Stripping of High-Dose Ion-Implanted Photoresist Using a Combination of Dry and Wet Single-Wafer Processing

Abstract

High dosed ion implanted (HDI) photoresist is well-known to be difficult to remove by conventional wet stripping e.g. sulfuric–peroxide mixture without substrate loss because of their carbonized crust layer. To overcome this issue, several methods are proposed such as dry etch + wet, assist of physical cleaning. In this paper, a new method to strip HDI photoresist using a combination of dry and wet processing in the same chamber is introduced to achieve HDI photoresist removal without substrate loss. A new process consists of two steps. The first process removes the carbonized crust layer by atmospheric-pressure inductively coupled hydrogen plasma, and the second process removes remaining the bulk photoresist by a sulfuric–ozone mixture. The new process enables removal of the HDI photoresist without any substrate loss, and with significantly shorter times.

Ion-Implanted Photoresist Stripping by Using Organic Solvents

“…It is difficult to remove the crust layer formed by ion-implantation using the single photoresist removal methods. A typical process of removing high-dose ionimplanted photoresist is to use plasma ashing followed by the treatment in the mixture of hot sulfuric acid and hydrogen peroxide (3,4). However, this method etches substrates when III-V semiconductors are used as a channel material (5)(6)(7).…”

Thermally Activated Gas-Phase Chemical Reactions in a Single-Wafer Wet Clean Process

“…Nonetheless, plasma-less ozone chemistry is a promising candidate for minimizing material loss and impact to device performance. More recent work has investigated adding energy sources into a wet clean chamber to enhance crust removal (15). Atmospheric oxygen plasma minimally removed the crust and showed material loss on oxide and nitride.…”

Removal of ion-implanted photoresists on GaAs using two organic solvents in sequence

“…It is known that photoresist components react with implanted cations to afford highly cross-linked polymers during the ion implantation process [12,13]. In addition, when the implantation dose is above 1 × 10 15 atoms/cm 2 , the cross-linked photoresist produces an amorphous carbonized crust and residue [12,14] that are not easily removed using conventional organic solvents [15,16]. Heavily implanted photoresists have been removed via dry plasma ashing with a subsequent wet chemical treatment at elevated temperatures [17,18].…”