JP2925289B2 - Automatic liquid management device - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an automatic liquid management apparatus that automatically detects deterioration of a processing liquid by using absorbance.

2. Description of the Related Art Conventionally, for example, a resist stripping solution (processing solution) used in a semiconductor manufacturing process or the like is analyzed and managed by various methods. Further, the analysis is performed for the purpose of labor saving and improvement of quality control. , Management has been automated.

As an automatic liquid management apparatus of this type, for example, an apparatus previously proposed by the present inventors (Japanese Patent Application No. 2-9539) is a method in which a resist stripping liquid containing a mixture of sulfuric acid and hydrogen peroxide is pumped on-line using a pump or the like. Then, the absorbance of the sampled stripping solution is measured by an absorbance meter to control the degree of deterioration, and the concentration is controlled by redox titration.

The resist stripping solution is colored by a resist (novolak resin or the like) laminated on the upper surface of the silicon wafer for semiconductor (object to be processed), and is treated with sulfuric acid and hydrogen peroxide as components of the resist stripping solution. The resist is decolorized by being decomposed. When observing the absorbance and change in absorbance of the resist stripping solution, whether the resist is present in the stripping solution and whether the resist is effectively decomposed by sulfuric acid and hydrogen peroxide Is determined.

"Problems to be Solved by the Invention" Incidentally, in the above-described automatic liquid management apparatus, the degree of deterioration is detected by measuring the absorbance of the stripping solution in which the resist is dissolved. In this case, it is difficult to distinguish between a case where the concentration of the active ingredient in the stripping solution has changed (particularly when H ₂ O ₂ has decreased) and a case where the concentration of the active ingredient has been sufficiently high and the solution has deteriorated. There was a problem that it could not be done.

Means for Solving the Problems Therefore, in the automatic liquid management apparatus of the present invention, a processing liquid supply path for supplying a processing liquid, and a reduced effective component in the processing liquid in the processing liquid in the processing liquid supply path Reagent supply means for supplying at least one of the above, measurement means for measuring the absorbance of the processing liquid supplied by the processing liquid supply path, calculation means for calculating the data obtained by the measurement means, these means Control means for controlling, the control means is provided with a deterioration determination function, the deterioration determination function, the time from exceeding the reference absorbance until returning to the reference absorbance again, a predetermined reference By making the determination by comparing the time, the above-described problem is solved by detecting only the deterioration of the processing solution without measuring the concentration of the active ingredient in the processing solution.

[Operation] According to the automatic liquid management apparatus of the present invention, the reagent supply means for supplying at least one of the active components in the treatment liquid is provided, and the deterioration determination function is provided in the control means. Is used for detecting the deterioration of the resist stripping solution, the time from when the absorbance exceeds the preset reference absorbance to when the absorbance returns to the above depends only on the resist dissolving (or decomposing) ability of the stripping solution. ,
The resist is dissolved (decomposed) by a certain amount by adding a certain amount of the active ingredient to the stripping solution in advance, and after the absorbance peak exceeds a predetermined reference absorbance, the absorbance becomes higher. By comparing the time required to return to the reference time set in advance, it is possible to quickly detect the deterioration of the processing liquid.

Embodiment An embodiment of the present invention will be described with reference to FIGS. In this embodiment, a resist processing solution (stripping solution) containing sulfuric acid and aqueous hydrogen peroxide as active ingredients according to the present invention is described.
It is an example when it is applied to a management device.

In FIG. 1, reference numeral 1 denotes an automatic liquid management device, 2 denotes a processing tank, and the processing liquid used in the processing tank 2 is supplied to the automatic liquid management device 1 by a measuring means (absorbance described later) of the automatic liquid management device 1. ) Is provided with a processing liquid supply path 3 for supplying the processing liquid.
A cooler 4, a three-way solenoid valve 5, a heater 6, a cooler 7, a pump 8, an absorbance meter 9, and a three-way solenoid valve 10 are sequentially provided in the processing liquid supply path 3.

A reagent supply path 11 is connected to the three-way solenoid valve 5, and a pump 12 is provided in the reagent supply path 11.
Further, a reagent tank 13 is provided downstream of the reagent supply path 11, and the reagent tank 13 has at least one kind of active ingredient in the processing solution, that is, sulfuric acid or peroxide having a predetermined concentration in this example. Hydrogen water and a mixture thereof are contained. Here, the reagent supply path 11 supplies the reagent (sulfuric acid or hydrogen peroxide solution) in the reagent tank 13 into the processing liquid in the processing liquid supply path 3 by driving the pump 12. That is, the reagent supply path, the pump 12, the reagent tank 13, and the three-way solenoid valve 5 constitute a reagent supply unit in the present invention.

In addition, the three-way solenoid valve 10 has a return path for returning the processing liquid whose absorbance has been measured by the absorbance meter 9 to the processing tank 2.
The drain 14 and the drain path 16 for discharging to the drain tank 15 are connected.

Further, as shown in FIG. 2, the automatic liquid management apparatus 1 includes a control means 100 for controlling the operation of each of the above components.
Is provided. The control means 100 includes an input means 101 such as a keyboard, a calculating means 102 for calculating measurement data obtained from the absorbance meter 9, an operating state and a processing state of the apparatus, and a measurement result by the calculating means 102 and the like. (For example, a display panel in which a system diagram similar to that shown in FIG. 1 is provided and a lamp or the like is provided at a location corresponding to each component) is provided.

Further, the control means 100 is provided with a deterioration determination function 104 for determining whether or not the processing liquid has deteriorated. The deterioration determining function 104 is input absorbance a ₀ as a pre-reference by the input means 101, and the peak of the absorbance obtained by the absorptiometer 9 measurements, absorbance a ₀ to be the reference
When the reference value t ₀ in advance also the time to return to the absorbance a ₀ is input from beyond, the peak absorbance obtained by absorbance meter 9, the absorbance a ₀ from beyond the absorbance a ₀ time tn to return to the when exceeding the above t _0, determines that the processing solution is deteriorated, and displays the determination by said output means 103 (output). Here, the absorbances a ₀ and t ₀ are determined in advance by experiments or the like in accordance with the use conditions of the stripping solution and the like.

Such perform automatic liquid control stripper by the management apparatus 1 receives an input of the reference absorbance a ₀ and the reference time t ₀ of the previously input unit 101, may be set entering the measurement interval, then the pump The processing liquid 8 is intermittently driven to flow the processing liquid (stripping liquid) from the processing tank 2 into the processing liquid supply path 3 at the above-described measurement intervals. Then, the processing liquid flowing into the processing liquid supply path 3 is adjusted to the optimum temperature for the absorbance measurement by the cooler 4, the heater 6, and the cooler 7, and reaches the absorbance meter 9, and the absorbance is measured at predetermined intervals. You.

Here, an example of the measurement data (peak of the absorbance) obtained by the absorbance meter 9 is shown in FIG. In FIG.
a ₀ is a reference value set in advance as described above, tn is the time from exceeding the absorbance a ₀ to return to the absorbance a _0.

As shown in FIG. 3, by continuing the measurement as a liquid management, and resist delamination progress of the processing solution over time, the reference value a ₀ absorbance with that its activity is deteriorated
The time tn before returning to becomes longer. That is, the ability to dissolve (decompose) the resist of sulfuric acid and hydrogen peroxide, which are the effective components of the processing liquid (stripping liquid), deteriorates, so that the time until the resist is decomposed and the processing liquid is decolorized becomes longer.

For example, when t ₃ shown in FIG. ₃ exceeds t ₀ , the three-way solenoid valve 5 shown in FIG. 3 mixed into the processing solution. Then, the processing solution has an increased resist dissolving (decomposing) capability by a degree newly set by the reagent newly supplied from the reagent tank 13. When the absorbance led to the absorbance meter 9 in this state is measured, the t ₄ than t ₃ peaks before reagents mixed as shown in FIG. 3, dissolution by reagents supplied to the novel (decomposition ) It becomes shorter by the height of Noh.

Then, it is determined whether the t ₄ exceeds the reference time t ₀ which is set in advance by the deterioration determining function 104, the determination by the output means 103 determines that the long as the treatment liquid over is degraded Is displayed (output), and if it does not exceed, the absorbance measurement of the processing liquid due to the mixing of the reagent is repeatedly performed until it is determined that the processing liquid has deteriorated, and the liquid is managed.

The processing liquid after the absorbance measurement is returned to the processing tank 2 or sent to the drain tank 15 by appropriately switching the three-way solenoid valve 10. Further, the heater 6 supplies the newly added reagent (sulfuric acid or hydrogen peroxide solution) to the processing tank 2.
Heating is performed to accelerate the dissolution (decomposition) of the resist so that the treatment liquid dissolves (decomposes) the resist in the same manner as the treatment liquid dissolves (decomposes) the resist. This is for adjusting the temperature of the treatment liquid heated in the step to an optimum temperature for the absorbance measurement.

In such an automatic liquid management apparatus 1, by mixing an effective component of the processing liquid into the processing liquid, deterioration can be quickly and easily detected by comparison with a preset reference time t _0. Therefore, the reliability of the treatment liquid management can be enhanced, and the liquid can be exchanged in an optimum state by rapid deterioration detection.

In the above embodiment, only the absorbance meter 9 was provided to manage only the degree of deterioration of the processing solution. However, for example, a concentration analysis unit using an oxidation-reduction potential electrode as a sensor was provided.
It may be possible to manage both the deterioration and the concentration of the liquid, in which case it is preferable to use, for example, a six-way solenoid valve as the sampling means.

[Effects of the Invention] As described above, the automatic liquid management apparatus of the present invention is provided with the reagent supply means for supplying at least one of the active components in the processing liquid, and the control means having the deterioration determination function. is there. Therefore, for example, when this apparatus is used for detecting the deterioration of the resist stripping solution, the time from when the absorbance exceeds a preset reference absorbance to when the absorbance returns to the absorbance is determined only by the resist dissolving (or decomposing) ability of the stripping solution. Therefore, the resist dissolution (decomposition) ability is increased by a certain amount by adding a certain amount of the active ingredient to the stripping solution in advance, and the absorbance at this time, which is a preset reference, is set as the absorbance peak. By comparing the time from when the absorbance is exceeded to the time when the absorbance returns to a predetermined reference time, it is possible to easily and quickly detect the deterioration of the processing liquid, thereby improving the reliability of the processing liquid management. In addition to this, the liquid exchange can be performed in an optimal state, so that the manufacturing cost can be reduced. Further, since it is the active ingredient in the processing solution that is mixed into the processing solution, the processing solution after the absorbance measurement is not contaminated by the measurement,
Therefore, even if the processing liquid after this measurement is returned to the processing tank, the processing in the processing tank is not impaired at all, and it is possible to prevent the quality of the product to be processed from deteriorating.

[Brief description of the drawings]

1 to 3 show an embodiment of the automatic liquid management apparatus of the present invention. FIG. 1 is an overall schematic configuration diagram, FIG. 2 is a diagram showing a control mechanism, and FIG. 6 is a graph showing an example of data measured by the device. DESCRIPTION OF SYMBOLS 1 ... Automatic liquid management apparatus, 3 ... Processing liquid supply path, 5 ... Three-way solenoid valve, 9 ... Absorbance meter, 11 ... Reagent supply path, 12 ... Pump, 13 ... Reagent tank, 100 ... Control means 102... Calculation means 104... Deterioration determination function.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification symbol FI // H05K 3/06 H01L 21/30 572B (56) References JP-A-59-182347 (JP, A) JP-A-58-58 153766 (JP, A) JP-A-63-138268 (JP, A) JP-A-2-152544 (JP, A) JP-A-2-244710 (JP, A) JP-A-4-130505 (JP, A) JP-B-47-10203 (JP, B1) (58) Field surveyed (Int. Cl. ⁶ , DB name) G01N 35/00-35/10

Claims (1)

(57) [Claims] A processing liquid supply path for supplying a processing liquid; a reagent supply means for supplying at least one of the reduced effective components in the processing liquid to the processing liquid in the processing liquid supply path; Measuring means for measuring the absorbance of the processing solution supplied by the supply path, calculating means for calculating data obtained by the measuring means, and control means for controlling these means; Is provided with a deterioration determination function, and the deterioration determination function compares the time from when the absorbance exceeds a reference value to when the absorbance value returns to the reference value with a reference time set in advance. Automatic liquid management device.