Bidirectional zener diode and method for manufacturing bidirectional zener diode

A method for manufacturing a bidirectional Zener diode, the method comprising:

• a step of implanting a second conductivity type impurity into a first conductivity type base region formed at a front surface portion of a substrate and then forming a first impurity region and a second impurity region away from each other by applying heat treatment;
• a step of forming an insulating layer on a front surface of the substrate;
• a step of forming an electrode film on the insulating layer so as to be electrically connected to the first impurity region and to the second impurity region;
• and
• a step of applying dry etching to the electrode film and hence forming the electrode film into an electrode pattern that includes a first electrode film electrically connected to the first impurity region and a second electrode film electrically connected to the second impurity region,
• wherein the electrode pattern has a first region that is sandwiched between the first electrode film and the second electrode film and that includes a portion having an aspect ratio of 1 or larger.