Compositions: coating or plastic – Coating or plastic compositions – Natural resin or derivative containing
Patent
1997-04-07
1998-02-17
Brunsman, David
Compositions: coating or plastic
Coating or plastic compositions
Natural resin or derivative containing
106237, 106239, C09J19304
Patent
active
057187517
DESCRIPTION:
BRIEF SUMMARY
This is a filing under 35-USC 321 of Pat./FI 95/00452 filed 24 Aug. 1995.
The present invention relates to an adhesive agent for adhering an object manufactured in a multi-stage process to its base for the duration of at least one process step.
When manufacturing objects to a desired purpose for instance of a ceramic or semiconductor material, the production of these objects includes a step or steps where the object under treatment is advantageously attached to its base in order to perform the treatment as advantageously as possible. In the production of this kind of object, the advantageous adhering step to the base is, however, usually followed by a step or steps where the object must be detached from its base and the adhesive agent removed from its surface. For instance, in order to carry out the polishing and cleaning of semiconductor products in an advantageous fashion, with respect to the smoothness and cleanness required thereby, the semiconductor products must be adhered to their base for the duration of the various processing steps. However, prior to the next process step, the semiconductor products must be cleaned so as to prevent the adhesive agent from accumulating an essentially thick layer on the rear surface of the semiconductor product. Therefore the agent used for adhering must have, in addition to a good adhesive capacity and good grip, also good solubility in the cleaning after the process step. Other properties required of this type of adhesive agent are liquidity and fluent applicability through a nozzle, because generally semiconductor products and ceramic objects are manufactured in large amounts.
The EP patent application 402,520 introduces an automatic adhering device for wafers, wherein the wafers are attached to their base by means of an adhesive wax for the duration of the wafer polishing step. In the adhesive wax, there is mixed some organic solvent in order to spread the adhesive wax as a smooth layer on the surface of the object to be adhered. Adhesive wax is fed through a nozzle onto the base prior to installing the wafer thereon. However, the said EP patent application 402,520 does not include any reference to the composition of the adhesive wax.
In adhering a semiconductor product to its base, there is generally used wax containing CFC compounds that are harmful to the earth's ozone layer as well as to the environment, for instance compounds commercially available under the trade mark FREON. Among these adhesives let us mention for example adhesives containing 1,1,1-trichloroethane (TCA) or trichloroethylene (TCE). In the removal of adhesive residues left on the surface of semiconductors, there are generally used solvents containing CFC compounds, among them the above mentioned TCA and TCE compounds.
From the Japanese patent application 03-203,981 there is known an adhesive agent employed for adhering wafers, the said agent avoiding the use of CFC compounds by using modified resin or a resin mixture as the main component of the adhesive agent. The employed resin is a tricyclic ring compound, such as abietic acid. This abietic acid is modified for instance by allowing it to react with maleic acid and by esterifying it, so that the acid value obtained for the modified resin is about 70. The obtained modified resin is further dissolved into an organic solvent while the content is within the region 1-50%.
In the above mentioned Japanese patent application 03/203,981, the original resin is highly modified in order to attain a low acid value. In naturally obtained resins, the acid value is within the region 160-180. By means of the acid value, it is possible to affect the adhesion of the adhesive agent, as well as its washability after the desired process step. Thus the modified resin suited in the adhesive agent according to the said Japanese patent application 03-203,981 must be strongly neutralized in order to attain the desired low acid value. The more the resin must be modified, the farther it is from an ecological product. This may cause unpredictable hazards to the enviro
REFERENCES:
patent: 4842691 (1989-06-01), Nakajima et al.
Ensio Logren Rauno Juha
Karvo Mikko Kalevi
Laakkonen Jari Tapio
Suomalainen Jukka Juhani
Brunsman David
Okmetic Oy
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