KR20010006799A - Etching and cleaning methods and etching and cleaning apparatuses used therefor - Google Patents

Abstract

PURPOSE: An etching apparatus, and a washing apparatus and their methods are provided, to remove the unnecessary material existed on a semiconductor wafer effectively without damaging the apparatus area. CONSTITUTION: The etching (or washing) apparatus comprises a rotation means which holds an apparatus area and a semiconductor wafer(10) provided with a surface surrounding area placed in the exterior of the apparatus area on the surface; an edge nozzle(18) which sprays an etching (or washing) liquid toward the surface surrounding area of the wafer, to etch (or remove) the unnecessary material existed in the surface surrounding area selectively; optionally a back face nozzle(16) which sprays an etching (or washing) liquid toward the center of back face(P2) of the wafer, to etch (or remove) the unnecessary material existed in the back face of the wafer; and optionally a front face nozzle(14) which sprays a protection liquid toward the center of front face(P1) of the wafer, to coat the apparatus area of the wafer and to protect the apparatus area from the etching liquid sprayed from the etching nozzle(18).

Description

Etching and Cleaning Methods and Etching and Cleaning Equipment {ETCHING AND CLEANING METHODS AND ETCHING AND CLEANING APPARATUSES USED THEREFOR}

Field of invention

Background of the Invention

FIELD OF THE INVENTION The present invention relates to etching and cleaning methods and etching and cleaning devices used in the manufacture of semiconductor devices, and more particularly to etching and cleaning methods for removing unwanted or unwanted materials from semiconductor wafers and to perform such etching or cleaning methods. Etch and cleaning apparatus.

Description of the Prior Art

BACKGROUND OF THE INVENTION In a method of manufacturing a semiconductor device on a semiconductor wafer, various etching methods are generally used to remove unnecessary or unwanted materials from the wafer, and various cleaning methods are used to clean contaminants attached to the wafer or the device. . In such cases, it is necessary to remove unwanted or unwanted materials present on the surface peripheral area of the wafer, back peripheral area of the wafer, or on the end face of the wafer.

Here, "end face" means the cross section of the wafer located between and substantially perpendicular to the front and back surfaces of the wafer. "Surface peripheral area" means the area of the wafer surface between the device area and the cross section. The device region is the region of the surface of the wafer on which the desired semiconductor device is formed. "Back peripheral area" means the area on the backside of the wafer where unwanted or unnecessary material is present to be removed.

Recently, copper (Cu) is used instead of aluminum (Al) as the wiring or interlayer material, because Cu has higher conductivity than Al. In this case, copper wiring lines are typically formed in the trenches of the silicon dioxide (SiO ₂ ) film, which is generally used to cover the grooves by forming grooves in the SiO ₂ film and by electroplating. A Cu film is formed on a SiO ₂ film, and the Cu film is selectively removed by Chemical Mechanical Polishing (CMP) to leave a Cu film in the groove. This method is called the "damascene process."

Next, the damascene method for the Cu wiring line will be described in detail.

First, grooves are formed in the SiO ₂ film to have a pattern for a predetermined wiring line by a known method, wherein the SiO ₂ film is formed on a single crystal silicon (Si) wafer or substrate. Second, a barrier metal film made of a metal such as tantalum (Ta) and tantalum nitride (TaN) is formed on the SiO ₂ film so as to cover the groove by sputtering. The barrier metal film prevents the diffusion of Cu atoms into the SiO ₂ film. Third, a seed Cu film is formed on the barrier metal film by sputtering. Fourth, a wiring Cu film is formed on the seed Cu film by electroplating.

In the fourth step of forming the wiring Cu film by electroplating, a ring-shaped blocking member is disposed on the surface of the wafer to surround the device region, and then an appropriate plating liquid or solution is provided inside the member. At this time, there is a possibility that the plating liquid leaks out of the member. If the liquid leaks, the wiring Cu film is formed not only in the device region but also in the region around the surface of the wafer. The wiring Cu film thus formed in the area around the surface is unnecessary and therefore must be removed. Due to the weak adhesion of the plated Cu film to the SiO ₂ film, the unnecessary Cu film is likely to fall from the SiO ₂ film in a subsequent step due to stress, which contaminates the process line of the semiconductor device. As a result, unnecessary Cu film must be removed.

In addition, after the CMP process is completed, the Si wafer is contaminated by the Cu contamination source generated from the polished Cu film. The Cu contaminant diffuses into the SiO ₂ film and the Si wafer by the subsequent heat treatment, which adversely affects the performance of the semiconductor device formed in the device region. Since Cu contaminants are attached to the front and back peripheral regions of the wafer and the cross section of the wafer, it is not easy to remove Cu contaminants from them. Therefore, Cu contaminants must be removed by washing.

When the diameter of the Si wafer is 8 inches, the distance between the edge of the device region and the cross section of the wafer is typically set to, for example, about 5 mm. In order to expand the device region, the SiO ₂ film on which the Cu wiring line is formed is preferably expanded until the distance between the edge and the cross section of the SiO ₂ film is reduced to 1.5 to 2.0 mm. In this case, however, when the seed Cu film is deposited onto the barrier metal film on the entire wafer by sputtering to cover the entire SiO ₂ film, it is covered not only with the device region but also with the front and back peripheral regions of the wafer and the cross sectional view of the wafer. Thus, if the plating liquid or solution provided inside the ring-shaped blocking member leaks out, the wiring Cu film will be formed not only on the seed film of the device region but also on the seed film of the front and back regions of the wafer and the wafer cross section.

Since the wiring Cu film is formed on the seed Cu film, it is not separated or peeled off. However, the wiring Cu film present on the wafer cross section will be attached to the wafer carrier and / or the robot arm during the transfer step in the semiconductor device manufacturing system. Therefore, the transport system is contaminated. This means that the wiring Cu film existing on the front and back peripheral areas of the wafer and on the wafer cross section must be removed before the wafer is transferred to the next step.

In addition, the removal of the above-mentioned wiring Cu film requires strict control. This is because the distance between the edge and the cross section of the SiO ₂ film is as short as 1.5 to 2 mm. The cleaning of the above-mentioned Cu contaminants generated during the CMP process also requires strict control.

In order to remove the unnecessary or unwanted contaminants described above, various etching and cleaning methods have been developed and disclosed, two of which are shown in FIGS. 1 and 2.

In the prior art cleaning / etching method as shown in FIG. 1, a protective film 112 having an etch-resistant property is selectively formed on the surface 110A of the semiconductor wafer 110 so as to provide a wafer. The entire device region formed on 110 is covered. Then, the wafer 110 having the protective film 112 is placed in the etching solution 114 contained in the appropriate container 113 to selectively etch the exposed regions of the wafer 110. Thus, the exposed area is washed away. The film 112 is then removed from the wafer 110.

As the etching solution 114, for example, a mixture of hydrogen fluoride (HF), hydrogen peroxide (H ₂ O ₂ ), and water (H ₂ O) can be used, which is often referred to as "fluorine- It is referred to as Hydroperoxide-Peroxide Mixture (FPM).

In the prior art cleaning / etching method shown in FIG. 2, the semiconductor wafer 110 is rotated in a horizontal plane by appropriate rotating means with the top face down. In this state, an etching solution 114 (eg, FPM) is provided from top to bottom toward the center of the back surface 110B of the wafer 110. At the same time, a protective gas 115 (eg, nitrogen gas N ₂ ) is provided from bottom to top toward the center of the surface 110A of the wafer 110.

The etching solution 114 thus provided on the backside 110B of the wafer 110 is moved out along the backside 110B toward the end face 110C of the wafer 110 and then along the vertical cross section 110C. It flows and falls at the end surface 110C. A portion of the solution 114 reaches and falls from the peripheral region of the surface 110A.

Thus, the protective gas 115 provided on the surface 110A prevents the device region from contacting the etching solution 114. The solution 114 selectively etches the back surface 110B, the end surface 110C, and the periphery of the surface 110A, thereby cleaning them.

In the prior art cleaning / etching method shown in FIG. 1, there is a disadvantage that some design is required to prevent the protective film 112 from being formed around the surface 110A of the wafer 110. In addition, the wiring line and the semiconductor device formed in the device region should not be damaged by the removal of the protective film 112 formed on the surface 110A. However, it is not easy to realize this. If the protective film 112 is made of a resist material, the number of necessary process steps is increased.

In the prior art cleaning / etching method shown in FIG. 2, the flow of the etching solution 114 toward the back surface 110B of the wafer 110 is characterized by the rotational speed of the wafer 110 and the protective gas toward the surface 110A. It is controlled by the flow rate of 115. Therefore, controllability is low.

In addition, the circular edge of the flowing solution 114, defined by the contact or collision of the solution 114 with the gas 115 and extending along the edge of the wafer 110, is waved or swung. As a result, solution 114 may reach some device regions and may etch them. Alternatively, solution 114 will not come into contact with a portion of the periphery of surface 110A, leaving undesired material.

As a result, the prior art cleaning / etching method shown in FIG. 2 cannot be applied when the distance between the cross section of the wafer and the edge of the device region is short as 1.5 to 2.0 mm.

Accordingly, it is an object of the present invention to provide an etching method and an etching apparatus that can effectively remove unnecessary materials present on a semiconductor wafer without damaging the device region.

It is another object of the present invention to provide an etching method and an etching apparatus capable of effectively removing unnecessary substances present on a semiconductor wafer with good controllability.

It is still another object of the present invention to provide an etching method and an etching apparatus for effectively removing unnecessary materials present on a semiconductor wafer even when the distance between the cross section of the wafer and the edge of the device region is short, about 1.5 to 2.0 mm.

It is still another object of the present invention to provide a cleaning method and a cleaning apparatus capable of effectively cleaning unnecessary materials present on a semiconductor wafer without damaging the device region.

Another object of the present invention is to provide a cleaning method and a cleaning apparatus capable of effectively cleaning unnecessary materials present on a semiconductor wafer with good controllability.

It is still another object of the present invention to provide a cleaning method and cleaning apparatus for effectively cleaning unnecessary materials present on a semiconductor wafer even when the distance between the cross section of the wafer and the edge of the device region is short, about 1.5 to 2.0 mm.

The above description and other objects not specifically mentioned will be apparent to those skilled in the art through the following description.

According to a first aspect of the present invention, there is provided an etching apparatus, the apparatus comprising:

(a) rotating means for holding a semiconductor wafer having a device region and a surface peripheral region located outside the device region on the surface and rotating the wafer in a horizontal plane;

(b) an edge nozzle for discharging the etching liquid toward an area around the surface of the wafer.

The etching liquid discharged from the edge nozzle selectively etches unwanted material present in the area around the surface of the wafer.

In the etching apparatus according to the first aspect of the present invention, the edge nozzle discharges the etching liquid toward the area around the surface of the wafer while the wafer is rotating in the horizontal plane. Therefore, the etching liquid released to the area around the surface does not move inside due to the centrifugal force caused by the rotation of the wafer. As a result, unnecessary materials present in the area around the surface of the wafer are effectively removed without damaging the device area of the wafer.

Further, the release of the etching liquid is controlled by the rotational speed of the wafer and the flow rate of the liquid, so that the etching operation can be performed under good control. This means that even if the distance between the cross section of the wafer and the edge of the device region is short, about 1.5 to 2.0 mm, unnecessary material present on the wafer can be effectively removed.

In a preferred embodiment of the etching apparatus according to the first aspect of the invention, the etching liquid discharged from the edge nozzle is directed along the direction of rotation of the wafer or near the point of contact where the etching liquid contacts the area around the surface of the wafer. It has a discharge direction directed outward with respect to the tangent of the formed wafer.

In another preferred embodiment of the etching apparatus according to the first aspect of the present invention, a back nozzle is additionally provided. The back nozzle ejects the etching liquid toward the back center of the wafer. The etching liquid discharged from the backside nozzle etches unnecessary materials present on the backside of the wafer. In this embodiment, there is an additional advantage that not only unnecessary materials existing in the area around the surface of the wafer but also unnecessary materials existing on the back of the wafer can be removed at the same time.

In another preferred embodiment of the etching apparatus according to the first aspect of the invention, a surface nozzle is additionally provided. The surface nozzle discharges the protective liquid towards the center of the surface of the wafer. The protective liquid discharged from the surface nozzle covers the device region of the wafer to protect the device region from the etching liquid emitted from the edge nozzle. In this embodiment, there is an additional advantage that even if a portion of the etching liquid enters the apparatus region from the surface peripheral region, it is possible to prevent the apparatus region from being damaged by the etching liquid emitted from the edge nozzle.

In another preferred embodiment of the etching apparatus according to the first aspect of the present invention, a back nozzle and a surface nozzle are additionally provided. The back nozzle ejects the etching liquid toward the back center of the wafer. The etching liquid discharged from the backside nozzle etches unnecessary materials present on the backside of the wafer. The surface nozzle discharges the protective liquid towards the center of the surface of the wafer. The protective liquid discharged from the surface nozzle covers the device region of the wafer to protect the device region from the etching liquid emitted from the edge nozzle.

In another preferred embodiment of the etching apparatus according to the first aspect of the invention, the etching liquid emitted from the edge nozzle is in the form of a beam. In this embodiment, there is an additional advantage that the controllability is further improved.

The rotating means may be in any form as long as it can hold the semiconductor wafer and rotate the semiconductor wafer in a horizontal plane. However, it is preferable that the rotating means has one of the following forms.

When the rotating means is of a roller-chucking type, the rotating means includes a roller disposed along the cross section of the wafer. The roller contacts the end surface of the wafer to support the wafer and rotate at the same time.

In the case where the rotating means is a pin-chucking type, the rotating means includes a pin supported by the support member and disposed along the cross section of the wafer. The pin contacts the end face of the wafer to support the wafer and rotate simultaneously by the member.

When the rotating means is pin-chucking, the rotating means comprises a first plurality of pins and a second plurality of pins supported by the support member. The first plurality of fins and the second plurality of fins are alternately arranged along the cross section of the wafer. The first plurality of pins and the second plurality of pins alternately contact the cross section of the wafer to support the wafer and rotate simultaneously by the member.

When the rotating means is pin-chucking, the rotating means comprises a first plurality of pins and a second plurality of pins supported by the support member. The first plurality of pins are disposed along the cross section of the wafer. The second plurality of pins are disposed along the cross section of the wafer. The first plurality of pins are in contact with the end face of the wafer for one period to support the wafer and are rotated simultaneously by the member. The second plurality of pins are in contact with the cross section of the wafer for another period to support the wafer and rotate at the same time.

According to a second aspect of the present invention, there is provided a cleaning device, the cleaning device comprising:

(a) rotating means for supporting a semiconductor wafer having on the surface a device region and a surface peripheral region located outside the device region and for rotating the wafer in a horizontal plane;

(b) an edge nozzle for discharging the cleaning liquid towards the area around the surface of the wafer.

The cleaning liquid discharged from the edge nozzle selectively removes unwanted material present in the area around the surface of the wafer.

In the cleaning apparatus according to the second aspect of the present invention, the edge nozzle discharges the cleaning liquid toward the area around the surface of the wafer while the wafer is rotating in the horizontal plane. Thus, the cleaning liquid discharged to the area around the surface cannot move inside due to the centrifugal force caused by the rotation of the wafer. As a result, unnecessary materials present in the area around the surface of the wafer are effectively removed without damaging the device area of the wafer.

In addition, the discharge of the cleaning liquid is controlled by the rotational speed of the wafer and the flow rate of the liquid, so that the cleaning operation can be performed under good control. This means that even if the distance between the cross section of the wafer and the edge of the device region is short, about 1.5 to 2.0 mm, unnecessary material present on the wafer can be effectively removed.

In a preferred embodiment of the cleaning apparatus according to the second aspect of the present invention, the cleaning liquid discharged from the edge nozzle is directed along the direction of rotation of the wafer or near the point of contact where the cleaning liquid contacts the area around the surface of the wafer. It has a discharge direction directed outward relative to the tangent of the formed wafer.

In another preferred embodiment of the cleaning device according to the second aspect of the invention, a back nozzle is additionally provided. The back nozzle ejects the cleaning liquid toward the back center of the wafer. The cleaning liquid discharged from the backside nozzle removes unnecessary material present on the backside of the wafer. In this embodiment, there is an additional advantage that not only unnecessary materials existing in the area around the surface of the wafer but also unnecessary materials existing on the back of the wafer can be removed at the same time.

In another preferred embodiment of the cleaning device according to the second aspect of the invention, a surface nozzle is additionally provided. The surface nozzle discharges the protective liquid towards the center of the surface of the wafer. The protective liquid discharged from the surface nozzle covers the device region of the wafer to protect the device region from the cleaning liquid discharged from the edge nozzle. In this embodiment, there is an additional advantage that even if a portion of the cleaning liquid enters the device area from the area around the surface, the device area can be prevented from being damaged by the cleaning liquid discharged from the edge nozzle.

In another preferred embodiment of the cleaning device according to the second aspect of the invention, a back nozzle and a surface nozzle are additionally provided. The back nozzle ejects the cleaning liquid toward the back center of the wafer. The cleaning liquid discharged from the backside nozzle removes unnecessary material present on the backside of the wafer. The surface nozzle discharges the protective liquid towards the center of the surface of the wafer. The protective liquid discharged from the surface nozzle covers the device region of the wafer to protect the device region from the cleaning liquid discharged from the edge nozzle.

In another preferred embodiment of the cleaning apparatus according to the second aspect of the invention, the cleaning liquid discharged from the edge nozzle is in the form of a beam. In this embodiment, there is an additional advantage that the controllability is further improved.

Also in the cleaning apparatus according to the second aspect of the present invention, the rotating means may be any shape as long as it can hold the semiconductor wafer and rotate the semiconductor wafer in a horizontal plane. However, it is preferable that the rotating means have any one of the forms of the rotating means described above in the section described with respect to the etching apparatus according to the first aspect.

According to a third aspect of the invention, there is provided an etching method, which method comprises

(a) rotating in a horizontal plane a semiconductor wafer having a device region and a surface peripheral region located outside the device region on the surface;

(b) discharging the etching liquid toward an area around the surface of the wafer by an edge nozzle.

In the etching method according to the third aspect of the present invention, for the same reason as described with respect to the etching apparatus according to the first aspect, unnecessary materials existing in the area around the surface of the wafer do not damage the device region of the wafer. Is effectively removed. In addition, the etching operation can be performed under good control. Thus, even when the distance between the cross section of the wafer and the edge of the device region is short, about 1.5 to 2.0 mm, unnecessary material present on the wafer can be effectively removed.

In a preferred embodiment of the etching method according to the third aspect of the invention, the etching liquid discharged from the edge nozzle is directed along the direction of rotation of the wafer or near the point of contact where the etching liquid is in contact with the area around the surface of the wafer. It has a discharge direction directed outward relative to the tangent of the formed wafer.

In another preferred embodiment of the etching method according to the third aspect of the present invention, the etching liquid is discharged toward the center of the back surface of the wafer by a back nozzle to etch unnecessary material present on the back surface of the wafer. . In this embodiment, there is an additional advantage that unnecessary materials existing in the area around the surface of the wafer as well as unnecessary materials existing in the back surface of the wafer can be removed at the same time.

In another preferred embodiment of the etching method according to the third aspect of the present invention, the protective liquid is released by the surface nozzle toward the center of the surface of the wafer to cover the device region of the wafer, so that the etching liquid is discharged from the edge nozzle. Protect the device area from In this embodiment, there is an additional advantage that even if a portion of the etching liquid enters the apparatus region from the surface peripheral region, it is possible to prevent the apparatus region from being damaged by the etching liquid emitted from the edge nozzle.

In another preferred embodiment of the etching method according to the third aspect of the present invention, the etching liquid is discharged toward the center of the back surface of the wafer by the back surface nozzle to etch unnecessary materials present on the back surface of the wafer, and by the surface nozzle Protective liquid is released toward the surface center of the wafer to cover the device region of the wafer, protecting the device region from the etch liquid emitted from the edge nozzle.

In another preferred embodiment of the etching method according to the third aspect of the invention, the etching liquid emitted from the edge nozzle is in the form of a beam. In this embodiment, there is an additional advantage that the controllability is further improved.

According to a fourth aspect of the present invention, there is provided a washing method, the washing method comprising:

(a) rotating in a horizontal plane a semiconductor wafer having a device region and a surface peripheral region located outside the device region on the surface;

(b) discharging the cleaning liquid towards the area around the surface of the wafer by an edge nozzle.

In the cleaning method according to the fourth aspect of the present invention, for the same reason as described with respect to the cleaning apparatus according to the second aspect, unnecessary material existing in the area around the surface of the wafer does not damage the device region of the wafer. Is effectively removed. In addition, the washing operation can be performed under good control. Thus, even when the distance between the cross section of the wafer and the edge of the device region is short, about 1.5 to 2.0 mm, unnecessary material present on the wafer can be effectively removed.

In a preferred embodiment of the cleaning method according to the fourth aspect of the invention, the cleaning liquid discharged from the edge nozzle is directed along the direction of rotation of the wafer or near the point of contact where the cleaning liquid contacts the area around the surface of the wafer. It has a discharge direction directed outward relative to the tangent of the formed wafer.

In another preferred embodiment of the cleaning method according to the fourth aspect of the present invention, the cleaning liquid is discharged toward the center of the back surface of the wafer by a back nozzle to wash out unnecessary material present on the back surface of the wafer. . In this embodiment, there is an additional advantage that unnecessary materials existing in the area around the surface of the wafer as well as unnecessary materials existing in the back surface of the wafer can be removed at the same time.

In another preferred embodiment of the cleaning method according to the fourth aspect of the present invention, the cleaning liquid is released by the surface nozzle toward the surface center of the wafer to cover the device region of the wafer, so that the cleaning liquid is discharged from the edge nozzle. Protect the device area from In this embodiment, there is an additional advantage that even if a portion of the cleaning liquid enters the device area from the area around the surface, the device area can be prevented from being damaged by the cleaning liquid discharged from the edge nozzle.

In another preferred embodiment of the cleaning method according to the fourth aspect of the present invention, the cleaning liquid is discharged toward the center of the back surface of the wafer by the back nozzle to remove unnecessary substances present on the back surface of the wafer and by the surface nozzle. The protective liquid is released toward the center of the surface of the wafer to cover the device area of the wafer, protecting the device area from the cleaning liquid emitted from the edge nozzles.

In another preferred embodiment of the cleaning method according to the fourth aspect of the invention, the cleaning liquid discharged from the edge nozzle is in the form of a beam. In this embodiment, there is an additional advantage that the controllability is further improved.

BRIEF DESCRIPTION OF THE DRAWINGS The present invention will be described with reference to the accompanying drawings so that the present invention can be easily implemented.

1 is a schematic diagram illustrating a prior art semiconductor wafer etching / cleaning method.

2 is a schematic diagram illustrating another prior art semiconductor wafer etching / cleaning method.

3 is a plan view schematically showing the configuration of an etching / cleaning apparatus according to a first embodiment of the present invention;

4 is a side view schematically showing the configuration of the apparatus according to the first embodiment of FIG.

FIG. 5 shows a support structure of a wafer used in the apparatus according to the first embodiment of FIG.

FIG. 6 is a side view schematically showing the supporting structure of the wafer shown in FIG. 5; FIG.

FIG. 7 illustrates another support structure of a wafer used in an etching / cleaning apparatus according to a second embodiment of the present invention. FIG.

FIG. 8 is a side view schematically showing the supporting structure of the wafer shown in FIG. 7; FIG.

FIG. 9 shows another bearing structure of a wafer used in an etching / cleaning apparatus according to a third embodiment of the present invention. FIG.

10 is a side view schematically showing the supporting structure of the wafer shown in FIG. 9;

FIG. 11 is a flowchart showing the steps of forming a Cu wiring line using the damascene method, using one of the etching / cleaning apparatuses according to the first to third embodiments of the present invention. FIG.

12A to 12F are schematic partial cross-sectional views of a semiconductor wafer showing formation of Cu wiring lines, each including a etching method and a cleaning method according to a fourth embodiment of the present invention.

FIG. 13 is a graph showing the composition ratio dependency of etch selectivity between Cu and SiO ₂ of FPM. FIG.

14A to 14F are schematic partial cross-sectional views of a semiconductor wafer showing formation of Cu wiring lines, each including a etching method and a cleaning method according to a fifth embodiment of the present invention.

15A to 15F are schematic partial cross-sectional views of a semiconductor wafer illustrating the formation of Cu wiring lines, each including a etching method and a cleaning method according to a sixth embodiment of the present invention.

FIG. 16 is a schematic cross sectional view of a semiconductor wafer, illustrating a variety of regions of the wafer used in an etching or cleaning method in accordance with the present invention; FIG.

FIG. 17 is a schematic cross-sectional view of a semiconductor wafer, showing a flow state of an etching or cleaning liquid and a protective liquid used in the etching or cleaning method according to the present invention. FIG.

♠ Explanation of the symbols for the main parts of the drawings.

10: wafer

14: surface nozzle

16: back nozzle

18: edge nozzle

Preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

First embodiment

The etching / cleaning apparatus according to the first embodiment has the configuration as shown in FIGS. 3 and 4. This apparatus operates as an etching apparatus when the etching liquid is supplied and as a washing apparatus when the cleaning liquid is supplied.

The etching / cleaning apparatus shown in FIGS. 3 and 4 includes a surface nozzle 14 for discharging the protective liquid L _P toward the surface center P1 of the surface 10A of the circular single crystal Si wafer 10, The back nozzle 16 for discharging the etching liquid L _E or the cleaning liquid L _C toward the back center P2 of the back surface 10B of the wafer 10, and an edge of the wafer 10. An edge nozzle 18 for discharging the etching or cleaning liquid L _E or L _C toward.

As shown in FIG. 16, the wafer 10 extends along a flat surface 10A, a flat back surface 10B, and the periphery of the wafer 10 between the surface 10A and the back surface 10B. End face 10C. The wafer 10 also has a device region 10D in the surface 10A. Various semiconductor devices and devices and their wiring lines are formed in the device region 10D. A surface peripheral region 10E having a substantially circular ring shape is formed on the surface 10A and extends along the cross section 10C between the device region 10D and the cross section 10C.

On the backside 10B of the wafer 10, a backside peripheral region 10F is formed, where there is unwanted or unnecessary material to be removed. Similar to the surface peripheral region 10E, the back peripheral region 10F has a substantially circular ring shape.

The positions and angles of these nozzles 14, 16, and 18 with respect to the wafer 10 vary with the size or diameter of the wafer 10. For example, for a wafer having a diameter of 150 mm, 200 mm, or 300 mm, the following setting is preferred. If these settings are taken, the object of the present invention can be easily achieved.

3 and 4, the height H ₁ of the tip of the surface nozzle 14 from the surface 10A of the wafer 10 is preferably set to a value within the range of 10 to 100 mm. The height H ₂ of the tip of the back nozzle 16 from the back surface 10B of the wafer 10 is preferably set to a value within the range of 10 to 100 mm. The height H ₃ of the tip of the edge nozzle 18 from the surface 10A is preferably set to a value within the range of 5 to 50 mm. In this embodiment, H ₁ is set to 50 mm, H ₂ is set to 50 mm, and H ₃ is set to 10 mm.

The distance L ₁ of the tip of the surface nozzle 14 from the surface center P1 of the wafer 10 is preferably set to a value within the range of 70 to 200 mm. The distance L ₂ of the tip of the back nozzle 16 from the back center P2 of the wafer 10 is preferably set to a value within the range of 70 to 200 mm. The distance L ₃ of the end of the edge nozzle 18 from the point P3 where the longitudinal axis of the edge nozzle 18 intersects the surface 10A of the wafer 10 is set to a value within the range of 1 to 50 mm. It is desirable to be. Within these ranges, the object of the present invention can be easily achieved. In this embodiment, L ₁ is set to 120 mm, L ₂ is 120 mm, and L ₃ is set to 10 mm.

The angle θ ₁ of the surface nozzle 14 from the surface 10A is preferably set to a value within the range of 15 ° to 60 °. The angle θ ₂ of the back nozzle 16 from the back surface 10B is preferably set to a value within the range of 15 ° to 60 °. The angle θ ₃ of the edge nozzle 18 from the surface 10A is preferably set to a value within the range of 10 ° to 50 °. In this embodiment, θ ₁ is set to 45 °, θ ₂ is 45 °, and θ ₃ is set to 35 °.

Angle θ ₄ of the edge nozzle 18 with respect to the tangent of the wafer 10 at a point P3 where the longitudinal axis of the edge nozzle 18 intersects the cross section 10C (ie, the edge) of the wafer 10. ) Is set to a value within the range of 0 ° to 90 °. In this embodiment, θ ₄ is set to 45 °. The value of the angle θ ₄ is determined so that the etching or cleaning liquid L _E or L _c emitted from the nozzle 18 does not flow inward from the surface peripheral region 10E.

The protective liquid L _P is discharged from the surface nozzle 14 toward the surface center P1 of the wafer 10. Since the wafer 10 is rotating at a certain speed in the horizontal plane during operation, the protective liquid L _P is affected by the centrifugal force due to the rotation. Thus, the protective liquid L _P moves outward from the vicinity of the center P1 along the surface 10A, covering the entire device region 10D and releasing the etching or cleaning liquid L emitted from the edge nozzle 18. _The device region 10D is protected from _E or L _C. The flow state of the protective liquid L _P is shown in FIG. 17.

The etching or cleaning liquid L _E or L _C is discharged from the edge nozzle 18 toward the surface periphery 10E or edge of the wafer 10. Thus, the etching or cleaning liquid L _E or L _C is in selective contact with the surface peripheral area 10E of the wafer. Due to the discharge direction and the centrifugal force by rotation, as shown in FIG. 17, the etching or cleaning liquid L _E or L _C does not enter the apparatus region 10D and falls along the cross section 10C. In addition, since the protective liquid L _P discharged from the surface nozzle 14 covers the entire apparatus region 14D, the separation of the apparatus region 14D from the etching or cleaning liquid L _E or L _C is To be sure.

The etching or cleaning liquid L _E or L _C is discharged from the backside nozzle 16, which also faces the backside center P2 of the wafer 10. Thus, the etching or cleaning liquid L _E or L _C can be brought into contact with the entire back surface 10B. Due to the centrifugal force due to the rotation of the wafer 10, as shown in FIG. 17, the etching or cleaning liquid L _E or L _C moves outward from the center P2 along the back surface 10B to cross-section 10C. Falls near).

As can be seen from the above description, the protective liquid L _P discharged from the surface nozzle 14 automatically moves from the surface center P1 toward the edge of the wafer 10 due to the centrifugal force. Thus, the release state of the protective liquid L _P can be arbitrarily changed as long as it provides a predetermined function of covering or protecting the device region 10D. For example, the protective liquid L _P may be released to form a beam, or may be emitted to form a suitable section or fan, or may be sprayed. This may also be applied to the etching or cleaning liquid L _E or L _C discharged from the back nozzle 16.

The ejection state of the etching or cleaning liquid L _E or L _C released from the edge nozzle 18 needs to be in contact with the cross section 10C and the surface peripheral region 10E of the wafer 10 with satisfactory controllability. This must be done without the etching or cleaning liquid L _E or L _C being in contact with the device region 10D. In this regard, for example, the etching or cleaning liquid L _E or L _C will be emitted to form a narrow beam having a diameter of 0.5 to 2.0 mm. Alternatively, it may be ejected to form a suitable section or fan that extends along the edge of the wafer 10 or may be selectively sprayed towards a portion of the surface periphery region 10E.

The etching / cleaning apparatus according to the first embodiment includes a wafer-rotation mechanism as shown in FIGS. 5 and 6. This mechanism, roller-chucking, comprises four rollers 22 connected to a corresponding rotational shaft 24. The rollers 22 are arranged at equal intervals along the periphery of the wafer 10 within the same horizontal plane. When the wafer 10 is supported, the wafer 10 engages with recesses 26 of four rollers 22 to be positioned in the horizontal plane. By simultaneous rotation of these rollers 22, as shown in FIGS. 5 and 6, the wafer 10 is rotated in the horizontal plane at a certain speed.

Although the number of rollers 22 is four in this embodiment, it is not limited to this. It is preferably set to a number ranging from three to eight.

In the wafer-bearing mechanism of FIGS. 5 and 6, each roller 22 does not always contact the end face 10C of the wafer 10 at the same position during operation. Therefore, this mechanism is good in the etching or cleaning method of the wafer 10 according to the present invention, which will be described below in which the entire cross section 10C needs to be subjected to an etching or cleaning action. In addition, since the positions of the shaft 24 and the roller 22 are fixed during operation, the etching or cleaning liquid L _E or L _C discharged from the back nozzle 16 may be blocked or obstructed by the shaft 24. There is no possibility. This provides the additional advantage that the etching or cleaning liquid L _E or L _C is in effective contact with the backside 10B of the wafer 10.

The number of edge nozzles 18 is one in this embodiment, but is not limited thereto. The number of nozzles 18 may be two or more as necessary.

In the etching / cleaning apparatus according to FIGS. 3 to 6, the wafer-bearing mechanisms of FIGS. 5 and 6 are provided to hold the wafer 10 in a horizontal plane and to rotate the wafer 10 at a certain rotational speed. In addition, the surface nozzle 14 is provided for discharging the protective liquid L _P toward the surface center P1 of the wafer 10, and the backside nozzle 16 faces the backside center P2 of the wafer 10. toward provided for emitting the etching or cleaning liquid (L _E or L _C) and the edge nozzle 18 is provided for emitting the etching or cleaning liquid (L _E or L _C) towards the edge of the wafer 10 .

In addition, the etching or cleaning liquid L _E or L _C discharged from the edge nozzle 18 is controlled to contact the area around the surface 10E of the rotating wafer 10 and at the same time is discharged from the backside nozzle 16. The etching or cleaning liquid L _E or L _C is controlled to be in full or partial contact with the backside 10B of the wafer 10. The protective liquid L _P released from the surface nozzle 14 protects the device region 10D of the wafer 10 from the etching or cleaning liquid L _E or L _C emitted from the edge nozzle 18. It is controlled to cover the whole apparatus area | region 10D of (10).

Therefore, the surface peripheral region 10E, the end face 10C, and the back surface 10B of the wafer 10 do not cause any damage to the wiring lines and semiconductor devices or devices in the device region 10D of the wafer 10. Thus, it can be effectively etched or cleaned to remove unwanted or unwanted or contaminants present on the wafer 10.

In addition, since the etching or cleaning liquid L _E or L _C can be discharged from the edge nozzle 18 toward the surface peripheral area 10E as a liquid beam or liquid pan, The contact point of the etching or cleaning liquid L _E or L _C can be set with a satisfactory high precision. As a result, the device region 10D may extend toward the edge or cross section 10C of the wafer 10 and consequently the width of the surface peripheral region 10E (ie, the distance between the regions 10D and 10E). Can be as short as possible (eg, about 1.5-2.0 mm).

Preferred examples of the etching liquid L _E , the cleaning liquid L _C , and the protective liquid L _P are described below.

Second embodiment

7 and 8 schematically show a wafer-holding mechanism used in the etching / cleaning apparatus according to the second embodiment, which is a variation of the holding mechanism shown in FIGS. 5 and 6. Description of the same configuration as the device according to the first embodiment of FIGS. 3 to 6 of the device according to the second embodiment is omitted for simplicity of description.

As shown in FIGS. 7 and 8, the wafer-bearing mechanism is pin-chucked and includes four pins 30 connected to the rotatable support member 28. The pins 30 are arranged at equal intervals along the circular edge of the member 28. Each pin 30 has a pocket 30A at which the edge of the wafer 10 is positioned and engaged. The wafer 10 is located and supported on four pockets of the pin 30. The wafer 10 is rotated in the horizontal plane by the rotation of the support member 28 as shown in FIGS. 7 and 8.

Although the number of the pins 30 is four in this embodiment, it is not limited to this and may be any number. It is preferably set to a number ranging from three to eight.

In the wafer-bearing mechanisms of FIGS. 7 and 8, unlike the instruments of FIGS. 5 and 6 in the first embodiment, each pin 30 has the backside of the wafer 10 at the same position during operation. 10B) and end surface 10C. Thus, a problem arises that a part of the cross section 10C covered by the fin 30 is not etched or cleaned. In order to prevent this problem, it is preferable that the chucking force of the wafer-holding mechanism is simultaneously relaxed or weakened so that the rotational speed is slowed down briefly during operation. Therefore, the supporting position of the wafer 10 may be changed by the inertial force of the rotating wafer 10.

Alternatively, rotation of the wafer 10 may be temporarily stopped to lift the wafer 10 from the pin 30 by a suitable handler (not shown) or the like. In this case, the holding position of the wafer 10 can be moved or changed. In addition, two wafer-bearing mechanisms of the pin-chucking type shown in FIGS. 7 and 8 may be provided to support the wafer 10. In this case, the first of the two instruments is used to support the wafer 10 and then the second one is used to support the wafer 10. Thus, the supporting position of the wafer 10 can be changed.

Of course, the apparatus according to the second embodiment has the same advantages as the apparatus according to the first embodiment.

In addition, the wafer-bearing mechanisms of FIGS. 7 and 8 may be combined with the instruments of FIGS. 5 and 6. In this case, the roller 22 is in contact with the end face 10C of the wafer 10 during the first half process of the etching or cleaning process, and then the pin 30 is in contact with the roller 22 during the second half process of the etching or cleaning process. Contact with the cross section 10C at a support position different from the support position with respect to ,, and vice versa. Therefore, the wafer 10 that rotates during the same process without changing the holding position of the wafer 10 can be changed or moved.

Third embodiment

9 and 10 schematically show a wafer-bearing mechanism used in the etching / cleaning apparatus according to the third embodiment, which is another variation of the holding mechanism shown in FIGS. 5 and 6. The same configuration as that of the device according to the first embodiment of the device according to the third embodiment is omitted for simplicity of description.

As shown in Figures 9 and 10, similar to the second embodiment, the wafer-bearing mechanism is pin-chucking. The mechanism comprises four pins 40 and four pins 41 coupled to the rotatable support member 38. The pins 40 and 41 are alternately arranged at equal intervals along the circular edge of the member 38. Each pin 40 has a pocket 40A at which the edge of the wafer 10 is positioned and engaged. Each pin 41 has a similar pocket 41A in which the edge of the wafer 10 is positioned and engaged. When the wafer 10 is rotated, the wafer 10 is positioned and supported on the eight pockets 40A and 41A of the pins 40 and 41. As shown in FIGS. 9 and 10, the wafer 10 is rotated in the horizontal plane by the rotation of the support member 38.

The number of the pins 40 and 41 is four in the present embodiment, but is not limited thereto and may be any number. It is preferable to set three pieces each.

In the wafer-bearing mechanisms of FIGS. 9 and 10, unlike the instruments of FIGS. 7 and 8 in the second embodiment, four fins 40 are used for the wafer 10 during the preceding half of the etching or cleaning process. Is in contact with the end face 10C. Thereafter, four pins 41 are in contact with the end face 10C during the second half process. Thus, the rotating wafer 10 can be changed or moved in its holding position during the same process. This has the additional advantage that no means for moving the holding position of the wafer 10 is needed.

Of course, the apparatus according to the third embodiment has the same advantages as the apparatus according to the first embodiment.

Fourth embodiment

FIG. 11 shows a flow of a process of forming a Cu wiring line using the damascene method, and FIGS. 12A to 12F respectively illustrate the steps, which include an etching method and a cleaning method according to a fourth embodiment. Included. In this process, any one of the etching / cleaning apparatuses according to the first to third embodiments described above can be used.

In this step, a plurality of Cu wiring lines are formed. However, for simplicity of explanation, only one wiring line is described and shown.

In step S1, a wiring trench is formed. Specifically, as shown in FIG. 12A, a silicon dioxide (SiO ₂ ) film 34 is formed on the surface 10A of the Si wafer 10 by a known method. The SiO ₂ film 34 is formed so as to cover the entire device region 10D and protrude sideways from the region 10D. Thus, the perimeter or edge of the SiO ₂ film 34 is located in the surface periphery region 10E. In this embodiment, the width of the surface peripheral region 10E is set to about 5 mm.

Wiring grooves 36 are then formed in the SiO ₂ film 34 to be located in the device region 10D by known methods. The state of this step is shown in FIG. 12A.

In step S2, a barrier metal film and a seed Cu film are formed. The barrier metal film is used to prevent Cu atoms from diffusing into the SiO ₂ film 34 and / or the wafer 10. The seed Cu film is used to form the seed for plating.

Specifically, as shown in Fig. 12B, after the wafer 10 is placed on the wafer stage 31 of the sputtering system, the barrier metal film 38 made of Ta or TaN or the like is sputtered. It is formed on the SiO ₂ film 34 to cover the groove 36. The state of this step is shown in FIG. 12B.

In FIG. 12B, reference numeral 33 denotes a shield ring to prevent sputtered species from being deposited on the surface periphery 10E and the cross section 10C of the wafer 10. The shield ring 33 is positioned on the wafer stage 31 during the sputtering process.

In step 33, a wiring Cu film is formed by electroplating. Specifically, a ring-shaped blocking member (ie, a so-called O-ring, not shown) is placed on the SiO ₂ film 34 to form a space on the seed Cu film 40. A suitable plating liquid or solution is then provided to the space to form a wiring Cu film 42 on the seed Cu film 40, as shown in Fig. 12C.

In this step, the plating liquid typically leaks out of the O-ring. Thus, an unnecessary Cu film 44 is formed on the SiO ₂ film 34 in the peripheral region 10E. This film 44 is easily separated from the film 34 and will therefore become a contaminant to the process line. As a result, the film 44 must be removed before the next process.

In step S4, the unnecessary Cu film 44 is removed by etching using the etching / cleaning apparatus according to the first, second or third embodiment described above. Since the etching liquid L _E is supplied, the above-described etching / cleaning apparatus operates as an etching apparatus.

Specifically, first, the wafer 10 having the films 34, 38, 40, 42, and 44 is held in a horizontal plane by a wafer-holding mechanism. Next, the protective liquid L _P is discharged from the surface nozzle 14 toward the surface center P1 of the wafer 10 to cover the entire device region 10D. As the protective liquid L _P , any liquid which does not perform any etching action on Cu, such as pure water or a water solution of any organic acid, is used. Preferably, as the solution of the organic acid, a solution of hydroxyl acid, citric acid, malonic acid or the like is used, and the concentration thereof is preferably set to 0.001 to 5%. This is because these solutions are readily available, these solutions are easily removed, and do not cause any damage to the device region 10D.

In this embodiment, pure water is used as the protective liquid L _P.

Simultaneously with the release of the protective liquid L _P , the etching solution L _E is released from the edge nozzle 18 toward the edge of the wafer 10 to cover the entire surface peripheral area 10E. As the etching solution L _E , any liquid having a large etch selectivity (Cu / SiO ₂ ) is used, because the SiO ₂ film 34 is not etched and at the same time the area around the surface ( This is because the unnecessary Cu film 44 present in 10E must be selectively etched.

Preferably, as the etching solution (L _E ), any acidic or alkaline solution comprising H ₂ O ₂ will be used. For example, FPM (HF / H ₂ O ₂ / H ₂ O), SPM (H ₂ SO ₄ / H ₂ O ₂ / H ₂ O), HPM (HCl / H ₂ O ₂ / H ₂ O), nitriding Aqueous solutions of hydrogen peroxide (HNO ₃ / H ₂ O ₂ / H ₂ O), APM (NH ₄ OH / H ₂ O ₂ / H ₂ O), concentrated nitric acid (HNO ₃ ), and the like are preferred. This is because these solutions have satisfactory etch selectivity between Cu and SiO ₂ and they are readily available.

These solutions have a suitable composition ratio that provides high etch selectivity (Cu / SiO ₂ ) in the following manner.

HF: H ₂ O ₂ : H ₂ O = 1-10: 1-20: 100

H ₂ SO ₄ : H ₂ O ₂ : H ₂ O = 1-10: 1-20: 100

HCl: H ₂ O ₂ : H ₂ O = 1-10: 1-20: 100

HNO ₃ : H ₂ O ₂ : H ₂ O = 1-10: 1-20: 100

NH ₄ OH: H ₂ O ₂ : H ₂ O = 1-10: 1-20: 100

HNO ₃ = 30% -80%

As an example, the composition ratio dependence of the etching selectivity (Cu / SiO ₂ ) of the FPM is shown in FIG. 13. As can be seen from this figure, the etching selectivity (Cu / SiO ₂ ) of the FPM is maximized to about 250 at a composition ratio of HF: H ₂ O ₂ : H ₂ O = 1: 10: 100.

In the fourth embodiment, FPM is used as the etching solution L _E discharged from the edge nozzle 18.

While the wafer 10 is being rotated in the horizontal plane by the wafer-holding mechanism, pure water (ie, protective liquid L _P ) is discharged from the surface nozzle 14 and FPM (ie, etching solution L _E ). ) Is discharged from the edge nozzle 18. Pure water provided near the surface center P1 of the wafer 10 spreads along the surface 10A toward the edge of the wafer 10 due to centrifugal force, and thus covers the entire device area 10D. . The FPM provided to the surface peripheral region 10E moves along the surface 10A toward the edge of the wafer 10 due to the centrifugal force, and comes into contact with the entire surface peripheral region 10E. Thus, even if the FPM emitted from the nozzle 18 enters slightly toward the device region 10D due to the rotational movement of the wafer 10, there is no possibility that the FPM contacts the device region 10D because of pure water. As a result, the wiring Cu film 42 and the SiO ₂ film 34 are not damaged by the FPM.

The FPM is also emitted from the edge nozzle 18 as a beam. Therefore, the point of contact of the FPM beam with the surface 10A can be adjusted correctly, which correctly removes unnecessary Cu film 44 in the region 10E with satisfactory controllability. The state of this step is shown in FIG. 12D, where the Cu film 44 is completely removed and the edges of the films 38, 40, and 42 located outside the device region 10D are removed.

In step S5, the remaining wiring Cu film 42 in the device region 10D is annealed by a known method to improve the quality of the film 42.

In step S6, a CMP process is performed to selectively remove the barrier metal film 38 protruding from the grooves of the wiring Cu film 42, the seed Cu film 40, and the SiO ₂ film 34. Thus, as shown in FIG. 12E, a Cu wiring line 46 is formed in the groove 36, and at the same time, the seed Cu film 40 and the barrier metal film 38 remain in the groove 36.

Through this CMP process, polishing waste 48 is deposited on the back surface 10B, the cross section 10C, and the surface 10A in the surface periphery region 10E of the wafer 10. In this embodiment, the polishing impurity 48 is made of Cu and a barrier metal.

In step S7, the abrasive impurities 48 are removed using the etching / cleaning apparatus according to the first, second or third embodiment described above. Since the cleaning liquid L _C is provided, the above-described etching / cleaning device operates as a cleaning device.

Specifically, first, the wafer 10 is supported on a wafer-bearing mechanism. Then, while the wafer 10 is being rotated in the horizontal plane by the wafer-holding mechanism, pure water (ie, the protective liquid L _P ) is transferred from the surface nozzle 14 to the surface center P1 of the wafer 10. ) To cover the entire device region 10D. At the same time, the FPM (ie, cleaning liquid L _C ) is released from the edge nozzle 18 toward the edge of the wafer 10 to cover the entire surface peripheral area 10E and at the same time the FPM is away from the back nozzle 16. It is discharged toward the center P2 of the back surface of the wafer 10 to cover the entire back surface 10B.

Pure water provided near the surface center P1 moves outward along the surface 10A due to the centrifugal force to cover and protect the entire device region 10D. The FPM provided to the surface periphery region 10E moves by the centrifugal force toward the edge of the wafer 10 along the surface 10A and falls away from the edge, and the abrasive impurities 48 present in the region 10E and the cross section 10C. ). Thus, the surface peripheral region 10E and the cross section 10C are completely cleaned.

On the other hand, the FPM provided near the rear center P2 moves and falls outward along the rear surface 10B by centrifugal force, and removes the abrasive impurities 48 present on the rear surface 10B. Thus, the back surface 10B of the wafer 10 is completely cleaned.

Since the device region 10D is completely covered with pure water during the cleaning step S7, even if the FPM discharged from the nozzle 18 enters the device region 10D slightly due to the rotational movement of the wafer 10, the FPM remains in the device region ( There is no possibility of contact with 10D). As a result, the wiring Cu film 46 and the SiO ₂ film 34 are not damaged by the FPM.

The state after the washing step S7 is shown in FIG. 12F.

As the cleaning liquid L _C , any acidic or alkaline solution containing H ₂ O ₂ can be used, similar to the etching liquid L _E. This is because H ₂ O ₂ performs a good washing operation on the abrasive impurities 48 of Cu. For example, SPM, HPM, aqueous solutions of hydrogen nitride peroxide, APM, or concentrated nitric acid are preferred. They are readily available, easily removed and do not cause any damage to the device region 10D.

As the protective liquid L _P in addition to pure water, any organic acid aqueous solution which does not dissolve Cu can be used. For example, an aqueous solution of hydroxyl, citric acid, malonic acid and the like can be used. The concentration of the organic acid solution is preferably 0.001% to 5%.

Fifth Embodiment

14A to 14F show the steps of a Cu wiring line forming process using the damascene method, respectively, and include an etching method and a cleaning method according to the fifth embodiment. In this process, any one of the etching / cleaning apparatuses according to the first to third embodiments described above is used.

In the fifth embodiment, in order to expand the device region 10D, the periphery of the device region 10D is moved to the outer side to reduce the width of the surface peripheral region 10E compared with the fourth embodiment. Let's do it. The remaining conditions are the same as those of the fourth embodiment described above.

As shown in FIG. 14A, in step S1 of FIG. 11, a SiO ₂ film 34 is formed on the surface 10A of the Si wafer 10 by a known method. SiO ₂ film 34 is formed so as to cover the entire device region 10D and protrude slightly from the device region 10D. Thus, the periphery of the SiO ₂ film 34 is located in the surface periphery region 10E. In this embodiment, the width of the surface peripheral region 10E is set to 2 mm.

Wiring grooves 36 are then formed in the SiO ₂ film 34 so as to be located in the device region 10D by known methods. The state of this step is shown in FIG. 14A.

In step S2, as shown in FIG. 14B, the wafer 10 is located on the wafer stage 31 ′ of the sputtering system. The stage 31 'is smaller in size than the stage 31 used in the fourth embodiment. Then, by sputtering using a shield ring 33 (not shown), a barrier metal film 38 made of Ta or TaN or the like is formed on the SiO ₂ film 34 to cover the grooves 36. . Next, a seed Cu film 40 is formed on the barrier metal film 38 by sputtering without using the shield ring 33 to cover the groove 36. The state of this step is shown in FIG. 14B.

As can be seen from FIG. 14B, unlike the fourth embodiment, the seed Cu film 40 covers the entire cross section 10C and a part of the back surface 10B. This is because the width of the surface peripheral area 10E is very small and the shield ring 33 is not used.

In step S3, a ring-shaped blocking member (ie, a so-called O-ring, not shown) is placed on the seed Cu film 40 to form a space on the film 40. A suitable plating liquid or solution is then provided to the space to form a wiring Cu film 42 on the film 40 by electroplating, as shown in Fig. 14C.

At this stage, due to leakage of the plating liquid, unnecessary Cu film 44 is additionally formed on the seed Cu film 40 in the peripheral region 10E, as shown in Fig. 14C. Since this film 44 is a contaminant that affects the performance of the semiconductor device in the device region 10D, it must be removed before the next process.

In step S4, first, the wafer 10 is supported on the wafer-bearing mechanism of the etching / cleaning apparatus according to the above-described first, second or third embodiment, and rotated in a horizontal plane.

Next, pure water (ie, the protective liquid L _P ) is discharged from the surface nozzle 14 toward the surface center P1 of the rotating wafer 10 to cover the entire device region 10D. At the same time, an FPM (ie, etching liquid L _E ) is released from the edge nozzle 18 toward the edge of the wafer 10 to cover the entire surface peripheral area 10E. In addition, the FPM is discharged from the back nozzle 16 toward the back center P2 of the wafer 10 to cover the entire back surface 10B. Thus, the wiring Cu film 40 present in the surface peripheral region 10E, the end face 10C, and the rear peripheral region 10F is completely removed, and at the same time, the seed Cu film (located outside the device region 10D) 40) is completely removed. The state of this step is shown in FIG. 14D.

In step S5, the remaining wiring Cu film 42 is annealed by a known method to improve the quality of the film 42.

In step S6, a CMP process is performed to selectively remove the wiring Cu film 42, the seed Cu film 40, and the barrier metal film 38 protruding from the groove 36 in the SiO ₂ film 34. do. Thus, as shown in FIG. 14E, a Cu wiring line 46 is formed in the groove 36, and at the same time, the seed Cu film 40 and the barrier metal film 38 remain in the groove 36.

Through this CMP process, as shown in FIG. 14E, abrasive impurities 48 are attached to the surface 10A in the back surface 10B, the cross section 10C, and the surface periphery region 10E of the wafer 10. In this embodiment, the abrasive impurity 48 is made of Cu and a barrier metal.

In step S7, the abrasive impurities 48 are removed using the etching / cleaning apparatus according to the first, second, or third embodiment described above.

Specifically, first, the wafer 10 is supported on a wafer-bearing mechanism. Next, while the wafer 10 is being rotated in the horizontal plane by the above mechanism, pure water (ie, the protective liquid L _P ) moves the surface center P1 of the wafer 10 from the surface nozzle 14. Is emitted to cover the entire device region 10D. At this time, it is preferable to remove Cu impurities present in the device region 10D by temporarily providing an appropriate organic acid to the device region 10D.

At the same time as the discharge of pure water, the FPM (i.e., cleaning liquid L _C ) is released from the edge nozzle 18 toward the edge of the wafer 10 to cover the entire surface periphery area 10E and at the same time the back side nozzle (FPM) 16 is discharged toward the center P2 of the back surface of the wafer 10 to cover the entire back surface 10B.

Pure water provided near the surface center P1 of the wafer 10 is moved outwards to cover and protect the entire device region 10D. The FPM provided near the edge of the wafer 10 is moved outwards to remove the abrasive impurities 48 present in the surface peripheral region 10E and the cross section 10C. The FPM provided near the center P2 of the back surface of the wafer 10 moves outward and falls to remove the abrasive impurities 48 present on the back surface 10B. Thus, the back surface 10B, the cross section 10C, and the surface peripheral region 10E of the wafer are completely removed without damaging the device region 10D. The state of this step is shown in FIG. 14F.

After the CMP process is complete, the wafer 10 will be completely immersed in the cleaning solution or in an additional process step of brushing the wafer 10.

Sixth embodiment

15A to 15F respectively illustrate the steps of the Cu wiring line forming process using the damascene method, and include an etching method and a cleaning method according to the sixth embodiment. In this process, any of the etching / cleaning apparatuses according to the first to third embodiments described above can be used.

In the sixth embodiment, unlike the fifth embodiment, the barrier metal film 38 and the seed Cu film 40 are formed to partially cover the back surface 10B of the wafer 10. Similar to the fifth embodiment, the periphery of the device region 10D is moved outward as compared to the fifth embodiment, extending the device region 10D and reducing the width of the surface peripheral region 10E. .

As shown in FIG. 15A, in step S1 of FIG. 11, a SiO ₂ film 34 is formed on the surface 10A of the Si wafer 10 by a known method. SiO ₂ film 34 is formed so as to cover the entire device region 10D and protrude slightly from the device region 10D. Thus, the periphery of the SiO ₂ film 34 is located in the surface periphery region 10E. In this embodiment, the width of the surface peripheral region 10E is set to about 2 mm.

Wiring grooves 36 are then formed in the SiO ₂ film 34 to be located in the device region 10D by known methods. The state of this step is shown in FIG. 15A.

In step S2, as shown in FIG. 15B, a barrier metal film 38 made of Ta, TaN or TaO _x is formed on the SiO ₂ film 34 by sputtering to cover the grooves 36. Then, a seed Cu film 40 is formed on the barrier metal film 38 by sputtering to cover the grooves 36. The state of this step is shown in FIG. 15B.

As can be seen from FIG. 15B, both the barrier metal film 38 and the seed Cu film 40 extend to the back surface 10B of the wafer 10. This condition is caused by sputtering without using the shield ring 33 and will make the width of the surface peripheral area 10E very small.

In step S3, an O-ring (not shown) is placed on the seed Cu film 40 to form a space on the film 40. A suitable plating liquid or solution is then provided to the space and by electroplating, a wiring Cu film 42 is formed on the film 40, as shown in FIG. 15C.

In this step, due to the leakage of the plating liquid, unnecessary Cu film 44 is additionally formed on the seed film 40 in the peripheral region 10E.

In step S4, using the etching / cleaning apparatus according to the above-described first, second or third embodiment, the wafer 10 is rotated in the horizontal plane. Next, pure water is discharged from the surface nozzle 14 toward the surface center P1 of the rotating wafer 10 to cover the device region 10D. At the same time, the FPM is discharged from the edge nozzle 18 to the edge of the wafer 10 to bring the FPM into contact with the entire surface peripheral area 10E. Further, the FPM is discharged from the back nozzle 16 toward the back center P2 of the wafer 10, so that the FPM is in contact with the entire back surface 10B. Thus, the unwanted Cu film 44 present in the peripheral surface area 10E and the end surface 10C and the rear peripheral area 10F is completely removed, and at the same time the seed Cu film (located outside the device area 10D) is removed. 40) is completely removed.

In order to remove the barrier metal film 38 made of Ta, TaN or TaO _x , hydrofluoric acid (HF) is used instead of FPM as the etching solution L _E. Then, the barrier metal film 38 located outside the device region 10D is removed in the same manner as the Cu films 40 and 44. The state of this step is shown in FIG. 15D.

In step S5, the remaining wiring Cu film 42 is annealed by a known method to improve the quality of the film 42.

In step S6, a CMP process is performed to selectively remove the wiring Cu film 42, the seed Cu film 40, and the barrier metal film 38 protruding from the groove 36 in the SiO ₂ film 34. do. Thus, as shown in FIG. 15, the Cu wiring line 46 is formed in the groove 36, and at the same time, the seed Cu film 40 and the barrier metal film 38 remain in the groove 36.

Through this CMP process, as shown in FIG. 15E, abrasive impurities 48 are attached to the surface 10A in the back surface 10B, the cross section 10C, and the surface periphery region 10E of the wafer 10.

In step S7, the abrasive impurities 48 are removed using the etching / cleaning apparatus according to the first, second or third embodiment described above. Specifically, first, the wafer 10 is supported on a wafer-bearing mechanism. Then, while the wafer 10 is rotating in the horizontal plane, pure water is discharged from the surface nozzle 14 toward the surface center P1 of the wafer 10 to cover the entire device region 10D. At the same time, the FPM is discharged from the edge nozzle 18 toward the edge of the wafer 10 to be in contact with the entire surface peripheral area 10E, and at the same time the FPM is located from the back nozzle 16 to the back center of the wafer 10 ( It is released toward P2) and comes into contact with the entire back surface 10B. Thus, the back surface 10B, the cross section 10C, and the surface peripheral region 10E of the wafer 10 are completely cleaned. The state of this step is shown in FIG. 15F.

In the fourth to sixth embodiments described above, the Cu wiring line 46 is formed in the groove 36 of the SiO ₂ film 34. However, the present invention is not limited thereto. It can be applied in any case where at least one of the etching and cleaning processes for the semiconductor wafer is required. For example, the present invention can be applied to the case where a metal wiring line or a metal electrode made of Pt, Ir, IrO, or the like is formed on a dielectric film. In addition, the present invention can be applied even when a ferroelectric film such as BST or PZT is formed on another film.

While the preferred form of the invention has been described above, it will be apparent to those skilled in the art that other modifications of the invention may be made without departing from the spirit thereof. Accordingly, the scope of the present invention will be limited only by the following claims.

Claims (49)

(a) rotation means for holding a semiconductor wafer having a device region and a surface peripheral region located outside the device region on the surface and rotating the wafer in a horizontal plane; And (b) an edge nozzle for ejecting etch liquid towards an area around the surface of the wafer; And the etching liquid discharged from the edge nozzle selectively etches unwanted material present in an area around the surface of the wafer. The wafer of claim 1, wherein the etch liquid discharged from the edge nozzle is directed along a direction of rotation of the wafer or is tangent to a wafer formed near a point of contact where the etch liquid contacts a region around the surface of the wafer. And a direction of release directed outward with respect to the etching apparatus. 2. The apparatus of claim 1, further comprising a back nozzle for ejecting etching liquid towards the back center of the wafer; And the etching liquid discharged from the backside nozzle etches unnecessary materials present on the backside of the wafer. 2. The apparatus of claim 1, further comprising a surface nozzle for discharging a protective liquid toward the center of the surface of the wafer; The protective liquid discharged from the surface nozzle covers the device region of the wafer to protect the device region from the etching liquid discharged from the edge nozzle. 10. The apparatus of claim 1, further comprising a back nozzle for releasing etching liquid toward a center of back surface of the wafer and a surface nozzle for releasing protective liquid toward a center of surface of the wafer; The etching liquid discharged from the backside nozzle etches unnecessary material present on the backside of the wafer, and the protective liquid released from the surface nozzle covers the device area of the wafer to release the etching liquid from the edge nozzle. Protecting the device region from corrosion. The etching apparatus according to claim 1, wherein the etching liquid discharged from the edge nozzle is in the form of a beam. 2. The roller of claim 1 wherein said rotating means is of a roller-chucking type, said means comprising a roller disposed along an end face of said wafer, said roller being said cross-section of said wafer. And the wafer is held in contact with and rotated at the same time. The device of claim 1, wherein the rotating means is of a pin-chucking type, the means comprising a pin supported by a support member and disposed along a cross-section of the wafer, wherein the pin is formed of the wafer. And the wafer is brought into contact with the end face and rotated simultaneously by the member. 2. The rotating apparatus of claim 1, wherein the rotating means is pin-chucking, the means comprising a first plurality of pins and a second plurality of pins supported by a support member; The first plurality of fins and the second plurality of fins are alternately disposed along a cross section of the wafer; And the first plurality of fins and the second plurality of fins alternately contact with the end face of the wafer to support the wafer and rotate simultaneously by the member. 2. The rotating apparatus of claim 1, wherein the rotating means comprises a first plurality of pins and a second plurality of pins supported by the support member; The first plurality of pins are disposed along a cross section of the wafer and the second plurality of pins are disposed along the cross section of the wafer; The first plurality of pins contacts the cross section of the wafer for one period to support the wafer and is rotated simultaneously by the member, and the second plurality of pins contacts the cross section of the wafer for another period. Thereby supporting the wafer and being rotated simultaneously by the member. The distance of the tip of the edge nozzle from the point where the longitudinal axis of the edge nozzle intersects the surface of the wafer is set to a value within the range of 1 mm to 50 mm, and the tangent of the wafer at the point. And the angle of the edge nozzle with respect to is set to a value within the range of 0 ° to 90 °. 4. The method of claim 3, wherein the distance of the tip of the back nozzle from the center of the back surface of the wafer is set to a value within a range of 70 mm to 200 mm, wherein the angle of the back nozzle with respect to the back surface of the wafer is 15 ° to 60 °. The etching apparatus is set to a value within a range. The method of claim 4, wherein the distance of the tip of the surface nozzle from the center of the surface of the wafer is set to a value within a range of 70 mm to 200 mm, wherein the angle of the surface nozzle with respect to the surface of the wafer is 15 ° to 60 °. The etching apparatus is set to a value within a range. (a) rotating means for supporting a semiconductor wafer having a device region and a surface peripheral region located outside the device region on the surface and rotating the wafer in a horizontal plane; And (b) an edge nozzle for discharging the cleaning liquid toward an area around the surface of the wafer, And the cleaning liquid discharged from the edge nozzle selectively removes unnecessary materials present in the area around the surface of the wafer. 15. The wafer of claim 14, wherein the cleaning liquid discharged from the edge nozzle is directed along the direction of rotation of the wafer or outside of the tangent of the wafer formed near the point of contact where the cleaning liquid contacts a region around the surface of the wafer. Cleaning device, characterized in that it has a discharge direction directed towards it. 15. The apparatus of claim 14, further comprising a back nozzle for discharging cleaning liquid toward the back center of the wafer; And the cleaning liquid discharged from the backside nozzle removes unnecessary substances present on the backside of the wafer. 15. The apparatus of claim 14, further comprising a surface nozzle for discharging a protective liquid towards the surface center of the wafer; The protective liquid discharged from the surface nozzle covers the device region of the wafer to protect the device region from the cleaning liquid discharged from the edge nozzle. 15. The apparatus of claim 14, further comprising a back nozzle for releasing cleaning liquid toward the center of the back surface of the wafer and a surface nozzle for releasing protective liquid toward the center of the surface of the wafer; The cleaning liquid discharged from the backside nozzle removes unnecessary material present on the backside of the wafer, and the protective liquid discharged from the surface nozzle covers the device area of the wafer and is released from the edge nozzle. Cleaning device characterized in that it protects the device area from damage. 15. The cleaning apparatus of claim 14, wherein said cleaning liquid discharged from said edge nozzle is in the form of a beam. 15. The roller of claim 14 wherein the rotating means is of a roller-chucking type, the means comprising a roller disposed along an end face of the wafer, wherein the roller is the cross-section of the wafer. And the wafer is held in contact with and rotated at the same time. 15. The device of claim 14, wherein the rotating means is of a pin-chucking type, the means comprising a pin supported by a support member and disposed along a cross section of the wafer, the pin of the wafer. And the wafer is brought into contact with the end face and rotated simultaneously by the member. 15. The apparatus of claim 14, wherein the rotating means is pin-chucking, the means comprising a first plurality of pins and a second plurality of pins supported by a support member; The first plurality of fins and the second plurality of fins are alternately disposed along a cross section of the wafer; And said first plurality of pins and said second plurality of pins alternately contact said cross-section of said wafer to hold said wafer and rotate simultaneously by said member. 15. The apparatus of claim 14, wherein the rotating means comprises a first plurality of pins and a second plurality of pins supported by a support member; The first plurality of pins are disposed along a cross section of the wafer and the second plurality of pins are disposed along the cross section of the wafer; The first plurality of pins contacts the cross section of the wafer for one period to support the wafer and is rotated simultaneously by the member, and the second plurality of pins contacts the cross section of the wafer for another period. Thereby supporting the wafer and being rotated simultaneously by the member. The distance of the end of the edge nozzle from the point where the longitudinal axis of the edge nozzle intersects the surface of the wafer is set to a value within the range of 1 mm to 50 mm, wherein the tangent of the wafer at the point. And the angle of the edge nozzle relative to is set to a value within the range of 0 ° to 90 °. The method of claim 16, wherein the distance of the end of the back nozzle from the center of the back surface of the wafer is set to a value within the range of 70mm to 200mm, the angle of the backside nozzle with respect to the backside of the wafer is 15 ° to 60 ° Washing apparatus, characterized in that set to a value within the range. 18. The method of claim 17, wherein the distance of the tip of the surface nozzle from the center of the surface of the wafer is set to a value within the range of 70 mm to 200 mm, wherein the angle of the surface nozzle relative to the surface of the wafer is between 15 ° and 60 °. Washing apparatus, characterized in that set to a value within the range. (a) rotating in a horizontal plane a semiconductor wafer having a device area and a surface peripheral area located outside the device area on the surface; And (b) releasing etching liquid toward an area around the surface of the wafer by an edge nozzle to selectively etch unnecessary material present in the area around the surface. 28. The wafer of claim 27, wherein the etching liquid discharged from the edge nozzle is directed relative to the direction of rotation of the wafer or outside of the tangent of the wafer formed near the point of contact where the cleaning liquid contacts a region around the surface of the wafer. And a direction of release directed towards. The etching method according to claim 27, wherein an etching liquid is discharged toward the center of the back surface of the wafer by a back surface nozzle to etch unnecessary material present on the back surface of the wafer. 28. The device of claim 27, wherein a protective liquid is released by a surface nozzle toward the center of the surface of the wafer to cover the device region of the wafer to protect the device region from the etch liquid emitted from the edge nozzle. Etching method. 28. The method of claim 27, wherein etching liquid is released by the back nozzle toward the center of the back surface of the wafer to etch unnecessary material present on the back surface of the wafer, and protection liquid is released by the surface nozzle towards the center of the surface of the wafer. And cover the device area of the wafer to protect the device area from the etching liquid discharged from the edge nozzle. 28. The method of claim 27, wherein said etching liquid emitted from said edge nozzle is in the form of a beam. The etching method according to claim 27, wherein an acidic or alkaline solution containing H ₂ O ₂ is used as the etching solution. 28. The method of claim 27, wherein said unnecessary material is Cu; The etching liquid may be FPM (HF / H ₂ O ₂ / H ₂ O), SPM (H ₂ SO ₄ / H ₂ O ₂ / H ₂ O), HPM (HCl / H ₂ O ₂ / H ₂ O), nitride An aqueous solution of hydrogen peroxide (HNO ₃ / H ₂ O ₂ / H ₂ O), APM (NH ₄ OH / H ₂ O ₂ / H ₂ O), and concentrated nitric acid (HNO ₃ ) Etching method. 35. The film of claim 34, wherein a SiO ₂ film is formed on or over the surface of the wafer; The composition ratio of the etching liquid is HF: H ₂ O ₂ : H ₂ O = 1-10: 1-20: 100 H ₂ SO ₄ : H ₂ O ₂ : H ₂ O = 1-10: 1-20: 100 HCl: H ₂ O ₂ : H ₂ O = 1-10: 1-20: 100 HNO ₃ : H ₂ O ₂ : H ₂ O = 1-10: 1-20: 100 NH ₄ OH: H ₂ O ₂ : H ₂ O = 1-10: 1-20: 100 Etching method characterized in that HNO ₃ = 30% -80%. 35. The film of claim 34, wherein a SiO ₂ film is formed on or over the surface of the wafer; The etching solution is an etching method characterized in that the FPM having a composition ratio of HF: H ₂ O ₂ : H ₂ O = 1: 10: 100. The etching method according to claim 27, wherein pure water or an aqueous organic acid solution is used as the protective liquid. 38. The method of claim 37, wherein the aqueous solution of organic acid is an aqueous solution of one selected from the group consisting of hydroxyl, citric acid, and malonic acid; Etching method, characterized in that the aqueous solution of the organic acid has a concentration of 0.001% to 5%. 28. The method of claim 27, wherein said unwanted material is Ta, TaN, or TaO _x ; Hydrofluoric acid (HF) is used as the etching liquid. (a) rotating in a horizontal plane a semiconductor wafer having a device area and a surface peripheral area located outside the device area on the surface; And (b) releasing the cleaning liquid toward the area around the surface of the wafer by an edge nozzle to selectively remove unwanted material present in the area around the surface. 41. The wafer of claim 40, wherein the cleaning liquid discharged from the edge nozzle is directed relative to the direction of rotation of the wafer or outside of the tangent of the wafer formed near a point of contact where the cleaning liquid contacts a region around the surface of the wafer. Cleaning direction characterized by the direction of release directed towards. 41. The method of claim 40, wherein a cleaning liquid is released by the back nozzle toward the center of the back surface of the wafer to remove unnecessary materials present on the back surface of the wafer. 41. The device of claim 40, wherein a protective liquid is released by a surface nozzle toward the center of the surface of the wafer to cover the device region of the wafer to protect the device region from the cleaning liquid discharged from the edge nozzle. How to wash. 41. The cleaning liquid of claim 40, wherein a cleaning liquid is released by the back nozzle toward the center of the back surface of the wafer to remove unnecessary material present on the back of the wafer, and a protective liquid is released by the surface nozzle toward the center of the surface of the wafer. And cover the device area of the wafer to protect the device area from the cleaning liquid discharged from the edge nozzle. 41. The method of claim 40, wherein said cleaning liquid discharged from said edge nozzle is in the form of a beam. 41. The method of claim 40, wherein an acidic or alkaline solution comprising H ₂ O ₂ is used as said washing solution. 41. The method of claim 40, wherein said unnecessary material is Cu; The washing liquid is FPM (HF / H ₂ O ₂ / H ₂ O), SPM (H ₂ SO ₄ / H ₂ O ₂ / H ₂ O), HPM (HCl / H ₂ O ₂ / H ₂ O), nitriding An aqueous solution of hydrogen peroxide (HNO ₃ / H ₂ O ₂ / H ₂ O), APM (NH ₄ OH / H ₂ O ₂ / H ₂ O), and concentrated nitric acid (HNO ₃ ) Washing method. 41. A method according to claim 40, wherein pure water or aqueous organic acid solution is used as said protective liquid. 49. The method of claim 48, wherein the aqueous solution of organic acid is an aqueous solution of one selected from the group consisting of hydroxyl, citric acid, and malonic acid; The aqueous solution of the organic acid washing method characterized in that it has a concentration of 0.001% to 5%.