CN213936114U - Etching chamber - Google Patents

Abstract

The utility model provides an etching chamber, include: the upper electrode is coupled with a first frequency radio frequency power source; the lower electrode is arranged opposite to the upper electrode and is coupled with a second frequency radio frequency power source and a third frequency radio frequency power source; an edge ring surrounding the lower electrode, the edge ring being coupled to a fourth frequency RF power source; wherein the first frequency is greater than the second, third, and fourth frequencies.

Description

Etching chamber

Technical Field

The utility model relates to a semiconductor technology especially relates to an sculpture cavity.

Background

In the fabrication of semiconductor devices, materials are often processed by plasma processing, for example, in etching and/or deposition processes. Examples of the method of forming Plasma include a Capacitively Coupled Plasma (CCP) system, an Inductively Coupled Plasma (ICP) system, and a Transform Coupled Plasma (TCP) system. Manufacturers often use capacitively-coupled plasma processing systems in the etching and/or deposition of semiconductor materials to fabricate semiconductor devices.

SUMMERY OF THE UTILITY MODEL

The to-be-solved technical problem of the utility model is to provide an etching cavity uses capacitive coupling plasma sculpture mode, realizes the sculpture effect of preferred.

In order to solve the technical problem, the utility model provides an etching chamber, include: the upper electrode is coupled with a first frequency radio frequency power source; the lower electrode is coupled with the second frequency radio frequency power source and the third frequency radio frequency power source; an electrostatic chuck disposed between the upper electrode and the lower electrode; an edge ring surrounding the lower electrode, the edge ring being coupled to a fourth frequency RF power source; wherein the first frequency is greater than the second, third, and fourth frequencies.

In an embodiment of the present invention, the fourth frequency is greater than the second frequency and less than the third frequency.

The utility model discloses an in an embodiment, the sculpture chamber is still including being located the gas injection region and the temperature control region at sculpture chamber top, the regional number of dividing of gas injection with the regional number of dividing of temperature control is the same.

In an embodiment of the present invention, the first frequency is greater than or equal to 100 MHz.

In an embodiment of the present invention, the fourth frequency is greater than 2MHz and less than 27 MHz.

In an embodiment of the present invention, the waveform of the rf power source is a sine wave or a square wave.

In an embodiment of the present invention, the upper electrode, the lower electrode and the edge ring are used for ionizing the gas injected through the gas injection region to form a plasma.

In an embodiment of the present invention, the material of the upper electrode and/or the lower electrode is silicon or silicon carbide.

In an embodiment of the present invention, the number of divisions is a positive integer greater than or equal to 3.

In an embodiment of the present invention, the electrostatic chuck is disposed on the lower electrode.

Compared with the prior art, the utility model has the advantages of it is following: the etching chamber can be arranged according to the requirements of etching patterns, and the radio frequency power source coupled with the upper electrode, the lower electrode and the edge ring is subjected to linkage adjustment, so that the depth requirement of etching the pattern with the large depth-to-width ratio is met, and the plasma density distribution can have better uniformity, thereby improving the section inclination degree of the etching pattern at the moment and realizing better pattern etching effect.

Drawings

The accompanying drawings, which are included to provide a further understanding of the application and are incorporated in and constitute a part of this application, illustrate embodiment(s) of the application and together with the description serve to explain the principle of the invention. In the drawings:

fig. 1 is a schematic cross-sectional view of an etching chamber according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view illustrating an etching effect of an etching scene.

Fig. 3 is a schematic cross-sectional view illustrating an etching process and an etching effect according to an embodiment of the present invention.

Fig. 4 is a schematic diagram of a work flow of etching to form a semiconductor device according to an embodiment of the present invention.

Detailed Description

In order to make the aforementioned objects, features and advantages of the present invention comprehensible, embodiments accompanied with figures are described in detail below.

In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present invention, but the present invention may be practiced in other ways than those specifically described herein, and thus the present invention is not limited by the specific embodiments disclosed below.

In the description of the present application, it is to be understood that the orientation or positional relationship indicated by the directional terms such as "front, rear, upper, lower, left, right", "lateral, vertical, horizontal" and "top, bottom", etc., are generally based on the orientation or positional relationship shown in the drawings, and are used for convenience of description and simplicity of description only, and in the case of not making a reverse description, these directional terms do not indicate and imply that the device or element being referred to must have a particular orientation or be constructed and operated in a particular orientation, and therefore, should not be considered as limiting the scope of the present application; the terms "inner and outer" refer to the inner and outer relative to the profile of the respective component itself.

Spatially relative terms, such as "above … …," "above … …," "above … …," "above," and the like, may be used herein for ease of description to describe one device or feature's spatial relationship to another device or feature as illustrated in the figures.

It should be noted that the terms "first", "second", and the like are used to define the components, and are only used for convenience of distinguishing the corresponding components, and the terms have no special meanings unless otherwise stated, and therefore, the scope of protection of the present application is not to be construed as being limited.

It will be understood that when an element is referred to as being "on," "connected to," "coupled to" or "contacting" another element, it can be directly on, connected or coupled to, or contacting the other element or intervening elements may be present. In contrast, when an element is referred to as being "directly on," "directly connected to," "directly coupled to" or "directly contacting" another element, there are no intervening elements present. Similarly, when a first component is said to be "in electrical contact with" or "electrically coupled to" a second component, there is an electrical path between the first component and the second component that allows current to flow. The electrical path may include capacitors, coupled inductors, and/or other components that allow current to flow even without direct contact between the conductive components.

Embodiments of the present application describe an etch chamber and a method of etching a semiconductor device.

FIG. 1 is a schematic cross-sectional view of an etching chamber according to an embodiment of the present disclosure.

In one embodiment, the etch chamber 100 includes an upper electrode 101, a lower electrode 102, an edge ring 103, and an electrostatic chuck 104. Since fig. 1 is a schematic cross-sectional structure diagram of the etching chamber, the upper electrode and the lower electrode are actually disk-shaped electrode plates, and the edge ring is annular, which is illustrated in a cross-sectional view in fig. 1. The electrostatic chuck may also be disk-shaped or other desired shapes.

The etch chamber may also include a baffle 105 to form the chamber. The material of the baffle is ceramic, for example.

In one embodiment, the Upper Electrode (Upper Electrode)101 is coupled to a first frequency RF power source RF 1. A Bottom Electrode (Bottom Electrode)102 is coupled to the second RF power source RF2 and the third RF power source RF 3. An Edge Ring (Edge Ring)103 is provided to surround the lower electrode 102. The thickness of the edge ring 103 can be set as desired, and thus the upper and lower surfaces of the edge ring 103 need not be perfectly flush with the lower electrode. The edge ring 103 is coupled to a fourth frequency RF power source RF 4. An Electrostatic Chuck (ESC) 104 is disposed between the upper electrode 101 and the lower electrode 102. In one embodiment, the electrostatic chuck 104 may be disposed on the bottom electrode 102, or may be disposed above the bottom electrode 102 via a support structure. A semiconductor material to be etched, such as a wafer, may be placed on the electrostatic chuck 104.

The material of the upper electrode 101 and/or the lower electrode 102 is, for example, silicon or silicon carbide. The material of the edge ring can be selected as required.

In some embodiments, the etch chamber 100 further comprises a gas injection zone and a temperature control zone located at the top of the etch chamber. The number of divisions of the gas injection region is the same as the number of divisions of the temperature control region. The number of divisions of the region is a positive integer of 3 or more. For example, the gas injection region may be divided into three parts, a Center region (Center zone), a Middle region (Middle zone), and an Edge region (Edge zone). The temperature control zone is also divided and arranged into the three partial zones. The arrangement of the temperature control area corresponds to the gas injection area, and the by-product distribution (by-product distribution) of the reaction process after the gas is injected into the chamber can be optimized, so that the etching process is facilitated. The location of the gas injection zone and the zone where the temperature control element is located is, for example, the zone indicated at 106 in fig. 1.

The temperature control area of the etching chamber is arranged corresponding to the division number of the gas injection area, and the distribution of byproducts in the reaction process after the gas is injected into the chamber can be optimized, so that the etching process is facilitated.

After the rf power is applied to the upper electrode 101, the lower electrode 102, and the edge ring 103, the gas injected through the gas injection region is ionized to form a plasma. The waveform of the rf power source is, for example, a sine wave or a square wave.

FIG. 2 is a cross-sectional view illustrating an etching effect of an etching scene.

In some application scenarios of the etching process, as the Aspect Ratio (AR) of the etched pattern increases, the energy of the etching ions needs to be increased to obtain a structure with a larger depth by etching. To increase the ion energy, the rf source power needs to be increased. But increasing the rf power source to achieve increased ion energy may degrade the morphology of the plasma density profile. The degree of uniformity (uniformity) of the plasma density distribution has an important influence on the profile tilting (profile tilting) of the etched deep hole structure. Particularly, as the Aspect Ratio (AR) of the etched pattern is increased, the influence of the uniformity degree of the plasma density distribution form on the section gradient of the etched deep hole structure is more obvious. For example, in the etching scenario shown in fig. 2, which may be a cross-sectional diagram illustrating the etching effect of a deep hole structure, as the ion density distribution changes, in some cases, the inclination degree of the hole structure exceeds the allowable deviation of the manufacturing process. For example, the deviation value ti in the horizontal direction of the center point and the bottom point of the top of the hole in fig. 2 has exceeded the allowable error value.

Meanwhile, in some cases, through adjustment of performance parameters of the etching process, the profile tilt (profile tilting) of the etching structure of a certain region of the wafer, such as the Center region (Center zone), the Middle region (Middle zone), or the Edge region (Edge zone), is improved, but the profile tilt (profile tilting) of the etching structure of other regions is deteriorated. A more sophisticated etch chamber configuration is needed to meet the profile tilting (profile tilting) process requirements for the etch structure over the entire etch region.

In the technical solution of the present application, the frequency F1 (referred to as the first frequency F1) of the first frequency rf power source is greater than the second frequency F2, the third frequency F3, and the fourth frequency F4. More specifically, the fourth frequency F4 is greater than the second frequency F2 and less than the third frequency F3.

In one embodiment, the first frequency is equal to or greater than 100 MHz. The second frequency F2 is equal to or less than 2 MHz. The third frequency is greater than or equal to 27MHz and less than 100 MHz. The fourth frequency is greater than 2MHz and less than 27 MHz. Of the second frequency RF power source RF2 and the third frequency RF power source RF3 coupled to the lower electrode, the second frequency F2 is small and the third frequency F3 is large. Accordingly, during the plasma etching process, the directionality and ion energy (ion energy) of the ions can be adjusted by controlling the second frequency RF power source RF2, and the distribution density (density) of the plasma can be adjusted by controlling the third frequency RF power source RF 3.

The first frequency RF power source RF1 coupled to the upper electrode 101 can adjust the plasma density. Since the first frequency F1 is greater than the second frequency F2, the third frequency F3, and the fourth frequency F4, the adjustment of the first frequency RF power source RF1 can affect the density distribution of the plasma.

The fourth RF power source RF4 coupled to the edge ring 104 has a different frequency from the second RF power source RF2 and the third RF power source RF3, so as to avoid RF coupling and influence on the etching process.

The cooperation of the first frequency RF power source RF1, the second frequency RF power source RF2 and the third frequency RF power source RF3 can increase the ion energy to realize the etching of high aspect ratio patterns and simultaneously adjust and realize the uniformity of the density distribution of plasma. The region 107 shown in fig. 1 is, for example, an etching plasma distribution region. Meanwhile, the first frequency RF power source RF1 may also cooperate with the fourth frequency RF power source RF4 to improve the distribution of the Plasma Sheath (Plasma Sheath)108 at the edge of the Plasma distribution region in fig. 1.

As the ion energy increases while the density distribution of the plasma also maintains a better uniformity (uniformity), the direction of the etching ions also more uniformly tends toward the vertical direction, such as illustrated in fig. 3. The dotted line in fig. 3 is a schematic view in the vertical direction. The actual etching ions are numerous and are only illustrated in fig. 3. Therefore, the technical scheme of the application can realize that the section inclination degree of the hole structure on the whole semiconductor structure, such as the whole wafer, meets higher process requirements when the hole structure, particularly the hole structure pattern with a large depth-to-width ratio is etched. The effect of the etching is illustrated in fig. 3, for example. Fig. 3 is a schematic cross-sectional view illustrating an etching process and an etching effect according to an embodiment of the present invention.

The cross-sectional structures 200 or 300 of fig. 2 and 3 may be partial cross-sections of a semiconductor structure, or cross-sections of a center region, middle region, or edge region of an etched semiconductor structure within a chamber.

According to the technical scheme of the etching chamber, the radio frequency power source coupled with the upper electrode, the lower electrode and the edge ring can be adjusted according to the requirement of an etching pattern during the process of etching, the depth requirement of etching a pattern with a large depth-to-width ratio is met, and the plasma density distribution can have better uniformity, so that the section inclination degree of the etching pattern at the moment is improved.

The technical scheme of the application can avoid redesigning the shape of the lower surface of the upper electrode and remanufacturing the upper electrode in order to enable the profile gradient of the etching pattern to meet the requirement. Redesigning and manufacturing the top electrode requires a long, months or half-year turnaround process, which is extremely time consuming. Meanwhile, the redesigned electrode cannot adapt to new requirements after the etching requirements change. Therefore, the technical scheme of the application can quickly meet the change of the etching requirement and has better process expansibility.

Fig. 4 is a schematic diagram of a work flow of etching to form a semiconductor device according to an embodiment of the present invention.

In one embodiment, as illustrated in fig. 4, the workflow of etching to form a semiconductor device includes,

step 401, applying a first frequency radio frequency power source to an upper electrode of an etching chamber;

step 402, applying a second frequency radio frequency power source and a third frequency radio frequency power source to a lower electrode of an etching chamber;

step 403, applying a fourth frequency radio frequency power source to the edge ring surrounding the lower electrode; and

at step 404, a semiconductor device is formed using plasma processing formed by ionization of the upper electrode, and the edge ring.

In some embodiments, the frequency F1 of the first frequency rf power source (referred to simply as the first frequency F1) is greater than the second frequency F2, the third frequency F3, and the fourth frequency F4. More specifically, the fourth frequency F4 is greater than the second frequency F2 and less than the third frequency F3.

Having thus described the basic concept, it will be apparent to those skilled in the art that the foregoing disclosure is by way of example only, and is not intended to limit the present application. Various modifications, improvements and adaptations to the present application may occur to those skilled in the art, although not explicitly described herein. Such modifications, improvements and adaptations are proposed in the present application and thus fall within the spirit and scope of the exemplary embodiments of the present application.

Also, this application uses specific language to describe embodiments of the application. Reference throughout this specification to "one embodiment," "an embodiment," and/or "some embodiments" means that a particular feature, structure, or characteristic described in connection with at least one embodiment of the present application is included in at least one embodiment of the present application. Therefore, it is emphasized and should be appreciated that two or more references to "an embodiment" or "one embodiment" or "an alternative embodiment" in various places throughout this specification are not necessarily all referring to the same embodiment. Furthermore, some features, structures, or characteristics of one or more embodiments of the present application may be combined as appropriate.

Similarly, it should be noted that in the preceding description of embodiments of the present application, various features are sometimes grouped together in a single embodiment, figure, or description thereof for the purpose of streamlining the disclosure and aiding in the understanding of one or more of the embodiments. This method of disclosure, however, is not intended to require more features than are expressly recited in the claims. Indeed, the embodiments may be characterized as having less than all of the features of a single embodiment disclosed above.

Although the present application has been described with reference to the present specific embodiments, it will be recognized by those skilled in the art that the foregoing embodiments are merely illustrative of the present application and that various changes and substitutions of equivalents may be made without departing from the spirit of the application, and therefore, it is intended that all changes and modifications to the above-described embodiments that come within the spirit of the application fall within the scope of the claims of the application.

Claims (10)

1. An etch chamber, comprising:

the upper electrode is coupled with a first frequency radio frequency power source;

the lower electrode is arranged opposite to the upper electrode and is coupled with a second frequency radio frequency power source and a third frequency radio frequency power source;

an edge ring surrounding the lower electrode, the edge ring being coupled to a fourth frequency RF power source;

wherein the first frequency is greater than the second, third, and fourth frequencies.

2. The etch chamber of claim 1, wherein the fourth frequency is greater than the second frequency and less than the third frequency.

3. The etch chamber of claim 1, further comprising a gas injection zone and a temperature controlled zone at a top of the etch chamber, the gas injection zone having a same number of divisions as the temperature controlled zone.

4. The etch chamber of claim 1, wherein the first frequency is equal to or greater than 100 MHz.

5. The etch chamber of claim 1, wherein the fourth frequency is greater than 2MHz and less than 27 MHz.

6. The etch chamber of claim 1, wherein the waveform of the RF power source is a sine wave or a square wave.

7. The etch chamber of claim 3, wherein the upper electrode, lower electrode, and edge ring are configured to ionize a gas injected through the gas injection region to form a plasma.

8. The etch chamber of claim 1, wherein the upper electrode and/or the lower electrode is made of silicon or silicon carbide.

9. The etch chamber of claim 3, wherein the number of divisions is a positive integer greater than or equal to 3.

10. The etch chamber of claim 1, further comprising an electrostatic chuck disposed on the lower electrode.

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