Focus ring for wafer etching

Abstract

A focus ring for wafer etching, of the present invention comprises: a first ring formed in a ring shape and disposed on the outside of a wafer; and a second ring formed in a ring shape and disposed under the first ring, wherein the first ring and the second ring are stacked while forming layers, and a contact part is formed at the point at which the first ring and the second ring are in contact with each other.

Description

Focus ring for wafer etching

[0001] The present invention relates to a focus ring for wafer etching, and more specifically, to a focus ring for wafer etching that can minimize the generation of polymeric particles between the first ring and the second ring by using a focus ring comprising a first ring and a second ring stacked in a horizontal direction for wafer etching.

[0002] In general, ensuring uniformity is very important in the semiconductor manufacturing process, and the uniformity of the semiconductor can be ensured or controlled during the etching process.

[0003] Meanwhile, in the semiconductor manufacturing process, the wafer can be supported by a wafer chuck. A wafer chuck is a device that supports and fixes the wafer during the etching process; it is installed inside the semiconductor process chamber to support the wafer.

[0004] A focus ring may be provided on the outside of the wafer chuck. The focus ring is a component used for semiconductor etching fixation, intended to maintain plasma density while fixing the wafer. Depending on the material and shape of the focus ring, the edge etch rate and center etch rate may be varied, and edge profile tilting may be corrected.

[0005] FIG. 1 illustrates a conventional focus ring. Referring to FIG. 1, the conventional focus ring may include a first ring (20) and a second ring (30) that form concentric circles around a wafer (10).

[0006] As shown in FIG. 1, when the first ring (20) and the second ring (30) are arranged to form concentric circles around the wafer (10), a vertical gap (40) may be formed between the first ring (20) and the second ring (30) to prevent the focus ring from being damaged due to thermal expansion occurring between the first ring (20) and the second ring (30).

[0007] However, when the vertical gap (40) is formed between the first ring (20) and the second ring (30), plasma can penetrate through the vertical gap (40) and polymeric particles can be generated.

[0008] Specifically, if the vertical gap (40) is maintained between the first ring (20) and the second ring (30), the penetration of ions and radicals, which are chemical species of plasma, cannot be avoided, and the generation of polymeric particles cannot be avoided. There is a problem in that mass production of wafers becomes difficult due to such polymeric particles.

[0009] The present invention is intended to solve the aforementioned problems, and more specifically, it relates to a focus ring for wafer etching that can minimize the generation of polymeric particles between the first ring and the second ring by using a focus ring comprising a first ring and a second ring stacked in a horizontal direction for wafer etching.

[0010] A focus ring for wafer etching according to one embodiment is a focus ring installed inside a chamber where plasma is formed and positioned on the outside of a wafer, comprising: a first ring having a ring shape and positioned on the outside of the wafer; and a second ring having a ring shape and positioned below the first ring; wherein the first ring and the second ring are stacked to form layers, and a contact portion is formed at the point where the first ring and the second ring come into contact.

[0011] The cross-section of the contact portion of the focus ring for wafer etching according to one embodiment may include an upwardly inclined portion formed with an upward slope from one side to the other side, and a downwardly inclined portion formed with a downward slope from one side to the other side.

[0012] The cross-section of the contact portion of the focus ring for wafer etching according to one embodiment may include a flat portion that extends flatly between the upward inclined portion and the downward inclined portion.

[0013] The cross-section of the contact portion of the focus ring for wafer etching according to one embodiment may be formed as a convex curve or a concave curve.

[0014] According to one embodiment, the cross-section of the contact portion of the focus ring for wafer etching comprises a first side flat portion extending flatly from one end toward the center and a second side flat portion extending flatly from the other end toward the center while being positioned at the same height as the first side flat portion, and between the first side flat portion and the second side flat portion, an upper protrusion protruding upward or a lower protrusion protruding downward may be provided.

[0015] The upper protrusion of the focus ring for wafer etching according to one embodiment may be extended in a flat shape, extended in a convex curve, or extended in a concave curve.

[0016] The lower protrusion of the focus ring for wafer etching according to one embodiment may be extended in a flat shape, extended in a convex curve, or extended in a concave curve.

[0017] The cross-section of the contact portion of the focus ring for wafer etching according to one embodiment may include a third side flat portion extending flatly from one end toward the center, a fourth side flat portion positioned below the third side flat portion and extending flatly from the other end toward the center, and a first vertical portion extending vertically and connecting the third side flat portion and the fourth side flat portion.

[0018] The cross-section of the contact portion of the focus ring for wafer etching according to one embodiment may include a third side flat portion extending flatly from one end toward the center, a fourth side flat portion positioned below the third side flat portion and extending flatly from the other end toward the center, and an inclined portion connecting the third side flat portion and the fourth side flat portion while forming a downward slope from one side toward the other.

[0019] The cross-section of the contact portion of the focus ring for wafer etching according to one embodiment may include a fifth side flat portion extending flatly in a direction toward the center from one end, and a first downward slope portion extending from the fifth side flat portion toward the other end while forming a downward slope.

[0020] A second vertical portion extending in a vertical direction may be provided between the fifth side flat portion and the first downward inclined portion of the wafer etching focus ring according to one embodiment.

[0021] The cross-section of the contact portion of the focus ring for wafer etching according to one embodiment may include a sixth side flat portion extending flatly in a direction toward the center from the other end, and a first upward slope portion extending while forming an upward slope toward one end from the sixth side flat portion.

[0022] The cross-section of the contact portion of the focus ring for wafer etching according to one embodiment may include a curved extension portion that extends in a convex or concave shape while forming a downward slope toward the center from one end, and a second downward slope portion that extends while forming a downward slope toward the other end from the curved extension portion.

[0023] The cross-section of the contact portion of the focus ring for wafer etching according to one embodiment may be extended in a flat shape, and may be provided with a protruding projection protruding upward in the middle.

[0024] According to one embodiment, the other end of the first ring of the focus ring for wafer etching protrudes outwardly more than the other end of the second ring, and the other end of the first ring may be extended in a vertical direction or extended while forming an incline.

[0025] A flat extension portion that extends flatly may be provided between the other end of the second ring and the other end of the first ring of the wafer etching focus ring according to one embodiment.

[0026] The resistivity value of the first ring of the wafer etching focus ring according to one embodiment may be smaller than the resistivity value of the second ring.

[0027] The present invention relates to a focus ring for wafer etching, and has the advantage of minimizing the generation of polymeric particles between the first ring and the second ring by using a focus ring comprising a first ring and a second ring stacked in a horizontal direction for wafer etching.

[0028] In addition, the present invention has the advantage of minimizing the generation of polymeric particles by geometrically changing the cross-sectional shape of the contact portion, which is the point where the first ring and the second ring come into contact.

[0029] In addition, the present invention has the advantage of being able to change the edge etch rate and the center etch rate by geometrically changing the cross-sectional shape of the contact portion, which is the point where the first ring and the second ring come into contact, and by adjusting the material of the first ring and the second ring.

[0030] Figure 1 is a drawing showing a conventional focus ring.

[0031] FIG. 2 is a drawing showing a focus ring in which a first ring and a second ring are stacked to form a layer according to an embodiment of the present invention.

[0032] FIG. 3 is a drawing showing that the cross-section of the contact portion according to an embodiment of the present invention is provided with an upward inclined portion, a downward inclined portion, and a flat portion.

[0033] FIG. 4 is a drawing showing that the cross-section of the contact portion according to an embodiment of the present invention is formed as a convex curve or a concave curve.

[0034] FIG. 5 is a drawing showing that a cross-section of a contact portion according to an embodiment of the present invention is provided with a first side flat portion, a second side flat portion, and an upper protrusion.

[0035] FIG. 6 is a drawing showing that a first side flat portion, a second side flat portion, and a lower protrusion are provided on the cross-section of a contact portion according to an embodiment of the present invention.

[0036] FIG. 7 is a drawing showing that a third side flat portion, a fourth side flat portion, a first vertical portion, and an inclined portion are provided on the cross-section of a contact portion according to an embodiment of the present invention.

[0037] FIG. 8 is a drawing showing that a fifth side flat portion, a first downward inclined portion, and a second vertical portion are provided on the cross-section of a contact portion according to an embodiment of the present invention.

[0038] FIG. 9 is a drawing showing that a sixth side flat portion and a first upward inclined portion are provided on the cross-section of a contact portion according to an embodiment of the present invention.

[0039] FIG. 10 is a drawing showing that a curved extension and a second downward slope are provided on the cross-section of a contact portion according to an embodiment of the present invention.

[0040] FIG. 11 is a drawing showing that a protruding projection is provided on the cross-section of a contact portion according to an embodiment of the present invention.

[0041] FIG. 12 is a drawing showing that the other end of the first ring according to an embodiment of the present invention protrudes outward more than the other end of the second ring.

[0042] This specification clarifies the scope of the present invention and explains the principles of the present invention and discloses embodiments so that those skilled in the art can practice the present invention. The disclosed embodiments may be implemented in various forms.

[0043] Expressions such as "comprising" or "may comprise" that may be used in various embodiments of the present invention indicate the existence of the disclosed function, operation, or component, etc., and do not limit one or more additional functions, operations, or components, etc. Furthermore, in various embodiments of the present invention, terms such as "comprising" or "having" are intended to specify the existence of the features, numbers, steps, operations, components, parts, or combinations thereof described in the specification, and should be understood as not precluding the existence or addition of one or more other features, numbers, steps, operations, components, parts, or combinations thereof.

[0044] When it is stated that a component is "connected or coupled" to another component, it should be understood that the component may be directly connected or coupled to the other component, but that a new component may also exist between the component and the other component. On the other hand, when it is stated that a component is "directly connected" or "directly coupled" to another component, it should be understood that no new component exists between the component and the other component.

[0045] The terms "first," "second," etc., as used in this specification may be used to describe various components, but the components should not be limited by these terms. The terms are used solely for the purpose of distinguishing one component from another.

[0046] The present invention relates to a focus ring for wafer etching, and more specifically, to a focus ring for wafer etching that can minimize the generation of polymeric particles between the first ring and the second ring by using a focus ring comprising a first ring and a second ring stacked in a horizontal direction for wafer etching. Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the attached drawings.

[0047] Referring to FIG. 2, the focus ring for wafer etching according to an embodiment of the present invention is installed inside a chamber where plasma is formed and can be positioned outside the wafer (10). Referring to FIG. 2, the focus ring for wafer etching according to an embodiment of the present invention can be positioned outside the center of a chuck (11) that supports the wafer (10).

[0048] A focus ring for wafer etching according to an embodiment of the present invention is intended to maintain plasma density while fixing the wafer (10), and the edge etch rate and center etch rate may change depending on the material and shape of the focus ring according to an embodiment of the present invention.

[0049] A focus ring for wafer etching according to an embodiment of the present invention may include a first ring (110) and a second ring (120).

[0050] Referring to FIG. 2, the first ring (110) is formed in a ring shape and is placed on the outside of the wafer (10). The first ring (110) is placed adjacent to the wafer (10), and the first ring (110) can be formed in a ring shape.

[0051] The first ring (110) may be positioned adjacent to the wafer (10), but the first ring (110) may not come into contact with the wafer (10), and a gap may exist between the first ring (110) and the wafer (10).

[0052] According to an embodiment of the present invention, the relative height of the first ring (110) with respect to the wafer (10) can be determined according to the etch profile tilting that occurs after etching the wafer (10). Specifically, the etch profile tilting can be corrected by adjusting the relative height of the first ring (110) with respect to the wafer (10).

[0053] The second ring (120) is formed in a ring shape and is positioned below the first ring (110). The second ring (120) can be in contact with the first ring (110) at the bottom of the first ring (110), and the second ring (120) can be formed in a ring shape. According to an embodiment of the present invention, the first ring (110) and the second ring (120) can be stacked to form layers.

[0054] When multiple rings are arranged concentrically with respect to a wafer, a vertical gap may be formed between the multiple rings, and polymeric particles may be generated by such a vertical gap. To prevent the formation of a vertical gap between the multiple rings, the first ring (110) and the second ring (120) according to an embodiment of the present invention may be stacked to form a layer.

[0055] Specifically, the first ring (110) and the second ring (120) can be stacked in a horizontal direction as shown in FIG. 2. As the first ring (110) and the second ring (120) are stacked in a horizontal direction, it is possible to prevent a vertical gap from being formed between the first ring (110) and the second ring (120).

[0056] According to an embodiment of the present invention, the first ring (110) and the second ring (120) may be made of the same material.

[0057] According to an embodiment of the present invention, the first ring (110) may be made of Al2O3. However, if the first ring (110) is made of Al2O3, the edge etch rate may be increased compared to the center etch rate, but the etching uniformity may be reduced.

[0058] According to an embodiment of the present invention, the first ring (110) may be made of Si or SiO2 to improve etching uniformity. If the first ring (110) is made of Si or SiO2, etching uniformity can be improved, but an edge etch rate lower than the center etch rate can be obtained.

[0059] Of course, this trend may be influenced by process pressure. The above applies to ICP chambers at low pressure (< 5 mTorr), and an opposite trend may appear as the pressure increases. Additionally, the trend may differ in CCP chambers.

[0060] Forming a high edge etch rate can be important for improving edge yield. Therefore, the edge etch rate can be increased by forming the first ring (110) in the ICP chamber with Al2O3. However, in this case, the etch uniformity may be reduced. At this time, the etch uniformity can be improved by forming the first ring (110) with Si or SiO2, but in this case, the edge etch rate may be reduced.

[0061] Accordingly, the first ring (110) positioned adjacent to the wafer (10) can be formed of Al2O3, and the second ring (120) can be formed of Si or SiO2, thereby increasing the edge etch rate and improving etch uniformity.

[0062] However, this is not limited thereto, and depending on the pressure of the chamber, the aforementioned tendency may appear in the opposite direction. Therefore, the first ring (110) may be formed of Si or SiO2, and the second ring (120) may be formed of Al2O3.

[0063] As such, the wafer etching focus ring according to the embodiment of the present invention can control the edge etch rate, center etch rate, etching uniformity, etc. by adjusting the materials of the first ring (110) and the second ring (120).

[0064] Referring to FIG. 2, a contact portion (130) may be formed at the point where the first ring (110) and the second ring (120) come into contact. As described above, the first ring (110) and the second ring (120) may come into contact while forming a layer. The contact portion (130) may be the point where the first ring (110) and the second ring (120) come into contact.

[0065] According to an embodiment of the present invention, the generation of polymeric particles can be minimized by geometrically changing the cross-sectional shape of the contact portion (130). Even if the first ring (110) and the second ring (120) come into contact while forming a layer, a gap may exist between the first ring (110) and the second ring (120).

[0066] If ions and radicals, which are chemical species of plasma, penetrate into such a gap, there is a risk of polymeric particles being generated. The wafer etching focus ring according to an embodiment of the present invention can minimize the penetration of ions and radicals, which are chemical species of plasma, into the gap by geometrically changing the cross-sectional shape of the contact portion (130), thereby minimizing the generation of polymeric particles.

[0067] Referring to FIG. 3, the cross-section of the contact portion (130) according to one embodiment of the present invention may include an upward slope portion (141) formed with an upward slope from one side to the other side, and a downward slope portion (142) formed with a downward slope from one side to the other side.

[0068] Here, the cross-section of the contact portion (130) may be a cross-section formed at the point where the first ring (110) and the second ring (120) come into contact when the first ring (110) and the second ring (120), which are formed in a ring shape, are stacked. Accordingly, the cross-section of the contact portion (130) according to an embodiment of the present invention may be formed by the lower shape of the first ring (110) and the upper shape of the second ring (120).

[0069] In the description above and the description to be described below, "one side" may refer to the opposite direction in which the wafer (10) is placed in the first ring (110) and the second ring (120). Specifically, it may refer to the opposite direction in which the wafer (10) is placed at the cross-section of the contact portion (130). Additionally, in the description above and the description to be described below, "one end" may refer to the end of the first ring (110) and the second ring (120) in the opposite direction in which the wafer (10) is placed. Specifically, it may refer to the end in the opposite direction in which the wafer (10) is placed at the cross-section of the contact portion (130).

[0070] In the description above and the description to be described later, the term "other side" may refer to the direction in which the wafer (10) is placed in the first ring (110) and the second ring (120). Specifically, it may refer to the direction in which the wafer (10) is placed in the cross-section of the contact portion (130). Additionally, in the description above and the description to be described later, the term "other end" may refer to the end of the first ring (110) and the second ring (120) in the direction in which the wafer (10) is placed. Specifically, it may refer to the end in the direction in which the wafer (10) is placed in the cross-section of the contact portion (130).

[0071] Referring to FIG. 3, the upward slope (141) may be formed at one end of the first ring (110) and the second ring (120) in a direction toward the center, and the downward slope (142) may be formed at the center of the first ring (110) and the second ring (120) in a direction toward the other end.

[0072] Additionally, referring to FIG. 3, the downward slope (142) may be formed at one end of the first ring (110) and the second ring (120) in a direction toward the center, and the upward slope (141) may be formed at the center of the first ring (110) and the second ring (120) in a direction toward the other end.

[0073] According to one embodiment of the present invention, the cross-section of the contact portion (130) may include a flat portion (143) that extends flatly between the upward slope portion (141) and the downward slope portion (142). The flat portion (143) may extend in a direction parallel to the upper surface of the first ring (110) or the lower surface of the second ring (120).

[0074] Referring to FIG. 3, the upward slope (141), the flat section (143), and the downward slope (142) can be formed as they extend from one end to the other of the first ring (110) and the second ring (120).

[0075] Additionally, referring to FIG. 3, the downward slope (142), the flat section (143), and the upward slope (141) may be formed as they extend from one end to the other of the first ring (110) and the second ring (120).

[0076] In this way, by forming the upward slope (141) and the downward slope (142) on the cross-section of the contact portion (130), or by forming the upward slope (141), the downward slope (142), and the flat portion (143) on the cross-section of the contact portion (130), the penetration of ions and radicals, which are chemical species of plasma, into the gap between the first ring (110) and the second ring (120) can be minimized. Through this, the generation of polymeric particles can be minimized.

[0077] Referring to FIG. 4, the cross-section of the contact portion (130) according to one embodiment of the present invention may be formed as a convex curve or a concave curve.

[0078] Referring to FIG. 4, the cross-section of the contact portion (130) may be formed as an upwardly convex curve in the direction from the second ring (120) toward the first ring (110). Additionally, the cross-section of the contact portion (130) may be formed as a downwardly concave curve in the direction from the first ring (110) toward the second ring (120).

[0079] Referring to FIG. 5, the cross-section of the contact portion (130) according to one embodiment of the present invention may include a first side flat portion (151) that extends flatly from one end toward the center, and a second side flat portion (152) that extends flatly from the other end toward the center.

[0080] The first side flat portion (151) and the second side flat portion (152) may extend in a direction parallel to the upper surface of the first ring (110) and the lower surface of the second ring (120). According to an embodiment of the present invention, the first side flat portion (151) and the second side flat portion (152) may be positioned at the same height.

[0081] In one embodiment of the present invention, between the first side flat portion (151) and the second side flat portion (152), an upper protrusion (153) protruding in an upward direction or a lower protrusion (154) protruding in a downward direction may be provided.

[0082] Referring to FIG. 5, the upper protrusion (153) protrudes in a direction toward the first ring (110) from the second ring (120), and the first side flat portion (151) - the upper protrusion (153) - the second side flat portion (152) may be formed on the cross-section of the contact portion (130).

[0083] Referring to FIG. 5, the upper protrusion (153) may be extended in a flat shape, extended in a convex curve, or extended in a concave curve.

[0084] Referring to FIG. 6, the lower protrusion (154) protrudes in a direction toward the second ring (120) from the first ring (110), and the first side flat portion (151) - the lower protrusion (154) - the second side flat portion (152) may be formed on the cross-section of the contact portion (130).

[0085] Referring to FIG. 6, the lower protrusion (154) may be extended in a flat shape, extended in a convex curve, or extended in a concave curve.

[0086] In this way, by forming the first side flat portion (151) and the second side flat portion (152) on the cross-section of the contact portion (130), and forming the upper protrusion (153) or the lower protrusion (154) between the first side flat portion (151) and the second side flat portion (152), the penetration of ions and radicals, which are chemical species of plasma, into the gap between the first ring (110) and the second ring (120) can be minimized. Through this, the generation of polymeric particles can be minimized.

[0087] Referring to FIG. 7, the cross-section of the contact portion (130) according to one embodiment of the present invention may include a third side flat portion (161) that extends flatly from one end toward the center, and a fourth side flat portion (162) that is positioned lower than the third side flat portion (161) and extends flatly from the other end toward the center.

[0088] The third side flat portion (161) and the fourth side flat portion (162) may extend in a direction parallel to the upper surface of the first ring (110) and the lower surface of the second ring (120). Here, the third side flat portion (161) may be positioned higher than the fourth side flat portion (162).

[0089] Referring to FIG. 7, the cross-section of the contact portion (130) according to one embodiment of the present invention may include a first vertical portion (163) together with the third side flat portion (161) and the fourth side flat portion (162).

[0090] The first vertical section (163) may be extended in a vertical direction and connect the third side flat section (161) and the fourth side flat section (162). The first vertical section (163) may be extended in a direction perpendicular to the direction in which the third side flat section (161) and the fourth side flat section (162) extend, and the third side flat section (161) and the fourth side flat section (162) may be connected through the first vertical section (163).

[0091] Referring to FIG. 7, the cross-section of the contact portion (130) according to one embodiment of the present invention may include an inclined portion (164) together with the third side flat portion (161) and the fourth side flat portion (162).

[0092] The above-mentioned inclined portion (164) may connect the third side flat portion (161) and the fourth side flat portion (162) while forming a downward slope in a direction from one side to the other. An incline may be formed between the third side flat portion (161) and the fourth side flat portion (162) through the above-mentioned inclined portion (164).

[0093] In this way, by forming the third side flat portion (161) and the fourth side flat portion (162) on the cross-section of the contact portion (130), and forming the first vertical portion (163) or the inclined portion (164) between the third side flat portion (161) and the fourth side flat portion (162), the penetration of ions and radicals, which are chemical species of plasma, into the gap between the first ring (110) and the second ring (120) can be minimized. Through this, the generation of polymeric particles can be minimized.

[0094] Referring to FIG. 8, the cross-section of the contact portion (130) according to one embodiment of the present invention may include a fifth side flat portion (171) that extends flatly from one end toward the center, and a first downward slope portion (172) that extends from the fifth side flat portion (171) toward the other end while forming a downward slope.

[0095] The fifth side flat portion (171) may extend in a direction parallel to the upper surface of the first ring (110) and the lower surface of the second ring (120). Referring to FIG. 8, the first downward slope portion (172) may extend from the fifth side flat portion (171) toward the other end while forming a downward slope.

[0096] Referring to FIG. 8, a second vertical section (173) extending in a vertical direction may be provided between the fifth side flat section (171) and the first downward slope section (172). The second vertical section (173) may extend in a vertical direction relative to the direction in which the fifth side flat section (171) extends.

[0097] As shown in FIG. 8, the fifth side flat section (171) and the first downward slope section (172) may be connected through the second vertical section (173) which extends in a vertical direction.

[0098] In this way, by forming the fifth side flat portion (171), the first downward inclined portion (172), and the second vertical portion (173) on the cross-section of the contact portion (130), the penetration of ions and radicals, which are chemical species of plasma, into the gap between the first ring (110) and the second ring (120) can be minimized. This allows for the minimization of the generation of polymeric particles.

[0099] Referring to FIG. 9, the cross-section of the contact portion (130) according to one embodiment of the present invention may include a sixth side flat portion (174) that extends flatly from the other end toward the center, and a first upward slope portion (175) that extends from the sixth side flat portion (174) toward one end while forming an upward slope.

[0100] The sixth side flat portion (174) may extend in a direction parallel to the upper surface of the first ring (110) and the lower surface of the second ring (120). Referring to FIG. 9, the first upward slope portion (175) may extend from the sixth side flat portion (174) while forming an upward slope toward one end.

[0101] In this way, by forming the sixth side flat portion (174) and the first upward slope portion (175) on the cross-section of the contact portion (130), the penetration of ions and radicals, which are chemical species of plasma, into the gap between the first ring (110) and the second ring (120) can be minimized. This allows for the minimization of the generation of polymeric particles.

[0102] Referring to FIG. 10, the cross-section of the contact portion (130) according to one embodiment of the present invention may include a curved extension portion (181) that extends in a convex or concave shape while forming a downward slope toward the center from one end, and a second downward slope portion (182) that extends from the curved extension portion (181) while forming a downward slope toward the other end.

[0103] Referring to FIG. 10, the curved extension (181) extends in a curve while forming a downward slope from one end toward the center. The curved extension (181) may be formed in a shape that is convex toward the top. Additionally, the curved extension (181) may be formed in a shape that is concave toward the bottom. The second downward slope (182) forms a downward slope from the curved extension (181) toward the other end.

[0104] In this way, by forming the curved extension (181) and the second downward slope (182) on the cross-section of the contact portion (130), the penetration of ions and radicals, which are chemical species of plasma, into the gap between the first ring (110) and the second ring (120) can be minimized. This allows for the minimization of the generation of polymeric particles.

[0105] Referring to FIG. 11, the cross-section of the contact portion (130) according to one embodiment of the present invention may be extended in a flat shape, and may be provided with a protruding projection (183) that protrudes upward in the middle. The cross-section of the contact portion (130) may be extended in a flat shape toward the center from one end and the other end of the first ring (110) and the second ring (120).

[0106] Specifically, the cross-section of the contact portion (130) extends in a direction parallel to the direction in which the upper surface of the first ring (110) and the lower surface of the second ring (120) extend, and may be provided with a protruding projection (183) in the middle that protrudes from the second ring (120) toward the first ring (110).

[0107] Referring to FIG. 11, the protruding jaw (183) may be formed in a triangular shape. However, it is not limited thereto, and the protruding jaw (183) may be formed in various shapes such as a square, a circle, or a semicircle and protrude upward.

[0108] In this way, by forming the protruding ridge (183) on the cross-section of the contact portion (130), the penetration of ions and radicals, which are chemical species of plasma, into the gap between the first ring (110) and the second ring (120) can be minimized. This allows for the minimization of the generation of polymeric particles.

[0109] According to an embodiment of the present invention, the resistivity value of the first ring (110) may be formed to be smaller than the resistivity value of the second ring (120). In order to improve the uniformity of the etching rate through the first ring (110) which is arranged adjacent to the wafer (10) and to improve the etching rate through the second ring (120) which is stacked on the lower part of the first ring (110), the resistivity value of the first ring (110) may be formed to be smaller than the resistivity value of the second ring (120).

[0110] Specifically, the first ring (110) may be made of Si, a material with a low resistivity value, to improve the uniformity of the etching rate. If the first ring (110) is made of a material with a high resistivity value, the edge etch rate may be greater than the center etch rate, which may reduce the uniformity of the etching rate. Therefore, it is desirable for the first ring (110) to be made of a material with a low resistivity value to improve the uniformity of the etching rate.

[0111] In addition, the second ring (120) stacked on the lower part of the first ring (110) to improve the etching speed may be made of any one of Al2O3, SiC, SiO2, or Si3N4, which has a higher resistivity value than the first ring (110).

[0112] If the first ring (110) is made of Si, it acts as an extended cathode as it is made of the same material as the wafer (10), thereby improving the uniformity of the etching rate. However, in this case, the center etch rate is formed to be greater than the edge etch rate, which may have a negative effect on the edge yield.

[0113] At this time, by forming the second ring (120) with any one of Al2O3, SiC, SiO2, or Si3N4, which has a higher resistivity value than the first ring (110), the edge etch rate can be improved, thereby improving the edge yield.

[0114] Referring to FIG. 12, according to one embodiment of the present invention, the other end of the first ring (110) may protrude outward more than the other end of the second ring (120). The first ring (110) is positioned adjacent to the wafer (10), and the first ring (110) may be positioned at the edge of the wafer (10).

[0115] The other end of the first ring (110) can be protruded outwardly more than the other end of the second ring (120), and the other end of the first ring (110) can be protruded outwardly closer to the wafer (10) than the other end of the second ring (120).

[0116] As described above, the first ring (110) may have a resistivity value smaller than that of the second ring (120). In this case, by protruding the other end of the first ring (110) outwardly more than the other end of the second ring (120), the uniformity of the etching rate of the wafer (10) can be improved.

[0117] However, this is not limited thereto, and the materials of the first ring (110) and the second ring (120) may be changed depending on the type of chamber and the pressure inside the chamber. Additionally, if necessary, the other end of the second ring (120) may protrude outward more than the other end of the first ring (110).

[0118] Referring to FIG. 12, the other end of the first ring (110) according to an embodiment of the present invention may be extended in a vertical direction or extended while forming an incline. Specifically, the other end of the first ring (110) may be formed in a flat shape while extending in a vertical direction.

[0119] Additionally, an upward slope may be formed at the other end of the first ring (110) in a direction from the bottom to the top of the wafer (10), thereby allowing the first ring (110) to be positioned adjacent to the wafer (10). As the first ring (110) is positioned adjacent to the wafer (10), the uniformity of the etching speed can be improved through the first ring (110).

[0120] Additionally, referring to FIG. 12, a flat extension portion (191) that extends flatly between the other end of the second ring (120) and the other end of the first ring (110) may be provided. Specifically, the first ring (110) extends flatly at the point where the second ring (120) contacts the other end, and a slope may be formed at the other end of the first ring (110). Through this, the first ring (110) can be positioned adjacent to the wafer (10), thereby improving the uniformity of the etching speed.

[0121] The focus ring for wafer etching according to the embodiment of the present invention described above has the following effects.

[0122] A focus ring for wafer etching according to an embodiment of the present invention has the advantage of minimizing the generation of polymeric particles between the first ring and the second ring by using a focus ring comprising a first ring and a second ring stacked in a horizontal direction for wafer etching.

[0123] In addition, the focus ring for wafer etching according to an embodiment of the present invention has the advantage of minimizing the generation of polymeric particles by geometrically changing the cross-sectional shape of the contact portion, which is the point where the first ring and the second ring come into contact.

[0124] In addition, the focus ring for wafer etching according to an embodiment of the present invention has the advantage of being able to change the edge etch rate and the center etch rate by geometrically changing the cross-sectional shape of the contact portion, which is the point where the first ring and the second ring come into contact, and by adjusting the material of the first ring and the second ring.

[0125] As such, the present invention has been described with reference to an embodiment illustrated in the drawings; however, this is merely illustrative, and those skilled in the art will understand that various modifications and variations of the embodiments are possible therefrom. Accordingly, the true scope of technical protection of the present invention should be determined by the technical spirit of the appended claims.

Claims

1. A focus ring installed inside a chamber where plasma is formed and positioned on the outside of a wafer, A first ring formed in a ring shape and disposed on the outer side of the wafer; It includes a second ring formed in a ring shape and disposed at the lower part of the first ring; The first ring and the second ring are stacked to form layers, and A focus ring for wafer etching characterized by having a contact portion formed at the point where the first ring and the second ring come into contact.

2. In Paragraph 1, The cross-section of the above contact portion is, An upward slope formed from one side toward the other, and A focus ring for wafer etching characterized by including a downward slope portion formed with a downward slope from one side toward the other.

3. In Paragraph 2, The cross-section of the above contact portion is, A focus ring for wafer etching characterized by including a flat portion extending flatly between the upward slope portion and the downward slope portion.

4. In Paragraph 1, The cross-section of the above contact portion is, A focus ring for wafer etching characterized by being formed of a convex curve or a concave curve.

5. In Paragraph 1, The cross-section of the above contact portion is, A first side flat section extending flatly from one end toward the center, and It includes a second side flat portion that extends flatly from the other end toward the center, Between the first side flat section and the second side flat section, A focus ring for wafer etching characterized by having an upper protrusion protruding in an upward direction or a lower protrusion protruding in a downward direction.

6. In Paragraph 5, A focus ring for wafer etching characterized in that the upper protrusion is extended in a flat shape, extended in a convex curve, or extended in a concave curve.

7. In Paragraph 5, A focus ring for wafer etching characterized in that the lower protrusion is extended in a flat shape, extended in a convex curve, or extended in a concave curve.

8. In Paragraph 1, The cross-section of the above contact portion is, A third side flat section extending flatly from one end toward the center, and A fourth side flat section positioned below the third side flat section and extending flatly from the other end toward the center, and A focus ring for wafer etching characterized by including a first vertical section that extends in a vertical direction and connects the third side flat section and the fourth side flat section.

9. In Paragraph 1, The cross-section of the above contact portion is, A third side flat section extending flatly from one end toward the center, and A fourth side flat section positioned below the third side flat section and extending flatly from the other end toward the center, and A focus ring for wafer etching characterized by including an inclined portion that connects the third side flat portion and the fourth side flat portion while forming a downward slope in a direction from one side to the other.

10. In Paragraph 1, The cross-section of the above contact portion is, A fifth side flat section extending flatly from one end toward the center, and A focus ring for wafer etching characterized by including a first downward slope portion that extends from the fifth side flat portion toward the other end while forming a downward slope.

11. In Paragraph 10, Between the above-mentioned fifth side flat section and the above-mentioned first downward slope section, A focus ring for wafer etching characterized by having a second vertical portion extending in a vertical direction.

12. In Paragraph 1, The cross-section of the above contact portion is, A sixth side flat section extending flatly from the other end toward the center, and A focus ring for wafer etching characterized by including a first upward slope portion that extends from the sixth side flat portion while forming an upward slope toward one end.

13. In Paragraph 1, The cross-section of the above contact portion is, A curved extension extending in a convex or concave shape while forming a downward slope from one end toward the center, and A focus ring for wafer etching characterized by including a second downward slope portion that extends from the above curved extension portion while forming a downward slope toward the other end.

14. In Paragraph 1, The cross-section of the above contact portion is, A focus ring for wafer etching characterized by being extended in a flat shape, with a protruding projection protruding upward in the middle.

15. In Paragraph 1, The other end of the first ring protrudes outward more than the other end of the second ring, and A focus ring for wafer etching characterized in that the other end of the first ring extends in a vertical direction or extends while forming an incline.

16. In Paragraph 15, A focus ring for wafer etching characterized by having a flat extension portion that extends flatly between the other end of the second ring and the other end of the first ring.

17. In Paragraph 1, A focus ring for wafer etching characterized in that the resistivity value of the first ring is smaller than the resistivity value of the second ring.

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