TWI809611B - Retaining ring assembly, semiconductor chamber and cleaning method thereof - Google Patents

Abstract

The invention relates to a retaining ring assembly, a semiconductor chamber and a cleaning method thereof. The retaining ring assembly comprises an upper retaining ring, and the lower surface edge is provided with a downward projecting upper retaining ring positioning foot; The upper surface edge of the lower retaining ring is provided with a lower retaining ring positioning groove matched with the upper retaining ring positioning foot, the lower retaining ring positioning groove is provided with a pressure detection element, and the pressure detection element is used to detect the extrusion force between the lower retaining ring positioning groove and the upper retaining ring positioning foot. Monitor the pressure between the positioning foot of the upper retaining ring and the positioning groove of the lower retaining ring to avoid the fragmentation of the positioning foot of the upper retaining ring caused by the separation of the two when the extrusion pressure between the positioning foot and the positioning groove is large.

Description

Retaining ring element, semiconductor chamber and cleaning method thereof

The invention relates to the field of semiconductor equipment, and more specifically, to a retaining ring element, a semiconductor chamber and a cleaning method thereof.

With the gradual development of the integrated circuit manufacturing process, the feature size is getting smaller and smaller. The traditional aluminum interconnection process is limited by the signal delay under the small line width. In order to solve this problem, people use copper interconnection instead of aluminum interconnection technology. The emergence of copper interconnection technology has solved the problem of signal delay very well, and the integration level of the chip and the density of the device have also been greatly improved. However, due to the problem of copper diffusion, and the chemical and electrical properties of tungsten are stable, Therefore, even though the feature size of integrated circuits has been shrinking, the contact hole process connecting the front-end device and the back-end interconnection line still uses tungsten plug (W-plug) technology.

Tungsten plug (W-plug) is a process widely used in the contemporary semiconductor industry. It uses a unique method to fill metal tungsten into holes (Via) or trenches (Trench). The anti-electromigration characteristics finally realize the process requirements of reliable electrical conduction between the front-end device and the back-end metal interconnection. In the tungsten plug process, the most important process index is the metal filling of structures such as holes and trenches. The current mainstream in the industry is to deposit tungsten by the CVD method, and the chemical vapor phase thin film deposition method can basically realize the metal filling of the above-mentioned microstructure (Via and Trench). The critical dimensions of the early semiconductor manufacturing process were relatively large, and the aspect ratio of the hole or trench was also small. Generally speaking, the opening of the structure is relatively wide and open. Filling such structures is therefore not a very serious challenge for the CVD process. The CVD process itself has its own advantages in terms of filling, and it can basically achieve complete filling for larger structures.

The tungsten contact hole process usually uses covered tungsten deposition (W-CVD), that is, non-selective deposition of tungsten on the surface of silicon dioxide and the opening of the contact hole, and then chemical mechanical polishing (CMP) to remove the tungsten on the surface of the wafer. Tungsten, leaving only the tungsten equiplanar to the silicon dioxide surface in the contact hole. Since the edge of the wafer is elliptical, in order to prevent the tungsten on the edge of the wafer from being completely removed during chemical mechanical polishing and affect the subsequent process, it is required that the width of the edge of the wafer be about 2mm when depositing tungsten in the tungsten contact hole process. The tungsten film cannot be deposited within the range, that is, there must be a "blanket". The effect diagram of the wafer with or without "blanking" after chemical mechanical polishing is shown in Figure 1.

In order to achieve the requirement of "blanking", the periphery of the wafer will be purged with inert gas during the process of depositing tungsten, so that the process gas cannot reach the edge of the wafer, thus realizing the technical requirement of "blanking".

In order to meet the above-mentioned technical requirements of "blanking", the existing technology realizes edge gas blowing during the process of depositing tungsten on the wafer through the cooperation of two ceramic rings: the upper stop ring and the lower stop ring, and the lower stop ring and the heating An oblique upward purge air channel is formed between the bases, and a horizontal air channel is formed between the upper retaining ring and the heating base, so that during the process of depositing tungsten, the purge gas passes through the edge purge air channel to purge the edge of the wafer So as to meet the requirements of blank pressing.

The upper retaining ring has positioning feet, and the lower retaining ring has positioning grooves matching with the positioning feet. When the tungsten film is deposited, the heating base rises to a high position. At this time, the positioning feet of the upper retaining ring fall into the positioning grooves of the lower retaining ring. It can ensure the stability of the upper retaining ring during the process.

When the film thickness in the chamber accumulates to a certain thickness, the chamber needs to be cleaned with a remote plasma source (RPS) to remove the accumulated tungsten film. The cleaning process includes high-level cleaning and low-level cleaning. When high-level cleaning is performed, the heating base rises to the high position. At this time, the positioning foot of the upper stop ring falls into the positioning groove of the lower stop ring. The bombardment heating causes the positioning foot of the upper retaining ring to expand due to heat, so that there is a squeezing force between the positioning foot of the upper retaining ring and the positioning groove of the lower retaining ring. Separation from the lower stop ring will cause the positioning foot of the upper stop ring to be pulled off, and the breakage will be in the positioning groove of the lower stop ring, which will seriously affect the subsequent manufacturing process.

The purpose of the present invention is to propose a retaining ring element, a semiconductor chamber and a cleaning method thereof, so as to monitor the extrusion force between the upper retaining ring positioning foot and the lower retaining ring positioning groove of the upper retaining ring, and avoid When the two are separated, the positioning foot of the upper retaining ring is broken.

In the first aspect, the present invention proposes a retaining ring element for a semiconductor chamber, including: The upper retaining ring, the edge of the lower surface of the upper retaining ring is provided with downward protruding upper retaining ring positioning feet; The lower stop ring, the upper surface of the lower stop ring is provided with a lower stop ring positioning groove that matches with the positioning feet of the upper stop ring, A pressure detecting element is arranged in the positioning groove of the lower retaining ring, and the pressure detecting element is used for detecting the extrusion force between the positioning groove of the lower retaining ring and the positioning foot of the upper retaining ring.

Optionally, the pressure detection element includes a pressure-sensitive positioning ceramic sleeve, and the pressure-sensitive positioning ceramic sleeve is embedded in the positioning groove of the lower stop ring and is attached to the inner surface of the positioning groove of the lower stop ring.

Optionally, a piezoelectric ceramic transducer is also included, the piezoelectric ceramic transducer is electrically connected to the pressure-sensitive positioning ceramic sleeve through a lead wire, and is used to convert the electrical signal variation generated by the deformation of the pressure-sensitive positioning ceramic sleeve into stress signal.

Optionally, the outer diameter of the upper stop ring is larger than the outer diameter of the lower stop ring.

Optionally, both the upper stop ring and the upper stop ring are made of ceramics.

Optionally, the top of the inner edge of the upper retaining ring is an inclined surface.

In the second aspect, the present invention proposes a semiconductor chamber, including a chamber upper cover, a side suction upper retaining ring, a side suction lower retaining ring and a base, the chamber upper cover, the side suction upper retaining ring, the side suction The air retaining rings are sequentially arranged from top to bottom and surround a cavity, the base is located in the cavity for heating and carrying the workpiece to be processed, and the base is provided with the retaining ring assembly described in the first aspect; The inner diameter of the side suction upper baffle ring is larger than the inner diameter of the side suction lower baffle ring, and the outer diameter of the upper baffle ring is larger than the inner diameter of the side suction lower baffle ring and smaller than the side suction upper baffle ring. the inside diameter of; The base can drive the retaining ring assembly to move up and down in the cavity, wherein the upper retaining ring can only move in the space above the lower retaining ring when the side is pumped. During the downward movement of the base, when the upper When the lower surface of the edge of the retaining ring is in contact with the top of the lower retaining ring of the side suction, the positioning foot of the upper retaining ring of the upper retaining ring is separated from the positioning groove of the lower retaining ring of the lower retaining ring; The pressure detection element is used to detect whether the pressing force between the positioning foot of the upper retaining ring and the positioning groove of the lower retaining ring is greater than a preset pressure value when the positioning foot of the upper retaining ring is separated from the positioning groove of the lower retaining ring, if If it is less than the preset pressure value, the upper stop ring positioning foot is separated from the lower stop ring positioning groove, and if it is greater than or equal to the preset pressure value, the upper stop ring positioning foot is separated from the lower stop ring positioning groove .

Optionally, the top of the base is provided with a boss for supporting the workpiece to be processed; The lower retaining ring is arranged on the outer side of the boss, the upper surface of the lower retaining ring is higher than the top surface of the boss, and an inclined upward pressure edge blow is formed between the inner side of the lower retaining ring and the outer side of the boss. Scavenging air passage, the inner lower surface of the upper retaining ring and the edge of the upper surface of the boss form a horizontal air passage.

Optionally, the side suction lower stop ring is provided with a side suction hole communicating with the cavity.

In terms of third parties, the present invention also proposes a method for cleaning a semiconductor chamber described in the second aspect, including: Raise the base to a first preset height, make the lower stop ring contact with the upper stop ring, wherein the upper stop ring positioning foot of the upper stop ring is inserted into the lower stop ring positioning groove of the lower stop ring and Contact with the pressure detection element in the positioning groove of the lower stop ring; Introduce plasma and process gas into the semiconductor chamber for high-level cleaning; After the high-level cleaning is completed, the actual pressure value of the extrusion force between the positioning foot of the upper stop ring and the positioning groove of the lower stop ring is collected through the pressure detection element; judging whether the actual pressure value is less than the preset pressure value, and if so, lowering the base to a second preset height to separate the upper retaining ring from the lower retaining ring for low-level cleaning; If the actual pressure value is greater than or equal to the preset pressure value, stop feeding the plasma into the semiconductor chamber, so that the upper stop ring and the lower stop ring cool down until the upper stop ring positioning foot and the lower stop ring After the actual pressure value of the extrusion force between the positioning grooves is less than the preset pressure value, the base is lowered to the second preset height, the upper stop ring is separated from the lower stop ring, and the valve is passed into the semiconductor chamber again. Inject the plasma and the process gas for low level cleaning.

The beneficial effects of the present invention are:

1. By setting the pressure detection element in the positioning groove of the lower retaining ring, the extrusion force between the positioning foot of the upper retaining ring and the positioning groove of the lower retaining ring can be monitored. When the positioning foot of the upper retaining ring of the upper retaining ring is heated and expanded 1. When the space in the heating groove of the lower stop ring positioning groove of the lower stop ring is reduced, and the extrusion force between the positioning foot of the upper stop ring and the positioning groove of the lower stop ring increases, based on the pressure value detected by the pressure detection element, it can be avoided. When the force is large, the positioning foot of the upper retaining ring is broken due to the separation of the two.

2. Use the pressure detection element to detect the pressure between the upper stop ring positioning foot and the lower stop ring positioning groove when switching from high-level cleaning to low-level cleaning, and set a certain pressure judgment value to effectively control the switching between high-level cleaning and low-level cleaning. The pressure environment has achieved the effect of avoiding the cracking of the upper retaining ring.

The device of the present invention has other features and advantages that will be apparent from, or will be apparent from, the drawings and detailed description that follow, incorporated herein. Set forth in detail in the manner, these drawings and the detailed description together serve to explain certain principles of the present invention.

The following disclosure provides many different embodiments, or examples, of different means for implementing the disclosure. Specific examples of components and configurations are described below to simplify the present disclosure. Of course, these are examples only and are not intended to be limiting. For example, in the following description a first member is formed over or on a second member may include embodiments in which the first member and the second member are formed in direct contact, and may also include embodiments in which additional members An embodiment may be formed between the first member and the second member so that the first member and the second member may not be in direct contact. Additionally, the present disclosure may repeat reference numerals and/or letters in various instances. This repetition is for simplicity and clarity and does not in itself indicate a relationship between the various embodiments and/or configurations discussed.

In addition, for ease of description, spatially relative terms such as "below", "below", "under", "above", "upper" and the like may be used herein to describe the relationship between one element or member and another(s) The relationship between elements or components, as illustrated in the figure. Spatially relative terms are intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures. The device may be otherwise oriented (rotated 90 degrees or at other orientations) and thus the spatially relative descriptors used herein should be interpreted similarly.

Notwithstanding that the numerical ranges and parameters setting forth the broad scope of the disclosure are approximations, the numerical values set forth in the specific examples are reported as precisely as possible. Any numerical value, however, inherently contains certain errors necessarily resulting from the standard deviation found in their respective testing measurements. Furthermore, as used herein, the term "about" generally means within 10%, 5%, 1%, or 0.5% of a given value or range. Alternatively, the term "about" means within an acceptable standard error of the mean when considered by one of ordinary skill in the art. Except in operating/working examples, or unless expressly specified otherwise, all numerical ranges such as for amounts of materials disclosed herein, durations of time, temperatures, operating conditions, ratios of amounts, and the like, Amounts, values and percentages should be understood as being modified by the term "about" in all instances. Accordingly, unless indicated to the contrary, the numerical parameters set forth in this disclosure and the accompanying claims are approximations that may vary as desired. At a minimum, each numerical parameter should at least be construed in light of the number of reported significant digits and by applying ordinary rounding techniques. Ranges can be expressed herein as from one endpoint to the other or as between two endpoints. All ranges disclosed herein are inclusive of endpoints unless otherwise specified.

An existing CVD chamber for tungsten deposition process on a wafer is shown in Figure 2, wherein an oblique upward blanking purge gas channel 7 is formed between the lower stop ring 6 and the heating base-8, and the upper stop ring 3 is connected to the heating base-8. A horizontal gas channel is formed between the susceptors 8 , so that during the process of depositing tungsten, the purge gas passes through the blank holder purge gas channel 7 to purge the edge of the wafer 12 to meet the requirement of blank holder. Among them, the process space 2 provides a reaction space for the tungsten deposition process, the upper cover 1 of the chamber can ensure the airtightness of the chamber, and the side suction upper stop ring 9 and the side suction lower stop ring 11 cooperate to provide a pumping system for the reaction , The gas in the reaction process is discharged through the side exhaust hole 10. When the tungsten film is deposited, the heating base 8 rises to a high position, and at this time, the upper stop ring positioning foot 4 falls into the lower stop ring positioning groove 5, which can ensure the stability of the upper stop ring during the process.

The tungsten deposition chamber has a self-cleaning function. When the film thickness in the chamber accumulates to a certain thickness, the chamber needs to be cleaned with a remote plasma source (RPS) to remove the accumulated tungsten film. In the cleaning process, "high-level cleaning" is carried out first, as shown in Figure 3, that is, the heating base 8 rises to a high position, at this time, the positioning foot 4 of the upper retaining ring falls into the positioning groove 5 of the lower retaining ring. Efficiently and quickly clean up the tungsten film on the surface of the chamber; after the high-level cleaning is completed, enter the "low-level cleaning" stage, as shown in Figure 4, that is, the heating base 8 is lowered to the low position, at this time the upper stop ring 3 and the lower stop ring 6 is separated, the upper retaining ring positioning foot 4 comes out from the lower retaining ring positioning groove 5, and the purpose of low position cleaning is to clean up the tungsten film between the upper retaining ring 3 and the lower retaining ring 6 gap.

During the cleaning process of the chamber, due to the bombardment of the remote plasma source (RPS), the temperature of the upper stop ring 3 and the lower stop ring 6 rises sharply. The groove 5 is heated and shrinks, so there is a pressing force between the upper stop ring positioning foot 4 and the lower stop ring positioning groove 5 during the high-level cleaning process, as shown in Figure 5, when the "high-level cleaning" is completed, it enters the "low-level cleaning" stage, as the heating base descends, the upper retaining ring 3 will be in contact with the lower retaining ring 11 of the side suction, because there is a pressing force between the upper retaining ring positioning foot 4 and the lower retaining ring positioning groove 5, so as As the heating base 8 descends further, the upper retaining ring 3 is pulled off, and the upper retaining ring positioning pin 4 is broken in the lower retaining ring positioning groove 5 .

The present invention monitors the extrusion force between the positioning foot of the upper retaining ring and the positioning groove of the lower retaining ring during the cleaning process of the chamber by embedding a pressure detection element in the positioning groove of the lower retaining ring, so as to judge whether the high position cleaning is satisfied The switching condition of low-level cleaning solves the problem of the upper retaining ring being broken during the switching process of high-level cleaning and low-level cleaning in the prior art.

The present invention will be described in more detail below with reference to the accompanying drawings. Although preferred embodiments of the invention are shown in the drawings, it should be understood that the invention may be embodied in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art.

Example 1

Fig. 6 shows a partial cross-sectional structural schematic diagram of a retaining ring element located in a semiconductor chamber according to an embodiment of the present invention.

As shown in Figure 6, a retaining ring element used in a semiconductor chamber includes:

The upper stop ring 103, the lower surface edge of the upper stop ring 103 is provided with a downward protruding upper stop ring positioning foot 104;

The lower stop ring 106, the upper surface of the lower stop ring 106 is provided with the lower stop ring positioning groove 105 which cooperates with the upper stop ring positioning foot 104, and the lower stop ring positioning groove 105 is provided with a pressure detection element, which is used to detect the lower stop ring. The squeezing force between the retaining ring positioning groove 105 and the upper retaining ring positioning foot 104.

Wherein, the outer diameter of the upper retaining ring 103 is larger than the outer diameter of the lower retaining ring 106, the materials of the upper retaining ring 103 and the upper retaining ring 103 are ceramics, and the top of the inner edge of the upper retaining ring 103 is an inclined surface.

The pressure detection element includes a pressure-sensitive positioning ceramic sleeve 112 . The pressure-sensitive positioning ceramic sleeve 112 is embedded in the positioning groove 105 of the lower stop ring, and is bonded to the inner surface of the positioning groove 105 of the lower stop ring. The pressure detection element also includes a piezoelectric ceramic transducer, which can be arranged outside the semiconductor chamber, and the piezoelectric ceramic transducer is electrically connected to the pressure-sensitive positioning ceramic sleeve 112 through a lead wire 113 for connecting the pressure The electrical signal variation generated by the deformation of the sensitive positioning ceramic sleeve 112 is converted into a pressure signal.

Specifically, the pressure-sensitive positioning ceramic sleeve 112 is made of pressure-sensitive ceramic material. The pressure-sensitive positioning ceramic sleeve 112 is embedded in the positioning groove 105 of the lower stop ring, and its size completely matches the positioning foot 104 of the upper stop ring. The positioning foot 104 expands when heated, and the lower stop ring expands when heated, which causes the positioning groove 105 to shrink and become smaller. The pressure-sensitive ceramic positioning sleeve will be deformed by the extrusion force. According to the piezoelectric effect, the change of the extrusion force will make the pressure-sensitive positioning ceramic The voltage signal on the sleeve 112 changes, and the change of the voltage signal is collected through the lead wire 113 of the pressure-sensitive positioning ceramic sleeve 112 and converted into a pressure signal. The signal conversion is completed by a piezoelectric ceramic transducer, and the conversion relationship is: P=d* U, where P is the pressure value, d is the piezoelectric constant, and U is the voltage.

Example 2

Referring to FIG. 7 , a semiconductor chamber includes a chamber upper cover 101, a side suction upper stop ring 109, a side suction lower stop ring 111 and a base 108, a chamber upper cover 101, a side suction upper stop ring 109, a side pump The air stop ring 111 is arranged sequentially from top to bottom and surrounds a cavity. The base 108 is located in the cavity for heating and carrying workpieces such as wafers waiting to be processed. The base 108 is provided with the stop ring assembly of the above embodiment;

The inner diameter of the side suction upper baffle ring 109 is greater than the inner diameter of the side suction lower baffle ring 111, and the outer diameter of the upper baffle ring 103 is greater than the inner diameter of the side suction lower baffle ring 111 and smaller than that of the side suction upper baffle ring 109. the inside diameter of;

The base 108 can drive the retaining ring assembly to move up and down in the cavity, wherein the upper retaining ring 103 can only move in the space above the lower retaining ring 111 of the side suction. During the downward movement of the base 108, when the upper retaining ring 103 When the lower surface of the edge is in contact with the top of the lower stop ring 111 of the side suction, the upper stop ring positioning foot 104 of the upper stop ring 103 is separated from the lower stop ring positioning groove 105 of the lower stop ring 106;

The pressure detection element is used to detect whether the pressure value of the extrusion force between the upper stop ring positioning foot 104 and the lower stop ring positioning groove 105 is greater than the preset pressure value when the upper stop ring positioning foot 104 is separated from the lower stop ring positioning groove 105 , if it is less than the preset pressure value, the upper stop ring positioning foot 104 is separated from the lower stop ring positioning groove 105, and if it is greater than or equal to the preset pressure value, the upper stop ring positioning foot 104 is separated from the lower stop ring positioning groove 105 .

Specifically, the semiconductor chamber of this embodiment is mainly used for the tungsten deposition process. A process space 102 is formed between the top of the base and the chamber cover 101. The process space 102 provides a reaction space for the tungsten deposition process. The chamber cover 101 can To ensure the airtightness of the chamber, the side suction upper baffle ring 109 and the side suction lower baffle ring 111 cooperate with each other, and the side suction lower baffle ring 111 is provided with a side suction hole 110 communicating with the cavity for providing reaction The air extraction channel during the reaction, the side air extraction upper retaining ring 109 and the side air extraction lower retaining ring 111 cooperate with each other, and the residual gas during the reaction is discharged from the chamber through the side air extraction hole 110. When the tungsten film is deposited, the heating base 108 rises to a high position, and at this time, the positioning foot 104 of the upper stop ring falls into the positioning groove 105 of the lower stop ring, which can ensure the stability of the upper stop ring 103 during the process.

In this embodiment, the top of the heating base 108 is provided with a boss for supporting the workpiece to be processed; the lower stop ring 106 is arranged on the outside of the boss on the heating base 108, and the upper surface of the lower stop ring 106 is higher than the top of the boss. surface, and an inclined upward purge air channel 107 is formed between the inner side of the lower retaining ring 106 and the outer side of the boss, and a horizontal air channel is formed between the inner lower surface of the upper retaining ring 103 and the edge of the upper surface of the boss.

Specifically, an oblique upward blanking purge gas channel 107 is formed between the lower retaining ring 106 and the heating pedestal 108, and a horizontal air channel is formed between the upper retaining ring 103 and the heating pedestal 108. The purge gas passes through the edge blanking purge gas channel 107 to purge the edge of the wafer so as to meet the requirement of blanking.

When the film thickness in the chamber accumulates to a certain thickness, the chamber needs to be cleaned with a remote plasma source to remove the accumulated tungsten film. During the cleaning process, the high-level cleaning is carried out first, that is, the heating base 108 rises to a high position, and at this time the upper stop ring positioning foot 104 falls into the lower stop ring positioning groove 105. The purpose of high-level cleaning is to clean up the chamber efficiently and quickly. The tungsten film on the surface; after the high-level cleaning is completed, enter the low-level cleaning stage, that is, the heating base 108 is lowered to the low position. At this time, the upper stop ring 103 is separated from the lower stop ring 106, and the upper stop ring positioning foot 104 is separated from the lower stop ring positioning groove 105. The purpose of internal prolapse and low position cleaning is to clean up the tungsten film between the gap between the upper stop ring 103 and the lower stop ring 106 . During the chamber cleaning process, due to the bombardment of the remote plasma source, the temperature of the upper stop ring 103 and the lower stop ring 106 increased sharply, and the temperature rise caused the thermal expansion of the upper stop ring positioning foot 104, and the thermal expansion of the lower stop ring resulted in The positioning groove 105 shrinks and becomes smaller, so there is a pressing force between the upper retaining ring positioning foot 104 and the lower retaining ring positioning groove 105 during the high-level cleaning process. 108 down, the upper stop ring 103 will be in contact with the side suction lower stop ring 111, because there is a pressing force between the upper stop ring positioning foot 104 and the lower stop ring positioning groove 105, the position of the upper stop ring is detected by the detection of the pressure detection element The pressure value obtained by the extrusion force between the foot 104 and the positioning groove 105 of the lower retaining ring can regulate the movement state of the base, thereby avoiding the breaking of the upper retaining ring positioning foot 104 caused by the separation of the two when the extrusion force is large. crack problem.

Example 3

As shown in FIG. 8, the embodiment of the present invention also proposes a method for cleaning the semiconductor chamber of the above embodiment, including:

S101: Raise the base to a first preset height so that the lower stop ring 106 contacts the upper stop ring 103, wherein the upper stop ring positioning foot 104 of the upper stop ring 103 is inserted into the lower stop ring positioning groove 105 of the lower stop ring 106 And contact with the pressure detection element in the positioning groove 105 of the lower stop ring;

In a specific application scenario, referring to Fig. 7, before cleaning, the remote plasma source is first turned on, and the plasma is turned on and supplied with Ar to get ready for the next step of cleaning. When performing high-level cleaning, the heating base 108 needs to be raised to a high position. At this time, the upper stop ring 103 is in full contact with the lower stop ring 106 .

S102: Introducing plasma and process gas into the semiconductor chamber for high-level cleaning;

In the above specific application scenarios, after the heating base 108 is raised to a high position, nitrogen trifluoride (NF3) and other process gases are introduced, and Ar in the plasma state bombards nitrogen trifluoride gas molecules to realize high-level cleaning and high-level cleaning. The purpose is to efficiently and quickly clean up the tungsten film in the chamber.

S103: After the high-level cleaning is completed, the pressure value between the upper stop ring positioning foot 104 and the lower stop ring positioning groove 105 is collected by the pressure detection element;

In the above-mentioned specific application scenarios, after the high-level cleaning is completed, it is necessary to compare the actual pressure value P of the extrusion force between the upper stop ring positioning foot 104 and the lower stop ring positioning groove 105 with the preset pressure value X to determine whether there is The conditions for switching from high flush to low flush.

S104: judging whether the actual pressure value is less than the preset pressure value, if so, the base is lowered to the second preset height, so that the upper stop ring 103 is separated from the lower stop ring 106 for low-level cleaning;

In the above specific application scenarios, if the actual pressure value P is less than the preset pressure value X, then enter the low-level cleaning stage, the low-level cleaning is to lower the heating base 108 to a low position, and turn on the remote plasma source. At this time, the upper stop ring 103 Separated from the lower retaining ring 106, the upper retaining ring positioning pin 104 escapes from the lower retaining ring positioning groove 105. The purpose of the low position cleaning is to clean up the tungsten film between the upper retaining ring 103 and the lower retaining ring 106 gap.

S105: If the actual pressure value P is greater than or equal to the preset pressure value X, stop feeding the plasma into the semiconductor chamber, so that the upper stop ring 103 and the lower stop ring 106 cool down until the upper stop ring positioning foot 104 and the lower stop ring After the actual pressure value between the positioning grooves 105 is less than the preset pressure value, the susceptor is lowered to the second preset height, the upper stop ring is separated from the lower stop ring, and plasma and process gas are introduced into the semiconductor chamber again , for low-level cleanup.

In the above-mentioned specific application scenarios, after the high-level cleaning is completed, it is necessary to compare the actual pressure value P of the extrusion force between the upper stop ring positioning foot 104 and the lower stop ring positioning groove 105 with the preset pressure value X to determine whether there is The conditions for switching from high-level cleaning to low-level cleaning, if P<X, then enter the low-level cleaning stage; if P≥X, then the switching conditions are not satisfied, and the plasma is turned off to cool the upper stop ring 103 and the lower stop ring 106 to relieve both The squeeze force between them, cool down and wait for a certain period of time to judge the pressure again, and so on, until P<X enters the low-level cleaning.

To sum up, the present invention monitors the extrusion force between the upper retaining ring positioning foot 104 and the lower retaining ring positioning groove 105 during the chamber cleaning process through the pressure-sensitive positioning ceramic sleeve 112. The pressure value of the extrusion force between positioning is monitored to determine whether the conditions for switching from high-level cleaning to low-level cleaning are met. If the conditions are not met, it will enter the cooling waiting stage. After the cooling waiting is over, the pressure judgment will be performed again. Clean up, if the conditions are not met, enter the cooling wait again, and proceed in a loop until the conditions are met. When switching from high position cleaning to low position cleaning like this, the accident that the upper stop ring positioning pin 104 breaks in the lower stop ring positioning groove 105 can be effectively avoided by judging the size of the extrusion force.

The foregoing content summarizes the features of several embodiments, so that those skilled in the art can better understand aspects of the present disclosure. Those skilled in the art should appreciate that they can readily use the present disclosure as a basis for designing or modifying other processes and structures for carrying out the same purposes and/or achieving the same advantages of the embodiments described herein. Those skilled in the art should also understand that such equivalent constructions do not depart from the spirit and scope of the present disclosure, and that they can make various changes, substitutions and alterations herein without departing from the spirit and scope of the present disclosure.

1: chamber cover 2: Process space 3: upper retaining ring 4: Positioning foot of the upper retaining ring 5: Locating groove of the lower retaining ring 6: Lower stop ring 7: Pressing edge to purge the airway 8: Heating base 9: Side suction upper retaining ring 10: side air hole 11: Side suction lower retaining ring 12:Wafer 101: chamber cover 102: Process space 103: Upper retaining ring 104: Upper retaining ring positioning foot 105: Locating groove of lower retaining ring 106: Lower stop ring 107: Blanket purge airway 108: Base 109: Side suction upper retaining ring 110: side air hole 111: Side suction lower retaining ring 112: Pressure-sensitive positioning ceramic sleeve 113: Lead

Aspects of the present disclosure are best understood from the following detailed description when read with the accompanying drawings. It should be noted that, in accordance with the standard practice in the industry, various components are not drawn to scale. In fact, the dimensions of the various components may be arbitrarily increased or decreased for clarity of discussion. FIG. 1 shows a schematic diagram of the effect of forming with and without a blank holder after processing a wafer through a conventional tungsten deposition process and chemical mechanical polishing. FIG. 2 shows a schematic diagram of a conventional CVD chamber performing a tungsten deposition process on a wafer. Fig. 3 shows a schematic diagram of high-level cleaning of a CVD chamber in the prior art. Fig. 4 shows a schematic diagram of low-level cleaning of a CVD chamber in the prior art. Fig. 5 shows a schematic diagram of the breakage of the upper stop ring positioning foot of the upper stop ring when the CVD chamber is cleaned at a low level in the prior art. Fig. 6 shows a partial cross-sectional structural schematic diagram of a retaining ring element located in a semiconductor chamber according to an embodiment of the present invention. FIG. 7 shows a schematic diagram of a cross-sectional structure inside a semiconductor chamber according to an embodiment of the present invention. FIG. 8 shows a flow chart of the steps of a method for cleaning a semiconductor chamber according to the present invention.

101: chamber cover

102: Process space

103: Upper retaining ring

104: Upper retaining ring positioning foot

105: Locating groove of lower retaining ring

106: Lower stop ring

107: Blanket purge airway

108: Base

109: Side suction upper retaining ring

110: side air hole

111: Side suction lower retaining ring

112: Pressure-sensitive positioning ceramic sleeve

113: Lead

Claims (9)

A semiconductor chamber, comprising: a chamber upper cover, one side suction upper stop ring, one side suction lower stop ring and a base, the chamber top cover, the side suction upper stop ring, the side suction lower The baffle rings are arranged sequentially from top to bottom and surround a cavity. The base is located in the cavity for heating and carrying a workpiece to be processed. A baffle ring assembly is arranged on the base; the baffle ring assembly includes: an upper The retaining ring and the lower retaining ring, the lower surface edge of the upper retaining ring is provided with an upper retaining ring positioning foot protruding downward; A pressure detection element is arranged in the positioning groove of the lower retaining ring; the inner diameter of the upper retaining ring of the side pumping is larger than the inner diameter of the lower retaining ring of the side pumping, and the outer diameter of the upper retaining ring is larger than the lower retaining ring of the side pumping The inner diameter of the baffle ring is smaller than the inner diameter of the upper baffle ring of the side suction; the base can drive the baffle ring assembly to move up and down in the cavity, wherein the upper baffle ring can only be used for the side suction and the lower baffle The space above the ring moves, and during the downward movement of the base, when the lower surface of the edge of the upper retaining ring contacts the top of the side suction lower retaining ring, the upper retaining ring positioning foot of the upper retaining ring is in contact with the lower retaining ring. The lower stop ring positioning groove of the stop ring is separated; the pressure detection element is used to detect the pressure between the upper stop ring positioning foot and the lower stop ring positioning groove when the upper stop ring positioning foot is separated from the lower stop ring positioning groove. Whether the pressure value of the extrusion force is greater than a preset pressure value, if it is less than the preset pressure value, the positioning foot of the upper stop ring is separated from the positioning groove of the lower stop ring, if it is greater than or equal to the preset pressure value, the The positioning foot of the upper stop ring stops separating from the positioning groove of the lower stop ring. The semiconductor chamber according to claim 1, wherein the pressure detection element includes a pressure-sensitive positioning ceramic sleeve, and the pressure-sensitive positioning ceramic sleeve is embedded in the positioning groove of the lower stop ring and positioned with the lower stop ring The inner surface of the groove is fitted. The semiconductor chamber as claimed in item 2, which also includes a piezoelectric ceramic transducer, the piezoelectric ceramic transducer is electrically connected to the pressure-sensitive positioning ceramic sleeve through a lead wire, and is used for the pressure-sensitive positioning ceramic sleeve The electrical signal variation generated by the deformation is converted into a pressure signal. The semiconductor chamber as claimed in claim 1, wherein the outer diameter of the upper stop ring is larger than the outer diameter of the lower stop ring. The semiconductor chamber according to claim 1, wherein the upper stop ring and the upper stop ring are made of ceramics. The semiconductor chamber as claimed in claim 1, wherein the top of the inner edge of the upper stop ring is an inclined surface. The semiconductor chamber as claimed in claim 1, wherein the top of the base is provided with a boss for supporting the workpiece to be processed; the lower stop ring is arranged on the outside of the boss, and the upper surface of the lower stop ring is higher than The top surface of the boss, and an inclined upward purge air channel is formed between the inner side of the lower retaining ring and the outer side of the boss, and the horizontal air channel is formed between the inner lower surface of the upper retaining ring and the edge of the upper surface of the boss . The semiconductor chamber according to claim 1, wherein the side suction lower stop ring is provided with a side suction hole communicating with the cavity. A method for cleaning a semiconductor chamber according to any one of Claims 1-8, including: raising the base to a first preset height, making the lower stop ring contact the upper stop ring, wherein the The upper stop ring positioning foot of the upper stop ring is inserted into the lower stop ring positioning groove of the lower stop ring and contacts the pressure detection element in the lower stop ring positioning groove; a plasma and a process gas for high-level cleaning; after the high-level cleaning is completed, an actual pressure value of the extrusion force between the positioning foot of the upper stop ring and the positioning groove of the lower stop ring is collected through the pressure detection element; it is judged whether the actual pressure value is less than A preset pressure value, if so, lower the base to a second preset height to separate the upper stop ring from the lower stop ring for low-level cleaning; if the actual pressure value is greater than or equal to the preset pressure value , then stop feeding the plasma into the semiconductor chamber, so that the upper and lower retaining rings cool down until the actual pressure of the pressing force between the upper retaining ring positioning foot and the lower retaining ring positioning groove After the pressure value is less than the preset pressure value, the base is lowered to the second preset height, the upper stop ring is separated from the lower stop ring, and the plasma and the process gas are introduced into the semiconductor chamber again , for low-level cleanup.