JPS6235520A - Manufacture of semiconductor device - Google Patents

Abstract

PURPOSE:To reduce the consumption of a resist separating solution and to decrease recontamination due to using the resist separating solution by repeating the immersion of a substrate in a vessel with the resist separating solution evaporated by heating, cooled and liquefied while circulating the resist separating solution. CONSTITUTION:A resist separating solution 11 is prepared in an evaporating vessel 13, a substrate W is filled together with wafer carrier C in a separating vessel 14, and the solution 11 is heated. Thus, vapor of the solution 11 generated in the vessel 13 is fed through a vapor supply tube 5 to the vessel 14, and cooled to become resist separating solution 12. The substrate W is completely immersed to dissolve and remove the resist. When the surface level of the solution 12 is further raised, it is returned to the vessel 13 by siphon action of a separating solution returning tube 18 so that the vessel 14 temporarily becomes vacant. The flaky resist is collected by a filter 19 by this return. The resist separating solution supplied to the vessel 14 becomes fresh through an evaporating step, and the substrate W is repeated to be immersed again with fresh separating solution 12.

Description

[Detailed Description of the Invention] [Summary] In removing resist from a substrate in the manufacture of semiconductor devices, the process of repeatedly immersing the substrate in a container with a resist stripping solution that has been evaporated by heating and liquefied by cooling is repeated while circulating the resist stripping solution. This reduces the amount of resist stripping solution consumed and reduces re-contamination caused by the resist stripping solution during use.

[Industrial application field]

The present invention relates to a method for manufacturing a semiconductor device, and particularly to an improvement in a method for removing resist from a substrate.

Photolithography technology is often used in wafer processes (substrate processing) in the manufacture of semiconductor devices, and in this technology, resists are often used as masks for processing such as etching and ion implantation. Although it is essential to remove the resist after this processing, it is desired that this removal be carried out economically without contaminating the substrate.

[Conventional technology]

FIG. 2 is a diagram illustrating a main part of an example of an apparatus for carrying out a conventional method of removing resist from a substrate.

In the figure, 1 and 2 are containers with an opening at the top for containing a resist stripping solution such as acetone or butyl acetate, and 3 and 4 are containers containing resist stripping solutions 1 and 2, respectively.

Removal of the regimen from the substrate (specifically, the wafer) W is as follows:
The substrates W are placed in a wafer carrier C that can accommodate multiple substrates W.
The substrate W together with the wafer carrier C is immersed in the resist stripping solution 1 as shown by arrow a and left for a certain period of time, for example, 5 minutes, and then immersed in the resist stripping solution 2 and left for a certain period of time, for example, 5 minutes. .

By this immersion, the resist is dissolved in the resist stripping solution (in some cases, a portion of the resist is peeled off in the form of scales), and the resist is removed from the substrate W.

Note that although not shown in the drawings, a pretreatment to ensure the wettability of the substrate W and a posttreatment to remove the resist stripping solution are usually performed.

The reason why we used two resist stripping solutions, 1 and 2, in the above resist removal process was because resist removal tends to become insufficient when the resist melt concentration in the resist stripping solution becomes high. This is because the substrate W is recontaminated, so in order to avoid this inconvenience, the method is divided into two for rough removal and one for final removal.

From this, when a certain number of substrates W from which the resist has been removed (a certain number of wafer carriers C) is reached, the resist stripping solution 1 in the container 3 is discarded, and the resist stripping solution 2 in the container 4 is transferred to the container 3. Transfer it to make a new resist stripping solution 1, and refill the container 4 with fresh resist stripping solution 2.
Generally, this is the case.

Therefore, in the conventional example above, there are two containers, 3 and 4.
The resist can be removed with one or three or more of them.

[Problem that the invention seeks to solve]

As is clear from the above explanation, in the conventional method, reducing the frequency of replacing the resist stripping solution increases recontamination of the substrate W, and increasing the frequency of replacement can reduce recontamination, but the amount of resist stripping solution consumed increases. There is a problem that is increasing and becoming uneconomical.

[Means for solving problems]

FIG. 1 is a block diagram of the main parts of an embodiment of an apparatus for carrying out the method of the present invention.

As shown in FIG. 1, the above problem is solved by placing the resist-coated substrate W in the first container 14, heating the resist stripping liquid 11 in the second container 13, evaporating it, and cooling it into liquid. While flowing into the first container 14, the resist that has accumulated in the first container 14 and soaked the substrate W is removed! ? The problem is solved by the method of the present invention in which the resist is removed from the substrate W by repeatedly returning the resists &12 to the second container 13 all at once.

[Effect]

According to the above configuration, resist removal is performed in the first container 14, and the resist stripping solution that is continuously replenished into the first container 14 is freshly distilled resist stripping solution 1. The resist stripping liquid 12 in the first container 14 in which the substrate W is immersed is periodically discharged all at once.

Therefore, resist removal by this method is always the same as immersing the substrate W in fresh resist stripping solution multiple times, and a state with reduced recontamination is maintained regardless of the number of substrates W.

Moreover, since the resist stripping solutions 11 and 12 are circulated, the amount of resist stripping solution consumed is significantly reduced compared to the conventional method.

〔Example〕

An example will be described below with reference to FIG.

The apparatus shown in FIG. 1 is a Soxhlet type extraction apparatus modified to be able to carry out the method of the present invention.

In the figure, reference numeral 13 denotes an evaporation container for evaporating the resist stripping solution 11 (the second container mentioned earlier), and 14 denotes a stripping container (first container) into which the substrate W is placed together with the wafer carrier C and the resist stripping solution 12 removes the resist. (first container mentioned), 1
5 is a heater that heats the resist stripping solution 11; 16 is a steam supply pipe that guides the vapor of the resist stripping solution 11 generated in the evaporation container 13 to the stripping container 14; and 17 is a cooling device that liquefies the vapor guided to the stripping container 14. , 18 is a stripping solution return pipe for returning the resist stripping solution 12 that has accumulated in the stripping container 14 due to the liquefaction and soaked the substrate W into the evaporation container 13 by a siphon action;
Reference numeral 19 is a filter provided in the middle of the stripping liquid return pipe 18 and made of, for example, glass wool, and 20 and 21 are a drain and a stripping solution supply port provided in the evaporation container.

To remove the resist from the substrate W, prepare the resist stripping solution 11 by putting the same conventional resist stripping solution into the evaporation container 13, put the substrate W together with the wafer carrier C into the stripping container 14, and strip the resist with the heater 15. This is done by heating the liquid 11.

Then, the vapor of the resist stripping liquid 11 continuously generated in the steaming container 13 passes through the steam supply pipe 16 and enters the stripping container 14.
It is cooled by the cooling device 17 and liquefied to become fresh resist stripping solution, which accumulates in the stripping container 14 and becomes the resist stripping solution 1.
It becomes 2.

Then, as the liquid level becomes higher, the substrate W is completely immersed, and the resist of base+aW is dissolved (some of it is peeled off in the form of scales as the case may be) and removed.

When the resist stripping liquid 12 reaches a higher level while dissolving the resist, the resist stripping liquid 12 is returned to the evaporation container 13 from the siphon of the stripping liquid return pipe 18, and the stripping container 14 is temporarily emptied.

By this return, the dissolved resist is transferred to the evaporation container 13, and the scaly resist is captured by the filter 19.

The resist stripping solution 11 is mixed with dissolved resist, but the resist stripping solution supplied to the stripping container 14 is
The substrate W becomes fresh through the process of evaporation and liquefaction, that is, distillation, and since the supply thereof is continuous, the substrate W is repeatedly immersed in fresh resist stripping liquid 12 again.

The inventor of the present application set the repetition period to about 2 minutes, and by repeating the process five times, was able to obtain sufficient resist removal without detecting recontamination.

When the number of substrates W from which resist has been removed increases, the lower part of the resist stripping solution 11 becomes stagnant with dissolved resist;
In that case, drain the stagnation through the drain 20,
The resist stripping solution may be replenished from the stripping solution supply port 21.

Further, the amount of the resist stripping liquid 11 that is lost due to dissipation from the upper opening of the stripping container 14 may be replenished in the same manner.

In this way, the amount of resist stripping solution consumed relative to the number of substrates W processed is actually less than 1/10 of the conventional amount.

Note that the filter 19 may be replaced at an appropriate time depending on its clogging state.

Further, the pre-processing and post-processing described in the conventional example may be performed as in the conventional example before and after this resist removal.

〔Effect of the invention〕

As explained below, according to the configuration of the present invention, when removing resist from a substrate in the manufacture of semiconductor devices, it is possible to reduce the consumption of a resist stripping solution and to reduce recontamination due to the resist stripping solution in use. This has the effect of making the work more economical and improving quality.

[Brief explanation of drawings]

FIG. 1 is a block diagram of main parts of an embodiment of an apparatus for carrying out the method of the present invention, and FIG. 2 is a block diagram of main parts of an example of a apparatus for carrying out a conventional method. In the figure, 1.2.11.12 is resist stripping liquid, 13 is evaporation container (second container), 14 is stripping container (first container), 15 is heater, 16 is steam supply pipe, 17 is cooling 18 is a stripping liquid return flow pipe, 19 is a filter, W is a substrate (wafer), and C is a wafer carrier.

Claims (1)

[Claims] The resist coated substrate (W) is placed in the first container (14).
The resist stripping solution is heated in the second container (13), evaporated, cooled, liquefied, and flows into the first container (14), while the resist stripping solution accumulates in the first container (14) and removes the substrate. (W)
The resist stripper soaked in the resist stripping solution is poured all at once into the second container (13
) by repeating the process of returning the resist to the substrate (W).
1. A method of manufacturing a semiconductor device, comprising: removing the material from the material.