JP4462577B2 - Nozzle system - Google Patents

Description

  The present invention relates to a nozzle system, and more particularly, to a nozzle system that sweeps a sample surface with a liquid extruded from the tip of a nozzle and collects contaminants on the sample surface by sucking the swept liquid with a nozzle.

In the manufacturing process of a semiconductor device, in order to examine the presence or absence of contaminants on a silicon wafer, the sample surface is swept with a liquid to absorb the pollutant, and the swept liquid is collected and analyzed. . Sweeping with a liquid is performed by moving a nozzle from which the liquid is extruded from the tip in the lateral direction on the surface of the sample rotating in a horizontal plane, and collecting the liquid is performed by sucking the liquid with the nozzle. (For example, refer to Patent Document 1).
US Pat. No. 6,960,265

  In the liquid extruded from the nozzle, the concentration of contaminants increases with the progress of the sweep. For this reason, depending on the type of pollutant and the degree of contamination, the concentration of the pollutant may be saturated during the sweep, and it may become impossible to absorb any more.

  Accordingly, an object of the present invention is to realize a nozzle system in which the concentration of contaminants in a liquid for collecting contaminants is not easily saturated.

  The present invention as a means for solving the above problems is a nozzle system that sweeps a sample surface with a liquid extruded from the tip of a nozzle and collects the contaminants on the sample surface by sucking the swept liquid with the nozzle. A nozzle having a liquid reservoir communicating with a capillary with a tip extrusion port; a part of the liquid in the liquid reservoir is extruded from the extrusion port through the capillary to sweep the sample surface; A sweeping means for sucking the liquid into the liquid reservoir through the capillary, mixing and diluting with the internal liquid, and extruding a part of the liquid in the liquid reservoir after mixing and dilution from the extrusion port through the capillary and restarting the sweep. This is a nozzle system.

  According to the present invention, the nozzle system that sweeps the sample surface with the liquid extruded from the tip of the nozzle and collects contaminants on the sample surface by sucking the liquid after the sweep with the nozzle is the capillary at the tip extrusion port. A nozzle having a liquid reservoir communicating therewith, a part of the liquid in the liquid reservoir is extruded from the extrusion port through the capillary to sweep the sample surface, and the liquid is sucked into the liquid reservoir through the capillary in the course of the sweep. Since it has a sweeping means for mixing and diluting with the internal liquid, and extruding a part of the liquid in the liquid reservoir after mixing and dilution from the extrusion port through the capillary and restarting the sweep, It is possible to realize a nozzle system in which the concentration of contaminants is not easily saturated.

The best mode for carrying out the invention will be described below in detail with reference to the drawings. Note that the present invention is not limited to the best mode for carrying out the invention.
FIG. 1 schematically shows the configuration of the nozzle system 1. The nozzle system 1 is an example of the best mode for carrying out the invention. The configuration of the nozzle system 1 shows an example of the best mode for carrying out the invention relating to the nozzle system.

  As shown in FIG. 1, the nozzle system 1 includes a nozzle 100, a syringe pump 200, and a controller 300. The tip of the nozzle 100 faces the surface of the sample 400 at a narrow interval. The sample 400 is a silicon wafer, for example.

  The nozzle 100 is a cylinder having a liquid reservoir 120 inside. The liquid reservoir 120 opens through the capillary 122 and the capillary 124 to the end surface 132 on the tube tip side and the end surface 134 on the tube base side, respectively. The inner diameter of the capillary 122 is considerably smaller than the inner diameter of the liquid reservoir 120. The nozzle 100 is an example of a nozzle in the present invention. The liquid reservoir 120 is an example of a liquid reservoir in the present invention. The capillary 122 is an example of a capillary in the present invention.

  The end surface 132 on the tube tip side is circular. The outer edge 132a of the end surface 132 protrudes in the distal direction. Thereby, the end surface 132 becomes a concave surface. The capillary 122 is provided greatly decentered from the central axis of the nozzle 100. For this reason, the opening 122a of the capillary 122 is positioned very close to the outer edge 132a as shown in FIG. Through this opening 122a, suction of the liquid into the liquid reservoir 120 and extrusion of the liquid from the liquid reservoir 120 are performed. The opening 122a is an example of the extrusion port in the present invention.

  The suction and extrusion of the liquid are performed by a syringe pump 200 connected by a tube 126 to the tube-side capillary 124. The syringe pump 200 is controlled by the controller 300. The controller 300 also controls the movement of the nozzle 100 and the sample 400. The syringe pump 200 and the controller 300 are an example of the sweep means in the present invention.

  The operation of the nozzle system 1 will be described. First, a liquid is sucked up by a nozzle 100 from a storage unit (not shown) and stored in the liquid reservoir 120. As a result, as shown in FIG. 3, the liquid 140 is stored in the liquid reservoir 120. The amount of liquid stored is, for example, 500 μL.

  Next, a part of the liquid 140 in the liquid reservoir 120 is extruded from the opening 122 a through the capillary 122. Thereby, as shown in FIG. 4, the gap between the end surface 132 of the nozzle 100 and the surface of the sample 400 is filled with the liquid. Since the surface of the sample 400 is hydrophobic, the liquid does not spread and becomes a substantially truncated droplet by surface tension. Hereinafter, the extruded liquid is referred to as a droplet 140a, and the liquid remaining in the liquid reservoir 120 is referred to as a residual liquid 140b.

  The amount of the droplet 140a is, for example, 100 μL. As a result, the amount of the residual liquid 140b becomes about 400 μL. That is, the amount of liquid remaining in the liquid reservoir 120 when a part of the liquid 140 is extruded from the opening 122a is larger than the amount of liquid extruded. The magnitude relationship between the extrusion amount and the residual amount is not limited to this, and both may be equal or the residual amount may be smaller than the extrusion amount.

  In this state, the surface of the sample 400 is swept. For example, as shown in FIG. 5, the sweep is performed by moving the nozzle 100 in the direction of the rotation radius (lateral direction) while rotating the sample 400 in a plane parallel to the surface. At this time, the nozzle 100 is opposed to the sample 400 so that the opening 122a is on the downstream side when viewed from the rotation direction of the sample 400. However, such a relationship is not essential.

  The pitch of the lateral movement of the nozzle 100 per rotation is set to be equal to or smaller than the diameter of the droplet 140a. By moving the nozzle 100 through the entire lateral range of the sample 400 at such a pitch, the entire surface of the sample 400 can be swept. Note that the sweep method is not limited to this, and may be an appropriate method capable of sweeping the entire surface of the sample 400.

  By sweeping with the droplets 140a, contaminants on the surface of the sample 400 are sequentially taken into the droplets 140a. As a result, the concentration of contaminants in the droplet 140a gradually increases with the progress of the sweep.

  The sweep is interrupted at a predetermined stage during the sweep, and the droplet 140a is sucked through the capillary 122 and collected in the liquid reservoir 120. At that time, as the suction proceeds, the droplets 140a gradually become smaller and gaps are formed, so that the liquid gathers along the outer edge 132a due to the surface tension. By being very close to 132a, the droplet 140a is sucked along the outer edge 132a, and the droplet 140a is not exhausted.

  When sucking the droplet 140a, the nozzle 100 may be relatively moved along the sample surface in a direction opposite to the eccentric direction of the opening 122a by rotating the sample 400, moving the nozzle 100, or a combination thereof. . By such relative movement of the nozzle 100, the droplet 140a can be sent along the outer edge 132a to the opening 122a, and the suction of the droplet 140a through the opening 122a can be further perfected.

  By sucking the droplet 140a through the capillary 122, the linear velocity of the sucked droplet 140a is increased. For this reason, the droplet 140a flows into the liquid reservoir 120 at a high speed and mixes well with the residual liquid 140b.

  When the droplet 140a is exhausted, the liquid reservoir 120 stores the entire amount of the liquid 140, as shown in FIG. In this state, since the sucked droplets 140a and the residual liquid 140b are well mixed, the contaminant sucked together with the droplets 140a is diluted and its concentration is lowered.

  On the other hand, with a nozzle whose inner diameter of the extrusion port is not much different from the inner diameter of the liquid reservoir, even if the liquid is sucked, the liquid only moves upward, and the sucked liquid is mixed with the residual liquid. Therefore, the contaminant is not diluted.

  After dilution of the pollutant, a part of the liquid 140 in the liquid reservoir 120 is again pushed out from the opening 122a. Thereby, as shown in FIG. 4, the gap between the end face 132 of the nozzle 100 and the surface of the sample 400 is filled with the droplet 140a. Since the concentration of the contaminant in the droplet 140a is reduced by dilution, the contaminant absorption capability of the droplet 140a is restored to a level comparable to that at the start of the sweep.

  In this state, sweeping of the surface of the sample 400 is resumed. For example, as shown in FIG. 5, the sweep is performed by moving the nozzle 100 in the direction of the radius of rotation while rotating the sample 400 in a plane parallel to the surface. The sweep after the restart is efficiently performed by the droplet 140a whose contaminant absorbing ability has been recovered.

  In this manner, the contaminant absorbing ability of the droplets 140a is recovered every predetermined sweep distance. The predetermined sweep distance is, for example, a distance that the nozzle 100 moves 50 mm in the horizontal direction. However, the present invention is not limited thereto, and may be performed every time the circumference or area of the sweep reaches a predetermined value.

  When the sweep is completed, the droplet 140a is sucked through the opening 122a and collected in the liquid reservoir 120. The suction of the droplet 140a is performed in the same manner as described above. Thereby, the droplet 140a is completely recovered in the liquid reservoir 120 together with the contaminants absorbed therein.

  After collection, the liquid 140 in the liquid reservoir 120 is discharged into a collection container (not shown). The liquid in the collection container is used for component analysis by the analyzer. As the analyzer, for example, an inductively coupled plasma mass spectrometer (ICP-MS) is used. Note that the analyzer is not limited thereto, and may be an appropriate analyzer such as an inductively coupled plasma optical emission spectrometer (ICP-OES).

It is a figure which shows the structure of the nozzle system of an example of the best form for implementing this invention. It is a top view of a nozzle tip. It is a figure which shows the state which the nozzle attracted | sucked the liquid. It is a figure which shows the state which the nozzle extruded the liquid. It is a figure which shows the sweep of the sample surface by a nozzle.

Explanation of symbols

1: Nozzle system 100: Nozzle 120: Liquid reservoir 122, 124: Capillary 122a: Opening 126: Tube 132: End face 132a: Outer edge 140: Liquid 140a: Liquid droplet 140b: Residual liquid 200: Syringe pump 300: Controller 400: Sample

Claims (1)

A nozzle system that sweeps the sample surface with liquid extruded from the tip of the nozzle and sucks the liquid after the sweep with the nozzle to collect contaminants on the sample surface,
A nozzle having a liquid reservoir communicating with a capillary through the extrusion port at the tip;
A part of the liquid in the liquid reservoir is extruded from the extrusion port through the capillary to sweep the sample surface, and the liquid is sucked into the liquid reservoir through the capillary in the course of the sweep to mix and dilute with the internal liquid, and mix A nozzle system comprising sweeping means for extruding a part of the diluted liquid from the extrusion port through the capillary and restarting sweeping.

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