etch stop in xsection

Hi, I am using the etch function in xsection tool.
I would like to etch via holes across several material layers, and at various locations stop at specific metal layers.
mask(via).etch(1 :into => [material1, material2, material3], :taper => 10)

However, what happens is that this etch does not stop at metal layers, but just jumps over the metal layers. So I ended up with hanging metal bridges with if the metal layer is somewhere between material1, 2, 3. I cannot just specify a specific height because sometimes etching stops at metal layer between material1 and 2, sometimes between 2 and 3, sometimes at bottom of 3. It depends on the metal layout.

How can I make it so that the via etch process at specific locations stops when hitting specified metal materials in xsection drawing?

Thanks!

Regards,
Jack

Comments

  • Punching through multiple metal layers would normally be a thing to avoid by process construction. You stop oxide etch on the first metal it hits and stop metal etch on oxide or silicon, in "normal" silicon processing.

    Vias normally are holes in insulator layers, not metal.

    In many modern technologies the vias are filled with tungsten plugs, and planarized before deposition of the overlayer. Many times the metal layer will be a composite, such as throwing down a TiW "adhesion layer" before the aluminum is deposited, but this is co-patterned (serial deps, single etch).

    Maybe you want to add some fake layers whose only purpose is to perform the etch stop where and when you say. klayout is not a process simulator, so do not expect the ability to faithfully emulate all processing (especially nonstandard series of events).

  • Hi,

    " stop oxide etch on the first metal it hits "
    Yes, that is my purpose.
    However, the first metals exist at different insulator layers. So hope the insulator etch stops whenever it hits the first metal. Was wondering if this can be done in klayout's xsection tool....

    "klayout is not a process simulator, so do not expect the ability to faithfully emulate all processing"
    If you happen to know any process simulator (preferably opensource/free) that can read GDS layout, and convert it to the final structure/profile, would you kindly share with me (and the folks on this forum)? Thanks!

    Regards,
    Jack

  • Maybe this program I wrote to make 3D cross sections from a GDS layout is useful for you: 3Dprocessviewer.com

    Regards, Jan

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