JPH03242536A - Automatic liquid managing apparatus - Google Patents

Abstract

PURPOSE:To achieve a highly accurate judgment of deterioration by judging that a treating liquid is aged when a peak value of absorbance of the treating liquid measured at a fixed time interval exceeds a reference value and when time exceeds a reference value until the absorbance reaches a reference value from a peak. CONSTITUTION:A treating liquid supplied from a supply system 1, for example, contains sulfuric acid and hydrogenperoxide is cooled with a cooler 2 to remove impurities undissolved with a filter 3 and to measure absorbance with a photo cell 4 and sent to a six-way valve 5. When a fixed amount of an object to be treated, for example, a resist to be generated in a production process of a silicon wafter for a semiconductor is fed into the treating liquid continuously at a time interval, the absorbance immediately after the feeding rises sharply but it lowers in time with the deposition of the resist in the sulfuric acid and hydrogenperoxide. It is judged that the treating liquid is aged when a peak value of the absorbance exceeds a specified threshold while time exceeds a reference value until the absorbance falls below the threshold.

Description

DETAILED DESCRIPTION OF THE INVENTION "Industrial field-j" This invention relates to an automatic liquid management device that uses absorbance to determine whether or not a processing liquid has deteriorated.

``Prior art'' Traditionally, cleaning liquids (processing liquids) used in semiconductor manufacturing processes, for example, have been analyzed and analyzed using various methods, both automatic and manual.
It was managed.

Specifically, when analyzing the Lennost stripping solution (processing solution) used in the manufacturing process of semiconductor medium silicon wafers, we conduct neutralization titration and redox titration of sulfuric acid and hydrogen peroxide, which are the components of the resist stripping solution. Alternatively, the degree of deterioration of the resist stripping solution is measured by measuring the absorbance of the resist stripping solution and its change using an absorbance meter.f2.

The resist stripping solution is colored by the resist (novolac resin, etc.) laminated on the top surface of the semiconductor silicon wafer (workpiece), and is colored by the resist stripping liquid, which is colored by the resist (novolac resin, etc.) that is layered on the top surface of the semiconductor silicon wafer (workpiece), and is also colored by the resist stripping liquid, which is colored by the resist (novolac resin, etc.) that is layered on the top surface of the semiconductor silicon wafer (workpiece). The color is removed by decomposing the resist. By this, when observing the absorbance and absorbance change of the resist stripping solution, it is possible to determine whether or not Renost is present in the stripping solution.
It is determined whether or not the renost has been effectively decomposed by sulfuric acid and hydrogen peroxide.

``Problem to be Solved by the Invention By the way, the above-mentioned method for determining the deterioration of the Lennost stripping solution is based only on the change in absorbance over time of the Lennost stripping solution. measured at the absorbance of f2:)-1
'This poses the problem of not being able to perform accurate analysis. Specifically, even if the change in absorbance is small and it is determined that the Lennost stripping solution has deteriorated, if this absorbance change η□ was done at a low level, the Lennost stripping solution will be removed. The liquid is in an active state, and in this 1.1 (the new f2 is required to provide a criterion for f2).

2J) f, II, [] ;Yo, above J)πIn view of the circumstances, I am speaking fKochinote;) Hete, II) ,; Changes with respect to time::)+-
:-F,) By parameter, Renost 4 (Surikou,)
Automatic liquid deterioration device, judge the total 1'-i process.
n,,) for the purpose of providing.

In order to solve the problem, the present invention:
The apparatus is equipped with an absorbance measuring means for measuring the absorbance of the treatment liquid at regular intervals, and an analysis means for analyzing the degree of deterioration of the treatment liquid based on the absorbance. The analysis means is provided with a deterioration determination function that determines the deterioration when the luminous intensity is greater than or equal to I and the time taken to reach the absorbance peak or the S reference absorbance is longer than a preset reference time. That's what I do.

According to this invention: i. Based on two parameters: the change in absorbance over time and whether the peak of absorbance is greater than or equal to a preset reference absorbance (absolute value),
Since we decided to judge whether the processing solution has deteriorated or not, for example: f, after adding lenost, the absorbance of the processing solution 7 changes slightly! In this case, it is necessary to make an erroneous judgment that the processing liquid has deteriorated and to prevent it. KoZ
- The effect is that it is possible to perform a highly accurate deterioration judgment.

One Embodiment One embodiment of the present invention will be described with reference to FIG. 1(A) and FIG. 1(B) to FIG. 3.

4. The general structure of the entire automatic liquid management apparatus will be explained with reference to FIG.

The treatment liquid may include one containing components such as sulfuric acid and hydrogen peroxide that peel off and dissolve the resist (such as Nohorasoku resin) on the semiconductor silicon wafer.

In the middle of the processing liquid supply path 1, along the flow direction X of the processing liquid, there are a cooler 2 for cooling the processing liquid, a filter 3 for removing impurities such as undissolved substances, a photocell 4, and a hexagonal 11-magnetic valve 5. They are set up sequentially.

The Fusaito cell 4 guides the Lennost stripping solution sent through the path 1 into the cell (as shown) and irradiates the Lennost stripping solution with a light beam of a certain wavelength, thereby removing the Lennost stripping solution. It measures the absorbance, and the absorbance that is the measurement result is supplied to the data processing device M as measurement data (a). This data processing device M includes a control means 10 as shown in FIG. 1(B).
3. 4 input stages +04, display panel 105 as output means
It is composed of

The details of the processing of the detected data (a) by the control means 103 of the data processing device M will be described in detail with reference to the flowchart of FIG. 3, which will be described later.

Further, the six-way solenoid valve 5 (-) is normally arranged as shown by the solid line, and the processing liquid is passed through the loop IO and paths 6 and 7 to the processing tank (as shown), and is drained through the paths 6 and 8. (d) When measuring the concentration of sulfuric acid and hydrogen peroxide in the processing liquid, switch to the position shown by the dotted line, and while the X-ray is placed at the The fco-processing liquid temporarily stored in the loop 10 is pushed out with purified water through a pure water supply system II (described later) and guided to a reaction cell (described later).

It should be noted that the amount of the processing liquid stored inside the loop 10 is preset, that is, the amount used for quantitative determination f2).

Those provided at the branching parts of routes 6 to 8 in f-1 and 17j are f-1, which guide particularly dirty processing liquid to the drain tank 9.
2') Three-way solenoid valve I2, one immersion in the middle of the path 6
The pump j3, which is installed in the middle of the above-mentioned path 8, is a PH pump for measuring the PH of the processing liquid.
This is electrode I4.

Second, the pure water supply system 11 includes a three-way solenoid valve 16, an intermediate tiger, and a lubricant provided along the pure water supply path 15.
, a pump 18, and a relief valve 20 installed in a branched path 19 to maintain the supply pressure of the pure water below a certain value. The pure water discharged by the relief valve 20 is transferred to the drain tank 9.
will be guided to.

5. rrlj record: After being temporarily stored in rape jO, it was pushed out due to pure lack c'! -bj second treatment liquid is route 21
~23 and the route 21~23 designed at the branch: 0) l-
, j: selectively guided to the reaction cells 25 and 26 by the three-way solenoid valve 21; Reagent supply systems 27 to 29 that supply reagents to this treatment liquid, and the reaction cell 25
- Redox electrodes 30 and 31 are provided to measure the redox potential of the solution in 26.

The reagent supply systems 27 to 29 include flasks 27A to 29A.
The reagent stored in the reaction cells 25 and 25 is passed through routes 27C to 29C by titration pumps 27B to 29B.
The oxidation-reduction electrodes 30 and 31 are used to detect the oxidation-reduction potential of the filtrate treated liquid when the reagent is dripped, and the redox electrodes 30 and 31 are used to detect the oxidation-reduction potential of the filtrate treated liquid when the reagent is dripped. The sulfuric acid and hydrogen peroxide concentrations of the treatment liquid can now be calculated.

In other words, the point at which the oxidation-reduction potential jumps is the end point of the reaction, and the amount of reagent dripped at the end point of the reaction (data indicating this amount of drip is sent from the titration pumps 27B to 29B to the control means +03 described later). ) or S, the sulfuric acid and hydrogen peroxide concentrations of the treatment liquid are calculated, respectively.

The reagents stored in flasks 27A to 29□8 include alkaline standard solutions such as sodium hydroxide, standard solutions that cause redox reactions such as potassium permanganate, and acidic standard solutions such as sulfuric acid. is appropriate.

On the other hand, in the lower part of the reaction cells 25 and 26, paths 32 to 34 are provided for discharging the processing liquid in the reaction cells 25 and 26 each time a measurement is completed. , filters 35 and 36, three-way solenoid valves 37 and 38 for discharging the solution from the reaction cells 25 and 26,
A drain pump 39 is sequentially provided. The solution discharged through the paths 32 to 34 is sent into the drain tank 9 described above.

In addition, in the configuration described above, the configuration in the range shown by the reference numeral 100 in FIG. .

Next, the control contents of the control means shown by the reference numeral 103 in FIG. 1(B) will be explained with reference to the graph showing the change in absorbance with respect to time in FIG. 2 and the flowchart in FIG. 3.

As shown in Figure 2, when a certain amount of Renosto is continuously added after a certain period of time, the absorbance increases immediately after the addition, but eventually the sulfuric acid, which is a component of the treatment solution,
The hydrogen peroxide decomposes the renost, and the absorbance decreases due to the heat. However, the degree of decrease in absorbance varies depending on the degree of deterioration of the processing solution.
The degree of this deterioration is determined using the flowchart shown in FIG.

Here, with reference to Figure 2, how about each input indicated by $~■? To explain this, it can be concluded that the processing solution is sufficiently active when the resist is charged at maximum yJJ as shown by :Yo, absorbance changes over time, and the amount of change in absorbance over time becomes larger. However, the former S self■・■
1. After a predetermined period of time after resist injection, the upper absorbance becomes constant and decreases to below Hertz, and the processing solution is
I can tell that it has deteriorated and is bad.

Against Kootsu, Rennost's pitch shown as ■: After pitching,
Although the absorbance increases during the absorption period, the absorbance does not decrease much after that.Furthermore, in the case of renost injection shown by ■, it increases after the addition and f
The absorbance did not decrease at all, indicating that the treated solution had completely deteriorated.

Here, the peak values of the absorbance peaks caused by the sagging are a1 to a, and each peak value a1 to a5 is the absorbance a, which is a preset standard. Assuming that the times until t and t5 are respectively, 1. ．． A specific value will be determined for 1°, but 1. The standard value is a because it does not exceed ao. I couldn't reach it, and I couldn't reach it, t+, ts
The absorbance is the reference value a. Therefore, the value ([t4.t5) cannot be detected.

In addition, n'J 3self tt, t3r stuck j knee t, <
There is a relationship between t and j, and as the number of inputs increases and the number of inputs increases, the value of L tends to increase due to deterioration. Deterioration judgment 2
H quasi iD a d is summarized in 3(-) and (d) below: (-) The absorbance peak an is the absorbance a that is the preset standard. (d) From the absorbance peak an, the reference absorbance a0
The time it takes to reach t is a preset standard. Deterioration is determined based on the above conditions. As a result, it is possible to assume the pattern of absorbance change after adding lenost shown in ■ and ■, and the absorbance decrease time is a certain time t.

It is considered to have deteriorated when it exceeds this limit.

A flow for determining the deterioration of the processing liquid using the deterioration determination criteria i1% (-) (d) will be described with reference to FIG. 3. Note that this deterioration determination flow represents the deterioration determination function of the control means 103.

Note that step X shown in the following explanation corresponds to rsPnj in FIG. 3.

<Step l> start.

<Step 2> Standard absorbance a. , and the absorbance a from the absorbance peak an. The time up to this point is set as the reference time t0.

<Step 3> Measurement data (a) indicating absorbance a is taken in from the photocell 4 at regular intervals.

<Step 4> Based on the amount of change in absorbance a with respect to time acquired from the measurement data (a), determine whether the peak value a of absorbance a has become equal to or higher than the reference absorbance a0 set in step 2. , if YES, proceed to step 5;
If no, return to step 3.

<Step 5> Based on the absorbance a taken at fixed time intervals according to the measurement data (a), the absorbance peak a is determined. From the reference absorbance a. Find the time tn until reaching , and use this time or the reference time t set in step 2 ↓5. It is determined whether or not the above is satisfied. If YES, the process proceeds to step 6; if NO, the process returns to step 3.

<Step 6> Peak value a of absorption ia. is the standard absorbance a.

In addition, the time tn until the absorbance peak a7 reaches the absorbance 11Lo, which is the reference time, is the reference time t.

If this is the case, it is determined that the condition has deteriorated, and the process proceeds to the next step 7.

Step 7> A notification signal (b) indicating that the processing liquid has deteriorated is output to the display panel 105.

<Step 8 end.

As explained above, according to the automatic liquid management device shown in this embodiment, the peak value an of the (-) absorbance a is used as the reference absorbance 1a. (d) Absorbance peak an or S standard absorbance a. The time tn until reaching t is the reference time t
. We decided to judge whether or not the processing liquid has deteriorated based on two parameters: In the case of injection), there is no (erroneous) determination that the processing liquid has deteriorated, and this has the advantage that a high MU deterioration determination can be made.

Effects of the Invention As explained in detail above, according to the present invention, changes in absorbance with respect to time and whether the absorbance is at its peak or greater than a preset reference absorbance (absolute value) can be determined. Since it is determined whether or not the processing liquid has deteriorated based on these two parameters, it is possible to perform a highly accurate deterioration determination.

[Brief explanation of drawings]

1(A) to 3 show one embodiment of the present invention, FIG. 1(A) is an overall schematic configuration diagram of an automatic liquid management device, and FIG. 1(B) is an automatic liquid management device. A diagram showing the control device of the management device, FIG. 2 is a graph showing the change in absorbance of χ·sip over time when resist is applied, and FIG. 3 is a flowchart showing the control contents of the control device.・1 ・Photocell (light absorption! measurement means) 103 ・
Control means (analysis means)

Claims (1)

[Scope of Claims] The apparatus comprises an absorbance measuring means for measuring the absorbance of the treatment liquid at regular time intervals, and an analysis means for analyzing the degree of deterioration of the treatment liquid based on the absorbance, wherein the peak of the absorbance is set in advance. The analysis means is provided with a deterioration determination function that determines deterioration when the absorbance is equal to or greater than a preset reference absorbance and the time from the absorbance peak to the reference absorbance is equal to or longer than a preset reference time. An automatic liquid management device characterized by: