TW201338012A - Adjustable apparatus for use in plasma processing device - Google Patents

Abstract

An adjustable plasma confinement apparatus for use in plasma processing device is disclosed, wherein the plasma confinement apparatus is configured between the processing zone and the exhaust zone. The plasma confinement apparatus comprises electric grounding elements; conductive elements located above the electric grounding elements and electrically insulated to each other, and the conductive elements are configured with several exhaust passages; and, spacers configured between the electric grounding elements and the conductive elements, wherein the spacer is made of insulation materials. The present invention may improve the asymmetry of the plasma processing zones and further improve the processing non-uniformity for the substrates.

Description

Adjustable restraint for plasma processing apparatus

The present invention relates to the field of semiconductor fabrication, and more particularly to an adjustable restraint device for a plasma processing apparatus.

The plasma processing apparatus performs processing of a substrate of a semiconductor substrate and a plasma flat plate using the working principle of the vacuum reaction chamber. The working principle of the vacuum reaction chamber is to pass a reaction gas containing a suitable etchant or a deposition source gas into the vacuum reaction chamber, and then input RF energy to the vacuum reaction chamber to start the reaction gas to ignite and sustain the plasma. The semiconductor substrate and the plasma plate are processed by separately etching a material layer on the surface of the substrate or depositing a material layer on the surface of the substrate. For example, capacitive plasma reactors have been widely used to process semiconductor substrates and display panels. In a capacitive plasma reactor, when RF power is applied to one or both of the electrodes, A capacitive discharge is formed between a pair of parallel electrodes.

The plasma is diffusive, although most of the plasma will stay in the processing area between a pair of electrodes, but part of the plasma may fill the entire working chamber. For example, the plasma may fill the area outside the processing area below the vacuum reaction chamber. If the plasma reaches these areas, these areas may corrode, deposit or erode, which may cause particle contamination inside the reaction chamber, which may reduce the reusability of the plasma processing apparatus and may shorten the reaction chamber or reaction chamber. The working life of the component. If the plasma is not confined within a certain working area, the charged particles will strike the unprotected areas, which in turn will cause impurities and contamination on the surface of the semiconductor substrate.

Thus, the industry generally also provides a confinement ring in the plasma processing apparatus for controlling the discharge of spent reactive gases and electrically neutralizing the charged particles in the reactive gas as they pass through the plasma confinement device. Thus, the discharge is substantially confined within the processing area to prevent cavity contamination problems that may occur during use of the plasma processing apparatus.

However, those skilled in the art should understand that the plasma process area in the plasma processing apparatus may cause unevenness, and the unevenness of the process area will further lead to process non-uniformity of the substrate. It is well known that the substrate process is not Uniformity is a core technical problem that needs to be solved in the field, and the present invention is based on this.

In view of the above problems in the background art, the present invention proposes an adjustable plasma confinement device applied to a plasma processing apparatus.

A first aspect of the present invention provides an adjustable plasma confinement apparatus for use in a plasma processing apparatus, wherein the plasma processing apparatus includes a plasma processing zone and an exhaust zone, and the plasma confinement device is located in the plasma processing apparatus Between the plasma process zone and the exhaust zone, a plurality of gas passages are used to neutralize gas from the process zone through the plasma confinement device into the exhaust zone, the plasma confinement device being disposed in the process zone and Between the venting zones, wherein: the plasma confinement device comprises: an electrical grounding element; a conductive element, the electrically conductive element being located above the electrical grounding element and electrically insulated from each other, the electrically conductive element being provided with a plurality of exhaust gases a channel; a spacer element disposed between the electrical ground element and the conductive element, wherein the spacer element is made of an insulating material.

Further, a first electrical insulating layer is disposed on the lower surface of the conductive element, and a second electrical insulating layer is disposed on the upper surface of the electrical grounding component, wherein The first electrically insulating layer is over the second electrically insulating layer.

Wherein the spacer element is disposed at a mounting point between the electrical ground element and the conductive element, the mounting point corresponding to a plasma concentration above the confinement ring being less than 10 above the confinement ring %Area.

Optionally, the mounting point is located on a side remote from the grounding element.

Optionally, the mounting point is located on a side where the upper electrode and the lower electrode of the plasma processing apparatus are at a larger distance.

Optionally, the mounting point is located on a side of the cavity of the plasma processing apparatus.

Optionally, the mounting point is located on a side of the vacuum pump remote from the plasma processing apparatus.

Further, the spacing element has an area that at least partially covers the first electrically insulating layer and the second electrically insulating layer.

Further, the thickness of the spacer element ranges from less than 90 microns.

A second aspect of the invention provides a plasma processing apparatus, wherein the plasma processing apparatus comprises the adjustable plasma confinement apparatus of the first aspect of the invention.

The adjustable restraint device provided by the present invention and the plasma device including the adjustable restraint device can improve the problem of process area asymmetry and further improve the process uniformity of the substrate.

1‧‧‧plasma processing unit

10‧‧‧Processing cavity

11‧‧‧Upper electrode

11'‧‧‧Upper electrode

12‧‧‧ gas source

13‧‧‧ lower electrode

14‧‧‧RF power supply

15‧‧‧vacuum pump

16‧‧‧Conducting components

16a‧‧‧Electrical insulation

17‧‧‧ Grounding

18‧‧‧Electrical grounding components

18a‧‧‧Electrical insulation

19‧‧‧ Spacer components

A‧‧‧ area

B‧‧‧Process Area

D1‧‧‧ distance

D2‧‧‧ distance

P‧‧‧Exhaust zone

W‧‧‧ substrates

Wa‧‧‧Area

Wb‧‧‧ area

Wc‧‧‧ edge section

Wd‧‧‧ edge section

1 is a schematic structural view of a conventional plasma processing apparatus; FIG. 2 is a schematic structural view of a plasma processing apparatus according to an embodiment of the present invention; and FIG. 3 is a plasma processing apparatus according to an embodiment of the present invention. An enlarged view of the upside detail of the adjustable restraint device; 4 is a detailed enlarged view of an adjustable restraint device of a plasma processing apparatus according to an embodiment of the present invention; and FIG. 5 is a schematic structural view of a plasma processing apparatus according to an embodiment of the present invention.

Specific embodiments of the present invention will be described below with reference to the accompanying drawings.

The inventive mechanism of the present invention is to provide at least one spacer element between the corresponding electrical grounding element and the conductive element by means of a portion having a lower plasma concentration in the processing region, thereby limiting the sheath generated therein and improving The asymmetry of the plasma treated regions ensures uniformity of the substrate process and other regions of the substrate.

1 shows a process area in a plasma processing apparatus prior to use of the present invention, as shown in FIG. 1, as it is illustratively grounded directly or not directly on the right side of the illustrated chamber, at the ground The process area A near the vicinity (the right side of the plasma processing apparatus shown) is "trailed up" higher, and the plasma concentration is lower than the other side of the chamber (the left side of the plasma processing apparatus shown) without the ground end. . Thereby, the process rate of the edge portion on the ground side of the substrate W to be processed in the drawing is lowered, and the process rate on the other side is relatively high, and the substrate W obtained in the process necessarily produces a defect of uniformity. .

Please refer to FIG. 2. FIG. 2 is a schematic view showing the structure of a plasma processing apparatus according to an embodiment of the present invention. The plasma processing apparatus 1 as shown has a processing chamber 10, the processing chamber 10 is substantially cylindrical, and the processing chamber side walls are substantially vertical, and the processing chamber 10 has upper electrodes 11 disposed in parallel with each other and Lower electrode 13. Typically, the area between the upper electrode 11 and the lower electrode 13 is the processing area B, which will form high frequency energy to ignite and sustain the plasma. A substrate W to be processed is placed above the lower electrode 13, which may be a semiconductor substrate to be etched or processed or a glass plate to be processed into a flat panel display. The reaction gas is introduced into the processing chamber 10 from the gas source 12, and the one or more radio frequency power sources 14 may be separately applied to the lower electrode 13 or simultaneously applied to the upper electrode 11 and The lower electrode 13 is used to transport radio frequency power onto the lower electrode 13 or the upper electrode 11 and the lower electrode 13, thereby generating a large electric field inside the processing chamber 10. Most electric field lines are contained in the processing area A between the upper electrode 11 and the lower electrode 13, which accelerates a small amount of electrons existing inside the processing chamber 11 to collide with gas molecules of the input reaction gas. These collisions result in ionization of the reactive gas and excitation of the plasma, thereby generating a plasma within the processing chamber 10. The neutral gas molecules of the reactive gas lose electrons when subjected to these strong electric fields, leaving positively charged ions. The positively charged ions are accelerated toward the lower electrode 13 to combine with the neutral species in the substrate being processed to excite the substrate processing, i.e., etching, deposition, and the like. An exhaust region is provided at a suitable position of the plasma processing apparatus 1, and the exhaust region is connected to an external exhaust device (for example, the vacuum pump 15) for using the used reaction gas during the process and The by-product gas extraction processing area B.

In one application scenario, since the restraining device is connected to the grounding end 17 in the vicinity of the right side cavity of the plasma processing apparatus as shown in FIG. 1, the plasma processing area A is "tumbled" above the right restraining device. Spatially, the plasma process area A exhibits an asymmetrical cloud shape. Specifically, in the vicinity of the restraining device connected to the ground end, the process area is "lifted up", and in the vicinity of the restraining device away from the ground end, the process area thereof Extends to the bottom of the substrate. Therefore, the plasma concentration of the substrate region Wa at this region is low. In contrast, the plasma concentration of the other side corresponding region Wb in the level direction of the substrate W is higher.

3 is a bottom plan enlarged view of an adjustable restraint device of a plasma processing apparatus in accordance with an embodiment of the present invention. Referring to Figure 3 in conjunction with Figure 2, a particular embodiment in accordance with the present invention. A first aspect of the present invention provides an adjustable plasma confinement apparatus for use in a plasma processing apparatus, wherein the plasma processing apparatus 1 includes a plasma processing zone B and an exhaust zone P, the plasma confinement device being located Between the plasma processing zone B and the exhaust zone P of the plasma processing apparatus 1, a plurality of gas passages are provided to neutralize gas flowing from the process zone through the plasma confinement device 1 into the exhaust zone P, the plasma constraint Device 1 is set to Between the process zone B and the exhaust zone P, wherein the plasma confinement device comprises: an electrical ground element 18 that can inhibit radio frequency energy emission from reaching an exhaust region of the plasma processing apparatus 1 P.

a conductive element 16 above the electrical ground element 18 and electrically insulated from each other, the conductive element 16 being provided with a plurality of exhaust passages to facilitate spent reaction in the processing region B Gas and by-product gases pass through this passage. Wherein the plasma includes charged particles and neutral particles, the channels being sized to neutralize the charged particles as they pass through the channels while allowing neutral particles to pass. Wherein, the conductive element 16 illustratively includes an integrally formed conductive support ring and a plurality of electrically conductive concentric rings.

In order to achieve electrical insulation between the conductive element 16 and the electrical ground element 18, at least one layer of an insulating layer 16a/18a may be disposed between the contact faces of the conductive element 16 and the electrical ground element 18. . The electrically insulating layer 16a/18a is at least partially or fully covered with at least a portion of the electrical ground element 18 or the electrically conductive element 16 to electrically insulate the electrically conductive element 16 from the electrical ground element 18. The electrical insulating layer may be a single insulating layer or a plurality of insulating layers formed by different processes or the same process to achieve a better insulating effect. Wherein, the electrically insulating layer 18a is disposed on the upper surface of the electrical grounding member 18, and the second electrically insulating layer 16a is disposed on the lower surface of the electrically conductive member 16.

Wherein, the plasma confinement device provided by the present invention is electrically floated from the ground. Specifically, the conductive element 16 and the electrical ground element 18 are both formed of a conductive material with an electrically insulating layer 16a/18a disposed therebetween. Therefore, an equivalent capacitance is formed between the conductive element 16, the electrical ground element 18 and the electrically insulating layer 16a/18a, wherein the upper and lower electrodes of the equivalent capacitance are respectively acted by the conductive element 16 and the electrical ground element 18, wherein The dielectric is served by an electrically insulating layer 16a/18a. The electrical grounding element 18 is further connected to the grounding end 17, and the grounding terminal 17 has a potential of zero. Conductive element 16 is located between the plasma and the ground potential, and is electrically floating.

In the present embodiment, the plasma confinement device further includes a spacer element 19 disposed between the electrical ground element 18 and the conductive element 16, wherein the spacer element 19 is made of an insulating material. Then, according to the basic formula of capacitance: C = εS / 4πkd, where ε is the dielectric constant and d is the distance.

Referring to Figure 3, since the spacer element 19 is embedded between the electrical ground element 18 and the conductive element 16, the distance between the "upper electrode" conductive element 16 and the "lower electrode" electrical ground element 18 is increased. According to the capacitance formula, the distance d is inversely proportional to the capacitance value C, and the equivalent capacitance value C becomes smaller. According to the capacitance impedance formula: Xc=1/ωc

It can be seen that when the equivalent capacitance value becomes small, the capacitive reactance becomes large, and the shell layer becomes thicker. The sheath provides an upward force on the charged ions. The presence of the sheath prevents the plasma from moving downwards, ie the plasma is lifted up. Therefore, the plasma concentration is lowered and the process rate is further lowered.

Therefore, referring to FIG. 4, when the plasma concentration of the process region is asymmetrical, a spacer member 19 is disposed between the electrical ground element 18 and the conductive member 16 in the restraining device near the region where the plasma concentration is higher/the process rate is higher, It can improve the process area unevenness and further improve the process uniformity of the substrate. It should be noted that the number of the spacer elements 19 can be adjusted according to a specific process, and should not be limited to a certain fixed value.

Further, the spacer element is disposed at a mounting point between the electrical ground element and the conductive element, and the mounting point corresponds to a plasma concentration above the restraint ring being less than other portions above the restraint ring being greater than 10% of the area.

Those skilled in the art will appreciate that the plasma processing region within the plasma processing apparatus produces a non-uniform phenomenon, the cause of which is varied.

For example, referring to Figures 1 and 2, the restraining device is sometimes provided with a connection to The ground terminal grounding element 17 can suppress the emission of radio frequency energy to the exhaust region of the plasma processing apparatus. However, since the electric field at one end connected to the ground end in the restraining device is stronger than other regions of the restraining device, the plasma concentration is also somewhat reduced, thereby making the process region A close to the restraining device region (see FIG. 1). Asymmetry. Spatially, the plasma process area A exhibits an asymmetrical cloud shape. Specifically, in the vicinity of the restraining device connected to the ground end, the process area A is "lifted", and in the vicinity of the restraining device far from the ground end, the process is performed. The area extends all the way to the bottom of the substrate. Thereby, the substrate processing rate in the vicinity of the restraining device far from the ground end is made higher, and the substrate W in the vicinity of the restraining device connected to the grounding end has a lower process rate, resulting in uniformity defects in the substrate W after the process. Gas asymmetry, such as uneven airflow distribution or hard asymmetry such as a single-sided slit valve, can cause asymmetric plasma distribution.

Therefore, in the above application scenario, as shown in FIG. 2, the spacer element 19 is disposed between the electrical grounding element and the conductive element of the restraining device on the side of the mounting point located away from the grounding element. With the use of the adjustable confinement ring provided by the present invention, the asymmetry of the plasma process region B is improved.

Moreover, it will be understood by those of ordinary skill in the art that the cavity of the plasma processing apparatus is not necessarily uniform and necessarily has some asymmetry. For example, assuming that the side wall side of the chamber is slightly concave, the process area of the side area can accommodate more plasma and has a higher concentration. Similarly, the edge of the substrate near the side also has a higher etching rate.

Therefore, in order to overcome the above drawbacks, the mounting point should be located on the side (not shown) where the cavity of the plasma processing apparatus is recessed.

As another example, the upper or lower electrode of the plasma processing apparatus is not necessarily in a horizontal plane in practical applications, which is not necessarily noticeable prior to the process. Referring to FIG. 5, the upper electrode 11' of the plasma processing apparatus is illustrated as being slightly inclined toward the right side of the illustrated plasma processing apparatus, and the distance D1 of the upper electrode 11' of the side portion and its corresponding lower electrode 13 is shortened while d1 Inevitably smaller than others The distance between the portion of the upper electrode 11' and its corresponding lower electrode 13. For example, the distance d2 of the upper electrode 11' on the left side of the figure and its corresponding lower electrode 13 is necessarily greater than d1. Therefore, as the distance d1 becomes shorter, the corresponding electric field intensity becomes larger, and plasma acceleration flows out of the process region through the restraining device 16, resulting in a decrease in plasma concentration of the process region. Spatially, the plasma process area A (see FIG. 1) exhibits an asymmetrical cloud shape. Specifically, in the vicinity of the restraining device with the shortest distance between the upper and lower electrodes, the process area A is "lifted up", and the distance between the upper and lower electrodes Near the longer restraint device of d2, the process area extends all the way to the bottom of the substrate. Therefore, the process rate of the corresponding substrate W, particularly the substrate edge portion Wc, is lowered. Similarly, the processing rate of the other side edge portion Wd of the corresponding substrate is higher.

In order to compensate for the non-uniformity of the substrate process, as shown in FIG. 5, the spacer element 19 is disposed on a side where the upper electrode 11' and the lower electrode 13 of the plasma processing apparatus 1 are at a larger distance, that is, The side of the d2 side, or the side of the substrate edge Wd.

As another example, the placement of the plasma pump vacuum pump can also result in an asymmetry in the plasma support region. Specifically, in the prior art, the vacuum pump is generally not disposed directly under the chamber of the plasma processing apparatus, but is disposed on one side of the plasma processing apparatus as shown in FIG. 2, and the vacuum pump 15 is exemplarily illustrated. Set to the right of the illustration. Since the vacuum pump 15 is used to draw the used reaction gas and by-product gas out of the processing region B during the process, the plasma concentration on the side where the vacuum pump 15 is disposed is inevitably lowered. Spatially, the plasma process area A (see FIG. 2) exhibits an asymmetrical cloud shape. Specifically, in the vicinity of the restraining device on the side where the vacuum pump 15 is disposed, the process area A is "lifted" and away from Near the restraining device provided by the vacuum pump 15, the process area extends all the way to the bottom of the substrate. Therefore, as shown in Fig. 2, the process rate of the portion W of the substrate having a lower plasma concentration, particularly the edge Wa of the substrate, is inevitably lowered, and the process rate of the portion W of the substrate on the other side, particularly the edge Wb of the substrate. Higher.

Therefore, the spacer element 19 should be disposed on the side away from the vacuum pump 15 of the plasma processing apparatus 1 to compensate for the non-uniformity of the process.

Further, the spacing element has an area that at least partially covers the first electrically insulating layer and the second electrically insulating layer. The spacer element may also be a notched ring, as long as an asymmetrically distributed insulating material is placed between the electrical ground element 18 and the plasma-constrained conductive element 16 to compensate for the plasma distribution due to the various reasons described above. symmetry. Therefore, the spacer element can be any shape that is asymmetrical in the entire plasma confinement ring. The spacers can also select materials with different impedance characteristics to adjust for different plasma distribution non-uniformities.

Further, the thickness of the spacer element ranges from less than 90 microns, even on the order of millimeters.

The present invention also provides a plasma processing apparatus, wherein the plasma processing apparatus comprises the adjustable plasma confinement apparatus provided by the first aspect of the invention.

It should be noted that regardless of the value of the area or width of the baffle, the range of values should be adjusted based on the width and position of the restraining device so that the baffle is suitable for the restraining device.

Although the present invention has been described in detail by the preferred embodiments thereof, it should be understood that the foregoing description should not be construed as limiting. Various modifications and alterations of the present invention will become apparent to those skilled in the <RTIgt; Therefore, the scope of the invention should be limited by the scope of the appended claims.

10‧‧‧Processing cavity

13‧‧‧ lower electrode

16‧‧‧Conducting components

16a‧‧‧Electrical insulation

18‧‧‧Electrical grounding components

18a‧‧‧Electrical insulation

19‧‧‧ Spacer components

Claims (11)

An adjustable plasma confinement device for use in a plasma processing apparatus, wherein the plasma processing apparatus includes a plasma processing zone and an exhaust zone, the plasma confinement device being located in a plasma process zone and an exhaust zone of the plasma processing apparatus Having a plurality of gas passages to neutralize gas from the process zone as it flows through the plasma confinement device into the exhaust zone, wherein the plasma confinement device comprises: an electrical ground element; a conductive element, a conductive element is located above the electrical ground element and electrically insulated from each other, the conductive element being provided with a plurality of gas passages; a spacer element disposed between the electrical ground element and the conductive element, wherein The spacer element is made of an insulating material. The adjustable plasma confinement device of claim 1, wherein a first electrical insulating layer is disposed on a lower surface of the conductive member, and a second electrical insulating layer is disposed on an upper surface of the electrical ground member. Wherein the first electrical insulating layer is located above the second electrical insulating layer. The adjustable plasma confinement device of claim 2, wherein the spacer element is disposed at a mounting point between the electrical ground element and the conductive element, the mounting point corresponding to a plasma above the confinement ring The concentration is less than the area above the confinement ring that reaches more than 10%. The adjustable plasma confinement device of claim 3, wherein the mounting point is located on a side remote from the electrical ground element. The adjustable plasma confinement device of claim 3, wherein the mounting point is located on a side of the plasma processing device where the upper electrode and the lower electrode are at a greater distance. The adjustable plasma confinement device of claim 3, wherein the mounting point Located on one side of the cavity of the plasma processing apparatus. The tunable plasma confinement device of claim 3, wherein the mounting point is located on a side of the vacuum pump remote from the plasma processing device. The adjustable plasma confinement device of claim 3, wherein the spacing element has an area that at least partially covers the first electrically insulating layer and the second electrically insulating layer. The tunable plasma confinement device of claim 8, wherein the thickness of the spacer element ranges from less than 90 microns. A plasma processing apparatus, wherein the plasma processing apparatus comprises the adjustable plasma confinement apparatus of any one of claims 1 to 9. An adjustable plasma confinement device for use in a plasma processing apparatus, wherein the plasma processing apparatus includes a plasma processing zone and an exhaust zone, the plasma confinement device being located in a plasma process zone and an exhaust zone of the plasma processing apparatus Having a plurality of gas passages to neutralize gas from the process zone as it flows through the plasma confinement device into the exhaust zone, wherein the plasma confinement device comprises: an electrical ground element; a conductive element, a conductive element is located above the electrical ground element and electrically insulated from each other, the conductive element is provided with a plurality of gas passages; in a corresponding space between the electrical ground element and the conductive element, a part of space exists by an insulating material The spacer element is formed to generate a high capacitance coupling region and a low capacitance coupling region between the electrical ground component and the conductive component, wherein the electrically grounded component and the conductive component in the high capacitance coupling zone have a more Strong equivalent capacitance.