Abstract: A plurality of side-surface patterns 11 and 12 are disposed on the wall surfaces of a mount opening portion 2 for mounting electronic parts thereat. The mount opening portion includes projection portions 21 that project toward an interior thereof from the wall surfaces thereof. End portions of the respective side-surface patterns 11 and 12 extend to the side surfaces of the projection portions 21. Also, a plurality of side-surface patterns can be provided on the wall surfaces of the mount opening portion by etching the side-surface pattern non-formation portions of the conductive layer formed on the entirety of the wall surfaces of the mount opening portion in a state where the side-surface pattern formation portions are coated with a side-surface pattern resist film made of a negative photosensitive resin. With this structure, the side-surface patterns can be prevented from being peeled off, and side-surface patterns having a plurality of potentials can be readily formed.

Abstract: Penem-3-carboxylic acid derivatives of formula (I): ##STR1## (wherein: R.sup.1 represents a hydrogen atom, an alkyl group, an alkoxy group, a hydroxyalkyl group, an acyloxyalkyl group, an alkylsulphonyloxyalkyl group, an arylsulphonyloxyalkyl group or a trialkylsilyloxyalkyl group;R.sup.2 represents a hydrogen atom or an alkyl group;R.sup.3 represents a hydrogen atom, an amino-protecting group or a group of formula ##STR2## in which R.sup.5 and R.sup.6 are the same or different and each represents a hydrogen atom or an alkyl group;A represents a branched-chain alkylene group; andR.sup.4 represents a carboxy group or a protected carboxy group)and pharmaceutically acceptable salts thereof, may be prepared by heating a corresponding phosphorus-ylide compound or by reacting a corresponding azetidin-2-one with a suitable phosphorous acid triester or triamide, and have been found to have excellent antibacterial activity accompanied by a very low acute toxicity.