JP2009182257A - Substrate treating apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a substrate treating apparatus capable of applying a uniform etching treatment to a principal plane of a substrate by preventing or suppressing the stay of an etchant at the peripheral edge part of the principal plane of the substrate. <P>SOLUTION: On the peripheral edge part of the upper surface of a wafer W held by a spin chuck 4, a first guide plate 23 and a second guide plate 33 are disposed facing each other. The first guide plate 23 and the second guide plate 28 are formed in a planar shape, have guide surfaces 28 and 38 facing the peripheral edge part of the wafer W, and are projected to the outer part of the wafer W. Nitrohydrofluoric acid existing at the peripheral edge part of the upper surface of the wafer W is smoothly discharged through the guide surfaces 28 and 38 to the outer part of the wafer W. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a semiconductor wafer, a glass substrate for a liquid crystal display device, a glass substrate for a plasma display, an FED (Field Emission Display) substrate, an optical disk substrate, a magnetic disk substrate, a magneto-optical disk substrate, a photomask substrate, etc. The present invention relates to a substrate processing apparatus for performing an etching process using an etchant on a main surface of a substrate.

  In a semiconductor device manufacturing process, a liquid processing using a processing liquid is performed on a semiconductor wafer (hereinafter simply referred to as “wafer”). One of such liquid processes is an etching process performed by supplying an etching liquid to the main surface of the wafer. In this etching process, an etching process for forming a pattern on the main surface of the wafer (the wafer itself or a thin film formed on the wafer) and an etching process for uniformly removing the surface layer region of the main surface of the wafer. In addition, a cleaning process for removing foreign substances on the main surface of the wafer by using an etching action is included.

  There are two types of substrate processing apparatuses for processing a main surface of a wafer with a processing solution: a batch type for processing a plurality of wafers at once, and a single wafer type for processing wafers one by one. There is a thing. The single-wafer type substrate processing apparatus includes, for example, a spin chuck that rotates while holding a wafer in a substantially horizontal posture, and a processing liquid nozzle that supplies a processing liquid toward the main surface of the wafer held by the spin chuck. And a nozzle moving mechanism for moving the processing liquid nozzle on the wafer.

For example, when it is desired to perform an etching process on a device forming surface on which a device is formed on the wafer, the wafer is held by the spin chuck with the device forming surface facing upward. Then, the etching liquid is discharged from the processing liquid nozzle onto the upper surface of the wafer rotated by the spin chuck, and the processing liquid nozzle is moved by the nozzle moving mechanism. As the processing liquid nozzle moves, the landing point of the etching liquid on the upper surface of the wafer moves. By scanning the landing point between the rotation center and the peripheral edge of the upper surface of the wafer, the etching solution can be spread over the entire upper surface of the wafer.
JP 2007-88381 A

  However, the etching solution supplied to the central portion of the upper surface of the wafer receives a centrifugal force due to the rotation of the wafer and moves outward in the rotational radius direction of the upper surface of the wafer. Therefore, an excessive amount of the etching solution is supplied to the peripheral portion of the upper surface of the wafer to which the etching solution moving from the central portion of the upper surface is applied in addition to the etching solution from the processing solution nozzle. For this reason, the etching rate is higher at the peripheral portion of the upper surface of the wafer than at the central portion, and there is a problem that non-uniform processing occurs in the upper surface of the wafer.

  The inventors of the present application have studied a process for thinning (thinning) a wafer by an etching process using a single-wafer type substrate processing apparatus. More specifically, the rear surface of the wafer (non-device formation surface where no device is formed) is directed upward, and fluoric nitric acid having a high etching power is supplied to the wafer rear surface (upper surface) as an etchant. The wafer material on the surface layer portion on the back surface of the wafer is removed by etching with hydrofluoric acid, thereby reducing the thickness of the wafer.

  The inventors of the present application have found that the higher the rotational speed of the wafer during the etching process, the greater the difference in the etching rate between the peripheral edge portion and the central portion of the upper surface of the wafer. If the wafer is rotated at a predetermined low rotation speed (40 to 60 rpm), the difference in the etching rate between the peripheral portion and the central portion is reduced, and the in-plane uniformity of the etching process becomes relatively good. I found out.

  However, when the wafer is rotated at such a low rotation speed, the centrifugal force acting on the etching solution on the upper surface of the wafer is small, and the etching solution that has moved to the peripheral portion of the wafer moves from the peripheral portion of the wafer to the side of the wafer. It is hard to be excluded. Therefore, the etching solution stays at the peripheral edge of the upper surface of the wafer, and a thick liquid film (liquid pool) of the etching solution is formed in this region. This thick liquid film contains a deactivated etching solution in a high ratio and has a low etching power, and also takes heat away from the peripheral edge of the wafer, causing a temperature drop at the peripheral edge of the upper surface of the wafer. As a result, there has been a problem that the etching rate is lowered at the peripheral edge of the upper surface of the wafer. Therefore, it is necessary to improve the etching rate also at the peripheral edge of the wafer and further improve the in-plane uniformity of the etching process.

In particular, when an etching process is performed on a wafer having high lyophobic properties such as a silicon wafer, the film thickness of the liquid film (liquid pool) formed on the peripheral edge of the upper surface of the wafer is increased. There has been a problem in that the etching rate at the periphery of the upper surface of the wafer is significantly reduced.
Accordingly, an object of the present invention is to provide a substrate processing apparatus capable of performing or uniformly etching the main surface of the substrate by preventing or suppressing the retention of the etchant at the peripheral portion of the main surface of the substrate. It is.

  According to the first aspect of the present invention, there is provided a substrate rotating means (4) for rotating around a predetermined rotation axis while holding the substrate (W), and an etching solution on the main surface of the substrate rotated by the substrate rotating means. An etching solution supply means (5) for supplying the substrate and a guide surface (28, 38; 48) along a plane intersecting the main surface of the substrate rotated by the substrate rotating means, A guide member that is disposed to be opposed to the main surface with a gap at the peripheral edge, and guides the etchant toward the outside of the substrate by bringing the liquid film of the etchant on the main surface into contact with the guide surface. (23, 33; 43). The substrate processing apparatus (1; 60; 70).

In addition, the alphanumeric characters in parentheses represent corresponding components in the embodiments described later. The same applies hereinafter.
According to this configuration, the guide member is disposed to face the peripheral edge portion of the main surface of the substrate. If a large amount of etchant is present at the peripheral edge of the main surface of the substrate facing the guide member, the guide surface of the guide member contacts the etchant at the peripheral edge of the main surface of the substrate, and the etchant is removed from the substrate. I will guide you to. Thus, the etchant at the peripheral edge of the main surface of the substrate can be smoothly discharged out of the substrate. Thereby, retention of the etching liquid in the peripheral part of the main surface of the substrate can be prevented or suppressed. Therefore, it is possible to suppress or prevent a decrease in the etching rate at the peripheral portion of the main surface of the substrate, and a uniform etching process can be performed on the main surface of the substrate.

The invention according to claim 2 is the substrate processing apparatus according to claim 1, comprising a plurality of the guide members, wherein the plurality of guide members (23, 33) are arranged at different positions in the circumferential direction of the substrate. .
According to this configuration, since the plurality of guide members are arranged on the peripheral edge portion of the main surface of the substrate, the etching solution can be discharged out of the substrate at a plurality of locations on the peripheral edge portion of the main surface of the substrate. Therefore, even when a large amount of etching solution is present in a wide range of the peripheral portion of the substrate, the retention of the etching solution in the peripheral portion of the main surface of the substrate can be prevented or suppressed.

As described in claim 3, the guide surface (28, 38, 48) may be formed of a flat surface. Thereby, the etching solution on the peripheral edge of the substrate can be smoothly discharged out of the substrate.
In this case, as described in claim 4, the guide member may be arranged such that the guide surface is along a direction orthogonal to the rotational radius direction of the substrate. As the substrate rotates, the etching solution on the peripheral edge of the substrate moves along the circumferential direction. If the guide surface is along a direction orthogonal to the rotational radius direction of the substrate, the etching solution moving along this direction can be guided to be squeezed out of the substrate. Thereby, etching liquid can be smoothly discharged | emitted out of a board | substrate from the peripheral part of the main surface of a board | substrate.

  Further, when the substrate held by the substrate rotating means is circular, the guide surface (28A) is formed by a curved surface along the peripheral edge shape of the substrate as described in claim 5. Also good. As the substrate rotates, the etchant on the peripheral edge of the substrate moves along the rotational radius of the substrate by centrifugal force, and also moves downstream of the substrate in the rotational direction by the frictional force between the main surface of the substrate and the etchant. Moving. If the guide surface is formed by a curved surface along the shape of the peripheral edge of the substrate, the etchant that moves along this direction can be smoothly moved out of the substrate both in the radial direction of the substrate and in the downstream side of the rotational direction of the substrate. It can be guided to rub out. Thereby, etching liquid can be smoothly discharged | emitted out of a board | substrate from the peripheral part of the main surface of a board | substrate.

According to a sixth aspect of the present invention, the guide member is provided so as to be swingable about a predetermined axis (C1, C2) extending in parallel with the rotation axis. It is a substrate processing apparatus of description.
According to the present invention, since the guide member is swingable about a predetermined axis, the attitude (angle) of the guide surface with respect to the flow of the etchant on the main surface of the substrate can be changed. Then, the guide member is held in such a posture (angle) that the guide surface can efficiently guide the etching solution on the main surface of the substrate to the outside of the substrate. The retention of the etchant can be more effectively prevented or suppressed.

The invention according to claim 7 further includes control means (50) for controlling a distance between the main surface of the substrate held by the substrate rotating means and the guide member. The substrate processing apparatus according to one item.
In order to keep the etching rate constant throughout the entire processing period, it is desirable that the liquid film of the etching solution on the main surface of the substrate has a constant thickness throughout the entire processing period. However, in the etching process for reducing the thickness of the substrate with the etchant, since the substrate material on the main surface of the substrate is removed by etching, the gap between the main surface of the substrate and the guide member increases as the etching process proceeds, There is a possibility that the liquid film of the etchant at the peripheral edge of the main surface of the substrate becomes thick.

  According to this invention, the clearance gap between the main surface of a board | substrate and a guide member can be adjusted. Therefore, for example, as the etching process proceeds, the distance between the substrate rotating means and the guide member is controlled so that the gap between the main surface of the substrate and the guide member is constant, so that the substrate can be used throughout the entire etching process. The liquid film of the etching solution at the peripheral edge of the main surface can be made uniform. Thereby, the etching rate can be kept constant throughout the entire processing period.

  Further, the etching solution supply means scans the etching solution on the main surface of the substrate along a linear scan path (T) along the rotation radius direction of the substrate rotated by the substrate rotation means. In this case, as described in claim 8, it is preferable that the guide member is disposed such that the upstream end portion in the substrate rotation direction is located on an extension line of the scan path.

  The etching solution supplied from the etching supply unit onto the main surface of the substrate gathers at a predetermined peripheral edge of the substrate. In particular, when the substrate is rotated at a low rotation speed (40 to 60 rpm), the etchant collects at the peripheral edge on the extension line of the scan path. Therefore, by arranging the guide member so that the upstream end portion thereof is located on the extension line of the scan path, the retention of the etching solution at the peripheral portion on the main surface of the substrate is further effectively prevented or suppressed. be able to.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.
FIG. 1 is a cross-sectional view schematically showing a configuration of a substrate processing apparatus 1 according to one embodiment (first embodiment) of the present invention.
The substrate processing apparatus 1 is used for thinning (thinning) a wafer W against a back surface (non-device forming surface) opposite to a device forming region side surface of a circular wafer W made of, for example, a silicon wafer. This is a single wafer type apparatus for performing an etching process. In this embodiment, for example, hydrofluoric acid (mixed liquid of hydrofluoric acid and nitric acid) is used as the etching liquid.

  The substrate processing apparatus 1 rotates a substrate in a processing chamber 2 partitioned by a partition wall (not shown) to rotate the wafer W about a vertical axis while holding the wafer W in a substantially horizontal posture with its back surface as an upper surface. A spin chuck 4 as means, a hydrofluoric acid nozzle (etching solution supply means) 5 for supplying hydrofluoric acid to the upper surface of the wafer W held by the spin chuck 4, and the upper surface of the wafer W held by the spin chuck 4 The DIW nozzle 6 for supplying DIW (deionized water) as a rinsing liquid toward the substrate and the peripheral portion of the upper surface of the wafer W held by the spin chuck 4 for removing hydrofluoric acid A first liquid discharge mechanism 7 and a second liquid discharge mechanism 8 are provided.

  The spin chuck 4 is a vacuum suction chuck. The spin chuck 4 is attached to a spin shaft 9 extending in a substantially vertical direction and an upper end of the spin shaft 9, and an adsorption base that adsorbs and holds the back surface (lower surface) of the wafer W in a substantially horizontal posture. 10 and a spin motor 11 having a rotation shaft coupled coaxially with the spin shaft 9. Accordingly, when the spin motor 11 is driven in a state where the back surface of the wafer W is sucked and held by the suction base 10, the wafer W rotates around the central axis of the spin shaft 9.

  The nitric acid nozzle 5 is a straight nozzle that, for example, discharges nitric acid in a continuous flow state, and is attached to the tip of the first arm 12 that extends substantially horizontally above the spin chuck 4. The first arm 12 is supported by a first arm support shaft 13 extending substantially vertically on the side of the spin chuck 4. A first arm swing drive mechanism 14 is coupled to the first arm support shaft 13, and the first arm support shaft 13 is rotated by the driving force of the first arm swing drive mechanism 14, thereby The arm 12 can be swung.

A fluorine nitrate supply pipe 17 is connected to the fluorine nitrate nozzle 5. The hydrofluoric acid supply pipe 17 is supplied with hydrofluoric acid from a hydrofluoric acid supply source, and in the middle of the hydrofluoric acid supply pipe 17 is a hydrofluoric acid supply pipe 17 for switching between supply and stop of the supply of hydrofluoric acid. A nitric acid valve 18 is interposed.
The DIW nozzle 6 is, for example, a straight nozzle that discharges DIW in a continuous flow state, and is disposed above the spin chuck 4 with its discharge port directed toward the center of the wafer W. A DIW supply pipe 19 is connected to the DIW nozzle 6 so that DIW from a DIW supply source is supplied through the DIW supply pipe 19. In the middle of the DIW supply pipe 19, a DIW valve 20 for switching between supply and stop of supply of DIW to the DIW nozzle 6 is interposed.

  The first liquid discharge mechanism 7 includes a second arm support shaft 21 that extends substantially vertically on the side of the spin chuck 4, a second arm 22 that is supported by the second arm support shaft 21 and extends substantially horizontally, A first guide plate 23 as a guide member, which is held at the tip of the second arm 22 and guides the hydrofluoric acid on the upper surface of the wafer W to the outside of the wafer W, and the second arm support shaft 21 are rotated. A second arm swing drive mechanism 24 for swinging the arm 22 and a second arm lift drive mechanism 25 for lifting the second arm 22 are provided.

  A columnar first plate holder 26 is attached to the tip of the second arm 22 so as to be rotatable around a vertical axis via, for example, a pair of bearings (not shown). The upper part of the first guide plate 23 is fixed to the lower end of the first plate holder 26. A first rotation drive mechanism 27 for rotating the first plate holder 26 together with the first guide plate 23 is coupled to the first plate holder 26.

The second arm swing drive mechanism 24 is coupled to the second arm support shaft 21, and the second arm 22 can be swung by rotating the second arm support shaft 21.
The second arm raising / lowering drive mechanism 25 is coupled to the second arm support shaft 21, and the second arm 22 can be raised and lowered by raising and lowering the second arm support shaft 21.
FIG. 2 is a perspective view showing a schematic configuration of the first guide plate 23.

  The first guide plate 23 is formed in a flat plate shape having a longitudinal length, and the length in the longitudinal direction is set to a length L1 that is about the radius of the wafer W. The first guide plate 23 is attached to the first plate holder 26 so that its longitudinal direction extends in the horizontal direction and its main surface is orthogonal to the horizontal plane. One side (the back side shown in FIG. 2) of the main surface of the first guide plate 23 forms a guide surface 28 for guiding hydrofluoric acid to the outside of the wafer W, and is formed by a flat surface. ing. During the etching process, the first guide plate 23 is disposed to face the peripheral edge of the upper surface of the wafer W.

Next, the second liquid discharge mechanism 8 will be described with reference to FIG.
The second liquid discharge mechanism 8 includes a third arm support shaft 31 that extends substantially vertically on the side of the spin chuck 4, a third arm 32 that is supported by the third arm support shaft 31 and extends substantially horizontally, A second guide plate 33 as a guide member, which is held at the tip of the third arm 32 and guides the hydrofluoric acid on the upper surface of the wafer W to the outside of the wafer W, and the third arm support shaft 31 are rotated, so that the third A third arm swing drive mechanism 34 for swinging the arm 32 and a third arm lift drive mechanism 35 for lifting the third arm 32 are provided.

  A cylindrical second plate holder 36 is attached to the distal end portion of the third arm 32 so as to be rotatable around a vertical axis via a pair of bearings (not shown), for example. The upper part of the second guide plate 33 is fixed to the lower end of the second plate holder 36. A second rotation drive mechanism 37 for rotating the second plate holder 36 together with the second guide plate 33 is coupled to the second plate holder 36.

The third arm swing drive mechanism 34 is coupled to the third arm support shaft 31, and the third arm 32 can be swung by rotating the third arm support shaft 31.
The third arm raising / lowering drive mechanism 35 is coupled to the third arm support shaft 31, and the third arm 32 can be raised / lowered by raising / lowering the third arm support shaft 31.
The second guide plate 33 is formed in the same specifications (size and shape) as the first guide plate 23. The second guide plate 33 is attached to the second plate holder 36 so that its longitudinal direction extends in the horizontal direction and its main surface is orthogonal to the horizontal plane. The second guide plate 33 has a flat guide surface 38 (see FIG. 3) for guiding the hydrofluoric acid to the outside of the wafer W. During the etching process, the second guide plate 33 is disposed to face the peripheral edge of the upper surface of the wafer W.

FIG. 3 is an illustrative plan view for explaining the arrangement positions of the first guide plate 23 and the second guide plate 33 during the etching process.
During the etching process, the nitric acid nozzle 5 is reciprocated (scanned) between the proximity position T1 and the substrate peripheral edge position T2 along the rotational radius of the wafer W while the nitric acid nozzle 5 is ejected. The The proximity position T1 is a position determined so as to be close to the rotation center C of the wafer W and so that the deposited fluorinated nitric acid can spread on the wafer W and pass through the rotation center C, and the distance L2 from the rotation center C. Only separated. When the wafer W having an outer diameter of 200 mm is used, the interval L2 can be exemplified by about 22.5 mm, for example. At this time, the liquid deposition point P of the fluorine nitric acid on the upper surface of the wafer W is an arc (substantially linear) in the arc-shaped trajectory passing through the rotation center C of the wafer W from the proximity position T1 to the substrate peripheral edge position T2. ) While moving along the path (scan path T).

  The first guide plate 23 has a longitudinal direction along the scan path T, and an upstream end of the wafer rotation direction at a position of 90 ° downstream from the scan path T on the upper surface of the wafer W in the rotation direction of the wafer W. It is arranged to be located in. In this arrangement state, the guide surface 28 of the first guide plate 23 faces the peripheral edge of the wafer W, and the downstream end of the guide surface 28 in the wafer rotation direction protrudes outward from the wafer W. At this time, the distance between the guide surface 28 and the rotation center C of the wafer W is L3. When the wafer W having an outer diameter of 200 mm is used, the distance L3 can be exemplified by about 70 mm, for example.

  The second guide plate 33 has a longitudinal direction along a direction perpendicular to the scanning path T, and an upstream end of the wafer rotation direction on the downstream side in the rotation direction of the wafer W from the scanning path T on the upper surface of the wafer W. It is arranged so as to be positioned at a position of 180 ° (on the extension line of the scan path T on the opposite side across the scan path T and the rotation center C of the wafer W). In this arrangement state, the guide surface 38 of the second guide plate 33 faces the peripheral edge of the wafer W, and the end of the guide surface 38 on the downstream side in the rotational direction protrudes outward from the wafer W. At this time, the distance between the guide surface 38 and the rotation center C of the wafer W is L3.

4 is a cross-sectional view taken along the section line DD of FIG.
During the etching process, the lower end surface of the second guide plate 33 is disposed opposite to the upper surface of the wafer W (wafer W before the etching process) held by the spin chuck 4 (adsorption base 10) with a gap S therebetween. As this gap S, for example, about 0.5 mm can be exemplified. When the third arm raising / lowering drive mechanism 35 is driven and the third arm 32 moves up and down, the gap S between the lower end surface of the second guide plate 33 and the upper surface of the suction base 10 changes.

  Although not shown, during the etching process, the lower end surface of the first guide plate 23 forms a gap S with the upper surface of the wafer W (wafer W before the etching process) held by the spin chuck 4 (adsorption base 10). They are arranged opposite to each other. As this gap S, for example, about 0.5 mm can be exemplified. When the second arm raising / lowering drive mechanism 25 is driven and the second arm 22 is raised and lowered, the gap S between the lower end surface of the first guide plate 23 and the upper surface of the suction base 10 changes.

FIG. 5 is a plan view for explaining the second guide plate 33.
The second guide plate 33 can swing around a vertical axis C <b> 2 passing through the upstream end portion (or the vicinity thereof) in the wafer rotation direction. Specifically, the third guide plate 33 is swung by the third arm swing drive mechanism 34 and the second guide plate 33 is rotated by the second rotation drive mechanism 37. 33 swings around the vertical axis C2 (the state after swinging is shown by a two-dot chain line in FIG. 5).

  Although not shown, the first guide plate 23 can swing around a vertical axis C1 (see FIG. 3) passing through the upstream end portion (or the vicinity thereof) in the wafer rotation direction. Specifically, the first guide plate 23 is oscillated by the second arm oscillating drive mechanism 24 and the first guide plate 23 is rotated by the first rotation drive mechanism 27 together. 23 swings around the vertical axis C1.

FIG. 6 is a block diagram showing an electrical configuration of the substrate processing apparatus 1.
The substrate processing apparatus 1 includes a control device 50 having a configuration including a microcomputer.
The control device 50 includes a spin motor 11, a first arm swing drive mechanism 14, a hydrofluoric acid valve 18, a DIW valve 20, a second arm lift drive mechanism 25, a second arm swing drive mechanism 24, and a first rotational drive. A mechanism 27, a third arm lifting drive mechanism 35, a third arm swing drive mechanism 34, a second rotation drive mechanism 37, and the like are connected as control targets.

FIG. 7 is a flowchart showing an example of processing of the wafer W in the substrate processing apparatus 1.
An unprocessed wafer W is loaded into the processing chamber 2 by a transfer robot (not shown) and delivered to the spin chuck 4 (step S1). At this time, the hydrofluoric acid nozzle 5, the first guide plate 23, and the second guide plate 33 are retracted to the retract position on the side of the spin chuck 4. Also, the hydrofluoric acid valve 18 and the DIW valve 20 are both controlled to be closed.

  After the wafer W is delivered to the spin chuck 4, the control device 50 drives the spin motor 11 to rotate the spin chuck 4 at a constant rotational speed at a low rotational speed (for example, 50 rpm). Further, the control device 50 drives the first arm swing drive mechanism 14 to guide the fluorine nitrate nozzle 5 to the upper side of the wafer W. Further, the controller 50 drives the second arm swing drive mechanism 24 to guide the first guide plate 23 to the processing position on the peripheral edge of the wafer W (see FIG. 3). Further, the control device 50 drives the third arm swing drive mechanism 34 to guide the second guide plate 33 to the processing position on the peripheral edge of the wafer W (see FIG. 3).

When the nitric acid nozzle 5 reaches above the wafer W, the control device 50 opens the nitric acid valve 18 to discharge the nitric acid from the nitric acid nozzle 5. Further, the control device 50 drives the first arm swing drive mechanism 14 to cause the hydrofluoric acid nozzle 5 to reciprocally scan between the proximity position T1 and the position above the substrate peripheral end position T2 at a constant speed (step). S2).
As a result, the liquid landing point P on the upper surface of the wafer W scans back and forth along the scan path T (see FIG. 3). It takes, for example, about 1.5 seconds for the fluorine nitric acid landing point P to return from the proximity position T1 to the proximity position T1 again via the substrate peripheral edge position T2. Thereafter, the reciprocating scan of the liquid nitric acid landing point P is repeatedly performed until a predetermined processing time elapses. During this reciprocating scan, the flow rate of the hydrofluoric acid discharged from the hydrofluoric acid nozzle 5 is kept constant (for example, 0.85 L / min).

  During this reciprocating scan, the nitric acid supplied to the upper surface of the wafer W is directed toward the outside of the wafer W while drawing a large vortex centered on the rotation center C, as shown in FIG. Moving. Since the rotation speed of the wafer W is the low rotation speed, the hydrofluoric acid discharged along the scan path T is 90 to 270 ° of the wafer W at the downstream side in the rotation direction of the wafer W from the substrate peripheral edge position T2. A wide range is supplied to the peripheral edge of the. In particular, a large amount reaches the vicinity of the peripheral region (shown by x in FIG. 3) at a position of 180 ° downstream of the substrate peripheral edge position T2 in the rotation direction of the wafer W.

  The nitric acid that has reached the peripheral edge of the wafer W contacts the guide surface 28 of the first guide plate 23 or the guide surface 38 of the second guide plate 33. The nitric acid in contact with the guide surface 28 is guided to the outside of the wafer W along the guide surface 28. Since the guide surface 28 is along the direction orthogonal to the wafer rotation radius direction at the upstream end position in the wafer rotation direction, the hydrofluoric acid moving along the circumferential direction of the wafer W is moved out of the wafer W. It is guided to rub out. Thereby, the hydrofluoric acid is smoothly discharged out of the wafer W from the peripheral edge of the upper surface of the wafer W.

  Further, the hydrofluoric acid that has come into contact with the guide surface 38 of the second guide plate 33 is guided to the outside of the wafer W through the guide surface 38. Since the guide surface 38 is along the direction orthogonal to the wafer rotation radius direction at the upstream end position in the wafer rotation direction, the hydrofluoric acid moving along the circumferential direction of the wafer W is moved out of the wafer W. It is guided to rub out. Thereby, the hydrofluoric acid is smoothly discharged out of the wafer W from the peripheral edge of the upper surface of the wafer W. Therefore, a significant liquid pool does not occur at the peripheral edge of the wafer W.

In the etching process, since the wafer material on the upper surface of the wafer W is removed by etching with hydrofluoric acid, the gap S between the upper surface of the wafer W and the first and second guide plates 23 and 33 increases with the progress of the etching process. There is a fear.
The control device 50 controls the second arm elevating drive mechanism 25 and the third arm elevating drive mechanism 35 every time a predetermined time elapses, so that the first and second guide plates 23 and 33 are predetermined. Lower by the amount of descent. This descending amount is an amount corresponding to the etching amount of the wafer W at a predetermined time. Accordingly, the gap S between the upper surface of the wafer W and the first and second guide plates 23 and 33 is kept constant regardless of the progress of the etching process.

  After performing the etching process for a predetermined time (for example, 300 seconds), the control device 50 closes the hydrofluoric acid valve 18 and stops the discharge of the nitric acid from the hydrofluoric acid nozzle 5. Further, the control device 50 drives the first arm swing drive mechanism 14 to retract the fluorine nitrate nozzle 5 to the retracted position on the side of the spin chuck 4. Further, the control device 50 drives the second arm swing drive mechanism 24 to retract the first guide plate 23 to the retracted position on the side of the spin chuck 4. Furthermore, the control device 50 drives the third arm swing drive mechanism 34 to retract the second guide plate 33 to the retract position on the side of the spin chuck 4.

  Next, the control device 50 controls the spin motor 11 to accelerate the rotational speed of the spin chuck 4 to a predetermined rinsing processing rotational speed (about 100 rpm), and opens the DIW valve 20, and from the DIW nozzle 6, DIW is supplied toward the center of rotation of the upper surface of the wafer W in a rotating state (step S3). Thereby, the hydrofluoric acid on the wafer W is washed away, and the wafer W is rinsed. The discharge flow rate of DIW from the DIW nozzle 6 in this rinsing process is, for example, 2.0 L / min.

  After performing this rinsing process for a predetermined time (for example, 60 seconds), control device 50 closes DIW valve 20 and ends the rinsing process. The control device 50 further controls the spin motor 11 to accelerate the rotation speed of the spin chuck 4 to a predetermined drying rotation speed (about 1000 to 2000 rpm). As a result, the DIW on the upper surface of the wafer W is shaken off by the centrifugal force, and the wafer W is spin-dried (step S4).

After performing spin drying for a predetermined time (for example, 30 seconds), the control device 50 controls the spin motor 11 to stop the rotation of the spin chuck 4. Thereafter, the processed wafer W is unloaded from the processing chamber 2 by the transfer robot (step S5).
As described above, according to this embodiment, the first and second guide plates 23 and 33 are arranged to face each other in the peripheral portion of the upper surface of the wafer W, where the nitric acid flowing on the wafer W gathers. Then, the first and guide surfaces 28 and 38 come into contact with the hydrofluoric acid on the peripheral edge of the upper surface of the wafer W, and guide the hydrofluoric acid outside the wafer W. Thus, the hydrofluoric acid at the peripheral edge of the upper surface of the wafer W can be smoothly discharged out of the wafer W. Thereby, it is possible to prevent or suppress the retention of hydrofluoric acid at the peripheral edge of the upper surface of the wafer W. Therefore, a decrease in the etching rate at the peripheral edge of the upper surface of the wafer W can be suppressed or prevented, and a uniform etching process can be performed on the upper surface of the wafer W.

In addition, since the plurality of guide plates 23 and 33 are arranged at the peripheral edge of the upper surface of the wafer W, the nitric acid is smoothly discharged out of the wafer W over a wide range of the peripheral edge of the wafer W. Therefore, even when fluorinated nitric acid is supplied over a wide range of the peripheral portion of the wafer W, the stagnation of the fluorinated nitric acid at the peripheral portion of the upper surface of the wafer W can be prevented or suppressed.
FIG. 8A is a plan view schematically showing the configuration of a substrate processing apparatus according to another embodiment (second embodiment) of the present invention. FIG. 8B is a perspective view schematically showing the configuration of the second guide plate applied to the substrate processing apparatus. In the second embodiment, parts corresponding to those shown in the above-described embodiment (first embodiment) are denoted by the same reference numerals as those in the first embodiment, and description thereof is omitted. To do.

In the substrate processing apparatus according to the second embodiment, the second guide plate 33A is formed in a curved plate shape instead of a flat plate shape. The second guide plate 33 </ b> A has a guide surface 38 </ b> A that is a curved surface along the peripheral end shape of the wafer W. The guide surface 38 guides the hydrofluoric acid on the wafer W to the outside of the wafer W.
Since the guide surface 38 </ b> A is formed by a curved surface along the peripheral end shape of the wafer W, it is possible to guide the hydrofluoric acid moving along the circumferential direction of the wafer W so as to be squeezed out of the wafer W. . As a result, hydrofluoric acid as an etchant is smoothly discharged from the upper surface of the wafer W to the outside of the wafer W.

FIG. 9 is a plan view schematically showing the configuration of a substrate processing apparatus according to another embodiment (third embodiment) of the present invention. In the third embodiment, parts corresponding to those shown in the above-described embodiment (first embodiment) are denoted by the same reference numerals as those in the first embodiment, and description thereof is omitted. To do.
The substrate processing apparatus according to the third embodiment includes only one guide plate 33. Specifically, the first guide plate 23 is omitted from the substrate processing apparatus 1 according to the first embodiment, and only the second guide plate 33 is disposed oppositely on the peripheral edge of the upper surface of the wafer W. Yes.

As described above, the nitric acid discharged along the scan path T during the etching process is a peripheral region at a position 180 ° downstream of the substrate peripheral edge position T2 in the rotation direction of the wafer W (illustrated by a cross in FIG. 3). ) Reaches a large amount in the vicinity, so that the nitric acid at the peripheral edge of the wafer W can be discharged out of the wafer W by the second guide plate 33.
Moreover, it can also be set as the structure provided only with the 1st guide plate 33 instead of the 2nd guide plate 23. FIG.

Further, instead of the first and second guide plates 23 and 33, a third guide plate 43 (shown by a two-dot chain line in FIG. 9) may be provided.
The longitudinal direction of the third guide plate 43 is along the scan path T, and the upstream end thereof is disposed at a position of 90 ° upstream of the scan path T on the upper surface of the wafer W in the rotation direction of the wafer W. ing. In this arrangement state, the guide surface 48 of the third guide plate 43 faces the peripheral edge of the wafer W, and the downstream end of the guide surface 48 in the wafer rotation direction protrudes outward of the wafer W. At this time, the distance between the guide surface 48 and the rotation center C of the wafer W is L3.

Each guide plate 23, 33, 43 may be formed in a curved plate shape like the second guide plate 33A shown in FIG. 8B, and may have a guide surface made of a curved surface 38A.
Next, examples and comparative examples will be described.
For thinning by supplying hydrofluoric acid from a hydrofluoric acid nozzle 5 configured in the form of a scan nozzle shown in FIG. 1 to the upper surface (back surface) of a wafer W made of a silicon wafer having an outer diameter of 200 mm in a rotating state. The test which performs the etching process of was performed.

  In this etching test, the point of contact P of the nitric acid from the nitric acid nozzle with the proximity position T1 separated from the rotation center C by 22.5 mm along the scanning path T shown in FIG. A reciprocating scan was performed with respect to the substrate peripheral edge position T2 on the edge. Fluoric nitric acid prepared by mixing nitric acid and hydrofluoric acid at a volume ratio of 5: 1 was discharged from the hydrofluoric acid nozzle 5 onto the wafer W at a flow rate of 0.85 L / min. The moving speed of the hydrofluoric acid nozzle 5 during the etching process was, for example, 160 mm / sec, and the rotation speed of the wafer W during the etching process was 52 rpm. The etching processing time was 300 seconds. Then, an in-plane distribution of the etching rate of the silicon wafer W (relation between radial position and etching rate) was obtained.

In Example 1, the etching process was performed using the substrate processing apparatus of FIG. 9 (adopting the second guide plate 33).
In Example 2, the etching process was performed using the substrate processing apparatus of FIG. 9 (adopting the third guide plate 43).
In Example 3, the etching process was performed using the substrate processing apparatus of FIG. 8A.

In the comparative example, the etching process was performed without using any of the first to third guide plates 23, 33, and 43.
As a result of the etching test, in Examples 1 to 3, deterioration of the etching rate at the peripheral edge of the wafer W could be suppressed.
Moreover, the etching uniformity represented by the following formula (1) was evaluated. In Example 1, the etching uniformity is 16.4%, in Example 2, the etching uniformity is 13.2%, in Example 3, the etching uniformity is 14.3%, and in the comparative example, the etching uniformity. The sex was 19.4%.

このことから、実施例１〜実施例３で、エッチング処理の面内均一性が良好であることが理解される。このうち実施例３では、エッチング処理の面内均一性がとくに優れていることが理解できる。

From this, it is understood that the in-plane uniformity of the etching process is good in Examples 1 to 3. Among these, in Example 3, it can be understood that the in-plane uniformity of the etching process is particularly excellent.

As mentioned above, although three embodiment of this invention was described, this invention can also be implemented with another form.
In the first to third embodiments, the guide plates 23 and 33 are swung around the vertical axes C 1 and C 2, and the guide surfaces 28 and 38 are most effective for transferring the nitric acid on the upper surface of the wafer W to the outside of the wafer W. It can also be held in a posture (angle) that can be guided well.

  In the first and second embodiments, the configuration in which the first guide plate 23 and the second guide plate 33 are combined has been described as an example. However, the first guide plate 23 and the third guide plate 43 may be combined. Combination may be sufficient and the combination of the 2nd guide plate 33 and the 3rd guide plate 43 may be sufficient. Furthermore, a combination of all of the first to third guide plates 23, 33, 43 may be used. And some of the 1st-3rd guide plates 23, 33, and 43 may be formed in the curved plate shape like FIG. 8A and FIG. 8B.

Further, in the first to third embodiments, scanning is performed within the in-plane range of the wafer W. However, the liquid deposition point P of the nitric acid from the nitric acid nozzle 5 exceeds the peripheral end surface of the wafer W, You may scan to the outside.
In the first to third embodiments, the case where the nitric acid nozzle 5 is reciprocally scanned has been described as an example, but the nitric acid nozzle 5 may be unidirectionally scanned. In this case, the unidirectional scan means that the nitric acid is discharged from the nozzle 5 only when the nozzle is moved in one direction, and the discharge of the hydrofluoric acid from the nozzle 5 is stopped when the nozzle is moved in the other direction.

  In the above-described three embodiments, the substrate processing apparatus 1 that performs an etching process for thinning the wafer W has been described as an example. However, for example, a disk-shaped wafer W made of an oxide film silicon wafer is used. In this case, an etching process for removing the oxide film may be performed on the upper surface (lower surface) on the device formation region side. In such a case, it is desirable to use, for example, hydrofluoric acid as an etchant. In addition, when performing an etching process for removing the nitride film of the wafer W, phosphoric acid can be used as an etching solution.

  In addition, various design changes can be made within the scope of the matters described in the claims.

It is sectional drawing which shows typically the structure of the substrate processing apparatus which concerns on the 1st Embodiment of this invention. It is a perspective view which shows schematic structure of the 1st guide plate of the substrate processing apparatus shown in FIG. It is an illustrative top view for demonstrating the arrangement position of the 1st guide plate and the 2nd guide plate at the time of an etching process. It is sectional drawing seen from the cut surface line DD of FIG. It is a top view for demonstrating rocking | fluctuation of the 2nd guide plate of the substrate processing apparatus shown in FIG. It is a block diagram which shows the electric constitution of the substrate processing apparatus shown in FIG. 3 is a flowchart showing an example of processing of a wafer W in the substrate processing apparatus shown in FIG. It is a top view which shows diagrammatically the composition of the substrate processing device concerning a 2nd embodiment of the present invention. It is a perspective view which shows diagrammatically the composition of the 2nd guide plate of the substrate processing apparatus concerning a 2nd embodiment of the present invention. It is a top view which shows diagrammatically the structure of the substrate processing apparatus which concerns on the 3rd Embodiment of this invention.

Explanation of symbols

1 substrate processing equipment 4 spin chuck (substrate rotating means)
5 Nitric acid nozzle (etching solution supply means)
23 First guide plate (guide member)
28, 38, 38A, 48 Guide surface 33, 33A Second guide plate (guide member)
43 Third guide plate (guide member)
50 Control device (control means)
C1, C2 Vertical axis S Gap T Scan path W Wafer (substrate)

Claims (8)

Substrate rotating means for rotating around a predetermined rotation axis while holding the substrate;
An etchant supplying means for supplying an etchant onto the main surface of the substrate rotated by the substrate rotating means;
The guide surface has a guide surface along a plane intersecting the main surface of the substrate rotated by the substrate rotating means, and is disposed opposite to the main surface with a gap between the main surface and a predetermined peripheral portion. And a guide member that guides the etching solution toward the outside of the substrate by contacting a liquid film of the etching solution on the main surface. Including a plurality of the guide members,
The substrate processing apparatus according to claim 1, wherein the plurality of guide members are arranged at different positions in the circumferential direction of the substrate.   The substrate processing apparatus according to claim 1, wherein the guide surface is a flat surface.   The substrate processing apparatus according to claim 3, wherein the guide member is disposed such that the guide surface is along a direction orthogonal to a rotation radius direction of the substrate. The substrate held by the substrate rotating means is circular,
The substrate processing apparatus according to claim 1, wherein the guide surface is formed by a curved surface along a peripheral end shape of the substrate.   The substrate processing apparatus according to claim 1, wherein the guide member is provided so as to be swingable about a predetermined axis extending in parallel with the rotation axis.   The substrate processing apparatus according to claim 1, further comprising a control unit that controls a distance between the main surface of the substrate held by the substrate rotating unit and the guide member. The etchant supply means scans the etchant on the main surface of the substrate along a linear scan path along the rotational radius direction of the substrate rotated by the substrate rotation means,
The substrate processing apparatus according to claim 1, wherein the guide member is disposed such that an upstream end portion in a substrate rotation direction is positioned on an extension line of the scan path.

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