JPS61118127A - Mixing apparatus of chemical for semiconductor - Google Patents

Abstract

PURPOSE:To reduce the contamination by foreign matter and to obtain homogeneous composition by providing a means for sucking a liq. in a mixing vessel and a filter means for removing foreign matter in the liq., and furnishing a circulating passage for circulating the liq. in the mixing vessel through the means. CONSTITUTION:Hydrogen peroxide soln. is supplied to the second mixing vessel 87 housed in the second mixing box from the second storage vessel 22 by using high-pressure gas as the driving source through a branch pipe 51b from a liq. feed pipeline 51 on the opening and closing valve 88 side, a spiral pipe, and an inlet pipe. Sulfuric acid is simultaneously supplied from the third storage vessel 23 through a liq. feed pipe 91 having an opening and closing valve 90, the respective supplies are measured by a platform balance 92, and both chemicals are mixed in a specified ratio. The liq. mixture is circulated through the inside of a circulating passage 96 including a circulated and delivery pump 93, a liq. filter 94, and a heat exchanger 95, and the agitation, filtration, and temp. regulation are carried out.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application 1] The present invention relates to a compounding apparatus for compounding semiconductor chemicals used in wafer processing processes.

[Prior art 1] In general, when fabricating semiconductor devices in a V-shaped manner, it is necessary to perform cleaning, etching, photolithography, etc. on the surface of a silicon wafer, which is the base of the device. Chemicals are used.

By the way, such chemicals are usually mixed by workers, but in that case, it is difficult to mix them immediately before processing, so there is a possibility that the ingredients may change due to reactions etc. during storage of the chemicals. There is a problem.

Also, the stock solutions used for compounding chemicals are mainly strong acids such as hydrochloric acid, sulfuric acid, and hydrochloric acid, as well as powerful chemicals such as hydrogen peroxide and ammonia, which are dangerous to handle and do not allow workers to mix them. If you do it by), it is the biggest source of cleansing! The probability that dust will be mixed into chemicals from other people increases.

As is well known, such dust contamination poses a major bottleneck to the refinement and high integration of semiconductor devices.

In addition, when mixing is performed by an operator, it is necessary to prevent dust from getting mixed in, so it is difficult to sufficiently stir the chemicals to obtain a uniform composition. This was done in view of the problem,
Another object of the present invention is to automatically prepare chemicals immediately before processing semiconductor materials. Another object of the present invention is to create chemicals with a uniform composition and less contamination by foreign substances such as dust. The goal is to provide the following.

[Structure of invention! t1 For this reason, the semiconductor material blending device according to the present invention includes: a plurality of storage containers for storing a plurality of stock solutions for blending semiconductor chemicals; a closed mixing container for mixing the stock solutions in the storage containers; A supply means for supplying the undiluted solution in the storage container to the mixing container, a measuring means for measuring the supply amount of the undiluted solution to be supplied to the mixing container, a suction means for sucking the liquid in the mixing container, and a filter for removing foreign matter from the liquid. and a circulation path for circulating the liquid in the mixing container via the suction means and filter means.

[Effect of the invention 1] According to the present invention, the preparation of chemicals for semiconductors is automated, so it is possible to quickly prepare the chemicals immediately before processing to prevent changes in the composition of the chemicals, and it is also possible to dangers can be avoided.

In addition, we have automated the blending process and used a closed mixing container for blending, which prevents foreign matter such as dust from entering the chemicals, and also prevents foreign matter from entering the stock solution in the circulation path. As it is circulated through the wax and removed by filter means, it is possible to provide a chemical with less impurities.

Furthermore, by circulating the prepared chemicals in the circulation path, the chemicals can be stirred and the composition of the chemicals can be made sufficiently uniform.

[Example 1 Hereinafter, embodiments will be described based on the accompanying drawings.

FIG. 3 shows a compounding device for chemicals for cleaning semiconductor materials, and the compounding device 6 includes ammonia NH, OH,
The first storage box l stores ! A second storage box 2 for storing hydrogen peroxide solution H,O□, and a third storage box 3 for storing sulfuric acid H2SO-,
A 111th mixing box 4 mixes a first cleaning chemical from the nitrogen 7, hydrogen peroxide solution, and pure water, and a 21st mixer box 4 mixes a second cleaning chemical from sulfuric acid and a hydrogen peroxide solution.
1 box 5 are arranged in series.

As shown in FIG. 4, inside the first storage box 1, there is a fixed type first storage container 7 for storing the 7 ummonium 7 and a movable first storage container 7 for replenishing the 7 ummoni 7 to the first bud storage container 7. The tA1 replenishment container 8 and the like are housed therein, and the tA1 replenishment container 8 can be carried out of the first storage box 1. Second.
The third storage box 2.3 is similarly constructed.

Further, as shown in FIG. 5, the first mixing box 4 includes a first mixing container 10 in which a first cleaning chemical is prepared, and a platform scale 11 on which the first mixing container 10 is placed. (such as a self-balancing electronic balance or an a-dossel type balance) and a fluid filter 12 for administering a first cleaning chemical. The second mixing box 5 is similarly configured.

The configuration of this blending device will be explained in more detail below.

As shown in FIG. 1, both the first replenishment container 8 and the first storage container 7 are of a closed type, and the liquid level of the liquid 7 in the first storage container 7 is always at a preset upper limit level. L,
Ammonia is supplied from the first replenishment container 8 to the first storage container 7 by the liquid feed pump 15 through the liquid feed pipe 14 in which the on-off valve 13 is interposed so that the ammonia is located between the lower limit level L2 and the lower limit level L2. It has become so. The first storage container 7 is provided with level detectors 16 and 17 that detect the above-mentioned upper limit level L1 and lower limit level L2.
A liquid detector 18 for detecting the flow status of the 7-monitor 7 is installed. When the nitrogen 7 is supplied from the first replenishment container 8 to the first storage container 7, the inside of the first replenishment container 8 becomes negative pressure. While clean air is supplied into the replenishment container 8, by closing the air supply on-off valve 20 and opening the exhaust on-off valve 21, the gas in the first storage container 7 is
The liquid is discharged through a common exhaust pipe 24 to the first to third storage containers 7, 22, and 23 accommodated in the third storage boxes 1 to 3, respectively. In this way, by making the first storage container 7 and the first replenishment container 8 airtight,
The incorporation of dust into ammonia can be minimized.

Further, a gas filter 25 is interposed in the exhaust pipe 24,
This gas filter 25 removes liquid and steam from the exhaust gas.

The outlet pipe 26 of the first storage container 7 is connected to a liquid feeding pipe 30 having an l111m valve 28 via a pipe joint 27,
As shown in FIG. 2, the liquid feeding pipe 30 is connected to a fixed frame F
It is connected to a helical tube 32 via a pipe joint 31 supported by a bar B horizontally suspended in Fll, so that the weight of the liquid supply piping 30 and the helical tube 32 does not act on the platform scale 11. The spiral tube 32 is made of a stretchable resin such as thiamin, and has a pipe joint 34 fixed to the lid 33 of the first airtight mixing container 10 attached to the main body via a packing 29. connected to the inlet pipe 35 via the
Platform scale 1 accompanying the supply of ammonia from the first storage container 7, etc.
The vertical displacement of the first mixing container 10 on the helical tube 32
It is designed to be absorbed by the expansion and contraction of.

7, open the air supply on-off valve 20 (FIG. 1), close the exhaust on-off valve 21, and open the pressurized gas supply port 36 and pressure gauge 37.
．． 38, relief valves 40, 41, on-off valves 42, 43, gas filters 44, etc. High pressure gas is fed to the first storage container 7 from the gas piping 45 of the pressure feeding system P using high pressure gas (nitrogen gas, etc.). As a result, the ammonia in the first storage container 7 is supplied to the first mixing container 10. The amount of 7 mmoni 7 supplied to the first mixing container IO is measured by the platform scale 11 as the amount of change in the weight of the first mixing container 10 before and after supply, and when the supplied amount of 7 mmoni 7 reaches the target value. Then, the on-off valve 28 is closed, and the supply is stopped.

In this way, if the supply amount is measured by weight, the supply amount can be adjusted steplessly.
It is not affected by the liquid temperature (viscosity) etc. of the liquid meter 7 and can always perform accurate measurement.
The lower end 35m of the inlet pipe 35 is detected by the output signal of the platform scale 11, that is, the weight of the first mixing container 1G, so that the lower end 35a is always immersed in the liquid in the first mixing container 10. It is located below the lower limit level L of the liquid in 10.

As a result, when the on-off valve 28 is closed, the supply of 7 ammonia 7 is immediately stopped, and the dynamic pressure ( (positive load) and the reaction force (load weight) of the inlet pipe 35 acting on the platform scale 11 due to the ejection of ammonia.
Since these are always canceled out, the supply amount of 7 mm can be measured even more accurately.

The second storage container 22 is replenished with hydrogen peroxide from a second replenishment container 46 by a liquid feed pump 50 through a liquid feed pipe 48 having an on-off valve 47 . By supplying high pressure gas from the pressure system P to the second storage container 22, the branch pipe 51a, the spiral pipe 53, and the inlet of the liquid delivery pipe 51 from the second storage container 22 are connected to the side where the on-off valve 52 is located. Hydrogen peroxide solution is supplied through pipe 54 . Further, pure water is supplied from the pure water supply port 55 to the first mixing container IO through the branch pipe 57a in which the on-off valve 58 of the pure water piping 57 having the flow rate control valve 56 is interposed, the spiral pipe 60, and the inlet pipe 61. Water is provided. In this way, the liquid 7, hydrogen peroxide, and pure water are sequentially supplied to the first mixing container 10, and the amounts of each are measured by the platform scale 11 and mixed at a predetermined mixing ratio.

The outlet pipe 62 of the first mixing container 10 includes a spiral pipe 63, a first discharge pipe 64 in the blending device 6, a pipe joint 65, and a spiral pipe 63, a first discharge pipe 64 in the blending device 6, a pipe joint 65,
It is connected to a processing tank 70 having a double structure consisting of an inner tank 67 and an outer tank 68 via an outer second discharge pipe 66 . The spiral pipe 63, the first discharge pipe 64, the return flow pipe 71 connected to the first discharge pipe 64, and the spiral pipe 72 connected to the return flow pipe 71 are arranged inside the first mixing container 10. A circulation path 75 is formed that includes a circulation/discharge pump 73 that sucks the liquid, the fluid filter 12, and a heat exchanger 74.

After mixing ammonia, hydrogen peroxide and pure water,
By opening the inlet valve 76 and the circulation on-off valve 77 and closing the discharge on-off valve 78, the circulation/discharge pump 73 sucks the liquid mixture in the first mixing container 10 and circulates it through the circulation path 75. The mixture can be stirred to prepare a uniform composition of the first cleaning chemical. Further, during circulation, foreign matter in the mixed liquid can be removed by the fluid filter 12, and the temperature of the mixed liquid can be adjusted by the heat exchanger 74.

After the first cleaning chemical having a uniform composition is prepared by circulating in the circulation path 75, the circulation on-off valve 77 is closed and the discharge on-off valve 78 is opened to prepare the first mixing container 1.
0 to the first and second discharge piping 6.
4.66 to the processing tank 70, and wafers such as silicon can be cleaned in the inner tank 67. Moreover, in this embodiment, the single pump 73 can circulate and discharge the mixed liquid. Note that the supply amount of the first cleaning chemical from the first mixing container 10 to the processing tank 70 is determined by the platform balance 1.
1.

” V-lens pipes 80 to 83 are drawn out from the bottom of the first mixing container 10, the return flow pipe 71, and the inner tank 67 and outer tank 68 of the cleaning tank 70, respectively. This is an air supply/exhaust pipe provided with a ventilation filter (not shown) for supplying or exhausting air to the first mixing container 10 during supply of air.

The third storage container 23 is replenished with sulfuric acid from a third replenishment container 85 by a liquid feeding pump 86 .

The second mixing container 87 housed in the second mixing box 5 is supplied with a branch pipe Slb on the side having the on-off valve 88 of the liquid feeding pipe 51 and a spiral pipe using high pressure gas from the second storage container 22 as a driving source. Hydrogen peroxide solution is supplied through the pipe and inlet pipe, and sulfuric acid is supplied from the third storage container 23 through a liquid supply pipe 91 having an on-off valve 90, and the respective supplied amounts are measured by a platform scale 92. and mixed at a predetermined mixing ratio. This mixed liquid is circulated in a circulation path 96 that includes a circulation/discharge pump 93, a fluid filter 94, and a heat exchanger 95, and is subjected to stirring, filtration, and temperature control, and the second cleaning liquid prepared in this way is Chemicals for use are discharged into a processing tank 98 via a discharge pipe 97. Note that pure water can be supplied to the second mixing container 87 via a branch pipe S7b of the pure water pipe 57, which is provided with an on-off valve 99.

Next, a second embodiment will be described based on FIG.

This second embodiment is devised so that a general-purpose flowmeter can be used to measure a highly corrosive stock solution such as heptahydrofluoric acid by flow rate.

That is, the blending device according to the second embodiment supplies a stock solution such as hydrochloric acid from the storage container 7 to the mixing container 10, and also supplies a less corrosive measuring liquid (water, oil, etc.) to the circulation path 1, which will be described later.
A bellows pump 163 that circulates counterclockwise at a constant flow rate with respect to the flow rate of the stock solution is provided in the pump 72, and the flow rate of the stock solution is determined by measuring the flow rate of the metering solution with a general-purpose flowmeter 174. It is.

The bellows pump 163 has first bellows pumps fixed to both sides of the main body 164. 1st within 2nd shillings 165.166. Second
Both bellows IG7.
168 are connected by a connecting shaft 7) 170, and the compressed air supplied from the air pipe 160 through the on-off valve 161 and the throttle valve 162 is transferred to the first. 2nd bellow X'167.1
68, both bellows 167
, '168 is constructed so that it can be inflated and deflated alternately. The first cylinder 165 is located in a circulation path 172 that includes a storage container 171 in which the measured liquid is stored, while the second cylinder 166 is a liquid feeding pipe that connects the first storage container 7 and the first mixing container 10. It is located in the middle of 173.

In the above bellows pump 163, the connecting shaft 7N?
When the cylinder 0 moves to the right, the measured liquid is sucked into the first cylinder 16S, and the stock liquid in the second cylinder 166 is sent to the first mixing container 1011. If the ratio of the amount of change in the internal volumes of both cylinders 165 and 166 during the stroke is determined in advance, the first
By detecting the amount of metered liquid sucked into the cylinder 165, the amount of the stock solution supplied to the first mixing container 10 can be determined. In this way, it becomes possible to measure a highly corrosive stock solution such as heptahydrofluoric acid using an inexpensive and highly accurate measuring device such as a general-purpose flowmeter.

[Brief explanation of the drawing]

FIG. 1 is a developed explanatory view of a compounding device for cleaning chemicals for semiconductor materials to which the present invention is applied, FIG. 2 is a partially enlarged view of FIG. 1, and FIG. 3 is a perspective view of the compounding device of FIG. 1. 4 is a schematic cross-sectional view taken along the line A-A in FIG. 3 with some of the internal mechanisms omitted; FIG. 5 is a schematic cross-sectional view taken along the line B-B in FIG. 3 with some of the internal mechanisms omitted; The figure is a partial explanatory diagram of another embodiment. 7.22.23...Storage container, 10.87...
Mixing container, 11.92... platform scale (measuring means),
12゜94...Fluid filter (filter means),
73°93...Circulation/discharge pump (suction means),
75°96... Circulation path, P... Pressure feeding system (supply means). Patent applicant: Kurashiki Boseki Co., Ltd. Representative: Patent attorney Mr. Hao and two others Figure 2 Figure 5

Claims (1)

[Claims] (1) A plurality of storage containers for storing a plurality of stock solutions for preparing semiconductor chemicals, a closed mixing container for mixing the stock solutions in the storage containers, and a supply means for supplying the stock solutions in the storage containers to the mixing container. , a measuring means for measuring the supply amount of the stock solution supplied to the mixing container, a suction means for suctioning the liquid in the mixing container, and a filter means for removing foreign matter from the liquid, the suction means and the filter means being 1. A compounding device for semiconductor chemicals, comprising: a circulation path for circulating a liquid in a mixing container through the mixing container.