在“介质隔离”的反外延工艺中,有时在淀积多晶硅的过程中会形成较大的颗粒,致使在隔离槽里产生空洞。磨片显示之后,由于空洞处对光线是乱反射的,因此,在显微镜下观察,空洞处发黑,通常叫作“黑槽”。我们观察到黑槽有两类:1,“A类黑槽”,空洞从隔离氧化层开始,见图1(a);2,“B类黑槽”,空洞发生在多晶硅的中间,见图1(b)。 In the “dielectric isolation” anti-epitaxy process, larger particles sometimes form during the deposition of polysilicon resulting in voids in the isolation trench. After the disc is displayed, since the cavity is irregularly reflected with respect to the light, it is observed under a microscope that the cavity is black and often referred to as a “black groove.” We have observed that there are two types of black trenches: 1. “Class A black trenches,” voids beginning with the isolating oxide, as shown in Figure 1 (a); 2. “Class B black trenches” where voids occur in the middle of polysilicon, 1 (b).