Segmented multi-channel, backside illuminated, solid state detector with a through-hole for detecting secondary and backscattered electrons

Patent metadata

Field	Value
Publication number	US-11699607-B2
Application number	US-202117483545-A
Country	US
Kind code	B2
Filing date	Sep 23, 2021
Priority date	Jun 9, 2021
Publication date	Jul 11, 2023
Grant date	Jul 11, 2023

Abstract

A segmented detector device with backside illumination. The detector is able to collect and differentiate between secondary electrons and backscatter electrons. The detector includes a through-hole for passage of a primary electron beam. After hitting a sample, the reflected secondary and backscatter electrons are collected via a vertical structure having a P+/P−/N+ or an N+/N−/P+ composition for full depletion through the thickness of the device. The active area of the device is segmented using field isolation insulators located on the front side of the device.

First claim

What is claimed is:

1. A solid state device, the device comprising:
a vertical structure comprising an N+/P−/P+ or a P+/N−/N+ structure for full depletion through the thickness of the device, the N+/P−/P+ or a P+/N−/N+structure including an N+ or P+ junction formed on the front side of the device, a P− or N− intrinsic layer in the middle, and a P+ or N+ layer formed on the backside of the device;
an active area for collecting secondary electrons (SEs) and backscatter electrons (BSEs), the active area being segmented into multiple channels in order to separate detection of secondary and backscatter electrons; and
a through hole placed in the center of the device to allow a primary beam to pass through the device, wherein the primary beam enters the through hole on the front side of the device.

2. The device of claim 1 , wherein the segmentation appears on the front side of the device and SEs and BSEs are collected on the back side of the device.

3. The device of claim 1 , wherein the front side of the device also includes metal contacts to maximize the available area for SE and BSE collection.

4. The device of claim 1 , wherein the P+ layer comprises boron or another acceptor dopant.

5. The device of claim 1 , wherein the P+ layer includes an additional conductive coating.

6. The device of claim 1 , further comprising a post lens element for controlling the SE and BSE signals on the device.

7. The method of claim 1 , wherein the segmented channels comprise a circular center channel surrounded by four quadrants of equal area, wherein each of the four quadrants has the same area as the circular center channel.

8. A system comprising
an electron source;
a ceramic substrate; and
a device coupled to the ceramic substrate, the device comprising:
a vertical structure comprising an N+/P−/P+ or a P+/N−/N+ structure for full depletion through the thickness of the device, the N+/P−/P+ or a P+/N−/N+ structure including an N+ or P+ junction formed on the front side of the device, a P− or N− intrinsic layer in the middle, and a P+ or N+ layer formed on the backside of the device;
an active area for collecting secondary electrons (SEs) and backscatter electrons (BSEs), the active area being segmented into multiple channels in order to separate detection of secondary and backscatter electrons; and
a through hole placed in the center of the device to allow a primary beam to pass through the device, wherein the primary beam enters the through hole on the front side of the device.

9. The system of claim 8 , wherein the segmentation appears on the front side of the device and SEs and BSEs are collected on the back side of the device.

10. The system of claim 8 , wherein the front side of the device also includes metal contacts to maximize the available area for SE and BSE collection.

11. The system of claim 8 , wherein the P+ layer comprises boron or another acceptor dopant.

12. The system of claim 8 , wherein the P+ layer includes an additional conductive coating.

13. The system of claim 8 , wherein the device further comprises a post lens element for controlling the SE and BSE signals on the device.

14. The system of claim 8 , wherein the segmented channels comprise a circular center channel surrounded by four quadrants of equal area, wherein each of the four quadrants has the same area as the circular center channel.

15. A electron detection system comprising:
an electron beam column including a detector for collecting secondary and backscatter electrons, the detector comprising:
a vertical structure comprising an N+/P−/P+ or a P+/N−/N+ structure for full depletion through the thickness of the device, the N+/P−/P+ or a P+/N−/N+ structure including an N+ or P+ junction formed on the front side of the device, a P− or N− intrinsic layer in the middle, and a P+ or N+ layer formed on the backside of the device;
an active area for collecting secondary electrons (SEs) and backscatter electrons (BSEs), the active area being segmented into multiple channels in order to separate detection of secondary and backscatter electrons; and
a through hole placed in the center of the device to allow a primary beam to pass through the device, wherein the primary beam enters the through hole on the front side of the device.

16. The electron detection system of claim 15 , wherein the segmentation appears on the front side of the device and SEs and BSEs are collected on the back side of the device.

17. The electron detection system of claim 15 , wherein the front side of the device also includes metal contacts to maximize the available area for SE and BSE collection.

18. The electron detection system of claim 15 , wherein the P+ layer comprises boron or another acceptor dopant.

19. The electron detection system of claim 15 , wherein the P+ layer includes an additional conductive coating.

20. The electron detection system of claim 15 , wherein the device further comprises a post lens element for controlling the SE and BSE signals on the device.

Assignees

• Kla Corp

Inventors

• Gerling John
• Muray Lawrence
• Brodie Alan
• Spallas James
• Trimpl Marcel

Classifications

• H10P72/0616 Primary

  Monitoring of warpages, curvatures, damages, defects or the like · CPC title

• G01N23/203

  Measuring back scattering · CPC title

• H01J37/244 Primary

  Detectors; Associated components or circuits therefor · CPC title

• G01N2223/6116

  semiconductor wafer · CPC title

• G01N23/2251

  using incident electron beams, e.g. scanning electron microscopy [SEM] · CPC title