JPH01309332A - Automatic control apparatus for etching - Google Patents

Abstract

PURPOSE:To perform automated etching while maintaining uniformity by computing a treating time with an operating device from a characteristic line, automatically differentiating the treating time of a substrate sequentially with the progress of etching of the substrate. CONSTITUTION:Etching liquid 1 is jetted on a substrate 2, e.g., on one surface of the substrate 2, as shown by an arrow, and etching is continuously performed. A characteristic line (a) having the expression of relation Y=A+B.X (A and B are constants) is plotted beforehand based on an etching rate Y and the Si-dissolved quantity X of the substrate 2. The characteristic lien (a) is stored in an operating device 3 comprising a semiconductor and the like. When an etching depth 4 of the substrate 2 is imparted into the device 3, a treating time T=(etching depth)/(etching rate) is computed in the device 3 from the characteristic line (a). With the progress of the etching of the substrate 2, the treating time T of the substrate 2 has the different values automatically and sequentially. Thus, the etching can be automated, and the uniform etching is carried out.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an automatic etching control device that sprays an etching liquid onto one side of a substrate, such as a Si substrate, to perform etching to a predetermined depth.

[Conventional technology]

When etching is carried out by spraying or immersing an etching liquid onto a Si substrate, the quality of the processing liquid gradually deteriorates, and it takes longer to process the last part of a predetermined number of substrates than the first part.

A solution to this problem is to replace the etching solution with a new one after a certain number of substrates have been processed, or to use the etching rate and the amount of substrate dissolved based on experimental data prepared in advance.
Etching is performed in anticipation of the processing time associated with a decrease in etching rate.

[Problem that the invention seeks to solve]

However, such a method has the following problems.

(a) After a predetermined number of sheets have been etched, the etching solution is replaced with a new etching solution, which not only requires a large amount of solution, but also incurs miscellaneous expenses such as personnel costs.

(E) As the etching rate decreases, it becomes troublesome to read the processing time from experimental data one by one and perform etching accordingly, and this work has to be done manually.

(c) When processing is performed for the same time, the etching solution will vary depending on the type of etching solution, temperature, etc., and variations will inevitably occur.

The present invention was devised in view of the above-mentioned points, and its purpose is to eliminate the need to replace the etching solution with a new one even if the etching solution deteriorates, and to eliminate manual etching by reading the processing time. The present invention provides an automatic etching control device that has various advantages in that all etching unevenness can be resolved within the permissible limits.

[Means for solving problems]

In other words, the means to achieve this goal is to use an apparatus that circulates an etching solution and performs etching processing continuously, by setting the etching rate Y and the dissolution tX of the substrate in advance.
From the constants A and B, create a characteristic line using the relational expression %Y=A+B-X, that is, the property that the etching rate decreases linearly with the amount of etching substance dissolved, and use it to By storing a signal of the etching depth of the substrate in the calculation device, the processing time; T=(etching depth)/(etching rate) is calculated from the characteristic line by the calculation device, and the etching process of the substrate is This automatic etching control device is characterized in that the processing time of the substrate automatically changes as the etching progresses. In addition, multiple types of characteristic lines are stored in the arithmetic unit, and the number of boards is automatically detected.
The use of characteristic lines may be made to correspond to the detected substrate.

[For production]

Its operation will be explained in detail in the following description of the embodiment.

The following is an explanation, Figure 2, which is an explanation, 2 explanation of the embodiment of the present invention based on the drawing, based on the drawing. It is a block diagram for explaining the technical idea.

FIG. 1 schematically shows the etching process of a substrate according to the present invention, and the structure of the present invention will be described below with reference to FIG.

That is, the etching solution 1 is continuously sprayed onto one side of a substrate, for example, a Si substrate 2, as shown by the arrow.

In the etching apparatus, a characteristic line a having the relational expression Y=A+B-X where A and B are constants is created in advance from the etching rate Y and the dissolved amount X of the Si substrate 2. This characteristic line a
The etching process is carried out for the same time, at the same temperature, and with the same etching mixture, and the amount X of the 8i substrate dissolved by the etching liquid 4 is calculated using a difference measuring device or the like.

That is, various methods can be used to create this characteristic line a, but for example, several tens of sheets are etched with a predetermined etching depth and area.

The amount of dissolution is calculated from this depth per area, and the amount of etching solution applied to the Si substrate per hour is measured. Then, the values obtained when the number of sheets to be etched are sequentially processed are plotted, and the characteristic line a is a straight line representing the values. Incidentally, since the relationship between the etching rate Y and the dissolution amount X is well known, a detailed explanation will be omitted here.

The characteristic line a thus obtained is stored in an arithmetic unit 3 made of a semiconductor or the like. Then, by giving the etching depth 4 of the 8i substrate 2 to the arithmetic unit 3, the processing time: T=(etching depth)/(etching rate) is calculated by the arithmetic unit 3 from the characteristic line a. This apparatus is constructed so that the processing time T of the Si substrate 2 automatically changes to different values as the etching process progresses.

The effect will be explained below.

First, a characteristic line input to the arithmetic device 3 is selected. The characteristic line shows the mixing ratio of the etching solution, for example HF:
HNOs:0HsOOOH, different types are created depending on their mixing ratio, temperature, etc., and various types are input, from which the characteristic line a shown in FIG. 2 is selected. Of course, it goes without saying that the storage device can be input to the arithmetic unit so that etching can be performed sequentially on the characteristic line a and after the etching process is completed on other characteristic lines. Incidentally, the reaction equation 4 between the etching liquid 1 and the Si substrate 2 is expressed as follows: Next, the etching depth 4 is input to the arithmetic unit 3. Before and after that, as shown in FIG. 1, a case 5 containing several stacked Si substrates 2 is set in the etching apparatus.

When the operation start button of the arithmetic device 3 is turned on in this state, the presence or absence and number of 8i substrates 2 housed in the case 51 are automatically detected by a sensor (not shown).
Thereafter, the Si substrate 2 housed in the case 5 is automatically transferred to the etching table 6.

Then, when the setting is completed, the etching table 6 rotates,
The etching liquid 1 is injected from the inclined nozzle 7 toward the 8i substrate 2 as shown by the arrow. The injected etching liquid 1' is stored in a tank 8 provided at the bottom, and is sent to a circulation pump 9.
The liquid is sucked up and sent to a tank on the side of the upper inclined nozzle 7 (not shown), and then discharged to the inclined nozzle 7 by a pump.

After a predetermined period of time has elapsed, that is, when the processing time on the characteristic line a is completed, the pump that injects the etching is stopped and, for example, when washing is performed on the etching table 6, the washing water is mixed with the etching solution 1. The wing 10 is in close contact with the tapered portion of the etching table 6 and is separated from the outflow path of the etching liquid 1 so as not to be mixed with the etching liquid. After that, when the water washing is completed, the Si substrate 2 is automatically transferred to the next step, draining.

Proceed to dry.

Next, the second Si substrate is automatically transferred from the case 5 to the etching table 6. Etching is automatically performed through the above-mentioned setup, but as the activity of the etching solution 1 weakens, the processing time gradually increases according to the characteristic line a.

In this way, the Si substrate 2 housed in the case 5
are sequentially etched, and on the other hand, the etching liquid 1 gradually deteriorates, so that the etching rate Y decreases along the characteristic line a. Etching of all the Si substrates 2 is completed, but depending on the pattern of the etching liquid 4 and the amount of dissolved Si substrates, the next set of Si substrates may be etched without replacing the etching liquid 1. Can be etched. Also, depending on how the program is set up, for example, up to five etchings may be etched at a certain depth and amount, and once that is completed, the etching depth may be etched at a depth and amount that is different from the etching depth value of 4. Various types of etching can be performed, such as etching the next five sheets.

〔Effect of the invention〕

As explained above, according to the present invention, compared to the conventional art.

When the etching solution 1 deteriorates, it needs to be replaced with a new solution, and even if the etching processing time is known, the accompanying etching work requires manpower, but etching according to characteristic line a of the present invention automation has become possible, and all that is required is the initial construction.

All you have to do now is set up a running program and start operation. Furthermore, by patterning the depth and amount of dissolution, the etching solution 1, which was wasted, can be rotated more efficiently, resulting in cost reductions.

Furthermore, since etching unevenness that could not be eliminated manually is automatically controlled using the characteristic line a, uniform etching has become possible.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram for explaining one embodiment of the automatic etching control device of the present invention, and FIG. 2 is a professional diagram for explaining the technical idea thereof. DESCRIPTION OF SYMBOLS 1... Etching liquid, 2... Si substrate, 3... Arithmetic device, 4... Etching liquid, 5... Case, 6...Etching table, 7...Incline nozzle, 8...Receiver is tank, 9...Circulation pump, 10...Wing.

Claims (2)

[Claims] (1) In a device that continuously performs etching treatment by circulating an etching solution, the etching rate Y is set in advance.
From the amount of dissolved substrate X and constants A and B, Y=A+B・
By creating a characteristic line having the relational expression of Automatic etching control characterized by calculating etching depth/(etching rate) using a calculation device, and automatically varying the substrate processing time as the substrate etching process progresses. Device. (2) A plurality of types of the characteristic lines are stored in the arithmetic unit, the number of substrates is automatically detected, and the appropriate use of the characteristic lines is made to correspond to the detected substrates. The automatic etching control device according to item (1).