A platform device for collecting reflectance spectra using a desktop reflective film thickness gauge

Abstract

This utility model relates to a platform device for collecting reflectance spectra using a desktop reflective film thickness gauge, belonging to the field of integrated circuit or discrete device manufacturing technology. It includes a platform with a vacuum chamber at its bottom and a vacuum connector at the center of the bottom of the platform, the inner cavity of the platform being connected to the vacuum chamber via the vacuum connector; multiple sets of vacuum adsorption holes are formed on the top surface of the platform; a vacuum switch is provided on the vacuum chamber; a rotating bracket is provided between the vacuum chamber and the platform, the rotating bracket being fixed to the bottom of the platform; the rotating bracket can rotate on the vacuum chamber, driving the platform to rotate synchronously; a moving unit is provided below the vacuum chamber, the moving unit having a mirror stage, and an inclined mirror and a plane mirror are provided on the mirror stage. This application simplifies the spectral acquisition process, prevents the sample to be tested from shifting or shaking, improves testing accuracy, and achieves efficient and stable film thickness testing.

Description

Technical Field

[0001] This utility model relates to a platform device suitable for collecting reflection spectra using a desktop reflective film thickness gauge, belonging to the field of integrated circuit or discrete device manufacturing technology. Background Technology

[0002] Desktop reflective film thickness gauges are widely used in process quality monitoring on manufacturing lines due to their advantages such as small footprint, fast processing speed, non-destructive optical measurement, and the ability to freely select media types from a material library to build film structures according to user needs. For samples without surface patterns, a desktop reflective film thickness gauge only needs one set of objective lenses for testing. However, for samples with surface patterns, a desktop reflective film thickness gauge often requires multiple sets of objective lenses, with the magnification of different objective lenses increasing sequentially, and the corresponding spot size within the lens decreasing, allowing users to select any small module area of ​​different patterns for testing.

[0003] Because it is an optical measurement, the intensity of ambient lighting has a certain impact on the acquisition of the sample spectrum. Therefore, it is necessary to filter out the influence of ambient lighting (i.e., background reflectance spectrum) before testing. A commonly used filtering method is to place a light-blocking plate in the grid slot of the optical path of the film thickness gauge's light source, blocking the light path close to the light source. In this case, because the light-blocking plate obstructs the light path, the film thickness gauge's own light source signal cannot reach the head signal collector, while ambient light can enter the head signal collector through diffuse reflection from the objective lens, thus acquiring the background reflectance spectrum information.

[0004] In addition to collecting the background reflectance spectrum, the reflectance thickness gauge also needs to collect the reflectance spectrum of a reference wafer before testing. Currently, the reference wafer used is mainly a bare silicon polished wafer. After collecting the background reflectance spectrum, the operator needs to remove the light-blocking plate from the grid slot, place the clean bare silicon polished wafer under the objective lens, adjust the lens to a suitable height, and press the run button to collect the reflectance spectrum of the reference wafer surface. Then, the operator removes the clean bare silicon polished wafer, places the sample to be tested under the objective lens, adjusts the lens to a suitable height, and presses the run button to start testing the film thickness of the sample.

[0005] The above procedure requires employees to first place the light-blocking plate in the grid slot to collect a background reflectance spectrum each time they switch objective lenses, and then remove the light-blocking plate; then place a clean, bare silicon wafer under the objective lens again to collect a reference reflectance spectrum, and then remove the bare silicon wafer again. Only then can the sample to be tested be placed. This process is quite cumbersome. Furthermore, the light-blocking plate is easily lost if not stored properly after removal. If lost, the background reflectance spectrum collection stage cannot be continued after the next objective lens switch, and the film thickness gauge cannot continue testing.

[0006] In addition, such as Figure 1 As shown, current desktop reflective film thickness gauges generally use a platform that is shifted in the XY direction. Long-distance movement causes the sample to be tested to shift or shake on the platform, which is very inconvenient for testing fixed points on wafers. Summary of the Invention

[0007] The technical problem to be solved by this utility model is to provide a platform device for collecting reflectance spectra of a desktop reflective film thickness gauge, which is simple in structure, easy to operate, avoids the loss of parts such as light-blocking plates, and prevents the sample to be tested from shifting or shaking during the test.

[0008] The technical solution adopted by this utility model to solve the above problems is as follows: a platform device suitable for collecting reflection spectra by a desktop reflective film thickness gauge, including a platform, a vacuum chamber at the bottom of the platform, a vacuum tube at the center of the bottom of the platform, and the inner cavity of the platform connected to the vacuum chamber through the vacuum tube; multiple sets of circumferentially distributed vacuum adsorption holes are opened on the top surface of the platform; a vacuum switch is provided on the vacuum chamber to control the on / off state of the vacuum tube; a rotating bracket is provided between the vacuum chamber and the platform, and the rotating bracket is fixed to the bottom of the platform; the rotating bracket can rotate on the vacuum chamber, driving the platform to rotate synchronously; a moving unit is provided below the vacuum chamber, a mirror stage is provided on the moving unit, and an inclined mirror and a plane mirror are provided on the mirror stage; the moving unit drives the vacuum chamber and the platform to move, causing the inclined mirror, the plane mirror and the platform to move closer to or away from the objective lens.

[0009] The moving unit includes a slide rail with a slider on it. The vacuum chamber is fixed to the slider, and a handle is provided on the side of the slider. Pushing the handle causes the slider to move along the slide rail.

[0010] Each of the vacuum adsorption pore groups comprises a plurality of vacuum adsorption pores evenly distributed along the radial direction.

[0011] An annular groove is formed on the bottom surface of the vacuum chamber, and the rotating support is located inside the annular groove.

[0012] Compared with the prior art, the advantages of this utility model are as follows: a platform device for collecting reflection spectra in a desktop reflective film thickness gauge has a simple structure and is easy to operate. The inclined mirror deflects the reflected light using the "extinction principle" and only collects the ambient light as the background reflection spectrum. The plane mirror is used to collect the reflection spectrum of the reference film. The spectral acquisition process is simplified, eliminating the need to frequently switch between the light-blocking plate and the bare silicon wafer. Vacuum adsorption fixes the sample to be tested, preventing the sample from shifting or shaking, improving the testing accuracy, and achieving efficient and stable film thickness testing. Attached Figure Description

[0013] Figure 1 A schematic diagram of a desktop reflective film thickness gauge with XY-direction displacement.

[0014] Figure 2 This is a schematic diagram of a platform device for collecting reflectance spectra using a desktop reflective film thickness gauge, according to an embodiment of the present invention.

[0015] Figure 3 for Figure 2 Top view;

[0016] Figure 4 for Figure 2 Side view;

[0017] Figure 5 This is a diagram illustrating the working principle of an inclined plane mirror.

[0018] Figure 6 This is a diagram illustrating the working principle of a plane mirror.

[0019] In the diagram: 1. Slide rail, 2. Handle, 3. Vacuum switch, 4. Rotary bracket, 5. Slider, 6. Platform, 7. Vacuum chamber, 8. Vacuum connector, 9. Mirror stage, 10. Inclined mirror, 11. Plane mirror, 12. Vacuum adsorption hole, 13. Objective lens. Detailed Implementation

[0020] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments.

[0021] like Figure 2-6As shown in this embodiment, a platform device for collecting reflectance spectra using a desktop reflective film thickness gauge includes a platform 6. A vacuum chamber 7 is located at the bottom of the platform 6, and a vacuum connector 8 is positioned at the center of the bottom of the platform 6. The inner cavity of the platform 6 is connected to the vacuum chamber 7 via the vacuum connector 8. Multiple sets of circumferentially distributed vacuum adsorption holes are formed on the top surface of the platform 6. A vacuum switch 3 is installed on the vacuum chamber 7, and a valve is installed on the vacuum connector 8. The valve is signal-connected to the vacuum switch 3. When the vacuum switch 3 is turned on, the valve opens, connecting the vacuum connector 8 to a vacuum source. Negative pressure is transmitted through the vacuum connector 8 to the vacuum adsorption holes, adsorbing and fixing the sample to be tested onto the platform 6, preventing the sample from moving or shaking. When the vacuum switch 3 is turned off, the valve closes, the vacuum connector 8 is disconnected from the vacuum source, the negative pressure in the vacuum adsorption holes disappears, and the pressure returns to normal, allowing the sample to be easily removed or its position adjusted. A rotating bracket 4 is provided between the vacuum chamber 7 and the platform 6, and the rotating bracket 4 is fixed to the bottom of the platform 6. A ring groove is formed on the top surface of the vacuum chamber 7, and a rotating support 4 is located in the ring groove, allowing the rotating support 4 to rotate within the ring groove and drive the stage to rotate 360°. A slider 5 is located below the vacuum chamber 7, and the vacuum chamber 7 is fixed to the top of the slider 5. The slider 5 is fitted onto a slide rail 1, and a handle 2 is located on the side of the slider 5. A mirror stage 9 is also located on the top of the slider 5, with an inclined mirror 10 and a plane mirror 11 mounted on it. Pushing the handle 2 moves the slider along the slide rail, causing the stage and mirror stage to move closer to or further away from the objective lens 13. When the inclined mirror on the mirror stage moves below the objective lens, the incident light is reflected by the inclined mirror and deflected out of the objective lens's field of view, with only ambient light entering the collector. When the plane mirror on the mirror stage moves below the objective lens, the spectrum of the bare silicon wafer is vertically reflected and enters the collector. The sample to be tested is placed on the stage, the vacuum switch is turned on, allowing the sample to be adsorbed and fixed on the stage. Then, the slider is moved and the stage is rotated to achieve multi-point film thickness testing of the sample. After the test is completed, turn off the vacuum switch and remove the sample.

[0022] There are 3 sets of vacuum adsorption pore groups, and the included angle between two adjacent sets of vacuum adsorption pore groups is 120°. Each set of vacuum adsorption pore groups includes multiple vacuum adsorption pores 12 evenly distributed in the radial direction.

[0023] The inclined mirror deflects the reflected light using the "extinction principle" and collects only the ambient light as the background reflection spectrum; the plane mirror is used to collect the reflection spectrum of the reference film; the spectral acquisition process is simplified, eliminating the need to frequently switch between the light-blocking plate and the bare silicon wafer; the sample to be tested is fixed by vacuum adsorption to prevent the sample from shifting or shaking, thereby improving the testing accuracy and achieving efficient and stable film thickness testing.

[0024] In addition to the above embodiments, this utility model also includes other implementation methods. All technical solutions formed by equivalent transformation or equivalent substitution should fall within the protection scope of the claims of this utility model.

Claims

1. A stage device suitable for desktop reflectance film thickness gauge to collect reflectance spectrum, characterized in that: The device includes a platform with a vacuum chamber at its bottom and a vacuum connector at the center of the bottom. The inner cavity of the platform is connected to the vacuum chamber via the vacuum connector. Multiple sets of evenly distributed circumferential vacuum adsorption holes are formed on the top surface of the platform. A vacuum switch is provided on the vacuum chamber to control the on / off state of the vacuum connector. A rotating bracket is provided between the vacuum chamber and the platform, and the rotating bracket is fixed to the bottom of the platform. The rotating bracket can rotate on the vacuum chamber, causing the platform to rotate synchronously. A moving unit is provided below the vacuum chamber, and a mirror stage is provided on the moving unit. An inclined mirror and a plane mirror are provided on the mirror stage. The moving unit moves the vacuum chamber and the platform, causing the inclined mirror, plane mirror, and platform to move closer to or further away from the objective lens.

2. The stage device for collecting the reflection spectrum of the desktop reflection film thickness gauge according to claim 1, characterized in that: The moving unit includes a slide rail with a slider on it. The vacuum chamber is fixed to the slider, and a handle is provided on the side of the slider. Pushing the handle causes the slider to move along the slide rail.

3. The stage device for collecting the reflectance spectrum of a desktop reflectance film thickness gauge according to claim 1, characterized in that: Each of the vacuum adsorption pore groups comprises a plurality of vacuum adsorption pores evenly distributed along the radial direction.

4. The stage device for collecting the reflectance spectrum of a desktop reflectance film thickness gauge according to claim 1, characterized in that: An annular groove is formed on the bottom surface of the vacuum chamber, and the rotating support is located inside the annular groove.

Images