TW201338025A - Method of cryogenic densification and planarization of material - Google Patents

Abstract

The present invention is a kind of method of cryogenic densification and planarization of material, which comprises a first supercritical fluid cleaning step, a cryogenic optimization step, and a second supercritical fluid cleaning step: the first supercritical fluid cleaning step is to place the process material in the vacuum, and then apply a supercritical fluid to the material to clean; the cryogenic optimization step is to exposure the cleaned process material to the environment of 30-860 degrees Celsius and 70-700 ATM, and then apply a supercritical fluid to the environment; the second supercritical fluid cleaning step is to clean the material by a supercritical fluid again. The process material is micro-granulating and recrystallizing, thereby gaining a uniform and good covering high grade material by processing on the relative cryogenic and superpressure environment.

Description

Low temperature densification and planarization method of materials

The present invention relates to a method for densification and planarization of a material, and more particularly to a method for densifying and planarizing in a low temperature and high pressure manner.

In the existing semiconductor and electronic product processing and production processes, most of them are deposited by physical vapor deposition (PVD), arc physical vapor deposition (PVD), or chemical vapor deposition (Chemical Vaper Deposition). A thin film is deposited on a substrate, and the pattern to be formed is transferred onto the substrate by using Lithography and Etching techniques and the desired three-dimensional structure is stacked.

The quality of the electronic products produced by the above method largely determines whether the quality of the film formed during the deposition process is good or not, and whether the static charge and the dirt accumulated on the semi-finished product in the process are completely removed. In the existing process, when the semi-finished product is deposited in a vacuum environment, it is necessary to break the vacuum and move to a high-temperature furnace tube machine, and then access the machine with a high-temperature ambient gas (Ambient gas) of more than 1000 degrees Celsius. The semi-finished product formed by the film is subjected to an anneaal treatment to uniformize the grain structure inside the material.

However, when the film material is treated at a high temperature for a long time, there is a problem that thermal stress accumulates in the produced film, and the thermal stress will have a serious disadvantage to the reliability of the final product, and the industry has an increasingly strict line width requirement. The existing technology that uses high-temperature and long-term constant temperature treatment to obtain high-quality thin films will be gradually eliminated in the future, and in future electronic products such as soft electronics and flexible electronics that are highly demanding in reliability, they may not continue to be application.

In addition, the existing process technology can not provide a complete and effective solution to the problem of accumulation of dirt and static charge in the process. This problem is bound to be more stringent in the trend of online width and reliability of finished products. Yield and reliability have a considerable impact.

Accordingly, it is an object of the present invention to provide a treatment method for improving the quality of a film material at a relatively low temperature.

Thus, the method of low temperature densification and planarization of the material of the present invention comprises a first supercritical fluid cleaning step, a low temperature optimization step, and a second supercritical fluid cleaning step.

The first supercritical fluid cleaning step is to first place a material to be treated in a vacuum environment, and then clean the material to be treated with a fluid in a supercritical state.

The low temperature optimization step is: exposing the material to be treated after being cleaned by the first supercritical fluid cleaning step to an environment having a pressure of 70 to 700 atm and a temperature of 30 to 860 degrees Celsius, and introducing a solution in the environment. A fluid in a supercritical state.

The second supercritical fluid cleaning step cleans the material to be treated that has passed through the low temperature optimization step with a fluid in a supercritical state.

The effect of the invention is to use the low temperature optimization in a relatively low temperature and a relatively high pressure environment to fine-grain and recrystallize the material to be treated to obtain uniformity (Uniformity) and coverage (Step). Coverage) Good quality materials. In addition, it is also possible to convert the film with the original quality unevenness or low cost into a fine film of high quality film (Thin Film) for the subsequent process.

The above and other technical features, features, and advantages of the present invention will be apparent from the following detailed description of the preferred embodiments.

Before the present invention is described in detail, it is noted that in the following description, similar elements are denoted by the same reference numerals.

Referring to FIG. 1, a first preferred embodiment of the method for low temperature densification and planarization of the material of the present invention comprises a first supercritical fluid cleaning step 1, a low temperature optimization step 2, and a second supercritical fluid cleaning step 3. .

The first supercritical fluid cleaning step 1 is to first place a material to be treated in a vacuum environment, and then clean the material to be treated with a fluid in a supercritical state. In actual implementation, the material to be treated is placed in a closed space, and the space is evacuated, and then the fluid is introduced into the space, and it is confirmed that a predetermined amount of fluid has passed into the space. After that, the pressure and temperature in the space are adjusted, and the target value of the adjustment is the critical condition of the fluid. In this embodiment, graphite is used as the material to be treated, and carbon dioxide is used as the fluid, so the temperature and pressure in the space should be increased to at least 31.1 degrees Celsius (°C) and 72.8 atmospheres (ATM), respectively. Of course, other types of fluids can also be used, such as nitrous oxide (critical temperature 36.4 ° C, critical pressure 72.5 ATM), trifluorochloromethane (critical temperature 28.8 ° C, critical pressure 38.7 ATM), difluoromethylene chloride ( The critical temperature is 111.7 ° C and the critical pressure is 37.4 ATM).

Using the first supercritical fluid cleaning step 1 to operate the fluid under the operating conditions of its critical conditions, so that the fluid enters a supercritical state, and the fluid in a supercritical state is cloud-like and has a very high solubility. The ability to dissolve impurities such as contamination, particles, and static charges adhering to the surface of the object to be treated, thereby effectively removing contaminants on the surface of the material to be treated, so that the material to be treated can The next process is carried out under clean conditions.

Continuing to refer to FIG. 1 , in the low temperature optimization step 2, the material to be treated after being cleaned by the first supercritical fluid cleaning step 1 is exposed to an environment having a pressure of 70 to 700 ATM and a temperature of 30 to 860 degrees Celsius. And in the environment, a fluid in a supercritical state is introduced. In the present embodiment, the trifluoromethane is used as the fluid to be introduced into the environment, and the amount of the fluid is about 0.1 to 45 vol%, and is operated at a temperature of 30 ° C and a pressure of 400 ATM. The object to be treated is subjected to a low temperature optimization treatment for 30 to 40 minutes.

Through the low temperature optimization of low temperature and high pressure state, the material to be treated can be subjected to fine granulation (Grain) and recrystallization (Recrystallization) process, and upgraded from amorphous phase to polycrystalline phase (Poly-crystal) ) Even single-crystal, which achieves high-quality materials with high grain uniformity and high coverage.

Referring to Fig. 2 and Fig. 3, Fig. 2 is an actual photomicrograph of the electron microscope before treatment, and Fig. 3 is an actual photomicrograph of the electron microscope after 30~40 minutes, 30 °C, and 400 ATM, which can be seen from Fig. 3. After 30 to 40 minutes of low temperature and high pressure and low temperature optimization, the grain structure of the material to be treated (graphite) has changed from a non-grained shape before untreated to a crystal shape resembling a fish scale, thereby making the material The overall uniformity is higher, and the gap between the crystal grains and the crystal grains is also greatly reduced, and the density, overall coverage and flatness of the material can be greatly improved.

It should be noted that the low temperature optimization step 2 of the embodiment is performed at a constant temperature (30 ° C) and a pressure (400 ATM), but in fact, the temperature and pressure of the low temperature optimization step 2 may also vary with time, for example In the low temperature optimization step 2, the material to be treated can be optimized at a low temperature of about 15 seconds at 45 ° C and 300 atm, and then the material to be treated is subjected to 30 ° C and 400 ATM conditions. 40 minutes of low temperature optimization, so that the finished product with higher grain density and overall coverage can be obtained, but it should be noted that the above processing time and corresponding working conditions are only for specific materials to be processed (in this embodiment) For the use of graphite, the actual implementation depends on the material to be treated to be treated, and is not limited here.

It should be noted that in the low temperature optimization step 2 of the embodiment, the material to be treated is also biased at 200 volts. Applying this bias condition helps the atoms to be densely packed along the [100] plane when rearranged, so that a fish scale-like crystal shape is formed. This fish scale-like crystal has densification and flattening of the material. Great help.

Referring back to FIG. 1, after the low temperature optimization step 2 is completed, the second supercritical fluid cleaning step 3 is performed. In the second supercritical fluid cleaning step 3, the material to be treated that has passed through the low temperature optimization step 2 is cleaned by the fluid in a supercritical state. In this embodiment, the second supercritical fluid cleaning step 3 The operation mode and conditions are the same as those of the first supercritical fluid cleaning step 1, and the functions and effects thereof are also the same, and thus will not be described herein.

The main object of the first preferred embodiment of the present invention is to re-quality the material to be processed which is to be further improved in quality, for example, if the material to be treated has been annealed (may not be annealed yet) Processing), but the finished product or the grain quality of the film formed thereon is not good, or there are fine cracks on the surface, and the method of the embodiment can be used to re-quality the material to be treated twice to obtain The grain structure with better density and overall coverage, even repairing the existing fine cracks.

Referring to FIG. 4, a second preferred embodiment of the method for low temperature densification and planarization of the material of the present invention is substantially the same as the first preferred embodiment, except that the second preferred embodiment further includes an The deposition step 4 between the first supercritical fluid cleaning step 1 and the low temperature optimization step 2 is to form a film on the surface of the material to be treated after the first supercritical fluid cleaning step 1 is cleaned. In this embodiment, the film is formed by chemical vapor deposition, but may also be formed by sputtering, sintering, physical vapor deposition, arc physical vapor deposition, or electron cyclotron resonance chemical vapor deposition. The film is deposited on the surface of the material to be treated, depending on actual needs.

The main purpose of the second preferred embodiment of the present invention is mainly to perform a quality treatment for a material product that needs to form a film, by integrating the deposition step 4 to form a film on the surface of the material to be treated, and then The low temperature optimization step 2 is used to optimize the film to form a consistent film deposition and material quality process, which is suitable for use in the processing of electronic or semiconductor products.

The first and second preferred embodiments of the low temperature densification and planarization method of the material of the present invention have the following advantages:

(1) Improving the material quality: after the low temperature and high pressure treatment of the low temperature optimization step 2, the overall uniformity of the grain structure of the material to be treated is higher, and the gap between the crystal grains and the crystal grains is also greatly reduced. In addition, the density and overall coverage of the material can be greatly improved, thereby improving the quality of the material.

(2) Reducing the accumulation of thermal stress: Through the low temperature optimization close to room temperature, the thermal stress inside the low material can be accumulated greatly, and the reliability of the finished product is more than that of the annealing process in which the dynamic enthalpy is higher than 1000 °C in the existing process. It is high and makes the method more suitable for use in the electronics and semiconductor industries where material reliability is critical.

In summary, the high-temperature treatment of the material to be treated by the low temperature and high pressure low temperature optimization method can not only enable the processed material to have high density, uniformity and flatness, but also avoid high temperature annealing heat treatment. The accumulation of thermal stresses inside the material, which in turn enhances the stability of the material, does indeed achieve the object of the present invention.

The above is only the preferred embodiment of the present invention, and the scope of the invention is not limited thereto, that is, the simple equivalent changes and modifications made by the scope of the invention and the description of the invention are All remain within the scope of the invention patent.

1. . . First supercritical fluid cleaning step

2. . . Low temperature optimization step

3. . . Second supercritical fluid cleaning step

4. . . Deposition step

Figure 1 is a flow chart showing a first preferred embodiment of the method for low temperature densification and planarization of the material of the present invention;

Figure 2 is a microscopic photomicrograph to assist in explaining the first preferred embodiment;

Figure 3 is a microscopic view of the first preferred embodiment; and

Figure 4 is a flow chart illustrating a second preferred embodiment of the method of low temperature densification and planarization of the material of the present invention.

1. . . First supercritical fluid cleaning step

2. . . Low temperature optimization step

3. . . Second supercritical fluid cleaning step

Claims (9)

A method for low temperature densification and planarization of a material comprises: a first supercritical fluid cleaning step of first placing a material to be treated in a vacuum environment, and then treating the material to be treated with a fluid in a supercritical state. Performing cleaning; a low temperature optimization step of exposing the material to be treated after the first supercritical fluid cleaning step to an environment having a pressure of 70 to 700 atm and a temperature of 30 to 860 degrees Celsius, and in the environment Passing a fluid in a supercritical state; and a second supercritical fluid cleaning step to clean the material to be treated that has passed through the low temperature optimization step with the fluid in a supercritical state. A method for low-temperature densification and planarization of a material according to claim 1, wherein in the low-temperature optimization step, the material to be treated after being cleaned by the first supercritical fluid cleaning step is exposed to pressure 400 atmospheres and a vacuum of 30 degrees Celsius. A method of low temperature densification and planarization of a material according to claim 1, wherein the pressure and temperature are varied with time in the low temperature optimization step. A method for low-temperature densification and planarization of a material according to claim 1, wherein in the low-temperature optimization step, a bias of 50 to 250 volts is applied to the material to be treated. The method of low temperature densification and planarization of a material according to any one of claims 1 to 4, wherein the first supercritical fluid cleaning step, the low temperature optimization step, and the second supercritical fluid cleaning step The fluid is selected from the group consisting of carbon dioxide, nitrous oxide, trifluoromethane, and difluoromethylene chloride. A method of low temperature densification and planarization of a material according to claim 5, wherein the first supercritical fluid cleaning step and the fluid used in the low temperature optimization step are different. A method for low-temperature densification and planarization of a material according to claim 6 wherein the amount of fluid introduced in the low-temperature optimization step is 0.1 to 45 vol%. The method for low-temperature densification and planarization of the material according to claim 7 further includes a deposition step between the first supercritical fluid cleaning step and the low temperature optimization step, wherein the deposition step is after the A supercritical fluid cleaning step cleans the surface of the material to be treated to form a film. A method for low temperature densification and planarization of a material according to claim 8 wherein the deposition step is selected from the group consisting of sputtering, sintering, physical vapor deposition, arc physical vapor deposition, and chemical gas. The film is deposited on the surface of the material to be treated by phase deposition or electron cyclotron resonance chemical vapor deposition.