Microscopic structure packaging method and device with packaged microscopic structure

A method comprising:

• providing a substrate;
• forming a sacrificial layer over the substrate, the sacrificial layer including a cavity;
• forming a first capping layer over the sacrificial layer and the cavity, the capping layer including a plurality of pores of sufficient size to allow a later-applied etchant to reach the sacrificial layer;
• removing at least a portion of the sacrificial layer by applying the etchant through the pores of the first capping layer;
• treating the first capping layer after removal of the sacrificial layer portion to reduce the size of the pores, wherein treating the first capping layer includes treating with a plasma cleaning that densifies the porous layer;
• and
• forming a second capping layer over the treated first capping layer.

A method of making a micro electro-mechanical structure comprising:

• providing a Si substrate with a SiO2 dielectric layer;
• forming a SiO2 sacrificial layer over the substrate;
• patterning the SiO2 sacrificial layer to form a cavity;
• depositing a SiC and SiGe support layer over the patterned SiO2 sacrificial layer;
• patterning the SiC and SiGe support layer to form holes for allowing material from the sacrificial layer to escape through the support layer;
• removing SiO2 material formed during the deposition of the support layer prior to the deposition of a porous SiOC capping layer;
• covering, at least a portion, of the patterned support layer with the porous SiOC capping layer having a pore size that is sufficient to allow an etchant to reach the patterned sacrificial layer, the porous SiOC capping layer being formed by plasma-enhanced chemical vapor deposition (PE-CVD);
• removing the sacrificial layer and a part of the SiO2 dielectric layer by applying an etchant that can penetrate the porous SiOC capping layer;
• following the removal of the sacrificial layer, cleaning the porous SiOC capping layer with a plasma process to densify the porous capping layer and reduce the pore size;
• depositing a hermetic capping layer, which is prevented from penetrating the cavity due to the densification of the porous capping layer;
• wherein a common plasma system is used to clean the porous SiOC capping layer and to deposit the hermetic capping layer.