Multi-step flow cleaning method and multi-step flow cleaning apparatus

• US 6,432,218 B1
• Filed: 12/07/1999
• Issued: 08/13/2002
• Est. Priority Date: 02/18/1998
• Status: Expired due to Fees

• Current Assignee: SPC Electronics Corp. (Mitsubishi Electric Corporation)
• Original Assignee: SPC Electronics Corp. (Mitsubishi Electric Corporation)
• Inventors: Tanaka, Hiroshi, Abe, Yusuke, Omori, Masashi, Hirokawa, Masatoshi, Oishi, Tetsuji, Sonoda, Haruki
• Primary Examiner(s): Gulakowski, Randy
• Assistant Examiner(s): SMETANA, JIRI F
• Application Number:
  US09/402,877
• Time in Patent Office: 980 Days
• Field of Search: 134/2, 134/10, 134/18, 134/221, 134/24, 134/34, 134/902, 137/50, 137/51, 137/54, 137/111, 137/112, 137/115.01, 137/247.17, 137/813, 137/814, 137/816, 137/818, 137/821, 137/825, 137/829, 137/830, 137/831, 137/832
• US Class Current: 134/34
• CPC Class Codes: B08B 3/10 with additional treatment of the liquid or of the object being cleaned, e.g. by heat, by electricity or by vibration
• CPC Class Codes: Y10S 134/902 Semiconductor wafer

Abstract

A multi-step flow cleaning method and a multi-step flow cleaning apparatus are provided which effectively clean workpieces with a stream of a cleaning solution and to suppress an increase of foreign matters adhering to the surfaces of the workpieces. A cleaning tank 10 for holding workpieces is provided, a supply line 14 for supplying a cleaning solution such as pure water from the bottom surface of the cleaning tank is provided, and a valve 12 for adjusting the flow of the cleaning solution is disposed in the middle of the supply line 14. The valve 12 is equipped with a switching section 12a for controlling the outflow of the cleaning solution by opening or closing the supply line 14, and a bypass 12b for supplying the cleaning solution, bypassing the switching section 12a. The valve 12 is provided such that it is able to adjust in two steps the supply flow of the cleaning solution supplied to the cleaning tank 10 by using the supply flow fed through the bypass 12b and the supply flow fed through the switching section 12a.

Claims

1. A multi-step flow cleaning method comprising:

placing a workpiece in a cleaning tank;

supplying a cleaning solution to the cleaning tank to clean the workpiece with a stream of the cleaning solution; and

adjusting a flow of the cleaning solution to the cleaning tank during a cleaning operation in such a manner that a flow rate is stepwisely increased.

2. The multi-step flow cleaning method according to claim 1, wherein:

the flow rate supplied to the cleaning tank is increased after the workpiece is fully immersed into the cleaning solution.

3. A multi-step flow cleaning method comprising:

placing a workpiece in a cleaning tank;

supplying a cleaning solution to the cleaning tank to clean the workpiece with a stream of the cleaning solution; and

adjusting a flow of the cleaning solution supplied to the cleaning tank during a cleaning operation in such a manner that a flow rate is linearly increased and then held constant.

4. The multi-step flow cleaning method according to claim 3, wherein:

the flow rate supplied to the cleaning tank is increased after the workpiece is fully immersed into the cleaning solution.