MAX ETCH 20

Old Bridge Chemicals, Inc.

MAX ETCH^TM20R

High Speed Alkaline Solution

MAX ETCH™20R is a high speed alkaline etchant solution for use in the manufacture of printed wiring boards. It provides improved undercut ratio thereby eliminating reduced line width. This etchant has greater stability than other etchants currently on the market. MAX ETCH™20R is compatible with most types of resists such as screenable inks and dry film photoresists. This product is suitable for use in continuous operation where specific gravity is adjusted by electronic gravity control. Old Bridge Chemicals, Inc. adheres to strict, on-going quality control of raw materials and finished goods to insure consistency and ease of operation in the printed wiring industry.

MATERIALS OF CONSTRUCTION

The following materials are compatible with the MAX ETCH™20R system: PVC, PVDC, Teflon, Tygon, Polyethylene, Polypropylene, glass, ceramic and titanium. Our staff of engineers and chemists is available to advise regarding the compatibility of materials other than those mentioned above.

ANALYTICAL METHODS
Determination of Copper (Thiosulfate Method)

Reagents Needed:
Ammonium Hydroxide
0.1N Sodium Thiosulfate Pentahydrate (24.8 gm./l.)
10% by volume Sulfuric Acid
Potassium Iodide Crystals
10% Potassium Thiocyanate (100 gm./l.)
2% Starch (10 gm./l.)

Analysis:

1.	Pipette 10.0 ml. of the working bath into a 100 ml. volumetric flask.
2.	Add 2-3 ml. of ammonium hydroxide dropwise and dilute to volume with D.I.
3.	Pipette 10.0 ml. of the diluted working bath (step 2) into a 250 ml. Erlenmeyer flask.
4.	Add 30 ml. of deionized water.
5.	Add 20 ml. of 10% by volume sulfuric acid. Solution will turn clear blue.
6.	Add 3 grams potassium iodide.
7.	Titrate with 0.1N sodium thiosulfate to a light straw color. Add 3 ml. potassium thiocyanate.
8.	Add 5 ml. of 2% starch solution.
9.	Continue to titrate slowly to milky, white endpoint.

Calculation:
(ml. of titrate) x (N of titrate) x 8.48 = oz./gal.
(x 7.5) = gm./l. Copper
Range - 20-22 oz./gal. (150-180 gm./l.)
High copper - Lower specific gravity sensor
Low copper - Increase operating specific gravity
Frequency of Analysis - Once per day.

Determination of Chloride

Reagents Needed:
5% Sodium Chromate Solution (Na₂CrO₄) (50 gm./l.)
10% Acetic Acid
0.1N Silver Nitrate (AgNO₃) (17 gm./l.)

Analysis:

1.	Pipette 3.0 ml. of the diluted MAX ETCH™20 bath made in Item 2 of the copper analysis into a 250 ml. Erlenmeyer flask. Add 50 ml. D.I. water.
2.	Add 3 ml. of the 5% sodium chromate solution.
3.	Add 10% acetic acid dropwise until solution turns clear yellow/green.
4.	Titrate with 0.1N Silver Nitrate until the solution turns light brown in color.

Calculation:
(ml. AgNO₃) x (N of titrant) x 3.33 = Chloride Molarity
Range - 5.0-5.8M of 0.1N Silver Nitrate
High Chloride - Reduce exhaust, lower temperature, increase turnover, add water and/or Ammonium Hydroxide
Low Chloride - Add Ammonium Chloride, reduce copper concentration
Frequency of Analysis - Once per day

The chloride molarity should be maintained above 5.0M. It should never be greater than 6.0M. For every 0.3 molarity above 6.0M a 5% addition of water or aqueous ammonia is required. Water can be added if the pH is above 8.3. A 1% addition of aqueous ammonia will increase the pH of the MAX ETCH™20 solution 0.1 unit. If excessive water dilution has occurred (4,5M), the etcher should be recharged with MAX ETCH STARTER solution to avoid possible sludging.

SPECIFIC GRAVITY (Baume)

Measurement can be made with a hydrometer placed in the etcher's standpipe or in a 100 ml. graduated cylinder containing the etchant. An alternate procedure involves weighing accurately (± 0.1 gm.) 100 ml. of etchant solution placed in a 100 ml. volumetric flask. Density (gm./ml.) is determined by diving the weight of the etchant by 100 ml.
Range - 1.20-1.225 (24-26.5°Be)
High Specific Gravity - Adjustment made to the specific gravity sensor
Low Specific Gravity - Adjustment made to the specific gravity sensor
Frequency of Analysis - Once per day

pH is usually most accurately measured at room temperature on a pH meter buffered in the range of 7.0-10.0.
Range - 8.2-8.4
High pH - Increase exhaust, raise copper concentration
Low pH - Dampen exhaust, lower copper concentration, add Ammonium Hydroxide
Frequency of Analysis - Once per shift

SAFE HANDLING

MAX ETCH is a corrosive solution and contact with the skin and eyes should be avoided. Protective clothing and safety goggles should be worn when handling MAX ETCH Solutions. In case of contact, flush eyes and skin immediately with plenty of water and obtain prompt medical attention for eyes. Contaminated clothing should be thoroughly laundered prior to reuse. Do not take internally. Adequate ventilation should be provided when using this etchant. In case of spills, flush with plenty of water to chemical sewers.

STORAGE

MAX ETCH Solutions have excellent stability when stored in their original, unopened shipping container in an area where the temperature range is between 40°F and 90°F. Bulk storage should also be maintained within this temperature range.

PACKAGE

Old Bridge Chemicals, Inc. ships MAX ETCH Solutions in 55 gallon Polyethylene drums (net weight 550 lbs.), tank trucks (3,000 to 6,000 gallon capacity), and railcars (20,000 gallon capacity).

DISPOSAL

Old Bridge Chemicals, Inc. eliminates all worries regarding waste disposal. The company purchases the Copper Chloride or Copper Ammonium Chloride which is used as a raw material in the production of chemicals. This eliminates the need for manifesting shipments of copper chloride or copper ammonium chloride from most states. This procedure has been approved by the Federal Environmental Protection Agency and New Jersey Department of Environmental Protection.

Click HERE to find out more about Copper Chloride or Copper Ammonium Chloride

Click HERE to view the MSDS for MAX ETCH™20R

Old Bridge Chemicals, Inc. gives no warranty of merchantability or of fitness for a particular purpose and all products are sold as is. Unless Old Bridge Chemicals, Inc. has, upon the request of the customer, in writing, provided a copy of an analysis with a product purchased, any product purchased from Old Bridge Chemicals, Inc. is sold by Old Bridge Chemicals, Inc. on the assumption that the purchasers will make their own tests to determine the quality and suitability of the product. Any waiver of modifications of this warranty disclaimer must be in writing and signed by a duly authorized agent of Old Bridge Chemicals, Inc. Old Bridge Chemicals, Inc. expressly disclaims any and all liability for incidental and/or consequential property damage rising out of the use of its product. No information or suggestions given by Old Bridge Chemicals, Inc. shall be deemed to be a recommendation to use any product in conflict with any existing patent rights.