Wafer thickness measuring system and measuring platform thereof

Abstract

A wafer thickness measuring system comprises a carrying platform and a measuring module. The carrying table comprises a base table and a through hole. The base is used for placing an object to be measured, and the through hole is formed in the base. The measuring module comprises a probe, a transmitting head and an analysis host. The probe is inserted into the through hole, is electrically insulated from the base, and is used for being covered by an object to be detected. The transmitting head is aligned with the probe and is used for transmitting a test signal to the to-be-tested object. The analysis host is electrically connected with the probe and the emission head, and is used for analyzing the test signal passing through the object to be tested. Through the structure, the opportunity that a test signal is interfered can be reduced, the precision of a measurement result is improved, errors are reduced, and therefore a more accurate test result is provided.

Description

TECHNICAL FIELD

[0001] The present application relates to a wafer thickness measurement system, and in particular to a wafer thickness measurement system and a measurement platform thereof for measuring wafer thickness. BACKGROUND

[0002] Generally, a thickness measurement device is capable of measuring the thickness of various objects. For example, the thickness measurement device emits a test signal (e.g. an electromagnetic pulse signal or an ultrasonic signal) to an object to be measured on a stage, so that the test signal passing through the object to be measured is transmitted to a back-end analyzer through the stage for thickness measurement of the object to be measured.

[0003] However, due to the size or material of the stage, the signal transmission capability of the stage is affected, so that the test signal passing through the object to be measured is interfered, resulting in inconsistent measurement results and errors, thereby affecting the test results of the object to be measured. Therefore, the existing thickness measurement device still has room for improvement.

[0004] Therefore, how to effectively solve the above-mentioned inconvenience and defects is one of the important research and development topics at present, and also becomes the goal of the current related field which needs to be improved. SUMMARY

[0005] An object of the present application is to provide a wafer thickness measurement system and a measurement platform thereof to solve the above-mentioned difficulties in the prior art.

[0006] An embodiment of the present application provides a wafer thickness measurement system. The wafer thickness measurement system comprises a stage and a measurement module. The stage comprises a base and at least one through hole. The base is used to place an object to be measured, and the through hole is formed on the base. The measurement module comprises at least one probe needle, a transmitting head and an analysis host. The probe needle is inserted into the through hole and electrically insulated from the base, so as to be covered by the object to be measured. The transmitting head is used to emit a test signal to the object to be measured. The analysis host is electrically connected to the probe needle and the transmitting head, and is used to analyze the test signal passing through the object to be measured.

[0007] According to one or more embodiments of the present application, in the above-mentioned wafer thickness measurement system, the base comprises a front surface and a back surface opposite to each other, the through hole connects the front surface and the back surface of the base, and the end surface of the probe needle is flush with the front surface of the base.

[0008] According to one or more embodiments of the present application, in the above-mentioned wafer thickness measurement system, the probe needle comprises a conductive needle body, a first insulating layer and a first shielding layer. The conductive needle body is located in the through hole. The first insulating layer is located in the through hole and surrounds the conductive needle body, so that the conductive needle body is electrically insulated from the base. The first shielding layer surrounds the first insulating layer and the conductive needle body, and is located between the base and the first insulating layer, so as to shield the test signal conducted on the conductive needle body.

[0009] According to one or more embodiments of the present application, the wafer thickness measurement system further comprises a first cable and at least a second cable. The first cable is electrically connected to the analysis host and the transmitting head, respectively, for transmitting the test signal from the analysis host to the object under test. The second cable is electrically connected to the analysis host and the conductive needle, respectively, for transmitting the test signal conducted on the conductive needle to the analysis host.

[0010] According to one or more embodiments of the present application, in the wafer thickness measurement system, the second cable comprises a core wire, a second insulating layer, a second shielding layer and an insulating outer skin. The core wire is electrically connected to the probe needle and the conductive needle, respectively, for transmitting the test signal conducted on the conductive needle to the analysis host. The second insulating layer surrounds the core wire and is connected to the first insulating layer. The second shielding layer surrounds the second insulating layer and the core wire and is connected to the first shielding layer for shielding the test signal conducted on the core wire. The insulating outer skin circumferentially covers the second shielding layer.

[0011] According to one or more embodiments of the present application, in the wafer thickness measurement system, the through hole comprises a plurality of through holes arranged on the base in an array. The probe needle comprises a plurality of probe needles respectively inserted into the through holes and collectively electrically connected to the analysis host.

[0012] According to one or more embodiments of the present application, in the wafer thickness measurement system, the measurement module further comprises a channel switching device. The channel switching device is electrically connected to the analysis host and the probe needles, respectively, for switchably connecting the analysis host to one of the probe needles.

[0013] According to one or more embodiments of the present application, in the wafer thickness measurement system, the transmitting head is movably arranged above the stage.

[0014] According to one or more embodiments of the present application, in the wafer thickness measurement system, the analysis host is a vector network analyzer.

[0015] One embodiment of the present application provides a measurement platform of a wafer thickness measurement system. The measurement platform comprises a stage and at least a probe needle. The stage comprises a base and at least a through hole. The base comprises a front surface and a back surface opposite to each other, the front surface of the base is used for placing an object under test, the through hole is formed on the base and is connected to the front surface and the back surface, respectively. The probe needle is inserted into the through hole and is electrically insulated from the base, one end of the probe needle is exposed to the front surface of the base, and the other end of the probe needle has a cable connector exposed to the back surface of the base.

[0016] According to one or more embodiments of the present application, in the measurement platform, the end surface of the one end of the probe needle is flush with the front surface of the base.

[0017] According to one or more embodiments of the present invention, in the above-described measurement platform, the probe includes a conductive needle body, a first insulating layer, and a first shielding layer. The conductive needle body is located within a through-hole. The first insulating layer is located within the through-hole and surrounds the conductive needle body, electrically insulating the conductive needle body from the base. The first shielding layer surrounds the first insulating layer and the conductive needle body, and is located between the base and the first insulating layer, for shielding the test signal conducted on the conductive needle body.

[0018] According to one or more embodiments of the present invention, in the above-described measuring platform, the through-holes include a plurality of through-holes arranged in an array on the base. The probes include a plurality of probes, which are respectively inserted into the through-holes.

[0019] Thus, through the above architecture, this disclosure can reduce the chance of test signals being interfered with, improve the accuracy of measurement results and reduce errors, thereby providing more accurate test results.

[0020] The above description is only used to illustrate the problem to be solved by the present invention, the technical means to solve the problem, and the effects produced, etc. The specific details of the present invention will be described in detail in the following embodiments and related drawings. Attached Figure Description

[0021] To make the above and other objects, features, advantages and embodiments of the present invention more apparent and understandable, the accompanying drawings are described below:

[0022] Figure 1 This is a side view of a wafer thickness measurement system according to an embodiment of the present invention;

[0023] Figure 2 for Figure 1 Exploded view of the wafer thickness measurement system;

[0024] Figure 3 for Figure 1 Top view of the wafer thickness measurement system;

[0025] Figure 4 for Figure 1 A cross-sectional view of the wafer thickness measurement system along line segment AA;

[0026] Figure 5 for Figure 4 A magnified view of a portion of region M.

[0027] [Symbol Explanation]

[0028] 10: Wafer Thickness Measurement System

[0029] 100: Platform

[0030] 110:Abutment

[0031] 111: Front

[0032] 112: reverse side

[0033] 120: through hole

[0034] 130: measurement platform

[0035] 200: measurement module

[0036] 300: probe needle

[0037] 310: first end

[0038] 320: second end

[0039] 330: cable joint

[0040] 340: conductive needle body

[0041] 350: first insulation layer

[0042] 360: first shielding layer

[0043] 400: transmitting head

[0044] 410: transmitting end

[0045] 500: analysis host

[0046] 600: channel switching device

[0047] 700: first cable

[0048] 800: second cable

[0049] 810: core wire

[0050] 820: second insulation layer

[0051] 830: second shielding layer

[0052] 840: insulating sheath

[0053] 850: cable joint

[0054] 900: third cable

[0055] AA: line segment

[0056] B: bottom surface

[0057] DUT: device under test

[0058] G: groove bottom distance

[0059] M: area

[0060] S: groove

[0061] T: top surface Detailed Implementation

[0062] Several embodiments of the present invention will be disclosed below with reference to the accompanying drawings. For clarity, many practical details will be described in the following description. However, it should be understood that these practical details are not intended to limit the invention. That is, these practical details are not essential in the various embodiments of the invention. Furthermore, for the sake of simplicity, some conventional structures and elements will be illustrated in the drawings in a simple schematic manner.

[0063] Figure 1 This is a side view of a wafer thickness measurement system 10 according to an embodiment of the present invention. Figure 2 for Figure 1 An exploded view of the wafer thickness measurement system 10. Figure 3 for Figure 1 A top view of the wafer thickness measurement system 10. (See figure) Figures 1 to 3 As shown, in this embodiment, the wafer thickness measurement system 10 includes a stage 100 and a measurement module 200. The stage 100 includes a base 110. The base 110 includes a front side 111 and a back side 112 facing each other. The front side 111 of the base 110 is used to place a device under test (DUT) (such as a semiconductor wafer). One or more through-holes 120 are formed on the base 110. For example, these through-holes 120 are arranged in an array on the front side 111 of the base 110. Each through-hole 120 penetrates the base 110 and connects the front side 111 and the back side 112 of the base 110.

[0064] The measurement module 200 includes one or more probes 300, a transmitter 400, and an analysis host 500. The probes 300 are respectively inserted into the through holes 120. In other words, each probe 300 is fixedly inserted into one of the through holes 120 and is electrically insulated from the base 110 (i.e., the inner wall of the through hole 120).

[0065] Figure 4 for Figure 1 A cross-sectional view of the wafer thickness measurement system 10 along line segment AA. Figure 5 for Figure 4 A magnified view of a portion of region M. For example... Figure 4 and Figure 5As shown, each probe 300 is cylindrical, having a first end 310 and a second end 320 opposite to each other. The first end 310 of the probe 300 exposes a corresponding through hole 120 from the front side 111 of the base 110, and the second end 320 of the probe 300 exposes a corresponding through hole 120 from the back side 112 of the base 110. More specifically, the end face of the first end 310 of each probe 300 is flush with the front side 111 of the base 110, so that the device under test (DUT) (such as a semiconductor wafer) can be placed flat on the front side 111 of the base 110 (i.e., the bottom surface B of the DUT covers the front side 111 of the base 110 and the first end 310 of the probe 300). However, the invention is not limited thereto. In addition, the second end 320 of the probe 300 has a cable connector 330 for connecting a cable.

[0066] The transmitter 400 is positioned above the stage 100, with a gap maintained between the transmitter end 410 of the transmitter 400 and the front surface 111 of the base 110 (or the top surface T of the test object DUT). The transmitter end 410 of the transmitter 400 faces the front surface 111 of the base 110 (or the top surface T of the test object DUT) perpendicularly. More specifically, in this embodiment, the transmitter end 410 of the transmitter 400 faces the first end 310 of one of the probes 300 perpendicularly, and the long axis direction of the transmitter 400 is parallel to the long axis direction of the probe 300. Furthermore, the transmitter 400 can be movably positioned above the stage 100 by automatic or manual means; however, the invention is not limited thereto.

[0067] like Figure 1 As shown, the analysis host 500 is electrically connected to the probe 300 and the transmitter 400. More specifically, the analysis host 500 is electrically connected to the transmitter 400 via a first cable 700, and to each of the probes 300 via multiple second cables 800. For example, the analysis host 500 is a vector network analyzer (VNA); however, the invention is not limited thereto.

[0068] Therefore, after the user places the device under test (DUT) (e.g., a semiconductor wafer) and covers the base 110 and probe 300, the user non-contactly aligns the transmitter end 410 of the transmitter head 400 coaxially with a predetermined area (e.g., trench S) on the top surface T of the DUT and the first end 310 of the probe 300. Next, the user activates the analysis host 500, and a test signal (e.g., an electromagnetic pulse signal or an ultrasonic signal) is emitted from the transmitter end 410 of the transmitter head 400 to the predetermined area (e.g., trench S) of the DUT, passing through the DUT and reaching the probe 300 with the shortest possible distance. Therefore, the test signal (i.e., the result signal) passing through the DUT is transmitted to the analysis host 500 via the corresponding probe 300 and the second cable 800.

[0069] Since the test signal (i.e. the result signal) passing through the DUT will have a corresponding frequency according to the thickness of the DUT, the analysis host 500 can analyze the test signal (i.e. the result signal) passing through the DUT and obtain the thickness information of the predetermined area of the DUT.

[0070] In this embodiment, since the frequency of the DUT has a relationship with the thickness, this characteristic can be used to measure the thickness of the DUT. The specific steps are as follows. After the test signal is input to the DUT, the DUT will generate a specific frequency, and the analysis host 500 can calculate the thickness information of the DUT according to the specific frequency. The DUT can be a quartz wafer, but is not limited thereto. However, the present application is not limited thereto, and in other embodiments, the thickness of the DUT can also be measured by using the characteristic that the capacitance of the DUT is related to the thickness. The specific steps are as follows. After the test signal is input to the DUT, the DUT will generate a specific capacitance, and the analysis host 500 can calculate the thickness information of the DUT according to the specific capacitance.

[0071] It should be understood that in addition to being suitable for thickness measurement of the DUT, if the top surface T and / or the bottom surface B of the DUT have grooves S, the wafer thickness measurement system 10 of the present application can also be used to calculate the groove bottom distance G between the two grooves S of the DUT, etc. Figure 5 ) and other information.

[0072] In addition, in this embodiment, the measurement module 200 also includes a channel switching device 600. The channel switching device 600 is electrically connected to the analysis host 500 through the third cable 900, and is electrically connected to the probe needles 300 through the second cables 800, respectively, for allowing the analysis host 500 to be switchably connected to one of the probe needles 300, so as to open the connection channel between the analysis host 500 and one of the probe needles 300 at a time.

[0073] As Figure 4 and Figure 5As shown, in the present embodiment, each probe needle 300 comprises a conductive needle body 340, a first insulating layer 350, and a first shielding layer 360. The conductive needle body 340 is located in the corresponding through-hole 120. The first insulating layer 350 is located in the through-hole 120 and surrounds the conductive needle body 340, and electrically insulates the conductive needle body 340 from the base 110 (i.e. the inner wall of the through-hole 120). The first shielding layer 360 surrounds the first insulating layer 350 and the conductive needle body 340, and is located between the base 110 (i.e. the inner wall of the through-hole 120) and the first insulating layer 350, in other words, the first insulating layer 350 is sandwiched between the conductive needle body 340 and the first shielding layer 360. The first shielding layer 360 is used to shield the test signal conducted on the conductive needle body 340, thereby providing a clean test signal and reducing the generation of noise.

[0074] Each second cable 800 comprises a core wire 810, a second insulating layer 820, a second shielding layer 830, and an insulating outer skin 840. The core wire 810 is electrically connected to the probe needle 300 and the conductive needle body 340 respectively, for transmitting the test signal conducted on the conductive needle body 340 to the analysis host 500. The second insulating layer 820 surrounds the core wire 810 and is connected to the first insulating layer 350. The second shielding layer 830 surrounds the second insulating layer 820 and the core wire 810, and is connected to the first shielding layer 360, for shielding the test signal conducted on the core wire 810. The insulating outer skin 840 circumferentially covers the second shielding layer 830, thereby providing a clean test signal and reducing the generation of noise. In the present embodiment, one end of each second cable 800 has a cable connector 850, and the cable connector 850 of the second cable 800 is detachably connected to the cable connector 330 of the probe needle 300.

[0075] It should be understood that, in the above embodiment, the combination of the stage 100 and the probe needles 300 therein is referred to as the measurement platform 130 of the wafer thickness measurement system 10. Figure 4 ), and as long as the probe needles 300 can electrically insulate the base 110 of the stage 100, the present application is not limited to the base 110 comprising an electrically insulating material or an electrically conductive material. The cable connector 330 and the cable connector 850 can be a Sub-miniature version A (SMA) connector or any other suitable type of connector. However, the present application is not limited thereto.

[0076] Through the above architecture, the wafer thickness measurement system and the measurement platform thereof of the present disclosure can reduce the chance of the test signal being disturbed, improve the accuracy of the measurement result and reduce the error, thereby providing a more accurate test result.

[0077] Finally, the above-described embodiments are not intended to define the limits of the present application. Any modification and variation that does not depart from the spirit and scope of the present application can be made by those skilled in the art, and can be protected by the present application. Therefore, the scope of the present application is defined by the appended claims.

Claims

1. A wafer thickness measurement system, characterized in that, Include: A stage, comprising a base and at least one through hole, the base for placing an object to be tested, the through hole being formed on the base; and A measurement module, comprising: At least one probe is inserted into the through hole and electrically insulates the base so as to be covered by the object to be tested; A transmitter head, used to send a test signal to the object under test; and An analysis host is electrically connected to the probe and the transmitter to analyze the test signal passing through the object under test.

2. The wafer thickness measurement system as described in claim 1, characterized in that, The base includes a front side and a back side that are opposite to each other. The through hole connects the front side and the back side of the base respectively, and one end face of the probe is flush with the front side of the base.

3. The wafer thickness measurement system as described in claim 2, characterized in that, The probe includes: A conductive needle is located inside the through hole; A first insulating layer is located inside the through hole and surrounds the conductive needle body, thereby electrically insulating the conductive needle body from the base. A first shielding layer surrounds the first insulating layer and the conductive needle, and is located between the base and the first insulating layer to shield the test signal transmitted on the conductive needle.

4. The wafer thickness measurement system as described in claim 3, characterized in that, Also includes: A first cable, electrically connected to the analysis host and the transmitter, is used to transmit the test signal from the analysis host to the device under test; and At least one second cable is electrically connected to the analysis host and the conductive needle respectively, for transmitting the test signal passing through the test object to the analysis host.

5. The wafer thickness measurement system as described in claim 4, characterized in that, The second cable includes: A single wire is used to electrically connect the probe and the conductive needle body to transmit the test signal conducted on the conductive needle body to the analysis host. A second insulating layer surrounds the core wire and is connected to the first insulating layer; A second shielding layer surrounds the second insulation layer and the core wire, and is connected to the first shielding layer to shield the test signal conducted on the core wire; as well as An insulating outer sheath surrounds and covers the second shielding layer.

6. The wafer thickness measurement system as described in claim 1, characterized in that, The through holes comprise a plurality of through holes, which are arranged in an array on the base; and The probe includes multiple probes, which are respectively inserted into the multiple through holes and are electrically connected to the analysis host.

7. The wafer thickness measurement system as described in claim 6, characterized in that, The measurement module also includes: A channel switching device is electrically connected to the analysis host and the plurality of probes respectively, so as to switchably connect the analysis host to one of the plurality of probes.

8. The wafer thickness measurement system as described in claim 1, characterized in that, The transmitter head is movably mounted above the platform.

9. The wafer thickness measurement system as described in claim 1, characterized in that, The host computer for this analysis is a vector network analyzer.

10. A measurement platform for a wafer thickness measurement system, characterized in that, Include: A stage includes a base and at least one through hole. The base includes a front side and a back side facing each other. The front side of the base is used to place an object to be tested. The through hole is formed on the base and connects the front side and the back side. At least one probe is inserted into the through hole and electrically insulated from the base. One end of the probe is exposed on the front side of the base, and the other end has a cable connector exposed on the back side of the base.

11. The measurement platform of the wafer thickness measurement system as described in claim 10, characterized in that, One end face of the probe is flush with the front face of the base.

12. The measurement platform of the wafer thickness measurement system as described in claim 10, characterized in that, The probe includes: A conductive needle is located inside the through hole; A first insulating layer is located within the through hole and surrounds the conductive needle body, electrically insulating the conductive needle body from the base; and A first shielding layer surrounds the first insulating layer and the conductive needle, and is located between the base and the first insulating layer to shield the test signal transmitted on the conductive needle.

13. The measurement platform of the wafer thickness measurement system as described in claim 10, characterized in that, The through holes comprise a plurality of through holes, which are arranged in an array on the base; and The probe includes multiple probes, which are respectively inserted into the multiple through holes.

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