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Dispense nozzle for Spin Coating System

IP.com Disclosure Number: IPCOM000013620D
Original Publication Date: 2002-Apr-11
Included in the Prior Art Database: 2003-Jun-18
Document File: 2 page(s) / 48K

Publishing Venue

IBM

Abstract

Disclosed is a S-shape dispense nozzle for spin coating of thick PMMA.

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Dispense nozzle for Spin Coating System

Disclosed is a S-shape dispense nozzle for spin coating of thick PMMA.

On MEMS (*1) fabrication, PMMA (*2) polymer is used as mold material for the 1st Ni(nickel) electro plating. The PMMA layer which is arround 43 micron in thickness is applied by using spin coating system. PMMA solution which is mixture of PMMA polymer and organic solvents such as PGMEA (*3) often exhibit insufficient coverage, because the viscosity is more than 10000cps and the dispense volume for the thick PMMA coating is as much as 50 cc. During the dispense of PMMA solution, solvent which is highly volatile evaporate rapidly resulting in an increase in viscosity. Therefore it prevents the film from forming with uniform thickness over the whole of the wafer substrate. The problem results from poor wettability of the PMMA solution. The problem becomes more severe as substrate size increases, especially 300 mm Si wafer substrate. The approach here describes the use of a S-shape nozzle to rapidly dispense large volume of PMMA solution to the wafer surface. This technique is schematically shown as follows.

Fig. 1. Pump Start Fig. 2. Dispense

Fig. 3. Pump Stop

1. Pump Start : PMMA solution moves in the direction of an arrow as shown in Fig. 1.

2. Dispense : Dispense of PMMA solution is started as shown in Fig. 2.

3. Pump Stop : Top surface of PMMA solution retreats as shown in Fig. 3.

4. Spin : Spin coating is started.

The technique described above has been...