Method of forming sheet having foreign material portions used for forming multi-layer wiring board and sheet having foreign portions

A sheet used as each layer when forming a laminated type electronic part, comprising:

• a conductive internal electrode having a first thickness and formed in a first area;
• a conductive post having a second thickness and formed in a second area existing over said first area and smaller than said first area;
• and
• an insulating substance including said internal electrode and said post,
• wherein at least said post is formed by a step consisting of a depositing process of depositing a photosensitive substance of which an exposed portion is removed by a developer, an exposure process of exposing the photosensitive substance, a developing process of developing the photosensitive substance, and a depositing process of depositing of a conductive substance into a spatial portion obtained by the developing process, and
• a ratio of a forming thickness to a width of at least one of said internal electrode and said post is equal to or larger than 1.