请问在LOCOS和第一层金属之间的BPSG层含义是什么？

自己顶

BPSG = Boron + Phosphorus doped Silicon Glass
in order to increase its ability of reflow to obtain a better (flat) dielectric surface flatness
Hopefully it works for you.

对，就是硼磷硅玻璃，做回流平坦化，记得以前在上华看他们是这样做的
但是那是.5/.6的工艺，现在好像都cmp了

不至于吧，.35也用这个BPSG的呢，另外这个CMP是啥呀，请教

没记错的话，是化学机械抛光吧

CMP = Chemical-Mechanical Polish, usually emerge for proceess <.35um