JP3985250B2 - Wafer edge etching equipment - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a wafer edge etching apparatus that removes an oxide film, a metal film, and the like existing at an edge portion of a wafer.
[0002]
[Prior art]
For example, a wafer with a metal film or oxide film formed on the surface will not cause metal contamination due to the metal film at the edge portion, generation of nodules or particles due to the oxide film, decrease in yield, variation in characteristics, etc. An etching process for removing a metal film or the like is performed. For such edge etching, various methods and apparatuses have been proposed. For example, a non-woven fabric impregnated with an etching solution is removed by sliding on the peripheral surface of the wafer (see Patent Document 1), or a grooved roller. An apparatus (for example, refer to Patent Document 2) is known in which an end face of a wafer is inserted in a non-contact state and an etching solution is held in a groove portion of the roller by surface tension.
[0003]
However, in the apparatus as described above, the etched metal or the like collects on the surface of the nonwoven fabric or in the roller groove and re-adheres to cause contamination, the supplied etching solution is wasted, or contamination at the etching interface. Often occurred. In addition, when the wafer edge is inserted into a groove or the like, the portion deep inside the groove is etched quickly, but the etching interface portion corresponding to the inlet portion of the groove is short in contact with the etching solution, so it is reliable. In order to perform the etching process, there is a problem that the etching process time must be extended. In addition, when the wafer is rotated in the spin cup, a vortex flow is generated. The vortex flow is affected by the etching solution, and the etching interface may become unstable.
[0004]
[Patent Document 1]
Japanese Patent No. 2546986 (Claims 2 and 3)
[Patent Document 2]
Japanese Patent Publication No. 5-29305 (Claims, Fig. 1)
[0005]
[Problems to be solved by the invention]
The problem to be solved by the present invention is that when etching the wafer edge, the etching solution is not wasted, the removed metal or the like is not reattached to the wafer, and the etching interface is clarified to prevent contamination on the interface. An object of the present invention is to provide a wafer edge etching apparatus capable of reducing the etching process time so as not to occur.
[0006]
[Means for Solving the Problems]
According to the present invention, there is provided a processing space into which a wafer edge is inserted, and a flow liquid wall is formed at the opening end of the processing space with a small gap between the wafer surface and facing. A nozzle is provided to supply an etching solution to the inner surface, and an etching unit having a recovery port for collecting an etching solution gas and a waste solution from the nozzle in the rotation direction of the wafer is provided. Is formed in a shape that bends along the circumferential direction of the wafer, the etching solution flowing down from the flow wall is brought into contact with the wafer edge, and the gas and waste solution of the etching solution after contact are collected from the collection port. A wafer edge etching apparatus characterized by the above is proposed, and the above-mentioned problems are solved.
[0007]
Further, a plurality of the nozzles may be provided along the circumferential direction of the wafer, and preferably a long hole is formed so as to be wide in the circumferential direction of the wafer.
[0008]
DETAILED DESCRIPTION OF THE INVENTION
1 (A) and 1 (B) are explanatory views of the present invention, and an outer periphery of a wafer (1) that rotates while being attracted and held by chuck means (2) such as a vacuum chuck in a spin cup (not shown). An etching unit (4) is provided so as to be able to contact and separate from the edge (3). Although the etching unit (4) is provided at two locations facing each other in FIG. 1 (A), it may be provided at three or more locations or at only one location. Note that an opening (not shown) is provided on the side surface of the spin cup so that the etching unit (4) can enter the spin cup, and an appropriate shutter mechanism is provided on the spin cup to open and close the opening. (Not shown).
[0009]
Referring to FIGS. 1B and 2, the unit body (5) of the etching unit (4) has a processing space (6) into which a wafer edge (3) is inserted on the front surface. At the opening end of 6), a liquid flow wall (8) is provided so as to be opposed to the wafer surface (7) with a minute gap (S), and etched along the inner surface of the liquid flow wall (8). The liquid (9) is configured to flow downward. A portion to be etched of the wafer edge (3) is defined by the flowing liquid wall (8), and an etching width is defined according to the insertion amount of the wafer edge inserted into the processing space (6). This etching width can be arbitrarily controlled by moving the etching unit (4) back and forth in the direction of the arrow (10) by a moving means (not shown) using a pulse motor or the like.
[0010]
As described above, since the inside of the liquid flow wall (8) is isolated from the outside, the influence of the spiral flow generated in the spin cup due to the rotation of the wafer can be prevented from affecting the inside of the liquid flow wall (8). The etching solution can flow down in a stable state. In addition, the gap (S) between the liquid flow wall (8) and the wafer surface (7) is in contact with the wafer edge portion immediately without the etching liquid flowing down from the liquid flow wall (8) falling into the shape of the edge. The gap should be as narrow as possible so as not to move from the portion toward the center of the wafer, and should be about 0.5 mm to 2 mm, preferably about 1 mm. Note that the flow wall (8) may be provided so as to be movable in the vertical direction so that the gap (S) can be adjusted.
[0011]
The etching solution (9) is supplied from the etching solution supply port (11) to the pool portion (12) formed on the inner surface of the liquid flow wall (8) by the minute supply pump or the pressurized / pressure feed minute supply means. From the nozzle (13) opened at the lower end of (12), it is transmitted to the inner surface of the liquid flow wall (8), falls from the lower end of the liquid flow wall (8) by gravity, and immediately contacts the wafer edge (3). A plurality of nozzles (13) may be provided along the circumferential direction of the wafer, for example, at two locations as in the embodiment shown in the figure, and preferably, the nozzles (13) may be formed in long holes so as to be wide in the circumferential direction of the wafer ( FIG. 4). When formed in this way, the liquid width of the etching liquid transmitted to the flowing liquid wall (8) can be widened, the time during which the etching liquid is in contact with the metal film or the like to be removed can be lengthened, and the etching process can be accelerated.
[0012]
In the nozzle (13) portion, as shown in FIG. 3, the liquid flow wall (8) protrudes in a substantially mountain shape so that the etching solution is surely brought into contact with the etching interface portion of the wafer surface. Further, the front surface of the liquid flow wall (8) is bent along the outer periphery of the wafer so that the etching interface is arcuate. The liquid flow wall (8) is formed separately from the unit main body (5), is detachably provided on the unit main body (5), is fixed with screws (14) (see FIG. 5), and is sized to a wafer size. It can be replaced with one having a curved surface.
[0013]
The etching solution (9) is supplied by a suitable sensor (15) for confirming the supply amount and the presence of supply so that the solution can be detected near the lower end of the supply port (11). 16), the excess etching solution is exhausted from the overflow channel (17), passed through the waste liquid cylinder (18), and collected in a collection unit (not shown). The sensor (15) is provided with a gas supply port (19) for supplying gas for protecting the sensor (15). In addition, the sensor can detect whether the supply of the etching solution from the etching solution supply port (11) is a drip supply or a continuous supply, and the etching solution is supplied at the wafer edge several seconds to several tens of seconds before etching. The amount of etching can be adjusted by monitoring the amount of etching with an appropriate means, and the reproducibility of etching can be confirmed.
[0014]
In the above embodiment, the etching solution is stored in the pool portion (12) from the etching solution supply port (11) and flows down along the flowing wall. However, the etching solution directly flows from the nozzle to the flowing wall (8 ). FIG. 6 shows an embodiment of the present invention, in which the lower end of the etching solution supply port (11) is extended and the tip is inserted into the nozzle (13) or is in contact with the nozzle (13) portion. The etchant flowing down from the mouth (11) is immediately transmitted to the inner surface of the flow wall (8) and comes into contact with the wafer surface. In this case, the amount of the etching solution may be detected using a highly accurate ultrasonic flow meter or the like.
[0015]
From the nozzle toward the wafer rotation direction (20), a recovery port (21) for recovering etching gas and waste liquid is opened, and the recovery port (21) is exhausted and waste liquid cylinder (18 ) Communicates with a recovery unit (not shown). The unit main body (5) is provided with local exhaust that flows toward the exhaust gas and the waste liquid cylinder (18) using the open end of the processing space (6) as an intake port. Therefore, the etching gas (mist) and waste liquid after contacting the wafer edge (3) are scattered on the outer periphery in the rotation direction of the wafer by the rotation of the wafer. 21) is provided, it is sucked into the unit main body (5) through the recovery port (21) and recovered from the exhaust and waste liquid cylinder (18) to the recovery unit. An inclined surface (22) is formed on the inner side surface and bottom surface of the unit body (5) so that the waste liquid and the like can easily flow toward the exhaust waste liquid port (18). A slide plate (23) is provided on the outer periphery of (18) so as to seal the exhaust port (not shown) through which the exhaust and waste liquid cylinders pass when the etching unit (4) is moved.
[0016]
The etching unit (4) may be provided with a back surface etching solution nozzle (24) facing the back surface side of the wafer (1). In this case, the etching solution (25) ejected from the back surface etching solution nozzle (24) may be brought into direct contact with the back surface of the wafer as shown in FIG. It should be noted that by providing a separate piping system for the etching solution supply port (11) and the back surface etching solution nozzle (24), it is also possible to supply different etching solutions, such as the front surface or back surface of the wafer. It is possible to etch only one side or to etch the front and back surfaces simultaneously.
[0017]
Thus, the etching unit (4) is brought close to the outer periphery of the wafer (1) held in the spin cup, and the wafer edge (3) is inserted into the processing space (6) of the etching unit (4). When the etching solution (9) is brought into contact with the wafer surface (7) through (8), the wafer edge (3) is etched using the flowing liquid wall (8) as an interface. At this time, the rotation of the wafer is, for example, about 300 to 1500 rpm, preferably about 1000 rpm, and in order to further shorten the etching time, a plurality of the etching units (4) are provided and processed. That's fine. Further, the waste liquid of the etching solution is sucked into the unit main body (5) from the collection port (21) located in the rotation direction of the wafer and collected by the collection unit.
[0018]
When the desired etching amount is reached, the etching unit (4) is retracted, the spin cup shutter is closed, and pure water is rinsed from the pure water nozzle (not shown) provided at an appropriate position to the wafer surface. The rotation of the wafer at this time is, for example, about 300 to 1500 rpm, preferably about 600 rpm. Thereafter, the wafer is rotated at about 300 to 1000 rpm, preferably about 300 rpm, and drained. Further, the wafer is rotated at about 1000 to 3000 rpm, preferably about 2500 rpm, and dried. Good.
[0019]
【The invention's effect】
The present invention is configured as described above, and the liquid flow wall stands up with a minute gap on the wafer edge, the etching liquid flows down along the inner surface of the liquid flow wall, and the etching liquid contacts the wafer edge. The etching interface portion can be clearly etched by the flowing liquid wall, and the etching solution gas and waste liquid are scattered on the outer periphery in the rotation direction of the wafer due to the rotation of the wafer. In addition, since the recovery port is opened on the outer periphery in the rotational direction without reattaching, the gas and waste liquid of the etching solution are recovered from the recovery port, and waste of the etching solution can be eliminated. By providing a plurality of etching units, the etching processing time can be further shortened.
[Brief description of the drawings]
FIG. 1 shows a schematic configuration of the present invention, in which (A) is an explanatory diagram viewed from a plane, and (B) is an explanatory diagram showing a cross section of a flowing liquid wall portion.
FIG. 2 is a cross-sectional view of an etching unit.
FIG. 3 is a front view of an etching unit.
FIG. 4 is a plan view of a flowing liquid wall.
FIG. 5 is a plan view of an etching unit.
6A and 6B show another embodiment, in which FIG. 6A is a partial front view, and FIG. 6B is a partial cross-sectional view.
FIG. 7 is a perspective view of an etching unit.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Wafer 3 ... Wafer edge 4 ... Etching unit 5 ... Unit main body 6 ... Processing space 8 ... Flowing liquid wall 9 ... Etching liquid
11 ... Etch supply port
12 ... Pool
13 ... Nozzle
15 ... Sensor
18… Exhaust, waste liquid cylinder
21 ... Recovery port
24 ... Back side etchant nozzle

Claims (3)

  It has a processing space into which a wafer edge is inserted, and a liquid flow wall is formed at the opening end of the processing space with a small gap between the wafer surface and facing, and an etching solution is supplied to the inner surface of the flow liquid wall. And an etching unit having a recovery port for recovering the gas and waste liquid of the etching solution from the nozzle in the rotation direction of the wafer, and the flow wall of the etching unit in the circumferential direction of the wafer. It is formed in a shape that bends along, and the etching solution flowing down from the flow wall is brought into contact with the wafer edge, and the gas and waste solution of the etching solution after contact are collected from the collection port. Wafer edge etching equipment.   2. The wafer edge etching apparatus according to claim 1, wherein a plurality of the nozzles are provided along a circumferential direction of the wafer.   3. The wafer edge etching apparatus according to claim 1, wherein the nozzle is formed in an elongated hole having a wide width in a circumferential direction of the wafer.

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