CN112981350A - Method and apparatus for uniform thin film deposition - Google Patents

Abstract

The invention discloses equipment for uniform film deposition, which comprises a deposition cavity, wherein a sputtering target material, a target support and a substrate table are arranged in the deposition cavity, a wafer placing area is arranged on the substrate table, and the equipment also comprises a process gas distribution system connected into the deposition cavity, wherein the process gas distribution system comprises a plurality of process gas guide channels, one end of each process gas guide channel, which extends into the deposition cavity, is positioned around the outer side of the wafer placing area, process gas can be guided into the deposition cavity, and each process gas guide channel is independently connected with a mass flow controller.

Description

Method and apparatus for uniform thin film deposition

Technical Field

The invention relates to a magnetron sputtering deposition film, in particular to a method and equipment for independently introducing process gas at multiple positions.

Background

Magnetron sputtering is one type of physical vapor deposition. The method is a technique for bombarding a target material by using plasma to make target material particles fall off and deposit on the surface of a substrate to form a film. Generally, after the magnetron is placed on the target, the magnetic field generated by the magnetron can control the movement area of electrons and ions on the surface of the target, thereby increasing the ionization rate of process gases such as Ar gas in the area, increasing the plasma concentration on the surface of the target and further increasing the film deposition rate. Magnetron sputtering technology is widely used in the field of semiconductor and microelectronic device manufacturing, and is the most common thin film deposition method.

FIG. 1 is a schematic view of a typical magnetron sputtering apparatus. The equipment mainly comprises a process cavity, wherein a substrate table is arranged in the process cavity, and a substrate, a process gas inlet, a target material and the like are loaded on the substrate table. The process cavity is connected with a vacuum pump and is pumped to be vacuum by the vacuum pump; the target material is connected to an external power supply, the power supply enables the surface of the target material to generate a negative electric field, process gas is ionized, and the process gas impacts the target material under the action of the electric field, so that target material particles are sputtered out.

To achieve uniformity of the deposited film, extremely uniform distribution of the process gases within the chamber is required. Typically, the process gas is introduced at a location in the chamber, either at the bottom, sides, or top of the chamber; there are also uniform porous process gas distribution devices designed around the target, similar to showerhead devices. These designs, while meeting the requirement of relatively high film deposition uniformity, have become more challenging as chamber structures become more complex and wafer sizes become larger, such as from 200mm to 300 mm. This is due to: strict symmetry with respect to the wafer is difficult to achieve in the design, manufacture and installation of a chamber vacuum system, resulting in a gradient distribution of process gas pressure within the chamber. For example, in FIG. 1, since the vacuum pump is on the right side of the chamber and the gas inlet is on the left side of the chamber, the pressure of the process gas at point A on the wafer near the vacuum pump is less than the pressure of the process gas at point B on the wafer near the process gas inlet. This affects the uniformity of film deposition.

Although, the uniformity of the process gas distribution can be improved by using a process gas introduction device like a shower head, or an optimized magnetron, thereby improving the uniformity of the deposited thin film. However, relying on them alone still has certain limitations; meanwhile, the optimization of the spray header and the magnetron requires a lot of experiments, the period is quite long, the cost is quite high, and the timely adjustment and improvement of the process are not facilitated.

Disclosure of Invention

Aiming at the defects of the prior art, the invention provides a process gas which is independently introduced at multiple positions, and the problem of asymmetric vacuum design in a deposition cavity is solved by adjusting the flow of the process gas at different positions, so that uniform gas flow distribution is formed, and the uniformity of film deposition is improved.

In order to achieve the purpose, the invention provides the following technical scheme: the utility model provides an equipment of even film deposition, includes the deposit cavity, is provided with sputtering target, target support and substrate platform in the deposit cavity, and the region is placed to the last wafer that is provided with of substrate platform, still including being connected to the process gas distribution system in the deposit cavity, and the process gas distribution system includes a plurality of process gas guide channel, and the one end that a plurality of process gas guide channel stretched into in the deposit cavity is located around the outside in the region is placed to the wafer, can be with in the leading-in deposit cavity of process gas, every process gas guide channel all is connected with mass flow controller independently.

The longitudinal direction of the further process gas guide channel is parallel to the radial direction of the substrate table.

The longitudinal direction of the further process gas guide channel is perpendicular to the radial direction of the substrate table and perpendicular to the surface of the substrate table.

Four process gas guide channels are further provided.

The further four process gas introduction channels are located at the same distance from the center of the wafer placement area.

The further four process gas guide channels are evenly distributed along the circumference.

Further all process gas introduction channels are connected to the same gas source.

A method of uniform thin film deposition comprising the steps of:

s1: placing and fixing a wafer on a wafer placing area of a substrate table;

s2: vacuumizing the deposition cavity by using a vacuum pump;

s3: selectively opening and using the process gas guide channels with corresponding quantity and positions according to the requirements, and inputting process gas into the deposition cavity;

s4: starting a power supply and other control parts connected with the sputtering target material, generating plasma in the deposition cavity, bombarding the target material, sputtering target material particles, and depositing the target material particles on the surface of the wafer to form a film;

s5: transporting the wafer out of the deposition chamber;

s6: measuring the thickness and uniformity of the deposition on the surface of the wafer, if the result reaches a target value, finishing debugging, and recording corresponding control parameters; if the result does not reach the target value, the mass flow controllers on different process gas guide channels are adjusted according to the measurement result to adjust the flow of the process gas until the target value is reached.

Compared with the prior art, the invention has the beneficial effects that: the problem of asymmetric vacuum design of a deposition cavity is solved by adjusting the flow of process gas at different positions, so that uniform gas flow distribution is formed, and the uniformity of film deposition is improved; meanwhile, the process gas flow of different positions can be adjusted in time and in situ in the process of process operation, so that the flexibility and efficiency of process debugging are greatly improved, and the productivity is improved.

Drawings

FIG. 1 is a schematic view of a prior art deposition chamber with single-sided gas inlet;

FIG. 2 is a schematic diagram of a dual-side gas inlet scheme for a deposition chamber according to the prior art;

FIG. 3 is a perspective view of a first embodiment of the apparatus for uniform thin film deposition according to the present invention;

FIG. 4 is a top view of the distribution of the process gas introduction channels in the first embodiment of the apparatus for uniform thin film deposition according to the present invention;

FIG. 5 is a perspective view of a second embodiment of the apparatus for uniform thin film deposition in accordance with the present invention;

FIG. 6 is a top view of the distribution of process gas introduction channels in a second embodiment of the apparatus for uniform thin film deposition according to the present invention;

FIG. 7 is a graph of the deposition thickness profile of the wafer surface obtained in one experiment;

FIG. 8 is a graph of the wafer surface deposition thickness profile obtained in experiment two;

FIG. 9 is a graph of the deposition thickness profile on the wafer surface obtained in experiment three;

FIG. 10 is a graph of the deposition thickness profile on the wafer surface obtained in experiment four.

Reference numerals: 1. a substrate stage; 11. a wafer placement area; 21. a first process gas introduction passage; 22. a second process gas introduction passage; 23. a third process gas introduction passage; 24. a fourth process gas introduction channel.

Detailed Description

Embodiments of the method and apparatus for uniform thin film deposition according to the present invention are further described with reference to fig. 1 to 10.

In the description of the present invention, it should be noted that, for the terms of orientation, such as "central", "lateral (X)", "longitudinal (Y)", "vertical (Z)", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", etc., indicate that the orientation and positional relationship are based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, but do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and should not be construed as limiting the specific scope of the present invention.

Furthermore, if the terms "first" and "second" are used for descriptive purposes only, they are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features. Thus, a definition of "a first" or "a second" feature may explicitly or implicitly include one or more of the features, and in the description of the invention, "a number" or "a number" means two or more unless explicitly specified otherwise.

The utility model provides an even equipment of film deposition, includes the deposit cavity, is provided with sputtering target, target support and substrate platform 1 in the deposit cavity, is provided with wafer on the substrate platform 1 and places district 11, still including being connected to the process gas distribution system in the deposit cavity, and process gas distribution system includes a plurality of process gas guide channel, and a plurality of process gas guide channel stretch into the one end in the deposit cavity and lie in around the outside that district 11 was placed to the wafer, can be with in the leading-in deposit cavity of process gas, every process gas guide channel all is independently connected with mass flow controller.

Wherein the wafer is also referred to as the substrate.

In the present invention, each process gas introduction passage may be individually or commonly connected to the same or multiple gas sources, and the process gas distribution system may further include a flow restriction device, such as a feedback control valve.

As shown in fig. 3 and 4, which are schematic diagrams of a first embodiment of the present invention, in the present embodiment, the process gas guide channels have four, the longitudinal direction of the process gas guide channels is parallel to the radial direction of the substrate table 1, and the four process gas guide channels form four process gas guide channels on the substrate table 1, namely, a first process gas guide channel 21, a second process gas guide channel 22, a third process gas guide channel 23 and a fourth process gas guide channel 24.

Taking the view of fig. 4 as an example, a first process gas is introduced into the deposition chamber from below through the first process gas introduction passage 21; the second process gas is fed into the deposition chamber from the left side through the second process gas guide passage 22; the third process gas is fed into the deposition chamber from above through a third process gas guide passage 23; the fourth process gas is fed into the deposition chamber from the right side through a fourth process gas guide channel 24.

Wherein the first process gas, the second process gas, the third process gas and the fourth process gas may be the same or different or a mixture of process gases.

As shown in fig. 5 and 6, it is an embodiment two of the present invention, which is different from the embodiment one in that the longitudinal direction of the process gas guide channel is perpendicular to the radial direction of the substrate table 1 in this embodiment, and perpendicular to the surface of the substrate table 1, that is, all the process gas guide channels deliver the process gas in the direction perpendicular to the surface of the substrate table 1, and the specific positions of the respective process gas guide channels in the embodiment two may not be at the positions of right above, right below, right left and right, but as shown in fig. 6, the first process gas guide channel 21 is located at the lower left of the substrate table 1, the second process gas guide channel 22 is located at the upper left of the substrate table 1, the third process gas guide channel 23 is located at the upper right of the substrate table 1, and the fourth process gas guide channel 24 is located at the lower right of the substrate table 1.

In another new embodiment, the number of the process gas guide channels may be 3, 5 or more, on one hand, the structure of the deposition chamber becomes complicated and the cost is increased due to more process gas guide channels, and meanwhile, the debugging parameters of the process are increased and the process debugging becomes complicated; on the other hand, the number of process gas guide channels is small, process debugging parameters are insufficient, the adjustment of a film process is not facilitated, and the requirement on the uniformity of a deposited film may not be met.

In the present embodiment, the distances from the four process gas guide channels to the center of the wafer placing region 11 are preferably the same, that is, the distances from the process gas guide channels of the four process gas guide channels to the center of the wafer placing region 11 are preferably the same.

The preferred four process gas introduction channels of this embodiment are evenly distributed along the circumference.

The process gas guide channel forms a plurality of process gas distribution areas in the deposition chamber, the process gas distribution areas can be overlapped with each other, when two or more process gas distribution areas exist, and when one process gas guide channel is asymmetrically distributed, the process gas flow of other process gas guide channels can be adjusted to make up and balance the uniform distribution of the process gas in the deposition chamber.

The flow rate of the process gas of the corresponding process gas guide channel is controlled by the mass flow controller.

A method of uniform thin film deposition comprising the steps of:

s1: placing and fixing a wafer on a wafer placing area 11 of a substrate table 1;

s2: vacuumizing the deposition cavity by using a vacuum pump;

s3: selectively opening and using the process gas guide channels with corresponding quantity and positions according to the requirements, and inputting process gas into the deposition cavity;

s4: starting a power supply and other control parts connected with the sputtering target material, generating plasma in the deposition cavity, bombarding the target material, sputtering target material particles, and depositing the target material particles on the surface of the wafer to form a film;

s5: transporting the wafer out of the deposition chamber;

s6: measuring the thickness and uniformity of the deposition on the surface of the wafer, if the result reaches a target value, finishing debugging, and recording corresponding control parameters; if the result does not reach the target value, the mass flow controllers on different process gas guide channels are adjusted according to the measurement result to adjust the flow of the process gas until the target value is reached.

Wherein the steps S1 to S6 actually include tuning processes for each parameter in the deposition process, and the main tuning parameter of the present invention is the flow rate of the process gas in each process gas guiding channel.

As shown in table 1, which is a data result obtained by performing four experiments using the structure of the first embodiment of the present invention, among the four experiments, the first experiment, the second experiment and the third experiment were obtained using the structure of the first embodiment, and the deposition chamber of the first embodiment is referred to as a below; the fourth example was obtained with the structure of the second example, and the deposition chamber of the second example is hereinafter referred to as B. In the four experiments, only the process gas flow in the process gas guide channel is different, and the other technical parameters are the same.

Table 1:

referring to fig. 7-10, the deposition thickness profiles for the wafer surfaces from experiment one to experiment four are shown.

As can be seen from table 1, in the deposition chamber a,

experiment one shows that: the first process gas introduction channel 21 is 105 sccm; the second process gas introduction channel 22 is 55 sccm; the third process gas introduction channel 23 is 55 sccm; the fourth process gas introduction channel 24 is 80 sccm. The mean square deviation of the thickness of the deposited film obtained under this condition was 1.06%, as shown in FIG. 7. Meanwhile, if a multi-pipeline airflow introducing mode is not available, the airflow is seriously unevenly distributed in the cavity. Therefore, it is necessary to introduce 105sccm of process gas into the first process gas introduction passage 21, much more than the other passages; the process gas introduced by the fourth process gas guide channel 24 is also higher than the second and third process gas guide channels, so that the process gas distribution is uniform, and the better uniformity of the thickness of the deposited film is obtained, namely the thickness mean square deviation of the film is close to-1.0%.

Experiment two shows that: on the basis of the first experiment, the uniformity of the thickness of the film can be further improved by adjusting the process gas flow of each channel. The first process gas introduction channel 21 is adjusted from 105sccm to 102 sccm; the second process gas introduction channel 22 is adjusted to 48sccm from 55 sccm; the third process gas introduction channel 23 is adjusted to 58sccm from 55 sccm; the fourth process gas introduction channel 24 is adjusted from 80sccm to 87 sccm. The mean square deviation of the thickness of the deposited film obtained under this condition was 0.91%, as shown in FIG. 8.

Experiment three shows that: on the basis of the second experiment, the uniformity of the thickness of the film can be further improved by adjusting the process gas flow of each channel. The first process gas introduction channel 21 is adjusted from 102sccm to 107 sccm; the second process gas introduction channel 22 is adjusted from 48sccm to 62 sccm; the third process gas introduction channel 23 is adjusted to 53sccm from 58 sccm; the fourth process gas introduction channel 24 is adjusted to 73sccm from 87 sccm. The mean square deviation of the thickness of the deposited film obtained under this condition was 0.81%, as shown in FIG. 9.

As can also be seen from table 1, in the deposition chamber B,

since the chamber B and the chamber a may have different distribution patterns of the process gas, the process gas flow rate of each channel is not set exactly as the chamber a in order to obtain excellent uniformity of the deposited film. Under this condition, the first process gas introduction passage 21 is 110 sccm; the second process gas introduction channel 22 is 110 sccm; the third process gas introduction channel 23 is 30 sccm; the fourth process gas introduction channel 24 is 60 sccm. The mean square deviation of the thickness of the deposited film obtained under this condition was 0.81%, as shown in FIG. 10. Thus, the method for introducing the process gas by multiple channels has wide applicability to different cavity structures; meanwhile, the process is quickly and efficiently adjusted.

The above description is only a preferred embodiment of the present invention, and the protection scope of the present invention is not limited to the above embodiments, and all technical solutions belonging to the idea of the present invention belong to the protection scope of the present invention. It should be noted that modifications and embellishments within the scope of the invention may occur to those skilled in the art without departing from the principle of the invention, and are considered to be within the scope of the invention.

Claims (8)

1. The utility model provides an even thin film deposition's equipment, includes the deposition cavity, is provided with in the deposition cavity and sputters target, target holder and substrate platform, and the region is placed to the last wafer that is provided with of substrate platform, its characterized in that: the wafer placing area is arranged on the inner side of the deposition chamber, the wafer placing area is arranged on the outer side of the deposition chamber, the wafer placing area is arranged on the inner side of the deposition chamber, the process gas distributing system is connected to the deposition chamber, the process gas distributing system comprises a plurality of process gas guiding channels, one ends of the plurality of process gas guiding channels extending into the deposition.

2. The apparatus for uniform thin film deposition according to claim 1, wherein: the longitudinal direction of the process gas guide channel is parallel to the radial direction of the substrate table.

3. The apparatus for uniform thin film deposition according to claim 1, wherein: the longitudinal direction of the process gas guide channel is perpendicular to the radial direction of the substrate table and perpendicular to the surface of the substrate table.

4. The apparatus for uniform thin film deposition according to claim 2 or 3, wherein: the number of the process gas guide passages is four.

5. The apparatus for uniform thin film deposition according to claim 4, wherein: the distances from the four process gas guide channels to the center of the wafer placing area are the same.

6. The apparatus for uniform thin film deposition according to claim 5, wherein: the four process gas guide channels are evenly distributed along the circumference.

7. The apparatus for uniform thin film deposition according to claim 6, wherein: all process gas introduction channels are connected to the same gas source.

8. A method of uniform thin film deposition, comprising the steps of:

s1: placing and fixing a wafer on a wafer placing area of a substrate table;

s2: vacuumizing the deposition cavity by using a vacuum pump;

s3: selectively opening and using the process gas guide channels with corresponding quantity and positions according to the requirements, and inputting process gas into the deposition cavity;

s4: starting a power supply and other control parts connected with the sputtering target material, generating plasma in the deposition cavity, bombarding the target material, sputtering target material particles, and depositing the target material particles on the surface of the wafer to form a film;

s5: transporting the wafer out of the deposition chamber;

s6: measuring the thickness and uniformity of the deposition on the surface of the wafer, if the result reaches a target value, finishing debugging, and recording corresponding control parameters; if the result does not reach the target value, the mass flow controllers on different process gas guide channels are adjusted according to the measurement result to adjust the flow of the process gas until the target value is reached.

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