CN213546294U

CN213546294U - Electrostatic chuck and plasma processing equipment

Info

Publication number: CN213546294U
Application number: CN202023146152.2U
Authority: CN
Inventors: 毛杰; 左涛涛; 倪图强
Original assignee: Advanced Micro Fabrication Equipment Inc Shanghai
Current assignee: Advanced Micro Fabrication Equipment Inc Shanghai; Advanced Micro Fabrication Equipment Inc
Priority date: 2020-12-24
Filing date: 2020-12-24
Publication date: 2021-06-25
Anticipated expiration: 2030-12-24

Abstract

The utility model discloses an electrostatic chuck and plasma treatment facility, electrostatic chuck includes: a substrate, a ceramic body, and a laminate; the laminated body is positioned between the substrate and the ceramic body; the ceramic body is used for bearing a wafer to be processed; a liquid channel is arranged in the substrate, and a refrigerant is introduced into the liquid channel to cool the ceramic body; the liquid channel is connected with the cooling device to realize the switching between the gas phase and the liquid phase of the refrigerant. The utility model discloses reduce the heat transfer loss between evaporimeter and coolant liquid, promoted cooling efficiency.

Description

Electrostatic chuck and plasma processing equipment

Technical Field

The utility model relates to the field of semiconductor technology, in particular to electrostatic chuck and plasma treatment device.

Background

In a semiconductor manufacturing process, an Electrostatic chuck (ESC) is generally used to fix and support a wafer to prevent a movement or a dislocation phenomenon during a processing process, and compared with a method of fixing the wafer by using a mechanical chuck, the ESC uses an Electrostatic attraction force to fix the wafer, thereby reducing wafer damage caused by pressure, collision, and the like, increasing an effective processing area of the wafer, reducing deposition of corrosive particles on the surface of the wafer, enabling the wafer and the ESC to conduct heat better, and being capable of working in a vacuum environment. When the wafer is subjected to an etching process, the wafer is adsorbed and fixed by the electrostatic chuck in the whole etching process, if radio frequency is introduced into the electrostatic chuck, direct-current bias voltage can be formed on the wafer by the radio frequency, the etching reaction of plasma on the wafer can be promoted, and meanwhile, the electrostatic chuck can realize temperature control on the wafer so as to increase the uniformity of wafer etching.

In the prior art, a refrigerating unit is used for cooling liquid flowing through an electrostatic chuck to cool the electrostatic chuck, and the refrigerating unit is matched with a heater which is inherent on the electrostatic chuck to realize real-time temperature control of the electrostatic chuck.

The refrigerating unit adopts an evaporator arranged on the refrigerating unit to be responsible for circulating a medium in the unit from high temperature to low temperature, and then achieves the purpose of cooling the cooling liquid by carrying out local heat exchange on the medium and the cooling liquid in the electrostatic chuck. From this, owing to need cool off the medium earlier, rethread medium and coolant liquid heat exchange are to the coolant liquid cooling, utilize the coolant liquid to flow through electrostatic chuck at last and cool down electrostatic chuck, and cooling efficiency is lower relatively, and the reaction rate of control by temperature change also can't accomplish very rapidly.

SUMMERY OF THE UTILITY MODEL

An object of the utility model is to provide an electrostatic chuck and plasma treatment equipment to reduce the heat transfer loss between evaporimeter and coolant liquid, promote cooling efficiency.

In order to realize the above purpose, the utility model discloses a following technical scheme realizes:

an electrostatic chuck comprising: a substrate, a ceramic body, and a laminate; the stack is positioned between the substrate and the ceramic body; the ceramic body is used for bearing a wafer to be processed; a liquid channel is formed in the substrate, and a refrigerant is introduced into the liquid channel to cool the ceramic body; the liquid channel is connected with a cooling device to realize the switching between the gas phase and the liquid phase of the refrigerant.

Preferably, the stacked body includes a heater, a first adhesive layer and a second adhesive layer, the first adhesive layer being located between the ceramic body and the heater for bonding the ceramic body and the heater; the second adhesive layer is located between the substrate and the heater for adhering the substrate and the heater.

Preferably, the refrigerant is freon.

Preferably, an inlet of the liquid passage communicates with an expansion valve of a cooling device; the outlet of the liquid channel is communicated with a compressor of the cooling device; the expansion valve is connected with the compressor through a condenser.

Preferably, when the refrigerant flows out from the outlet of the liquid channel, the refrigerant is changed into low-temperature and low-pressure gas; the compressor is used for processing the low-temperature low-pressure gas and outputting high-temperature high-pressure gas; the condenser is used for carrying out heat exchange treatment on the high-temperature high-pressure gas to output high-temperature high-pressure liquid, and the expansion valve is used for processing the high-temperature high-pressure liquid to obtain low-temperature low-pressure liquid; and the low-temperature and low-pressure liquid is introduced into the liquid channel through the inlet of the liquid channel so as to cool the ceramic body.

Preferably, the inlet and outlet of the liquid channel open onto the substrate.

Preferably, the liquid passage curves along a tortuous path within the substrate.

Preferably, the liquid channels are single liquid channels distributed in a spiral shape in the same plane in the substrate.

Preferably, the liquid channel is a plurality of liquid channels, and the plurality of liquid channels are communicated with each other; alternatively, a plurality of the liquid passages are not communicated.

On the other hand, the utility model also provides a plasma processing apparatus, include: a vacuum reaction chamber, and an electrostatic chuck as described above located within the vacuum reaction chamber.

The utility model discloses at least, have following advantage:

the utility model discloses a set up liquid channel in the basement, it has the refrigerant to lead to among the liquid channel, lets the refrigerant that flows among the refrigerating unit directly at the electrostatic chuck circulation flow to cool off electrostatic chuck. From this, it is right the ceramic body has reduced the heat transfer loss between evaporimeter and coolant liquid when cooling, has reached better cooling effect, simultaneously, cooperation liquid passage's tortuous design has increased the area of contact in the coolant liquid basement again, has both promoted cooling efficiency, has also promoted cooling rate, provides the possibility for ultra-low temperature sculpture and quick control by temperature change.

Drawings

Fig. 1 is a block diagram illustrating a main structure of a cooling system in an electrostatic chuck according to an embodiment of the present invention;

fig. 2 is a schematic view of a main structure of an electrostatic chuck according to an embodiment of the present invention.

Detailed Description

The electrostatic chuck and the plasma processing apparatus according to the present invention will be described in further detail with reference to the accompanying drawings and the detailed description. The advantages and features of the present invention will become more apparent from the following description. It is to be noted that the drawings are in a very simplified form and are not to precise scale, which is merely for the purpose of facilitating and distinctly claiming the embodiments of the present invention. To make the objects, features and advantages of the present invention more comprehensible, please refer to the attached drawings. It should be understood that the structure, ratio, size and the like shown in the drawings attached to the present specification are only used for matching with the content disclosed in the specification, so as to be known and read by those skilled in the art, and are not used for limiting the limitation of the implementation of the present invention, so that the present invention does not have the essential significance in the technology, and any modification of the structure, change of the ratio relationship or adjustment of the size should still fall within the scope of the technical content disclosed in the present invention without affecting the function and the achievable purpose of the present invention.

Referring to fig. 2, the present embodiment provides an electrostatic chuck 100, including: a substrate 1020, a ceramic body 1001, and a laminate; the stack is located between the substrate 1020 and the ceramic body 1001; the ceramic body 1001 is used for carrying a wafer to be processed; a liquid channel 1021 is formed in the substrate 1020, a refrigerant is communicated in the liquid channel 1021, the heat of the substrate 1020 is taken away through the contact between the refrigerant and the inside of the substrate 1020 to achieve heat balance, the laminated body is a good heat conductor, and the substrate 1020 is cooled through the heat exchange between the laminated body and the ceramic body 1001; the liquid passage 1021 is connected to a cooling device to switch between a gas phase and a liquid phase of the refrigerant.

The stacked body includes a heater 1012, a first adhesive layer 1011 and a second adhesive layer 1013, the first adhesive layer 1011 is located between the ceramic body 1001 and the heater 1012 to bond the ceramic body 1001 and the heater 1012; the second adhesive layer 1013 is located between the substrate 1020 and the heater 1012 and is used to bond the substrate 1020 and the heater 1012, and the heater 1012 is used to control the temperature of the ceramic body 1001 and to control the temperature of the ceramic body 1001 together with the coolant in the liquid channel 1021.

In this embodiment, the refrigerant is freon, but in other embodiments, difluoromethane or propane may be used as another refrigerant.

As shown in fig. 1, an inlet of the liquid passage 1021 communicates with an expansion valve 202 of the cooling device; the outlet of the liquid channel 1021 is communicated with the compressor 200 of the cooling device; the expansion valve 202 is connected to the compressor 200 via a condenser 201.

When the refrigerant flows out from the outlet of the liquid channel 1021, the refrigerant is changed into low-temperature and low-pressure gas due to the absorption of heat of the substrate 1020; the compressor 200 is used for processing the low-temperature low-pressure gas and outputting high-temperature high-pressure gas; the condenser 201 is configured to perform heat exchange treatment on the high-temperature high-pressure gas to output high-temperature high-pressure liquid, and the expansion valve 202 is configured to perform treatment on the high-temperature high-pressure liquid to obtain low-temperature low-pressure liquid; the low-temperature and low-pressure liquid is introduced into the liquid passage 1021 through the inlet of the liquid passage 1021, and continues to cool the ceramic body 1001 by heat transfer with the substrate 1020 through internal heat exchange with the stacked body.

The inlet and the outlet of the liquid channel 1021 are arranged on the substrate 1020, the substrate 1020 is positioned at the bottom of the plasma reaction cavity, and can be connected with an extra-cavity cooling device through the shortest pipeline design to form a circulation loop, in some embodiments, the cooling device can also be arranged in the chamber, the inlet and the outlet are arranged on the substrate 1020 and are far away from a reaction region above the substrate, so that the interference on the etching of the substrate can be reduced as much as possible, in other embodiments, the inlet and the outlet are arranged at the bottom of the substrate 1020, and the smaller interference of the etching environment is realized.

The liquid channel 1021 is curved along a tortuous path within the substrate 1020 to increase the contact area with the interior of the substrate 120 for faster cooling.

The liquid channels 1021 are single liquid channels distributed in a spiral shape in the same plane of the substrate 1020, and the spiral intervals can be the same, so that more uniform temperature control is realized.

The number of the liquid channels 1021 is multiple, and the liquid channels are communicated with each other; alternatively, a plurality of the liquid passages are not communicated. In the present embodiment, the plurality refers to two or more. More flexible temperature control is achieved through the plurality of liquid channels 1021, for example, in an embodiment where the plurality of liquid channels 1021 are not communicated, when rapid cooling is required, the plurality of liquid channels are simultaneously added to a refrigerant cycle, and when rapid cooling is not required, a certain number of the liquid channels are closed. In the embodiment where the liquid channels 1021 are connected, the distribution density of the liquid channels can be changed to achieve the purpose of uniform temperature control, for example, a denser liquid channel is disposed near the outlet relative to the inlet, so that the contact area between the refrigerant near the outlet and the substrate 1020 is larger, and the uneven cooling of the substrate 1020 caused by the temperature difference between the refrigerant at the inlet and the refrigerant at the outlet is offset.

Therefore, in the embodiment, the liquid channel is formed in the substrate, and the refrigerant is introduced into the liquid channel, so that the refrigerant flowing in the refrigerating unit directly flows into the electrostatic chuck, and the electrostatic chuck is cooled. From this, it is right the ceramic body has reduced the heat transfer loss between evaporimeter and coolant liquid when cooling, has reached better cooling effect, has both promoted cooling efficiency, has also promoted cooling rate, simultaneously, provides more nimble liquid passage design, can carry out the adjustment of different distributions and shapes to liquid passage according to actual need, provides the possibility for ultra-low temperature sculpture and quick control by temperature change.

On the other hand, the utility model also provides a plasma processing apparatus, include: a vacuum reaction chamber, and an electrostatic chuck 100 as described above located within the vacuum reaction chamber.

Except the air inlet, the air outlet and the to-be-processed wafer inlet and outlet channel, other parts of the vacuum reaction cavity are kept closed and isolated from the outside in the processing process. The gas inlet is connected to an external gas source for continuously supplying the reaction gas to the vacuum reaction chamber during the process. And the gas injection device is arranged on the top of the vacuum reaction cavity, is communicated with the gas inlet and is used for supplying reaction gas to the vacuum reaction cavity.

The exhaust port is connected with an external pump, and is used for exhausting waste gas generated in the treatment process out of the vacuum reaction cavity and controlling the air pressure in the vacuum reaction cavity.

The gas injection device serves as an upper electrode of the vacuum reaction chamber, the electrostatic chuck 100 serves as a lower electrode of the vacuum reaction chamber, and a reaction region is formed between the upper electrode and the lower electrode. At least one radio frequency power supply is applied to one of the upper electrode or the lower electrode through a matching network, a radio frequency electric field is generated between the upper electrode and the lower electrode so as to dissociate reaction gas into plasma, the plasma contains a large number of active particles such as electrons, ions, excited atoms, molecules, free radicals and the like, and the active particles can generate various physical and chemical reactions with the surface of a substrate to be processed, so that the appearance of the surface of the substrate is changed, and the etching process is completed.

It should be noted that, in this document, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising an … …" does not exclude the presence of other identical elements in a process, method, article, or apparatus that comprises the element.

In the description of the present invention, it is to be understood that the terms "center", "height", "thickness", "upper", "lower", "vertical", "horizontal", "top", "bottom", "inner", "outer", "axial", "radial", "circumferential", and the like, indicate orientations or positional relationships based on those shown in the drawings, and are used merely for convenience of description and for simplicity of description, and do not indicate or imply that the device or element being referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore, should not be construed as limiting the present invention. In the description of the present invention, "a plurality" means two or more unless otherwise specified.

In the description of the present invention, unless expressly stated or limited otherwise, the terms "mounted," "connected," and "fixed" are to be construed broadly, e.g., as meaning either a fixed connection, a removable connection, or an integral part; can be mechanically or electrically connected; either directly or indirectly through intervening media, either internally or in any other relationship. The specific meaning of the above terms in the present invention can be understood in specific cases to those skilled in the art.

While the present invention has been described in detail with reference to the preferred embodiments thereof, it should be understood that the above description should not be taken as limiting the present invention. Numerous modifications and alterations to the present invention will become apparent to those skilled in the art upon reading the foregoing description. Accordingly, the scope of the invention should be limited only by the attached claims.

Claims

1. An electrostatic chuck, comprising: a substrate, a ceramic body, and a laminate; the stack is positioned between the substrate and the ceramic body; the ceramic body is used for bearing a wafer to be processed;

a liquid channel is formed in the substrate, and a refrigerant is introduced into the liquid channel to cool the ceramic body; the liquid channel is connected with a cooling device to realize the switching between the gas phase and the liquid phase of the refrigerant.

2. The electrostatic chuck of claim 1, wherein said laminate comprises a heater, a first adhesive layer and a second adhesive layer, said first adhesive layer being positioned between said ceramic body and said heater for bonding said ceramic body and said heater; the second adhesive layer is located between the substrate and the heater for adhering the substrate and the heater.

3. The electrostatic clamp of claim 1 or 2, wherein said coolant is freon.

4. The electrostatic clamp of claim 1, wherein an inlet of said fluid passageway is in communication with an expansion valve of a cooling device;

the outlet of the liquid channel is communicated with a compressor of the cooling device;

the expansion valve is connected with the compressor through a condenser.

5. The electrostatic clamp of claim 4, wherein said coolant is changed into a low-temperature and low-pressure gas when flowing out of said outlet of said liquid channel;

the compressor is used for processing the low-temperature low-pressure gas and outputting high-temperature high-pressure gas;

the condenser is used for carrying out heat exchange treatment on the high-temperature high-pressure gas to output high-temperature high-pressure liquid,

the expansion valve is used for processing the high-temperature high-pressure liquid to obtain low-temperature low-pressure liquid;

and the low-temperature and low-pressure liquid is introduced into the liquid channel through the inlet of the liquid channel so as to cool the ceramic body.

6. The electrostatic chuck of claim 5, wherein said fluid channel inlet and outlet are open to said substrate.

7. The electrostatic chuck of claim 6 wherein said fluid passageway curves along a tortuous path within said substrate.

8. The electrostatic chuck of claim 6 wherein said fluid channel is a single fluid channel extending in a spiral pattern in the same plane in said substrate.

9. The electrostatic chuck of claim 6, wherein said fluid passageway is a plurality of said fluid passageways in communication with one another;

alternatively, a plurality of the liquid passages are not communicated.

10. A plasma processing apparatus, comprising: a vacuum reaction chamber, and the electrostatic chuck according to any one of claims 1 to 9 located in the vacuum reaction chamber.