JP2023154948A - Liquid supply device for semiconductor manufacturing - Google Patents

Abstract

To provide a liquid supply device for semiconductor manufacturing in which a plurality of types of liquids for semiconductor manufacturing are supplied to a common discharge port while being switched, the liquid supply device being capable of preventing the mixing of the liquids for semiconductor manufacturing during switching.SOLUTION: Provided is a liquid supply device for semiconductor manufacturing, which includes: a nozzle 15 discharging a liquid for semiconductor manufacturing; a plurality of liquid supply lines for semiconductor manufacturing, the liquid supply lines being connected to the nozzle 15; and switching valves 13, 17 for switching liquids for semiconductor manufacturing, the liquids being supplied to the nozzle 15. The liquid supply device for semiconductor manufacturing is provided with a purge section that supplies inert gas or ultra pure water to the nozzle 15 to purge a residual liquid.SELECTED DRAWING: Figure 1

Description

The present invention relates to an apparatus for supplying a liquid from a discharge part to a workpiece such as a wafer, and in particular, a liquid supply apparatus for semiconductor manufacturing that supplies two or more liquids to a common discharge part by switching from each supply source. Regarding.

In the process of cleaning silicon wafers for semiconductors, etc., a liquid in which a solute is dissolved in ultrapure water at a very low concentration or less than a few tens of percent (hereinafter sometimes referred to as semiconductor manufacturing liquid) is used. In order to prepare liquids for semiconductor manufacturing, for example, acids, alkalis, oxidizing agents, reducing agents, etc. are added to ultrapure water, ultrapure water is added to dilute chemical solutions, and H ₂ , NH ₃ , O ₃ and other gases are dissolved in ultrapure water. When manufacturing semiconductors, the various semiconductor manufacturing liquids and ultrapure water described above are used. When each liquid for semiconductor manufacturing or ultrapure water is discharged onto an object to be processed such as a wafer from separate nozzles (dedicated for each liquid), the liquids do not mix. However, for various reasons (for example, to maintain an inert gas atmosphere in the chamber), the number of nozzles is limited, and multiple types of semiconductor manufacturing liquids must be switched and supplied to a single nozzle, which can be used to process objects such as wafers. In such a case, the remaining liquid from the previous time may be mixed in at the initial stage of switching the liquid.

Patent Document 1 describes that a chemical liquid remaining in a nozzle is sucked by an aspirator to prevent liquid dripping. However, there is no description of a configuration for preventing mixing when a plurality of chemical solutions are ejected from the same nozzle.

Japanese Patent Application Publication No. 2013-59735

The present invention provides a semiconductor manufacturing liquid that can prevent the semiconductor manufacturing liquids from mixing with each other at the time of switching, in a semiconductor manufacturing liquid supply device that switches and supplies multiple types of semiconductor manufacturing liquids to a common discharge part. The purpose is to provide a feeding device.

A semiconductor manufacturing liquid supply apparatus of the present invention includes a discharge part that discharges a semiconductor manufacturing liquid, a plurality of semiconductor manufacturing liquid supply lines connected to the discharge part, and a semiconductor manufacturing liquid supplied to the discharge part. The liquid supply apparatus for semiconductor manufacturing has a switching section for switching between the two, characterized in that a purge section is provided for supplying an inert gas or ultrapure water to the discharge section to purge residual liquid.

A semiconductor manufacturing liquid supply device according to one aspect of the present invention includes a control unit that operates the purge unit when the switching unit switches supply of the semiconductor manufacturing liquid to the discharge unit.

According to the liquid supply device for semiconductor manufacturing of the present invention, in the liquid supply device for semiconductor manufacturing that switches and supplies multiple types of semiconductor manufacturing liquids to a common discharge portion, when switching the semiconductor manufacturing liquid, liquid remains in the discharge portion. Purging prevents different semiconductor manufacturing liquids from mixing with each other.

FIG. 1 is a configuration diagram of a liquid supply device for semiconductor manufacturing according to an embodiment. FIG. 1 is a configuration diagram of a liquid supply device for semiconductor manufacturing according to an embodiment. FIG. 2 is a configuration diagram of a liquid supply device for semiconductor manufacturing according to a comparative example.

Hereinafter, embodiments will be described with reference to FIGS. 1 and 2.

In the liquid supply apparatus for semiconductor manufacturing shown in FIG. 1, a liquid mixture of liquids A and B and liquid C are switched and supplied to a nozzle 15 serving as a discharge section, and are discharged toward a wafer 22 on a wafer table 21. The wafer stand 21 is installed in a chamber 23 having an inert gas atmosphere.

Liquid A is supplied to a concentration adjustment chamber 3 via a pipe 1 having an integrated flow meter 2 . The liquid B is supplied to the concentration adjustment chamber 3 via a pipe 4 having an integrated flow meter 5 and a pipe 1 located downstream of a confluence point 1a in the middle of the pipe 1. An inert gas supply pipe 6 is connected via a valve 7 to a confluence point 1b downstream of the confluence point 1a. Preferably, the liquid in the concentration adjustment chamber 3 is pumped out by an inert gas such as nitrogen from the pipe 6.

A monitoring pipe 8 is connected to the concentration adjustment chamber 5, and the monitoring pipe 8 is provided with a conductivity meter 9 and an ORP meter 10.

The liquid in the concentration adjustment chamber 3 is supplied to the nozzle 15 via a pipe 12, a valve 13, and a pipe 14. A liquid C supply pipe 16 is connected to a confluence point 14a in the middle of the pipe 14 via a valve 17.

By switching the opening and closing of the valves 13 and 17, the supply of the mixed liquid from the concentration adjustment chamber 3 and the liquid C from the pipe 16 to the nozzle 15 is switched.

The concentration adjustment chamber 5 may be a tank or a thick pipe. A unit such as a filter for removing impurities may be installed in at least some of the pipes. Moreover, although it is desirable to use the suckback type as the type of each of the above-mentioned valves, the present invention is not limited thereto.

As shown in Figures 1 and 2, by installing integrating flowmeters 2 and 5 in the pipes 1 and 4 for liquids A and B, respectively, different types of chemical solutions can be supplied to the concentration adjustment chamber 3 at predetermined liquid volume ratios. I can do it. The number of liquids supplied to the concentration adjustment chamber 3 may be three or more types instead of two. As an alternative to the integrating flowmeters 2 and 5, a weight sensor may be installed to measure the weight of a tank storing liquid, and the transfer amount of various chemical solutions may be detected by reading changes in weight. The inside of the storage tank is preferably pressurized with an inert gas to a pressure higher than atmospheric pressure, preferably higher than 0.1 MPa.

It is desirable to install a line mixing device such as a static mixer before the concentration adjustment chamber 3, but if the viscosity and density of each liquid are approximately equal, the piping system should be designed so that the Reynolds number is 4000 or more. By adjusting the flow rate during transfer mixing, sufficient mixing can be performed using an elbow or orifice without the need to install a static mixer.

In a typical cleaning recipe, the time for one liquid to be delivered is often about 0.5 to 1 minute, and the flow rate is about 2 L/min to 4 L/min, so the volume of the concentration adjustment chamber is 5L is enough. The piping system preferably has an inner diameter of 8 mm or less, but is not limited to this as long as it can obtain a flow velocity sufficient to cause turbulence.

By using the conductivity meter 9 and the ORP meter 10, it is possible to strictly control whether the mixture is at a predetermined concentration (for example, with an error of ±5% or less), but it is possible to control only with the integrating flowmeters 2 and 5. You may.

By mixing various liquids in advance in the concentration adjustment chamber 3, it is possible to instantaneously supply liquids adjusted to the optimum concentration. By using the concentration adjustment chamber 3, various types of chemical solutions can be adjusted to desired concentrations. Furthermore, by using an inert gas to feed the adjusted liquid, it is possible to always feed the appropriate amount of liquid in an optimal condition.

By switching the opening and closing of the valves 13 and 17, the liquid supplied to the nozzle 15 is switched. At the time of this switching, the remaining liquid in the concentration adjustment chamber 3, the pipes 12 and 14, the valve 13, and the nozzle 15 is purged by opening the valve 7 and supplying inert gas.

This prevents the residual liquid from mixing with the next nozzle supply liquid when switching between supplying the mixed liquid from the concentration adjustment chamber 3 to the nozzle 15 and supplying the liquid C to the nozzle 15 from the piping 16. .

The liquid supply device for semiconductor manufacturing shown in FIG. 2 is the same as the liquid supply device for semiconductor manufacturing shown in FIG. It is something. The rest of the structure of the liquid supply apparatus for semiconductor manufacturing shown in FIG. 2 is the same as that of the liquid supply apparatus for semiconductor manufacturing shown in FIG. 1, and the same reference numerals indicate the same parts.

In the system shown in FIG. 2, when switching between supplying the mixed liquid from the concentration adjustment chamber 3 to the nozzle 15 and supplying the liquid C to the nozzle 15 from the piping 16, the valve 19 is opened and the piping 14 and the nozzle 15 are switched. Purge the remaining liquid inside with ultrapure water. Note that when switching the mixed liquid supply from the concentration adjustment chamber 3 to the nozzle 15 to the supply of liquid C from the piping 16 to the nozzle 15, the valve 7 is opened and the inert gas The remaining liquid in the concentration adjustment chamber 3, the pipes 12 and 14, the valve 13, and the nozzle 15 may be purged by the following steps.

As mentioned above, it is preferable to purge (purge) residual liquid using an inert gas or ultrapure water, but if it has been proven in advance that it will not adversely affect wafer quality, other fluids may be used. There is no problem even if it is done using . For example, if a certain degree of dilution is observed, a method for replacing the liquid may be to send a liquid used for rinsing semiconductor wafers, such as ultrapure water or CO ₂ water, to the concentration adjustment chamber 3 .

Although it is preferable that the piping 14 downstream of the flow path switching valve 13 be as short as possible, even if it is long, it does not affect concentration controllability and avoidance of mixing of liquids.

By purging the liquid accumulated inside the nozzle with an inert gas or ultrapure water, it is possible to prevent mixing of the liquids and the resulting unexpected wafer surface contamination and surface roughening.

[Example 1]
As liquid A, an alkaline aqueous solution was used, as liquid B, an H ₂ O ₂ aqueous solution was used, and as liquid C, an HF aqueous solution was used.

Using the liquid supply device for semiconductor manufacturing shown in Figure 1, wiring materials were cleaned in step 1 (HF pretreatment with liquid C), step 2 (alkali + H ₂ O ₂ rinsing), and step 3 (spin drying) under the following conditions. went. The residual liquid was purged with inert gas.

Flow rate: 2L/min.
Processing time for each step: 30 seconds
Wafer rotation speed: 1,000 rpm

[Example 2]
Cleaning was performed in the same manner as in Example 1 using the semiconductor manufacturing liquid supply apparatus shown in FIG. The residual liquid was purged with ultrapure water.

[Comparative example 1]
The liquid supply device for semiconductor manufacturing shown in FIG. 3 supplies the liquid to the nozzle 15 in the order of steps 1, 2, and 3, and discharges the liquid toward the wafer 22 on the wafer stand 21 in the chamber 23.

The liquid supply apparatus for semiconductor manufacturing shown in FIG. 3 supplies liquid A to a tank 33 through a pipe 31 having an integrating flow meter 32, and supplies liquid B to the tank 33 through a pipe 34 having an integrating flow meter 35. Liquids A and B are mixed in a tank 33. A water level sensor 36 is provided in the tank 33.

The liquid in the tank 33 is supplied to the nozzle 15 via a pump 37 and piping 38. The pipe 38 is provided with an ORP meter 40, a conductivity meter 41, and an instantaneous flow meter 42 in this order from the upstream side to the downstream side. A pipe 43 for supplying liquid C is connected to a junction 38a between the conductivity meter 41 and the instantaneous flow meter 42 via a valve 44.

In Comparative Example 1, the remaining liquid in the pipe 38 on the downstream side of the nozzle 15 and the confluence point 38a is not purged.

<Results/Discussion>
Table 1 shows the results of Examples 1 and 2 and Comparative Example 1.

As shown in Table 1, there is no difference in conductivity error between the methods of Examples 1 and 2 and Comparative Example 1. This revealed that there is no problem even if the two liquids are mixed in advance in the concentration adjustment chamber 3.

It can be seen that when the residual liquid in the nozzle is not purged as in Comparative Example 1, the amount of loss of wiring material increases due to mixing of hydrofluoric acid and oxidizing agent. From this, the effect of discharging the remaining liquid in the nozzle was recognized.

Claims (2)

a discharge unit that discharges a liquid for semiconductor manufacturing;
a plurality of semiconductor manufacturing liquid supply lines connected to the discharge section;
A semiconductor manufacturing liquid supply device having a switching unit for switching the semiconductor manufacturing liquid supplied to the discharge unit,
A liquid supply device for semiconductor manufacturing, characterized in that a purge section is provided for supplying inert gas or ultrapure water to the discharge section to purge residual liquid. 2. The semiconductor manufacturing liquid supply apparatus according to claim 1, further comprising a control unit that operates the purge unit when the switching unit switches the supply of the semiconductor manufacturing liquid to the discharge unit.

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