JPH0737780A - Resist removal device and resist removal method wherein it is used - Google Patents

Abstract

PURPOSE:To provide a resin removal device which enables effective removal of a resist layer and metallic impurities involved therein, and a method thereof. CONSTITUTION:In a plasma ashing part 2, plasma ashing treatment by oxygen plasma is performed for a substrate 5 inside a chamber 6 and a resist layer is removed practically. Then, in a wet etching part 3, the substrate 5 wherein plasma ashing treatment is carried out is immersed in a treatment liquid bath 9 and metallic impurities introduced to a foundation material layer are removed together with a surface layer part of the base material layer. Furthermore, in a drying part 4, the substrate 5 wherein wet etching treatment is carried out is dried.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a resist removing apparatus for effectively removing a resist layer and metal impurities derived therefrom, and to a resist removing method using the same.

[0002]

2. Description of the Related Art In the process of manufacturing a semiconductor device, in a process such as ion implantation or etching in which the processing range is limited, a patterned resist layer is used to mask the area other than the processing range. Then, after the predetermined process is completed, it is necessary to remove the resist layer.

As a method for removing the resist layer, conventionally, wet etching has been mainly used to remove the resist layer with a solvent, a weak alkaline solution and a solution having a strong oxidizing action (a mixed solution of sulfuric acid, nitric acid and hydrogen peroxide solution). I was doing. However, wet etching has a small effect on the underlying material layer and enables extremely gentle peeling, but on the other hand, there are problems with particles in the processing liquid, waste liquid processing equipment, and the like.

Therefore, plasma ashing using oxygen plasma discharge has been used as a method capable of keeping a clean environment because the performance of peeling a resist layer made of an organic material is very high and the process is dry. It has become to.

[0005]

However, when the resist layer is removed by plasma ashing, the metal impurities contained in the resist layer are struck by the underlying material layer and cannot be removed. It is known that the resist layer contains metal impurities such as Na, Mg, Al, K, Ca, Fe, Cu, and Pb in the order of ppb, but the ions accelerated in the ion sheath. And the electrostatic energy of the plasma electric field cause such metal impurities to be hammered into the base material layer.

When the above-mentioned metal impurities are hammered into the underlying material layer, the breakdown voltage is deteriorated when the underlying material layer is an oxide film such as SiO ₂ . In addition, the above Si
When impurities introduced into the O ₂ layer diffuse into the Si substrate due to heat or an electric field, problems such as crystal defects and impurity levels occur. Such a problem has come to have a great influence on the characteristics of the device with the miniaturization and thinning of the device. For example, the occurrence of white scratches on a CCD is a typical example.

Further, it is very difficult to remove the resist layer of the substrate that has been subjected to the high-concentration ion implantation treatment, even by plasma ashing. After the high-concentration ion implantation process, the surface of the resist layer has deteriorated. Especially, the novolac-based resist and phosphorus, the rubber-based resist and boron, etc., have changed into a very hard film, so they are oxygen neutral. It is said that exfoliation is almost impossible only with atoms.

Even if such a resist layer is treated with a general plasma ashing apparatus, the resist surface alteration layer is not ashed. Then, by degassing from the inside of the resist layer, when a phenomenon called pumping or burst occurs, the resist surface alteration layer scatters and redeposits on the surface of the underlying material layer, resulting in a resist residue that cannot be removed by plasma ashing, This leads to a decrease in yield and contamination in the next process.

Therefore, the present invention has been proposed in view of the above conventional circumstances, and enables the removal of metal impurities that have been hit into the underlying material layer by plasma ashing, and further high-concentration ion implantation processing has been performed. An object of the present invention is to provide a resist removing apparatus that does not leave a resist residue even afterward. Another object of the present invention is to provide a resist removing method using such a resist removing device.

[0010]

The present invention has been proposed to achieve the above object. That is, the resist removing apparatus of the present invention comprises a plasma ashing means and a wet etching means housed in the same main body,
The plasma ashing of the resist layer and the wet etching of the surface layer portion of the base material layer of the resist layer are continuously performed.

In the resist removing method of the present invention, the resist removing apparatus is used to substantially remove the resist layer by plasma ashing, and then the surface layer portion of the underlying material layer of the resist layer is removed by wet etching. It is a thing. The resist removing method of the present invention is particularly effective when the base material layer is a silicon compound layer.

[0012]

When the wet etching is performed after the plasma ashing, the metal impurities introduced into the base material layer by the plasma ashing are removed together with the surface layer portion of the base material layer. Also, if the altered resist layer after high-concentration ion implantation is adhered to the underlying substrate layer as a resist residue after plasma ashing, remove it together with the surface layer of the underlying material layer by performing wet etching. You can

Further, in the present invention, since the processing by plasma ashing and the processing by wet etching can be carried out in the same apparatus, element contamination can be prevented,
Yield improves.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Specific embodiments to which the present invention is applied will be described below with reference to the drawings.

As shown in FIG. 1, the resist removing apparatus 1 is
The plasma ashing unit 2, the wet etching unit 3, and the drying unit 4 are mainly included.
The resist removing operation is carried out while being transported.

The plasma ashing section 2 is a region for performing a plasma ashing process on the substrate 5, a chamber 6 in which the substrate 5 can be placed, a gas supply system 7 for supplying oxygen gas into the chamber 6, and an exhaust. And a plasma discharge means (not shown). Examples of the discharge type in this case include the commonly known counter electrode type, coaxial electrode type, and RF downflow type, which are the RF excitation type, microwave downflow type, and microwave standing wave type. Any discharge type can be used here.

The wet etching section 3 is an area for performing a wet etching process on the substrate 5 for which the plasma ashing process has been completed, and includes a processing liquid tank 9 containing an etching processing liquid and the processing liquid tank 9. It comprises a processing liquid supply system 10 for supplying the processing liquid and a drainage system 11 for discharging the used processing liquid from the processing liquid tank 9.

The drying section 4 is an area for drying the substrate 5 which has been subjected to the wet etching process, and is adapted to be dried by spin drying or isopropanol cleaning.

The plasma ashing section 2 and the wet etching section 3 are connected via a connecting section 12, and the wet etching section 3 and the drying section 4 are connected to each other by the connecting section 1.
4 are connected. Then, the substrate 5 subjected to the plasma ashing process in the plasma ashing unit 2 is transported by the substrate transport arm 13 to the wet etching unit 3 through the connection unit 12, and is subjected to the wet etching process in the wet etching unit 3. Then, the substrate transfer arm 15 transfers the substrate to the drying unit 12 through the connection unit 14.

Therefore, in order to remove the resist by using the resist removing apparatus 1 having the above-described structure, first, in the plasma ashing unit 2, oxygen plasma is generated in the chamber 6 to perform the plasma ashing process on the substrate 5. After that, the substrate 5 is wet-etched by the wet etching unit 3
And is subjected to wet etching treatment in the treatment liquid tank 9. Furthermore, the substrate 5 that has been subjected to wet etching treatment
Is transferred to the drying unit 4 and dried to complete the resist removing operation.

The steps of resist removal will be described below. Here, the wafer having the novolac-based resist mask 23 formed in a predetermined range of the SiO ₂ layer 22 formed on the Si substrate 21 as shown in FIG. 2 is used as the substrate 5 and the resist removal having the above-described configuration is performed. The processing by the apparatus 1 was performed. It should be noted that the substrate 5 has been subjected to phosphorus high-concentration ion implantation in the previous step.

First, the substrate 5 on which the high-concentration ion implantation of phosphorus has been completed is placed in the chamber 6 of the plasma ashing unit 2, and oxygen gas having a controlled flow rate is supplied from the gas supply system 7 by plasma discharge means. Plasma was generated in the chamber 6. As a result, the resist mask 23 of the wafer 20 placed in the chamber was ashed.

Substrate 5 after the above plasma ashing treatment
As shown in FIG. 3, most of the SiO ₂ layer 22 is exposed, but when the resist residue 24 is attached, the metal impurities 25 are attached on the SiO ₂ layer 22, or the SiO ₂ layer 22 is exposed.
It was in a state of being introduced into the surface layer portion 22a of the layer 22 at a depth of about 1 nm.

The resist residue 24 is not removably attached to the surface of the SiO ₂ layer 22 because the surface of the resist mask 23, which is a novolac compound, is deteriorated by the high concentration ion implantation of phosphorus and cannot be removed by the plasma ashing process. It is thought that it was done. In addition, the metal impurities 25
What is contained in the resist mask 23 is left on the surface of the SiO ₂ layer 22 due to the ashing of the resist mask 23, or is struck into the SiO ₂ layer 22 and the surface layer portion 22
It is considered that it was introduced in a.

Next, the substrate 5 that has been subjected to the plasma ashing treatment is connected by the substrate transfer arm 13 to the connecting portion 12.
And was transported into the processing liquid tank 9 of the wet etching section 3. A treatment liquid for etching is contained in the treatment liquid tank 9, and by immersing the substrate 5 for 20 to 40 seconds,
The SiO ₂ layer 22 was etched about 1-2 nm.

[0026] Accordingly, or stick to the resist residue 24, SiO ₂ layer 22 surface which is attached to the SiO ₂ layer 22 surface, the metal impurities 25 are introduced into the surface layer portion 22a, the surface layer portion as shown in FIG. 4 It was removed from the substrate 5 together with 22a.

The treatment liquid may be any solution capable of etching the SiO ₂ layer, but in the present embodiment, a solution of HCl: HF: H ₂ O = 1: 1: 100 was used.

Further, the substrate 5 which has been subjected to the wet etching process as described above is transported by the substrate transport arm 15 to the drying unit 4 through the connecting portion 14 and is subjected to a drying process by spin drying or isopropanol cleaning. This completes the entire resist removal process.

As described above, by performing the plasma ashing process in the plasma ashing unit 2 and the wet etching process in the wet etching unit 3 in succession, the resist mask 23 is sufficiently removed from the substrate 5 and the SiO ₂ layer is formed. The metal impurities introduced into the surface layer portion 22a of 22 could also be removed.

[0030]

As is apparent from the above description, when the resist layer is removed using the resist removing apparatus of the present invention,
The metal impurities introduced into the base substrate by the plasma ashing process can be removed together with the surface layer portion of the base material layer by the wet etching process.
Further, no resist residue is left on the substrate after the high-concentration ion implantation. Therefore, the dust removal rate is improved.

By removing the surface layer of the base substrate, the damaged layer of the base substrate damaged by the plasma ashing process can also be removed.

Further, in the present invention, since the plasma ashing process and the wet etching process are performed in the same apparatus, element contamination is prevented and the yield is improved, and the area occupied by the apparatus in the clean room is of course improved. Because it is less expensive, it has a great economic effect.

Even when the underlying material layer is an oxide film such as SiO _2, no metal impurities are introduced into the surface layer portion, so that the breakdown voltage does not deteriorate. Further, since the metal impurities do not diffuse into the underlying Si substrate, generation of crystal defects and impurity levels can be suppressed and the device characteristics can be improved. Therefore, the application of the resist removing apparatus and the resist removing method of the present invention is effective for miniaturization and thinning of the device.

[Brief description of drawings]

FIG. 1 is a schematic diagram showing a configuration of a resist removing apparatus of the present invention.

FIG. 2 is a cross-sectional view schematically showing the substrate before removing the resist mask.

FIG. 3 is a cross-sectional view schematically showing the substrate after being subjected to the plasma ashing process.

FIG. 4 is a cross-sectional view schematically showing the substrate after being subjected to the wet etching process.

[Explanation of symbols]

1 ... Resist removing device 2 ... Plasma ashing unit 3 ... Wet etching unit 4 ... Drying unit 5 ... Substrate 6 ... Chamber 7 ... Gas supply system 8 ... Vacuum exhaust System 9 ... Treatment liquid layer 10 ... Treatment liquid supply system 11 ... Drainage system 21 ... Si substrate 22 ... SiO ₂ layer 23 ... Resist mask 24 ... Resist residue 25. ..Metallic impurities

Claims (3)

[Claims] 1. A plasma ashing means and a wet etching means housed in the same main body are provided, and the plasma ashing of the resist layer and the wet etching of the surface layer portion of the underlying material layer of the resist layer are continuously performed. Resist remover. 2. The resist removing apparatus according to claim 1, wherein the resist layer is substantially removed by plasma ashing, and then the surface layer portion of the underlying material layer of the resist layer is removed by wet etching. Method for removing resist. 3. The resist removing method according to claim 2, wherein the base material layer is a silicon compound layer.