|Publication number||US20090065032 A1|
|Application number||US 12/230,293|
|Publication date||12 Mar 2009|
|Filing date||27 Aug 2008|
|Priority date||26 Jun 2003|
|Also published as||US7431855, US20040266205|
|Publication number||12230293, 230293, US 2009/0065032 A1, US 2009/065032 A1, US 20090065032 A1, US 20090065032A1, US 2009065032 A1, US 2009065032A1, US-A1-20090065032, US-A1-2009065032, US2009/0065032A1, US2009/065032A1, US20090065032 A1, US20090065032A1, US2009065032 A1, US2009065032A1|
|Inventors||Donggyun Han, Woosung Han, Changki Hong, Sangjun Choi, Hyungho Ko, Hyosan Lee|
|Original Assignee||Donggyun Han, Woosung Han, Changki Hong, Sangjun Choi, Hyungho Ko, Hyosan Lee|
|Export Citation||BiBTeX, EndNote, RefMan|
|Referenced by (3), Classifications (11)|
|External Links: USPTO, USPTO Assignment, Espacenet|
Photoresist is an organic polymer which becomes soluble when exposed to light. Photoresist is used in many applications within various industries, such as the semiconductor, biomedical engineering, holographic, electronics, and nanofabrication industries. As an example, photoresist is used to help define circuit patterns during chip fabrication in the semiconductor industry. The use of photoresist prevents etching or plating in the area the photoresist covers (this is also know as resist).
The removal of photoresist, commonly known as “stripping” is preceded by plasma ashing, etching, or other manufacturing steps. These steps can degrade or carbonize the photoresist and leave a photoresist reside that is difficult to remove by current stripping methods. In particular, ion implantation with a dose of 3×1015 ions/cm2 or higher creates a photoresist exhibiting a hard outer crust covering a soft core.
Residue may also be a problem.
Conventionally, photoresist has been removed by a plasma ashing process followed by a stripping process. The plasma ashing process utilizes O2 plasma which may cause damage to the sublayer and thereby degrade the electrical performance of the underlying semiconductor device. The stripping process requires high quantities of toxic and/or corrosive chemicals to remove photoreactive polymers or photoresist from chip surfaces.
In order to overcome these problems, other stripping methods have been developed including organic and/or inorganic stripping solvents with supercritical carbon dioxide (SCCO2) or ozone (O3) gas. Techniques which remove resist using SCCO2 utilize a densified CO2 cleaning composition which includes CO2 and at least one cosolvent such as a surfactant, alcohol, or amine. However, the methods utilizing SCCO2 and a cosolvent are incapable of dissolving a hard outer crust of a photoresist caused by ion implantation.
A second method for removing photoresist or other organic material from a substrate such as a semiconductor wafer includes partially immersing the substrate in a solvent, for example, deionized water, in a reaction chamber, injecting an oxidizing gas, for example, ozone, into the reaction chamber and rotating or otherwise moving the substrate through the solvent to coat a thick film of solvent over the organic component on the substrate surface and expose the solvent-coated component to the ozone gas to remove the organic material from the surface. Again, the resist removal techniques utilizing ozone are incapable of dissolving a hard outer crust caused by an ion implantation step.
In exemplary embodiments, the present invention is directed to a method of removing photoresist from a substrate, which includes treating the photoresist with a first reactant to cause swelling, cracking or delamination of the photoresist, treating the photoresist with a second reactant to chemically alter the photoresist, and subsequently removing the chemically altered photoresist with a third reactant.
In exemplary embodiments, the present invention is directed to a method of removing photoresist from a substrate, which includes treating the photoresist with supercritical carbon dioxide (SCCO2), treating the photoresist with an ozone-based reactant, and removing the photoresist with deionized water.
In exemplary embodiments, the present invention is directed to a method of removing photoresist from a substrate, which includes loading the substrate into a chamber, injecting a first reactant into the chamber and converting the first reactant to supercritical condition, maintaining contact between the substrate and the supercritical first reactant, depressurizing the chamber, injecting a second reactant into the chamber, maintaining contact between the substrate and the second reactant, purging the chamber and unloading the substrate, removing the photoresist, and drying the substrate.
In exemplary embodiments, the present invention is directed to an apparatus for removing photoresist from a substrate, which includes at least one chamber for treating the photoresist with a first reactant to cause swelling, cracking or delamination of the photoresist, for treating the photoresist with a second reactant to chemically alter the photoresist, for rinsing the substrate, for drying the substrate and for holding the substrate and a transfer device for transferring the substrate between chambers.
In exemplary embodiments, the present invention may also be used to remove normal photoresist in addition to the hard outer crust. Still further, exemplary embodiments of the present invention do not damage the underlying photoresist. Still further, exemplary embodiments of the present invention do not use organic contaminants or leave an organic residue.
The present invention will become more fully understood from the detailed description given below and the accompanying drawings, which are given for purposes of illustration only, and thus do not limit the invention.
As shown in
Further, at step 818, ozone gas and water vapor are provided at elevated temperature. In an exemplary embodiment, the ozone gas is provided at a temperature of about 105° C. and water vapor is provided at a temperature of about 115° C. At step 820, the reaction is maintained until the photoresist is converted into a water-soluble product and at step 822, the second chamber is depressurized to normal atmosphere and vented. At step 824, the substrate is rinsed and the water-soluble product removed.
An exemplary embodiment of the method of the present invention includes three steps. The first step is a treatment with a first reactant, to cause swelling, cracking, or delamination of a photoresist, the second step is treatment with a second reactant to chemically alter the photoresist, and the third step is removing the chemically altered photoresist with a third reactant. In an exemplary embodiment, the first reactant is SCCO2, the second reactant is an ozone-based reactant, and the third reactant is deionized water. In other exemplary embodiments, the ozone-based reactant is ozone vapor, in another exemplary embodiment, highly concentrated ozone vapor. In other exemplary embodiments, the ozone vapor has a concentration equal to or greater than 90,000 ppm. In other exemplary embodiments, the ozone-based reactant is ozone gas mixed with water vapor
Another exemplary embodiment of the method of the present invention includes three steps. The first step is a treatment with SCCO2, the second step is treatment with an ozone-based reactant, and the third step is a rinsing step. For each of these three steps, exemplary process conditions may be maintained. With respect to the SCCO2 treatment step, the temperature within the chamber may be maintained between 100 and 150° C. and the pressure between 150 and 200 bars. With respect to the highly saturated ozone vapor treatment statement, the temperature of the chamber may be maintained at 105° C. and the temperature of the vapor at 115° C. In an exemplary embodiment, a temperature gap between the chamber and the vapor is in the range of about 10° C. to 15° C. and a pressure gap is between 60 kPa and 80 kPa. It is noted that a pressure higher than 80 kPa may be maintained, as long as proper safety precautions are observed. With respect to the concentration of the ozone gas, in an exemplary embodiment, the concentration is 90,000 ppm or greater at the ozone generator.
It is noted that the arrangement of the apparatuses illustrated in
The invention being thus described, it will be obvious that the same may be varied in many ways. Such variations are not to be regarded as a departure from the spirit and scope of the invention, and all such modifications as would be obvious to one skilled in the art are intended to be included within the scope of the following claims.
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|International Classification||H01L21/461, H01L21/302, H01L21/304, H01L21/311, B32B38/10, H01L21/306|
|Cooperative Classification||Y10S438/906, H01L21/02043, H01L21/31138|