The subject invention relates to a laser processing method and a laser processing apparatus for forming a laser processed hole, a conclusive final rejection was issued by the Korean Intellectual Property Office (KIPO) on the basis that the subject invention lacks an inventive step over the prior art references (“D1” and “D2”). However, LEE INTERNATIONAL successfully convinced the Intellectual Property Trial and Appeal Board (IPTAB) to acknowledge the inventive step of the invention relating to laser processing method and apparatus by emphasizing a feature distinguished from the prior art references and differences in technological objective and effect.
Specifically, the subject invention relates to a laser processing method for forming a laser processed hole reaching to a second member in a first member in a workpiece configured by bonding the first member and the second member. Further, the subject invention is characterized by lowering the power of a pulsed laser beam before the second member is exposed. In accordance with this feature, even if the pulsed laser beam approaches the surface where the second member is bonded to the first member, the laser processed hole reaching to the second member can be formed in the first member while no cracking is incurred in the first member. The KIPO examiner issued the final rejection on the basis that since D2 discloses lowering laser beam energy when the intensity of a radiation beam, upon measurement, is found to be equal to or greater than a predetermined value, it would be obvious for one of ordinary skill in the art to anticipate that it is possible to remove a portion of a top layer without a crack by lowering the laser beam energy to a degree not to cause such crack in the top layer when adjusting the laser beam energy to be lower than the previous degree of energy. In response, LEE INTERNATIONAL appealed to the final rejection and argued as follows: i) D1 is silent on the feature of lowering the energy of the laser beam in the process of forming the laser processed hole; ii) D2 merely discloses lowering the energy of the irradiating laser beam after the intensity of the radiation beam from the underlying layer increases and reaches to a predetermined value, and it does not disclose lowering the energy of the irradiating laser beam after the intensity of the radiation beam from the top layer decreases and reaches to a predetermined value; and iii) D1, which does not disclose lowering the energy of the laser beam, and D2, which discloses lowering the energy of the irradiating laser beam based on the intensity of the radiation beam from the underlying layer, are different in terms of technological objective and effect from the subject invention, which aims to prevent the cracking in a top layer by lowering the energy of the irradiating laser beam before the underlying layer is exposed. IPTAB was persuaded by LEE INTERNATIONAL’s arguments and conceded that the characteristic feature of the subject invention is not disclosed in D1 and D2, and an unpredictable distinctive effect would result therefrom. As a result, the IPTAB rendered the decision in which the inventive step of the subject invention is acknowledged in view of D1 and D2.
From the subject case, it is worthwhile to notice that it would be sufficient to overcome an inventive step rejection by arguing that a structural difference of the claimed invention from the compared prior art could not have been easily derived and there exists the technical significance resulting therefrom. To do so, specifically, it would be advantageous to clearly present distinctive objective and effect of the claimed invention, which can be derived from such structural difference.