阅读说明：本技术 一种改善反应过程中反射功率稳定性的等离子体发生装置 (Plasma generating device for improving stability of reflected power in reaction process ) 是由 张亚梅 姜崴 苏欣 蔡新晨 于 2020-06-13 设计创作，主要内容包括：本发明属于半导体薄膜沉积技术领域,具体提供了一种改善反应过程中反射功率稳定性的等离子体发生装置,通过优化挡板结构来确保了等离子体发生装置的上极板喷淋头、挡板和腔体上板之间的等势体；该发明还通过优化等离子体发生装置下极板加热盘上的晶圆支撑装置的材质,将铝制加热盘外缘镶嵌陶瓷环的普通陶瓷材质改为特殊改性过后的LLT陶瓷,能更大程度的降低非晶碳膜沉积过程带电荷在边缘聚集过多而引起放电的几率。通过优化上下极板相应的结构或材质,从而确保了两极板之间等离子体稳定性,进而确保了薄膜沉积过程中腔体反射功率的稳定性,有效提高了工艺稳定性。(The invention belongs to the technical field of semiconductor film deposition, and particularly provides a plasma generating device for improving the stability of reflected power in a reaction process, wherein equipotential bodies among an upper polar plate spray header, a baffle and a cavity upper plate of the plasma generating device are ensured by optimizing a baffle structure; the invention also changes the common ceramic material of the aluminum heating plate with the embedded ceramic ring into the specially modified LLT ceramic by optimizing the material of the wafer supporting device on the heating plate of the lower polar plate of the plasma generating device, thereby greatly reducing the probability of discharge caused by excessive accumulation of charges on the edge in the deposition process of the amorphous carbon film. By optimizing the corresponding structures or materials of the upper and lower polar plates, the stability of plasma between the two polar plates is ensured, the stability of the cavity reflection power in the film deposition process is further ensured, and the process stability is effectively improved.)

1. A plasma generating device for improving the stability of reflected power in the reaction process is characterized in that: comprises a reaction chamber, wherein an upper polar plate and a lower polar plate are arranged in the reaction chamber; the upper polar plate is sequentially provided with a cavity upper cover plate, a baffle plate and a spray header from top to bottom; the baffle and the spray header are both connected with the upper cover plate; the lower polar plate comprises an object stage, and a wafer supporting device is arranged on the object stage;

the supporting device is in a ring shape, the inner side of the supporting device is provided with a concave step, and the difference d between the radius of the concave step and the radius of the wafer is 1.65 mm-1.85 mm.

2. The plasma generating apparatus for improving the stability of reflected power during a reaction as claimed in claim 1, wherein: the film is a ceramic film containing carbon.

3. The plasma generating apparatus for improving the stability of reflected power during a reaction as claimed in claim 1, wherein: the diameter of the baffle is 336mm, through holes distributed in a triangular array are arranged on the baffle, and the aperture is not more than 3 mm.

4. The plasma generating apparatus for improving the stability of reflected power during a reaction as claimed in claim 1, wherein: the side length of the repeating units arranged in a triangle of the baffle is not less than 10mm, and the diameter of the through hole is 1 mm.

5. The plasma generating apparatus for improving the stability of reflected power during a reaction as claimed in claim 1, wherein: the baffle is coupled with the cavity cover plate at multiple positions, and the edge of the baffle is reinforced by a gasket and connected with the cavity upper cover plate.

6. The plasma generating apparatus for improving the stability of reflected power during a reaction as claimed in claim 1, wherein: the center of the spray header is designed to be recessed downwards, and the edge of the spray header is coupled with the upper cover plate of the cavity.

7. The plasma generating apparatus for improving the stability of reflected power during a reaction as claimed in claim 1, wherein: the distance between the baffle and the spray header is 10-15 mm.

8. The plasma generating apparatus for improving the stability of reflected power during a reaction as claimed in claim 1, wherein: the support means is made of a material having improved dielectric properties.

9. A plasma generating apparatus for improving the stability of reflected power during a reaction as recited in claim 8, wherein: the support device is made of LLT ceramic.

10. A plasma generating apparatus for improving the stability of reflected power during a reaction as recited in claims 1 to 9, wherein: the generating device is based on a rough vacuum operating environment, and the temperature is lower than 400 ℃.

Technical Field

The invention belongs to the technical field of semiconductor film deposition, and particularly provides a plasma generating device for improving the stability of reflected power in a reaction process.

Background

When the existing machine is used for depositing the amorphous carbon film, a large radio frequency input power is required, and the value of the radio frequency input power is about 1500W-2500W. The upper spray header of the plasma generating device of the existing machine platform is connected with the upper cover plate of the cavity through a screw, and a baffle for adjusting pressure and transmitting a gaseous source is arranged between the upper spray header and the upper cover plate. If the three are not equipotential bodies, not only the stability of the radio frequency is affected, but also spontaneous discharge can be caused among the three in serious cases. In addition, in the deposition chamber of the amorphous carbon film, a high concentration of carbon-containing gas causes charge density to accumulate in a short time. If the particles are not evacuated in time, spontaneous discharge is easy to occur. The lower plate heating plate of the plasma generating device of the existing machine table and the inner diameter of the wafer supporting device placed on the lower plate heating plate have a smaller distance of about 0.825 mm-0.925 mm at the deposition temperature (about 400 ℃). How to evacuate the electric charge between the gaps in time is easy to generate spontaneous discharge, so that the hardware damage to the side wall of the wafer, the heating plate and the wafer supporting device is caused, and the particle problem is also caused.

Disclosure of Invention

In order to solve one of the above problems, the present invention provides a plasma generating device for improving the stability of the reflected power in the reaction process, which comprises a reaction chamber, wherein an upper electrode plate and a lower electrode plate are arranged in the reaction chamber; the upper polar plate is sequentially provided with a cavity upper cover plate, a baffle plate and a spray header from top to bottom; the baffle and the spray header are both connected with the upper cover plate; the lower polar plate comprises an object stage, and a wafer supporting device is arranged on the object stage;

the supporting device is in a ring shape, the inner side of the supporting device is provided with a concave step, and the difference d between the radius of the concave step and the radius of the wafer is 1.65 mm-1.85 mm.

Further, the film is a ceramic film containing carbon.

Furthermore, the diameter of the baffle is 336mm, through holes distributed in a triangular array are arranged on the baffle, and the aperture is not more than 3 mm.

Furthermore, the side length of the repeating units arranged in a triangle of the baffle is not less than 10mm, and the diameter of the through hole is 1 mm.

Furthermore, the baffle is coupled with the cavity cover plate at multiple positions, and the edge of the baffle is reinforced by a gasket and connected with the cavity upper cover plate.

Furthermore, the center of the spray header is designed to be recessed downwards, and the edge of the spray header is coupled with the upper cover plate of the cavity.

Furthermore, the distance between the baffle and the spray header is 10-15 mm.

Further, the support means is made of a material having improved dielectric properties.

Further, the support device is LLT ceramic.

Further, the generating device is based on a rough vacuum operating environment, and the temperature is lower than 400 ℃.

The plasma generating device has the advantages that the equipotential bodies among the upper polar plate spray header, the baffle and the upper plate of the cavity of the plasma generating device are ensured by optimizing the structure of the baffle; the invention also changes the ceramic material of the ceramic ring embedded at the outer edge of the aluminum heating plate into LLT ceramic by optimizing the material of the wafer supporting device on the heating plate of the lower polar plate of the plasma generating device, thereby greatly reducing the probability of discharge caused by excessive accumulation of charges at the edge in the deposition process of the amorphous carbon film. By optimizing the corresponding structure or material of the upper and lower polar plates, the stability of plasma between the two polar plates is ensured, and the stability of the cavity reflection power in the film deposition process is further ensured.

Drawings

FIG. 1 is a schematic structural view of the present invention;

FIG. 2 is a schematic top view of the baffle;

FIG. 3 is a schematic view of the structure of the lower plate in FIG. 1;

FIG. 4 is a schematic perspective view of the upper plate shown in FIG. 1;

FIG. 5 is a graph showing the variation of the reflected power before and after the plasma generator is used;

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is further described in detail with reference to the following embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

Referring to fig. 1-4, the present invention provides a plasma generator for improving the stability of reflected power in the reaction process, which comprises a reaction chamber 1, wherein an upper electrode plate and a lower electrode plate are arranged in the chamber 1; the upper polar plate is sequentially provided with a cavity upper cover plate 2, a baffle plate 3 and a spray header 4 from top to bottom; the baffle 3 and the spray header 4 are both connected with the upper cover plate 2; the lower pole plate comprises an object stage 5, the object stage 5 can be a heating plate, a wafer 6 supporting device 7 is arranged on the object stage 5, and the supporting device 7 is LLT ceramic.

The supporting device 7 is ring-shaped, the inner side is provided with a concave step, and the difference d between the radius of the concave step and the radius of the wafer 6 is 1.65 mm-1.85 mm.

As an improvement of the scheme, the diameter of the baffle 3 is 336mm, through holes distributed in a triangular array are arranged on the baffle, and the aperture is 1-3 mm. The baffle 3 and the spray header 4 below the baffle are the final stage of conveying gas to the wafer, the distribution of holes is crucial to the dispersion uniformity of the gas, the arrangement of small holes on the baffle 3 is consistent in principle, and the number of holes in a unit area is consistent, and a triangle is the first choice for achieving regular arrangement; the arrangement of the aperture is related to the flowing state of the gas, 1-3MM can uniformly disperse the gas above the spray header 4, the etching rate and the deposition rate can be influenced when the aperture is too small, and the effect of uniformly dispersing the gas cannot be achieved when the aperture is too large

As an improvement of the scheme, the triangular arrangement is adopted, the side length is 10mm, and the diameter of the through hole is 1 mm.

As the improvement of scheme, baffle 3 and cavity apron through being equipped with a plurality of long screw connections, and 3 edges of baffle pass through the gasket and consolidate and be connected with cavity upper cover plate 2. The baffle 3 used in the amorphous carbon film process is proved to be suitable by process verification, the gap between the baffle 3 and the top plate (RF leading-in part) is larger than that of other equipment, longer screws are required for locking, and the phenomenon that short screws are in critical contact in screw holes causes unstable RF connection; baffle 3 can not have too much screw distribution on the surface because of providing the gas distribution function, and its near pressure is bigger when the screw is locked, can't let roof top plate and 3 contact forces of baffle everywhere even, for reaching the equipotential body effect of three, increases packing ring conducting pad in the position of no screw fastening, can increase area of contact like this when not increasing screw quantity to the stability of RF connection has been guaranteed.

As the improvement of the scheme, the center of the spray header 4 is designed to be recessed downwards, and the edge of the spray header is reinforced on the upper cover plate 2 of the cavity through a screw.

As an improvement of the scheme, the distance between the baffle 3 and the spray header 4 is 10-15 mm. The advantages are that: the distance design is that the applicant finds that the distance parameter between the baffle plate 3 and the spray header 4 has special technical significance on the radio frequency stability in an accidental situation, when the distance between the baffle plate 3 and the spray header 4 is 16mm, plasma ignition can occur between the baffle plate 3 and the spray header 4, so that discharge can occur between the baffle plate 3 and the spray header 4, and the radio frequency stability in the deposition process can be influenced on the one hand; on the other hand, the service life of the hardware is affected (after the glow is started, discharge traces are left on the baffle 3 and the spray header 4, and the discharge traces cannot be cleaned). After the distance between the baffle 3 and the spray header 4 is 10-15mm, plasma glow is not generated between the baffle 3 and the spray header 4, the process parameters of the distance play a vital role in radio frequency stability, and the probability of plasma glow is greatly reduced.

A wafer 6 to be deposited is placed on the lower plate heating plate in the chamber 1 and held in place by a wafer support 7. During the experiment, a gaseous source enters the reaction chamber 1 through the baffle plate 3 and the spray header 4. Applying radio frequency voltage between the upper and lower polar plates to form stable plasma field between the shower head 4 and the heating plate, and depositing amorphous carbon film on the wafer 6. As shown in fig. 5, the reflected power changes before and after the plasma generator is used. An RF system has an input power (RF going path) and also a reflected power (RF return path). The reflected power stability is good, or is smaller, or is regular, the process controllability is good, the process reproducibility is good, and the equipment is double-station (A and B).

The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, and any modifications, equivalents and improvements made within the spirit and principle of the present invention are intended to be included within the scope of the present invention.