JP4464293B2 - Semiconductor substrate processing apparatus and semiconductor substrate processing method - Google Patents

Description

The present invention relates to a semiconductor substrate processing apparatus and a semiconductor substrate processing method for preventing a processing liquid such as an etching liquid from flowing around to the back side of an edge portion of a semiconductor substrate (wafer).

In order to remove the processing strain on the surface of the semiconductor substrate, etc., when a single wafer etching process is performed on the semiconductor substrate with an etching solution, a method as shown in FIG. 3 has been proposed (for example, Patent Document 1).
In the method shown in FIG. 3, when the surface 71 of the semiconductor substrate 70 is etched with the etchant 72, the etchant 72 is supplied to the surface 71 of the rotating semiconductor substrate 70 while the etchant 72 is at the edge of the semiconductor substrate 70. From a ring-shaped slit 77 formed in a ring blow nozzle 76 disposed immediately below the semiconductor substrate 70 so as not to enter the back surface 75 along the outer periphery 74 of the portion 73 (semi-circular cross section), nitrogen gas or the like An inert gas 78 is sprayed radially outward on the back surface 75 of the semiconductor substrate 70.

Japanese Patent Application No. 2003-341121

However, this etching method still has the following problems to be solved.
Although the etching solution 72 does not go around to the back surface 75 of the semiconductor substrate 70, the cross-sectional shape of the edge portion 73 of the semiconductor substrate 70 after the etching process is below the outer periphery 74, that is, as shown in FIG. Since the etching is performed up to the portion where 72 has gone around, when both surfaces are etched one by one, a double-etched portion is formed, and uniform etching of the edge portion 73 is difficult. As described above, the etching solution 72 can be prevented from wrapping around the back surface 75, but the position of the etching solution 72 at the edge portion 73 at the edge is the outer end of the back surface 75 of the semiconductor substrate 70 and the lower end of the outer periphery 74 of the edge portion 73. It was near the boundary position K.
The cause of the wraparound of the etching solution 72 is considered to be that the surface tension acting on the etching solution 72 is larger than the resultant force of centrifugal force and gravity acting on the etching solution 72. In particular, when the rotation speed of the semiconductor substrate 70 is slow, the etching solution 72 is likely to go around.

The present invention has been made in view of such circumstances, and the quality of the product is improved by making the etching solution wrap around to the center position in the thickness direction of the semiconductor substrate and by making the treatment range uniform on both sides. An object of the present invention is to provide a semiconductor substrate processing apparatus and a semiconductor substrate processing method.

A semiconductor substrate processing apparatus according to the present invention that meets the above object includes a semiconductor substrate fixing means having a table portion for holding a central portion of a disk-shaped semiconductor substrate by vacuum suction, and the semiconductor substrate together with the semiconductor substrate fixing means. In the semiconductor substrate processing apparatus, comprising: a rotary drive lifting / lowering means for rotating and further raising / lowering; and an etching liquid supply means for supplying an etching liquid from a nozzle to the surface of the semiconductor substrate held by the semiconductor substrate fixing means. Of the semiconductor substrate mounted on the table portion and below the rear surface side of the semiconductor substrate mounted on the table portion, and gas is obliquely upward toward the radially outer side of the outer peripheral portion of the back surface of the semiconductor substrate placed on the table portion. A ring-shaped slit that uniformly ejects the gas, and the semiconductor along the back side of the semiconductor substrate on which the ejected gas is mounted on the table portion A ring blow nozzle having a guide portion for guiding to the outer end portion of the center in the thickness direction of the plate, are completely independent provided with the semiconductor substrate fixing means.

In the semiconductor substrate processing apparatus according to the present invention, the guide portion of the ring blow nozzle may be provided with a downward inclined surface of 10 to 60 degrees with respect to the horizontal, radially outward from the upper end position.
In the semiconductor substrate processing apparatus according to the present invention, the inside of the guide portion of the ring blow nozzle may be formed in a curved surface having an arcuate cross section.

The semiconductor substrate processing method according to the present invention that meets the above-mentioned object supplies an etching solution to the surface of a rotating semiconductor substrate, and uniformly ejects gas obliquely upward toward the radially outer side of the outer periphery of the back surface of the semiconductor substrate. A method of etching both sides of each side of the semiconductor substrate while the gas uniformly ejected to the outer peripheral portion of the back surface of the semiconductor substrate is located at the center position in the thickness direction of the semiconductor substrate along the back side of the semiconductor substrate. The etching solution is guided to the outer end of the semiconductor substrate, prevents the etchant from flowing to the lower surface side from the outer end, and stops etching at the center position in the thickness direction of the semiconductor substrate.
In the semiconductor substrate processing method according to the present invention, the gas may be air or nitrogen gas.

4. The semiconductor substrate processing apparatus according to claim 1, and the semiconductor substrate processing method according to claim 4, wherein the gas uniformly ejected to the outer peripheral portion of the back surface of the semiconductor substrate is an outer edge at the center position in the thickness direction of the semiconductor substrate. Since the etching solution can be prevented from flowing from the outer edge to the lower surface side and the etching can be stopped at the center position in the thickness direction of the semiconductor substrate, the edge portion is uniform when both surfaces are etched. Can be etched.

Particularly, in the semiconductor substrate processing apparatus according to claim 2, since the downward inclined surface of 10 to 60 degrees with respect to the horizontal is provided radially outward from the upper end position of the guide part of the ring blow nozzle, the etching solution is lowered. It can be easily discharged along the inclined surface, and as a result, the etching liquid is difficult to go around to the lower surface side of the semiconductor substrate.
In the semiconductor substrate processing apparatus according to claim 3, since the inside of the guide part of the ring blow nozzle is formed in a curved surface having an arc-shaped cross section, the gas flow path becomes smooth and there is no flow disturbance (vortex generation). A gas layer can be created, and the effect of preventing wraparound is enhanced.

Next, embodiments of the present invention will be described with reference to the accompanying drawings for understanding of the present invention.
Here, FIG. 1 is a schematic configuration diagram of a semiconductor substrate processing apparatus according to an embodiment of the present invention, and FIG. 2 is an explanatory diagram showing a relationship between a semiconductor substrate and a ring blow nozzle in the semiconductor substrate processing apparatus. .

As shown in FIG. 1, a semiconductor substrate processing apparatus 10 according to an embodiment of the present invention is an apparatus that etches a surface 15 of a semiconductor substrate 11 one side at a time, and etches both sides. The vacuum suction chuck 13 is an example of a semiconductor substrate fixing means having a table portion 12 that holds the central portion 11 by vacuum suction, and the rotary drive lifting means 14 that rotates the semiconductor substrate 11 together with the vacuum suction chuck 13 and further moves it up and down. And an etching solution supply means 18 for supplying the etching solution 17 from the nozzle 16 to the surface 15 of the semiconductor substrate 11 held by the vacuum suction chuck 13.

The semiconductor substrate processing apparatus 10 is further provided at a position outside the table portion 12 and below the back surface 19 side of the semiconductor substrate 11 mounted on the table portion 12, and the back surface 19 of the semiconductor substrate 11 placed on the table portion 12. A ring-shaped slit 21 that uniformly ejects nitrogen gas 20, which is an example of a gas, obliquely upward toward the outer side in the radial direction of the outer peripheral portion, and a semiconductor substrate 11 mounted on the table portion 12 with the ejected nitrogen gas 20. A ring blow nozzle 23 having a guide portion 22 that leads to the outer end S of the thickness direction center position T of the semiconductor substrate 11 along the back surface 19 side is provided completely independently of the vacuum suction chuck 13. Hereinafter, these will be described in detail.

The nozzle 16 of the etching solution supply means 18 is fixed to the tip of an L-shaped support arm 24, the base of the support arm 24 is configured to be pivotable by a motor 25, and the nozzle 16 is at the center position of the rotating semiconductor substrate 11. Can be scanned along the outside in the radial direction.
A ring-shaped cup 26 that can be moved up and down is provided around the outer periphery of the semiconductor substrate 11 mounted on the table portion 12 of the vacuum suction chuck 13, and the radial direction of the semiconductor substrate 11 is caused by centrifugal force generated by the rotation of the semiconductor substrate 11. The etching solution 17 scattered outside is collected, and the collected used etching solution 17 is discharged to the outside. A bottomed sink 27 is provided to house the ring blow nozzle 23 and the cup 26 therein, and a support portion 28 of the rotary drive lifting / lowering means 14 is provided through the center of the bottom of the sink 27.

As shown in FIG. 2, the ring blow nozzle 23 has a two-part structure, and the ring blow nozzle 23 includes an upper inclined surface 30 that is inclined upward along the radially outer side on the lower side of the outer peripheral portion 29. A lower side provided with a ring plate-like upper nozzle divided body 31 and a lower inclined surface 32 disposed with a slight parallel gap (slit width) G facing the upper inclined surface 30 of the upper nozzle divided body 31. The nozzle division body 33 is provided. The ring-shaped slit 21 is formed by the upper inclined surface 30 and the lower inclined surface 32 facing each other, and the nitrogen gas 20 is formed on the outer periphery of the back surface 19 of the semiconductor substrate 11 having a thickness t (for example, 0.6 to 1.2 mm). It is designed to blow evenly.

The ring blow nozzle 23 is provided with a downwardly inclined surface 35 having an inclination angle β of 10 to 60 ° (45 ° in the present embodiment) with respect to the horizontal, radially outward from the upper end U of the guide portion 22. . The distance c in the vertical direction of the descending inclined surface 35 is 1.5 to 3 mm (2 mm in the present embodiment). The horizontal distance d between the upper end U of the guide portion 22 and the outer end portion S of the semiconductor substrate 11 is set to 0.1 to 0.7 mm (0.5 mm in the present embodiment).
The inner side of the guide portion 22 of the ring blow nozzle 23 is formed in a curved surface having a circular arc cross section (radius R = 1-3 mm, 2 mm in the present embodiment).

With this configuration, as shown in the enlarged view of FIG. 1, the nitrogen gas 20 is uniformly ejected from the ring-shaped slit 21 of the ring blow nozzle 23 to the outer peripheral portion of the back surface 19 of the semiconductor substrate 11, and the guide portion 22 and the semiconductor substrate 11. The etchant 17 is guided by a minute gap formed between the outer peripheral portion of the back surface 19 and the jet liquid at the jet outlet position formed by the upper end U of the guide portion 22 and the outer end portion S of the semiconductor substrate 11. It can be prevented from flowing into the outlet. Therefore, unlike the prior art, the etching solution 17 does not flow from the upper side to the lower side of the edge portion 36. That is, the nitrogen gas 20 prevents the etchant 17 on the front surface 15 side of the semiconductor substrate 11 from entering the back surface 19 side of the edge portion 36 of the semiconductor substrate 11 due to surface tension against the centrifugal force and its own weight. Can do.

Next, a semiconductor substrate processing method according to an embodiment of the present invention using the semiconductor substrate processing apparatus 10 will be described. Note that the outer diameter D of the semiconductor substrate 11 is 200 mm and the thickness t is 0.8 mm.
The semiconductor substrate 11 is mounted on the table portion 12 of the vacuum suction chuck 13 and the semiconductor substrate 11 is fixed to the table portion 12 by vacuum suction.
By operating the rotary drive lifting / lowering means 14, the semiconductor substrate 11 is rotated at a rotational speed = 600 rpm or less with the central axis of the semiconductor substrate 11 being vertical.

The motor 25 is driven to rotate the nozzle 16 fixed to the support arm 24 above the semiconductor substrate 11 to the outer side in the radial direction from the center position of the semiconductor substrate 11 while etching the liquid 17 on the surface 15 of the semiconductor substrate 11. Supply. At the same time, nitrogen gas 20 is jetted from the ring-shaped slit 21 of the ring blow nozzle 23 to the outer peripheral portion of the back surface 19 of the semiconductor substrate 11.
Thereby, the nitrogen gas 20 ejected from the ring-shaped slit 21 is guided in a minute gap between the inside of the guide portion 22 and the outer peripheral portion of the back surface 19 of the semiconductor substrate 11, and the upper end U of the guide portion 22 and the semiconductor substrate. Since the minute gap formed at the outer end S of 11 is set to a positive pressure, the etching solution 17 can be prevented from flowing into the minute gap.

The present invention is not limited to the above-described embodiments, and can be changed without departing from the gist of the present invention. For example, some or all of the above-described embodiments and modifications are included. The combination of the semiconductor substrate processing apparatus and the semiconductor substrate processing method of the present invention in combination also falls within the scope of the present invention.

In the present embodiment, the downward inclined surface 35 of 10 to 60 degrees with respect to the horizontal is provided radially outward from the upper end U of the guide portion 22 of the ring blow nozzle 23. However, the present invention is not limited to this, and as necessary. The down inclined surface can be omitted.
The inner side of the guide part 22 of the ring blow nozzle 23 is formed in a curved surface having a circular arc cross section, but is not limited to this, and may have other shapes as required. Further, although the gas ejected toward the outer side in the radial direction of the outer peripheral portion of the back surface of the semiconductor substrate is nitrogen gas, it may be air.

1 is a schematic configuration diagram of a semiconductor substrate processing apparatus according to an embodiment of the present invention. It is explanatory drawing which shows the relationship between the semiconductor substrate and ring blow nozzle in the same semiconductor substrate processing apparatus. It is explanatory drawing which shows the relationship between the semiconductor substrate and ring blow nozzle in the semiconductor substrate processing apparatus which concerns on a prior art example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10: Semiconductor substrate processing apparatus, 11: Semiconductor substrate, 12: Table part, 13: Vacuum suction chuck (semiconductor substrate fixing means), 14: Rotation drive raising / lowering means, 15: Surface, 16: Nozzle, 17: Etching liquid, 18 : Etching solution supply means, 19: back surface, 20: nitrogen gas (gas), 21: ring slit, 22: guide part, 23: ring blow nozzle, 24: support arm, 25: motor, 26: cup, 27: Sink, 28: support portion, 29: outer peripheral portion, 30: upper inclined surface, 31: upper nozzle divided body, 32: lower inclined surface, 33: lower nozzle divided body, 35: downward inclined surface, 36: edge portion

Claims (5)

Semiconductor substrate fixing means having a table portion that holds the central portion of a disk-shaped semiconductor substrate by vacuum suction, rotational drive lifting means for rotating the semiconductor substrate together with the semiconductor substrate fixing means, and further raising and lowering, and the semiconductor In a semiconductor substrate processing apparatus comprising: an etching solution supply unit that supplies an etching solution from a nozzle to the surface of the semiconductor substrate held by the substrate fixing unit;
Provided at an outer position of the table portion and below the back surface side of the semiconductor substrate mounted on the table portion, and obliquely upward toward the radially outer side of the back surface outer peripheral portion of the semiconductor substrate placed on the table portion A ring-shaped slit for uniformly ejecting gas in the direction, and a guide for guiding the ejected gas along the back surface side of the semiconductor substrate mounted on the table portion to the outer end of the center position in the thickness direction of the semiconductor substrate A semiconductor substrate processing apparatus, wherein a ring blow nozzle having a portion is provided completely independently of the semiconductor substrate fixing means. 2. The semiconductor substrate processing apparatus according to claim 1, wherein the guide portion of the ring blow nozzle is provided with a downward inclined surface of 10 to 60 degrees with respect to the horizontal from the upper end position in the radial direction. A semiconductor substrate processing apparatus. 3. The semiconductor substrate processing apparatus according to claim 1, wherein an inner side of the guide portion of the ring blow nozzle is formed in a curved surface having an arcuate cross section. 4. An etching solution is supplied to the surface of the rotating semiconductor substrate, and both surfaces of the semiconductor substrate are etched one by one while uniformly ejecting a gas obliquely upward toward the radially outer side of the back surface outer peripheral portion of the semiconductor substrate. There,
The gas uniformly ejected to the outer peripheral portion of the back surface of the semiconductor substrate is guided along the back surface side of the semiconductor substrate to the outer end portion of the central position in the thickness direction of the semiconductor substrate, and the etching liquid is introduced from the outer end portion. A method of processing a semiconductor substrate, wherein the etching is stopped at the center position in the thickness direction of the semiconductor substrate while preventing the semiconductor substrate from going to the lower surface side. 5. The semiconductor substrate processing method according to claim 4, wherein the gas is air or nitrogen gas.

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