Printing on Integrated Circuits

In recent years, integrated circuits are used in various apparatuses, and marking where characters, symbols, or logo marks are printed is generally performed on such electronic components (7). Therefore, a printing technique where marking suitable for the electronic components performed is required. 

A radiation curable inkjet ink composition has been described that contains vinyl monomers, a photopolymerization initiator such as described in Ref. (8) and poly(siloxane) that allows marking, can be performed on a package substrate or a semiconductor substrate. The ink composition has the excellent visibility of a recorded image, ejection stability of the ink, and scratch resistance. 

The poly(siloxane) is preferably a polyether or polyester-modified poly(dimethyl siloxane). The hydrophdic-lipophilic balance value of the poly (siloxane) should be in a range of 9 to 12. In this range, the visibility of a recorded image, the ejection stability, and the scratch resistance becomes excellent. 

In addition, for printing on electronic circuits, as pigment, titanium oxide is preferred. Titanium oxide is a white pigment that yields a good brightness (7). 

The titanium oxide material is preferably a rutile type titanium oxide. This material may be produced by three basic steps, which are reduction, removal of iron by leaching or aeration and removal of other impurities by leaching in a solution of a strong mineral acid such as hydrochloric acid or sulfuric add (9,10). 

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