| 摘要 |
<p>PURPOSE:To guarantee the sensitivity and response speed of a sensor permanently, by preventing floating particles from attaching to a membrane resistance and to a substrate therewith. CONSTITUTION:A taper 61b is provided on the upstream of a substrate 61 of a membrane type resistance constituting a direct heat type sensor for measuring air flow rate of an internal combustion engine and a taper 61c on the down stream. These tapers 61b and 61c are obtained by anisotropic etching off a silicon monocrystalline substrate 61. With such an arrangement, the taper 61b can help almost eliminate a stagnant part of air current on the upstream of the membrane type resistance and boundary parts to prevent or reduce the attachment of floating particles in the air intake. The tape 61c can also prevent or reduce the attachment of floating particles due to reversion of the air current caused by blow back or the like of a combustion gas from a combustion chamber. The formation of a Pt pattern layer 62, particularly a lead thereof in a recess of the substrate 61 can make a passivation film 63 thin and roughly flat. This can lower the possibility that floating particles to the membrane type resistance, particularly film 63.</p> |
