ARALDITE® AW 4825 / HARDENER HW4826

• Suited for manual and automated bonding processes
• Long open time
• Easy to spread
• Debonding in weak acids or in hot water

• The resin and the hardener may be mixed by hand or with a static mixer.
• The mix ratio should be as accurate as possible within the tolerance of +/- 5%. The mix ratio should be checked regularly.
• The resin/hardener mix may be applied manually or robotically to the pretreated and dry glass and silicon joint surfaces. 
• A layer of adhesive 0.1 to 0.25 mm thick will normally be best for silicon slicing.
• The components should be assembled and secured in a fixed position as soon as the adhesive has been applied.
• No additional pressure is necessary, the weight of the silicon ingot is sufficient.
• The excess of adhesive which may overflow on the edges of the assembly should be limited either by wiping the excess off if the operation is carried out manually or by controlling the amount of adhesive if an automatic bonding unit is used.

      Pretreatment : silicon ingot and glass beam

• For the glass beam, it is recommended to bond on a sandblasted or mechanicaly abraded surface.
• Both silicon ingot and glass beam surfaces should be cleaned with a good degreasing agent such as acetone, iso-propanol or other proprietary degreasing agents in order to remove all traces of oil, grease and dirt. Low grade alcohol, gasoline (petrol) or paint thinners should never be used.

Times to minimum shear strength

• Determined by testing standard specimens made by lap-jointing 114 x 25 x 1.6 mm strips of aluminium alloy. The joint area was 12.5 x 25 mm in each case.

Lap shear strength according to ISO 4587

LSS = Lap shear strength.

Process times for silicon slicing (operation at 25°C)

Bonding Equipment maintenance

• All tools should be cleaned with hot water and soap before adhesives residues have had time to cure.
• The removal of cured residues is a difficult and time-consuming operation.
• If solvents such as acetone are used for cleaning, operatives should take the appropriate precautions and, in addition, avoid skin and eye contact.

Storage in PEG (Polyethyleneglycol)

• After sawing, it is possible to place the ingot in PEG for storage.
• The storage in PEG should only be done if absolutly necessary because it may affect the properties of the adhesive.
• This operation should be done at room temperature (25°C +/- 5°C) and the time of immersion should not exceed 2 hours.
• The thinner the wafers will be, the more critical the storage in PEG may be.

Precleaning process

• The precleaning operation should be carried out preferably with water with a temperature of maximum 35°C.
• The streaming of the precleaning fluid should not be too strong in order not to create peel forces in the adhesive joint.
• The thinner the wafers will be, the more critical the precleaning process may be.

Minimum debonding conditions

Note : debonding conditions may vary depending on the thickness of the wafers being produced. For thinner wafers the debonding will be achieved with less severe conditions.

        Storage

• Araldite® AW4825 / HW 4826 may be stored for up to 3 years at room temperature provided the components are stored in sealed containers.

       Handling Precautions

• Our products are generally quite harmless to handle provided that certain precautions normally taken when handling chemicals are observed.
• The uncured materials must not, for instance, be allowed to come into contact with foodstuffs or food utensils, and measures should be taken to prevent the uncured materials from coming in contact with the skin, since people with particularly sensitive skin may be affected.
• The wearing of impervious rubber or plastic gloves will normally be necessary; likewise the use of eye protection.
• The skin should be thoroughly cleansed at the end of each working period by washing with soap and warm water.
• The use of solvents is to be avoided. Disposable paper - not cloth towels - should be used to dry the skin.
• Adequate ventilation of the working area is recommended.