Resin Quality Inspection
TWO IMPORTANT ASPECTS:   1. RESIN DISSOLUTION RATE (ADR)   2. PHOTORESIST Eth VALUE(SENSITIVITY)

10.1 RESIN DISSOLUTION RATE QC

g(436nm), i(365nm) LINES RESIN,(NOVOLAK)、KrF(248nm)PHS RESINS 。THEY ALL DISOLVE IN ALKALINE DEVELOPER。SO RESIN MAKERS USE DISSOLUTION RATE AS CRITERIA TO INSPECT QUALITY.



10.1.1 ASSESSING EQUIPMENT AND PROCEDURE

WE CAN USE RDA(Resist Development Analyzer),WE CAN ADJUST RESIN DISSOLUTION RATE IN DEVELOPER 10-1: RESIN DEVELOPMENT INSPECTION EQUIPMENT。

FIG 10-1 RESIN ANALYSER
FIG 10-2 RDA BASIC UNDERSTANDING

REFLECTING LIGHT FROM SURFACE OF DECREASING RESIST AND WAFER WILL CREATE INTERFERENCE UNTIL BREAK POINT WHEN ALL RESIST DISSOLVE.

FIG 10-3 INTERFERENCE WAVELENGTH(EXAMPLE OF PHSRESIN,THICKNESS 2.6um,MONITOR WAVELENGTH950nm)
FIG 10-4 EXAMPLE OF QC

FIG 10-4 DATA SHOWS PHS RESIN QUALITY CONTROL 。OBSERVE CPT(CONTROL POINT TIME)30 SECONDS, 28-32 SECONDS BECOMES RANGE OF ACCEPTANCE。SETTING CPT VALUEFOR QC RANGE OF ACCEPTANCE.

10.2 PHOTOSENSITIVE RESIN PHOTOSPEED QC

PHOTOSPEED ISWITHIN PRESET TIME AND FILM THICKNESS TO COMPLETE DEVELOPEMNT USING MINIMUM EXPOSURE DOSE (Eth)

PROCEDURE??
(1) EXPOSURE
(2) PRESET DEVELOPMENT TIME
(3) MEASURE REMAINING THICKNESS,AND BY CALCULATION GET Eth VALUE。LTJ PROVIDES ALL THREE TYPES OF EQUIPMENT


(1) UVES-2500 EXPOSURE SYSTEM

CHANGING LENS TO ACHIEVE 248、365、405、436nm & BROADBAND。(FIG10-7)。

FIG 10-5 UVES-2500
FIG 10-6 CAN BE EQUIPPED WITH ALIGNMENT
FIG10-7 DIFFERENT SELECTION OF WAVELENGTH

FIRST GET WAFER SURFACE EXPOSURE DOSE,THEN EXPOSE STEP BY STEP。EXPOSURE DOSE IS MONITOR In-situ,EXPOSURE TIME CAN BE SET.

FIG 10-8 SHOWS EXPOSURE STEP,FIG 10-9 CALCULATION PANEL。

FIG10-8 DURING EXPOSURE
FIG10-9 CALCULATION INTERFACE


(2) SD-200 DEVELOPING EQUIPMENT

FIG 10-10 SHOWS SD-200。
FIG 10-11 DEVELOPEMNT CUP。TEMPERATURE SET 23℃ ± 0.1℃
HIGH PRECISION DEVELOPMENT

FIG 10-10 FOR QC USE SD-200 DEVELOPER
FIG 10-11 DEVELOP CUP


(3) MEASURING REMAINING FILM THICKNESS AND (Eth)

EXPOSURE COMPLETED WAFER SHOWN IN FIG 10-12。ACCORDING TO DOSAGENOW WE HAVE DIFFERENT REMAINING THICKNESSES。


FIG 10-12 DEVELOPMENT FINISHED WAFER(FROM 2.0mj/cm2 DOSAGE ONWARDS)

FIG 10-13SHOWS,ACCORDING TO REMAINING THICKNESSES,WE GET THICKNESS VS DOSAGE CURVE AND Eth VALUE RESULTS。


FIG 10-13 gamma CURVE AND Eth VALUE

LTJ CAN CONSTRUCT YOUR QC ACCORDINGLY.