments of the present invention, which are not provided in detail for the sake of simplicity. Therefore, any omissions, modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the embodiments of the present invention should be included in the scope of protection of the embodiments of the present invention.

Claims

1. A method for etching a thin film resistor on an aluminum wire etching machine, characterized in that: The following steps are involved: forming a SiON dielectric layer, a TiN mask and a SiCr dielectric layer in sequence on a semiconductor substrate; Etching each layer on the semiconductor substrate according to the gate pattern to be formed; When etching the silicon chromium dielectric layer, the bias RF power source is increased and the flow rate of the introduced gas and the etching time are adjusted.

2. The method for etching a thin film resistor on an aluminum wire etching machine according to claim 1, wherein: The introducing of gas includes: introducing Cl2 first, then introducing BCl3, and finally introducing O2.

3. The method for etching a thin film resistor on an aluminum wire etching machine according to claim 2, wherein: The flow rate of Cl2 is in the range of 70 to 90 sccm.

4. The method for etching a thin film resistor on an aluminum wire etching machine according to claim 2, wherein: The flow rate of BCl3 is in the range of 50 to 70 sccm.

5. The method for etching a thin film resistor on an aluminum wire etching machine according to claim 2, wherein: The flow rate of O2 is in the range of 10 to 30 sccm.

6. The method for etching a thin film resistor on an aluminum wire etching machine according to claim 1, wherein: The power range of the bias radio frequency power source is 140-160W.

7. The method for etching a thin film resistor on an aluminum wire etching machine according to claim 1, wherein: The etching time ranges from 30 to 50 seconds.

8. The method for etching a thin film resistor on an aluminum wire etching machine according to claim 1, wherein: The etching is wet etching.

9. The method for etching a thin film resistor on an aluminum wire etching machine according to claim 1, wherein: The method also includes a plasma radio frequency power source.

10. The method for etching a thin film resistor using an aluminum wire etching machine according to claim 9, wherein: The power of the plasma radio frequency power source is 1000w.

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