Precision Cleaning Service

This page provides basic knowledge about precision cleaning performed at TDC. For information on TDC’s processing facilities, please also refer to “Processing Equipment” and for more information on wafer cleaning, please refer to “Wafer Cleaning Equipment“.

What is Precision Cleaning?

Precision cleaning refers to the process of removing adhesive substances from the surfaces of parts, products, semiconductors, etc., and finishing cleaning with ultrapure water and ultrasonic waves. This cleaning also removes invisible dirt and residue, and removes particulates and ionic matter to levels that are not problematic. For example, in semiconductor manufacturing, vaporized materials and reaction products adhere to and accumulate in the manufacturing process. Precision cleaning is an indispensable process, because a certain amount of adhering matter or deposits can cause product defects or production problems.

TDC’s Precision cleaning Service

In April 2021, TDC set up precision cleaning equipment, enabling us to handle from precision polishing to precision cleaning in house. Please feel free to contact us.

Flow of TDC’s precision cleaning

We have two types of wafer cleaning equipment: a “single wafer cleaning type” that cleans one wafer at a time and a “batch type” that cleans several wafers at once. Although it may vary depending on the material and shape, the basic cleaning process for each is as follows.

Single wafer cleaning

1. wafer setting
2. ultrasonic spot shower
3. scrub cleaning
4. ultrasonic spot shower
5. spin drying
6. case packaging
7. degassing

The following flow is the basic cleaning process for single wafer cleaning.

(1)Wafer setting / (2)Ultrasonic spot shower

The water coming out of the white circle in the photo is called spot cleaning, and this is an ultrasonic transducer, and the water passing through it becomes ultrasonic water that removes dirt, including where the water hits and flows.

 

(3)Scrub cleaning

After ultrasonic cleaning, scrubbing is performed with brush rollers. This roller acts like a rinse, lifting dirt with ultrasonic waves and then completely removing it with scrubbing.

 

(4)Ultrasonic spot shower

Ultrasonic cleaning is performed once again as a finishing touch.

(5)Spin drying

The table is rotated at high speed to dry.

(6)Inspection

(7)Deaerated and Packing

 

Batch cleaning

There are work sinks inside the equipment, starting from the left side viewed from the front of the equipment, and a total of five cleaning tanks: a storage tank, a chemical tank, a QDR tank, an OF tank, and a hot water tank. This equipment have a heater and ultrasonic generator 38 kHz/600 W in the chemical tank, an ultrasonic generator 160 kHz/600 W in the OF tank, and a heater in the hot water tank. Currently, the basic wafer cleaning operation in batch mode is performed in the following flow.

1. Hand scrub cleaning using PVA sponge in sink
2. Store in liquid (pure water) in a storage tank to prevent drying out and transfer from storage tank to chemical tank for chemical cleaning (chemical + heating + ultrasonic)
3. After chemical rinsing, the QDR (Quick. Dump. Rinse.) in which tank is filled with deionized water at once and drained and rinsed rapidly at the same time.
4. OF water rinse (rinse while keeping pure water flowing in the tank and allowing it to overflow + ultrasonic waves)
5. Finally, the stage is placed in a hot water bath and raised at a rate of 0.5 to 1 mm/sec to dry. Wafers are placed in carriers and cleaned in each tank.

TDC’s Cleaning Equipment

TDC has the following wafer cleaning equipment in house.

HOZAN	Clean Booth	10m×5m ISO Class３ （Particular Size 0.1μm）
HOZAN	Clean Booth	6m×3m ISO Class３ （Particular Size 0.1μm）
ORGANO	Ultra-pure water System	UC–2600
HORIBA	Water Quality Analyzer	LAQUA　WQ330
Temtec	Wafer Cleaning System	1
In-house	Wafer Cleaning System	1
ELGA	Ultra-pure water System Purelab Chorus	60L
KOKEN	Clean Bench ISO Class1	Table Koach
Japan airtech	Clean Booth	6m×3.5m　ISO Class 3 （Particular Size 0.1μm）

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