TWI810714B - Chemical Mechanical Polishing Process Method - Google Patents

Abstract

A chemical-mechanical grinding and polishing process method, which is characterized in that gas, corrosive gas, plasma gas or nano-micron particles are coated into the inside of microbubbles or inverse microcells, added to the polishing liquid, and the surface of the wafer or workpiece is processed , Microbubbles are easy to burst in the liquid and generate instantaneous high temperature in a small area, as well as a series of highly dense micro shock waves. The instantaneous high temperature in the micro area and high-density shock waves help to perform more detailed processing on the surface of the wafer or workpiece , and it is easy to eliminate the large bubbles generated in the process, reduce the fluctuation of the concentration of the polishing solution, and assist in stabilizing the quality of the chemical mechanical polishing process; among them, the substance coated in the microbubbles can be gas, corrosive gas, plasma gas or Nai Micron particles, etc., are materials that are helpful for processing, or appear in the form of inverse cells. In the above-mentioned chemical mechanical polishing process, plasma can be used to modify the processing area or polishing liquid, or to generate liquid plasma processing; and/or can apply electric field or magnetic field to generate DC, AC or pulse form Processing the processing area; wherein, the chemical mechanical polishing process can be the operation of the above single steps or a combination.

Description

Chemical Mechanical Polishing Process Method

The invention relates to a chemical mechanical grinding and polishing process method, especially relates to a method that can add extra energy to the planarization process through microbubbles, inverse cells, plasma, and electromagnetic fields to achieve the desired effect.

In the fabrication process of semiconductor microelectromechanical chips, chemical mechanical polishing (CMP) is often embedded in each process for the planarization of insulating layers and wafers, the formation of metal wires and wiring, and the back crystal Round thinning etc. In the field of mechanical processing, it is also commonly used in the grinding and polishing of optical lenses. With the continuous shrinking of the limit size, the flatness of the surface of the large-sized wafer or the film layer, the refinement of the metal connection line, and the increasing demand for the reliability of the chip and the stability of the film layer make chemical mechanical polishing The process precision of the method must be improved accordingly.

According to the existing patented technology of chemical mechanical processing, most of them focus on the chemical formula of the processing fluid, the structure and material of the polishing pad, the adjustment of the mechanical structure, or the monitoring of the processing environment. There is no patent or literature on chemical mechanical processing, using microbubbles, inverse cells, plasma, and electric and magnetic fields to improve the flatness and stability of chemical processing.

Since the chemical mechanical polishing planarization technology is commonly used in the thinning process of semiconductor wafers and film layers, it is a process that any company that produces integrated circuits must use. Therefore, in view of the fact that the chemical mechanical planarization process uses a combination of chemical etching and mechanical polishing to achieve a wide range of wafer planarization, the development of a set of chemical mechanical polishing methods can improve the process accuracy and solve the problem. The invention is necessary to overcome the technical shortcomings of the solution.

The main purpose of the present invention is to overcome the above-mentioned problems encountered in the prior art and provide a kind of chemical mechanical polishing that can add extra energy to the planarization process through microbubbles, reverse microcells, plasma, and electromagnetic fields to achieve the desired effect. Polishing process method.

To achieve the above purpose, the present invention is a chemical mechanical polishing process method, which is characterized in that gas, corrosive gas, plasma gas or nano-micron particles are coated into microbubbles (Fine bubbles, Microbubbles or Ultrafine bubbles) or Inside the reverse micelle, it is added to the grinding liquid to assist in the processing of the wafer or the surface of the workpiece. The microbubbles are easy to burst in the liquid and generate instantaneous high temperature in a small area, as well as a series of dense micro shock waves. The instantaneous micro-zone high temperature and high-density shock wave help to process the wafer or the surface of the workpiece more carefully, and it is easy to eliminate the large bubbles generated during the process, reducing the fluctuation of the concentration of the polishing liquid to assist in stabilizing the chemical machinery Grinding and polishing process quality; wherein, the substance encapsulated in the microbubbles is any material that is helpful for processing in gas, corrosive gas, plasma gas, and nano-micron particles, or appears in the form of the reverse microcell; , in the chemical mechanical grinding and polishing process, plasma can be further used to modify the processing area or the polishing liquid, or to generate liquid plasma processing; and/or can further apply an electric field or a magnetic field to generate DC, The processing area is processed in the form of alternating current or pulse; wherein, the chemical mechanical polishing process can be a single operation or a combination of the above-mentioned steps.

In the above-mentioned embodiments of the present invention, the microbubbles can wrap different gases, plasma gases, or corrosive gases into the microbubbles depending on the acid-base and chemical properties of the processing conditions, so that the gas, the plasma The gas or the corrosive gas is mixed with the microbubbles into the polishing liquid to the processing area.

In the above-mentioned embodiments of the present invention, the plasma gas encapsulated in the microbubbles or the inverse microcells is firstly generated and then coated into the microbubbles or the inverse microcells.

In the above-mentioned embodiments of the present invention, the plasma gas wrapped in the microbubble or the inverse microcell The body is that the gas that has not been plasmaized is wrapped into the microbubble or the inverse microcell first, and then an electric field is applied to make the gas inside the microbubble or the inverse microcell plasmatized.

In the above-mentioned embodiments of the present invention, the microbubbles or the nanoparticle coated in the inverse microcell can be assisted with an electric field or a magnetic field to drive the nanoparticle during processing to assist in processing.

In the above embodiments of the present invention, before or after the nanomicron particles are encapsulated into the microbubbles or the inverse cells, an electric field is used to generate charges on the nanonanoparticles to enhance processing.

In the above-mentioned embodiments of the present invention, the electric field is applied during the processing, and an electric field or a high-energy electric field is applied to the processing area to cause electrochemical processing during the processing, and the electric field can also generate charges on the particles in the polishing liquid. And drive the movement of charged particles to assist in processing.

In the above-mentioned embodiment of the present invention, when the nano-micron particle is a magnetic particle with a nano-micron size, the application of the magnetic field is to make the magnetic particle process the wafer or the surface of the workpiece by magnetic force, or use high frequency or A pulsed magnetic field heats the magnetic particles to assist processing, or generates eddy currents in the processing environment to assist processing.

In the above-mentioned embodiments of the present invention, the microbubbles refer to bubbles with a diameter less than 1 mm.

1: Bubbles

2: microbubble

2a: Inverse microcell

3: Grinding liquid

31: Delivery pipeline

4: Plasma gas

5, 9: High frequency voltage generator

6: nano-micron particles

7: Wafer

71: Wafer carrier

8: Electric field or magnetic field generator

s1~s3: steps

Fig. 1 is a schematic flow chart of the chemical mechanical polishing process of the present invention.

Fig. 2A is a schematic diagram of microbubbles and common bubbles mentioned in the present invention.

Figure 2B is a schematic diagram of the generation of microbubbles of the present invention.

Figure 2C is a schematic diagram of the plasma gas wrapped in the microbubbles of the present invention.

Figure 2D is a schematic diagram of the present invention applying an electric field to form plasma inside the microbubbles after the microbubbles are formed.

Fig. 2E is a schematic diagram of nano-micron particles coated in microbubbles of the present invention.

Figure 2F is a schematic diagram of the reverse microcell of the present invention.

Fig. 3 is a schematic diagram of applying plasma, electric field or magnetic field in the processing area of the present invention.

Figure 4 is a schematic diagram of the experimental results of Example 1 of the present invention.

Fig. 5 is a schematic diagram of the experimental results of the second embodiment of the present invention.

Based on the above reasons, the present invention provides a process method for enhancing chemical mechanical polishing. The following detailed description is merely exemplary in nature, and is not intended to limit the present invention or the application and use of the present invention.

Please refer to "Fig. 1 ~ Fig. 5", which are respectively the schematic flow diagram of the chemical mechanical polishing process of the present invention, the schematic diagram of the microbubbles and ordinary bubbles mentioned in the present invention, the schematic diagram of the generation of microbubbles in the present invention, and the present invention. The schematic diagram of the plasma gas wrapped in the microbubbles of the present invention, the schematic diagram of the electric field formed inside the microbubbles in the present invention to form a plasma after the formation of the microbubbles, the schematic diagram of the nanomicron particles coated in the microbubbles of the present invention, the inverse microparticles of the present invention A schematic diagram of cells, a schematic diagram of the application of plasma, electric field or magnetic field in the processing area of the present invention, a schematic diagram of the experimental results of the first embodiment of the present invention, and a schematic diagram of the experimental results of the second embodiment of the present invention. As shown in the figure: the present invention is a chemical mechanical grinding and polishing process method, which can be used in the confidential micro-process method of chemical mechanical grinding and polishing (CMP). Its manufacturing process is as follows:

Step s1: Coating gas, corrosive gas, plasma gas, or nano-micron particles into microbubbles (Fine bubbles, Microbubbles, or Ultrafine bubbles) or reverse micelles (Reverse micelles), adding them to the polishing liquid for wafer Or the surface of the workpiece is polished.

Generally, the bubbles 1 in the solution will float up to the liquid surface, burst and dissipate. If they exist in the solution, they will usually hinder the processing. When the size of the bubbles is small to a specific size, it is called microbubbles (usually less than 1mm in diameter), so microbubbles 2 are smaller than ordinary bubbles, and microbubbles 2 are easy to burst in the liquid and generate instantaneous high temperature in a small area, And a series of highly dense micro-shock waves, as shown in Figure 2A. Adding microbubbles 2 to the polishing liquid 3, the instantaneous micro-zone high temperature and high-density shock waves are helpful to the wafer or workpiece surface Surface, for more detailed processing, and easy to eliminate the large bubbles generated in the process, reduce the fluctuation of the concentration of the polishing liquid 3, to assist in stabilizing the quality of the chemical mechanical polishing process, as shown in Figure 2B. The gas in the microbubbles 2 can be ordinary or any gas that can improve the processing quality, and the plasma gas 4 can be wrapped in the microbubbles 2, as shown in FIG. 2C. The plasma gas 4 wrapped into the microbubble 2 can be wrapped into the microbubble 2 after generating the plasma gas 4 first, as shown in Figure 2B, or the unplasmed gas can be wrapped first Cover into the microbubbles 2, and then apply an electric field through the high-frequency voltage generator 5, so that the gas inside the microbubbles 2 becomes plasma, as shown in FIG. 2D. Nanoparticles 6 can also be coated into the microbubbles 2, and the nanoparticle 6 is driven by an electric field or a magnetic field during processing to assist processing, as shown in FIG. 2E. Before or after the nanomicron particles 6 are coated into the microbubbles 2 , the electric field can be used to make the nanonanoparticles 6 generate electric charge, so as to enhance the processing effect. The aforementioned microbubbles 2 can also be replaced by inverse microcells 2a formed by mixing different solutions, as shown in FIG. 2F. Therefore, the present invention packs gas or particles into microbubbles or inverse microcells, and utilizes the two to assist processing. Gases or particles can use an electric field to become plasma, or to charge the particles. The microbubbles, inverse cells, and nano-micron particles in Figures 2A-2F are only illustrative, and do not represent actual sizes and proportions. The structures and sizes in the figures are also illustrative, and are not intended to limit the form of the structure.

The above-mentioned microbubbles 2 can wrap different gases, plasma gases or corrosive gases into the microbubbles 2 according to the acid-base and chemical properties of the processing conditions, so that the gas, plasma gas or corrosive gas can be mixed into the polishing solution with the microbubbles 2 3 to the processing area.

Step s2: In the above-mentioned chemical mechanical polishing process, the plasma is used to modify the processing area (ie, the surface of the wafer 7 or the workpiece) or the polishing liquid 3 or produce a processing effect.

During the chemical mechanical grinding and polishing process, additional plasma is applied through another high-frequency voltage generator 9 at the same time, and the free radicals generated by the plasma can generate Modification, or the processing effect of producing liquid plasma, as shown in Figure 3.

Step s3: In the above-mentioned chemical mechanical grinding and polishing process, an electric field or a magnetic field is used to generate The device 8 applies an electric field or a magnetic field to generate direct current, alternating current or pulses to process the processing area (ie, the surface of the wafer 7 or the workpiece).

In the chemical mechanical grinding and polishing process, applying an electric field refers to applying an electric field or a high-energy electric field to the processing area (ie, the surface of the wafer 7 or the workpiece) during the processing, so that the processing produces the effect of electrochemical processing. The electric field can also make the particles in the grinding liquid 3 generate charges and drive the charged particles to move to assist processing. In terms of the magnetic field, when the nano-micron particles are magnetic particles with a nano-micron size, applying a magnetic field allows the magnetic particles to perform micro-processing on the wafer 7 or the surface of the workpiece through magnetic manipulation. In addition, if a high-frequency or pulsed magnetic field is used, it can be Make the magnetic particles in the grinding liquid 3 generate heat to assist the processing effect. Or generate eddy current assisted processing in the processing environment, as shown in Figure 3.

The above steps s2 and s3 are both processing steps. During processing, the plasma in step s2 and/or the electric field and magnetic field in step s3 can be applied to the surface of the wafer 7 or workpiece to achieve the effect of auxiliary processing. Therefore, the chemical mechanical polishing process of the present invention may be an operation or a combination of the above-mentioned single steps. If so, a brand-new chemical-mechanical grinding and polishing process method is constituted by the above-mentioned disclosed process.

The following examples are only examples for understanding the details and connotation of the present invention, but are not intended to limit the patent scope of the present invention.

[Example 1]

Grind the silicon wafer 7 (as shown in Figure 3) by chemical mechanical polishing, fix the silicon wafer 7 on the wafer stage 71, install a microbubble generator on the pipeline 31 of the polishing liquid 3, and use nitrogen gas to Nitrogen in the plasma state is used as the gas covered by the microbubbles. The results are shown in Figure 4. Experiments have shown that the polishing effect on silicon wafers is better when the polishing liquid contains microbubbles and plasma gas. After the micro-bubbles are mixed into the polishing liquid, the high-frequency voltage generator is used to improve the processing effect on the polishing liquid. However, the processing conditions of simply mixing microbubbles into the polishing liquid are slightly better than those of purely using the polishing liquid for chemical mechanical polishing.

[Example 2]

Grinding silicon wafers by chemical mechanical polishing, installing a microbubble generator on the path of the polishing liquid, using carbon tetrafluoride (CF ₄ ), ammonia (NH ₃ ), sulfur hexafluoride (SF ₆ ), etc. Corrosive gases, together with their plasma gases, act as microbubble-coated gases. The results are shown in Figure 5. Experiments show that microbubbles containing corrosive gases have a better processing effect of chemical mechanical polishing. And mixed with microbubbles containing plasma gas, the processing effect is better than the processing conditions without plasma.

[Embodiment three]

Grinding silicon wafers by chemical mechanical polishing, adding inverse microcells to the polishing liquid, the inverse microcells are coated with magnetic particles with a diameter of 20~50nm, and the material is ferric oxide (Fe ₃ O ₄ ), which is clamped on the wafer. Below the platform, an electromagnetic coil wound with enameled wire is placed. During wafer grinding, an alternating current is applied to the electromagnetic coil to generate an alternating magnetic field of about 500 Gauss. The experimental results show that the inverse microcells containing magnetic particles are mixed into the grinding liquid, and the processing effect is better than that without the inverse microcells.

Thus, the key points of the proposed technology in the present invention are as follows:

(1) Using high-density micro-bubbles in the solution to generate micro-zone high temperature and shock waves in the solution to provide energy during processing, the micro-bubbles can also use inverse cells produced by different solutions.

(2) The microbubbles can also wrap different gases into the bubbles, and can also wrap high-energy plasma into the microbubbles.

(3) In the process of processing and grinding, the energy of the processing environment can be applied to the electric field to produce the effect of electrochemical processing; or a high-energy electric field can be used to generate plasma or manipulate charged particles in the polishing liquid.

(4) Through the application of a magnetic field, the magnetic particles can be manipulated and the surface can be finely processed; or the magnetic particles can be heated by high-frequency AC or pulse waveform to change the processing conditions.

To sum up, the present invention is a chemical mechanical grinding and polishing process method, which can effectively improve various conventional defects, and add extra energy to the planarization process through microbubbles, inverse cells, plasma, and electromagnetic fields to achieve the desired effect. , so that the production of the present invention can be more advanced, more practical, and more in line with the needs of users, and it has indeed met the requirements of the invention patent application, and the patent application is filed in accordance with the law.

However, what is described above is only a preferred embodiment of the present invention, and should not be limited thereto. The scope of implementation of the present invention; therefore, all simple equivalent changes and modifications made according to the patent scope of the present invention and the content of the description of the invention should still fall within the scope covered by the patent of the present invention.

s1~s3: steps

Claims (8)

A chemical mechanical grinding and polishing process method, which is characterized in that microbubbles (Fine bubbles, Microbubbles or Ultrafine bubbles) or reverse micelles (Reverse micelle) are added to the polishing liquid to assist in the processing of the wafer or workpiece surface. Microbubbles are easy to burst in the liquid and generate instantaneous high temperature in a small area, as well as a series of highly dense micro-shock waves. The instantaneous micro-area high temperature and high-density shock waves help the wafer or the surface of the workpiece to be more detailed. processing, and it is easy to eliminate the large bubbles generated in the process, reduce the fluctuation of the concentration of the polishing liquid, and assist in stabilizing the quality of the chemical mechanical polishing process; wherein, the substances covered in the microbubbles are gases, corrosive gases, and plasma gases Any kind of material that is helpful for processing in nano-micron particles, or appears in the form of the reverse microcell; in which, the microbubbles can be different from the gas, the plasma gas, depending on the acid-base and chemical properties of the processing conditions. Or the corrosive gas is coated into the microbubbles, so that the gas, the plasma gas or the corrosive gas is mixed with the microbubbles into the polishing liquid to the processing area; wherein, in the chemical mechanical polishing process, can Further use plasma to modify the processing area or the grinding liquid, or generate liquid plasma processing; and/or further apply an electric field or magnetic field to generate direct current, alternating current or pulse form to process the processing area; Wherein, the chemical mechanical polishing process may be an operation or a combination of the above-mentioned single steps. According to the chemical mechanical grinding and polishing process method described in item 1 of the scope of the patent application, the plasma gas encapsulated in the microbubbles or the inverse microcells is firstly generated after the plasma gas, and then encapsulated into the microbubbles or the inverse microcells. According to the chemical mechanical grinding and polishing process method described in item 1 of the scope of the patent application, the plasma gas encapsulated in the microbubbles or the inverse microcells is firstly coated with the unplasmed gas into the microcells. In the bubble or the inverse microcell, an electric field is applied to make the gas plasma inside the microbubble or the inverse microcell change. According to the chemical mechanical grinding and polishing process method described in item 1 of the scope of the patent application, wherein the nano-micron particles coated in the microbubbles or the inverse cells can be driven by an electric field or a magnetic field during processing Granules to aid in processing. According to the chemical mechanical grinding and polishing process method described in item 1 of the scope of the patent application, before or after the nano-micron particles are coated into the microbubbles or the inverse microcells, an electric field is used to allow the nano-micron particles to generate charges to Enhance processing. According to the chemical mechanical grinding and polishing process method described in item 1 of the scope of the patent application, the electric field is applied during the processing, and an electric field or a high-energy electric field is applied to the processing area to cause electrochemical processing during the processing, and the electric field also The particles in the slurry can be charged and driven to move to assist processing. According to the chemical mechanical grinding and polishing process method described in item 1 of the scope of the patent application, when the nano-micron particles are magnetic particles with a nano-micron size, the application of the magnetic field is to make the magnetic particles operate on the wafer or The surface of the workpiece is processed, or the magnetic particles are heated with high frequency or pulsed magnetic field to assist processing, or eddy current is generated in the processing environment to assist processing. According to the chemical mechanical polishing process method described in claim 1, the microbubbles refer to bubbles with a diameter less than 1mm.

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