Apparatus for cleaning wafer and method of pre-cleaning wafer for gate oxide formation
An apparatus and a method for cleaning a wafer are described. A wafer is inserted into a bath by a loader, is supported by a guide in the bath, and is rotated by a roller. A cleaning solution such as dilute HF may remove impurities from the wafer by an etching operation, and then DI water is used to rinse the wafer. Since the wafer rotates by the roller, etching may be relatively uniform. Moreover, the rotation of the wafer during the rinse step can prevent or reduce the incidence of impurities combining with silicon dangling bonds on the wafer. Therefore, the apparatus and the method of the invention can effectively reduce or prevent defects on the wafer, regardless of loading configuration of the wafers.
1 . An apparatus for cleaning a wafer, comprising:
a cleaning bath housing adapted to perform a cleaning process;
a loader configured to load the wafer into the cleaning bath housing;
a guide in the cleaning bath housing, configured to support the wafer;
a roller configured to rotatably turn or drive the wafer.
2 . The apparatus of claim 1 , further comprising one or more solution supply lines configured to supply one or more solutions to the bath.
3 . The apparatus of claim 2 , further comprising a solution drain line configured to remove the solutions from the bath.
4 . The apparatus of claim 1 , wherein the loader is configured for either a front-to-back wafer loading configuration or a front-to-front wafer loading configuration.
5 . The apparatus of claim 1 , wherein the roller is on the loader.
6 . The apparatus of claim 1 , wherein the guide is configured to support a plurality of wafers at the same time, thus allowing a batch process.
7 . A method of cleaning a wafer, comprising the steps of:
loading at least one wafer into a cleaning bath;
rotating the wafer in the bath;
removing impurities from a back surface of the wafer with a cleaning solution; and
rinsing the wafer with a rinsing agent comprising DI water.
8 . The method of claim 7 , further comprising stopping the rotating step.
9 . The method of claim 7 , wherein loading the wafer includes loading the wafer on a loader, inserting the wafer on the loader into the bath.
10 . The method of claim 9 , further comprising supporting the wafer with a guide.
11 . The method of claim 7 , comprising loading a plurality of wafers into the cleaning bath.
12 . The method of claim 9 , wherein the loader has either front-to-back wafer loading configuration or front-to-front wafer loading configuration.
13 . The method of claim 10 , wherein the guide supports the plurality of wafers.
14 . The method of claim 7 , wherein rotating the wafer comprises circumferentially turning or rotating a roller to drive the wafer.
15 . The method of claim 14 , wherein the roller rotates a number of wafers in different directions.
16 . The method of claim 7 , wherein rotating the wafer in the bath comprises turning or rotating a roller in contact with a circumference of the wafer.
17 . The method of claim 7 , wherein the cleaning solution includes dilute HF.
18 . The method of claim 7 , further comprising:
treating the wafer with HCl and ozone.
19 . The method of claim 18 , further comprising:
drying the wafer after treating the wafer.