CN102701146B - Device for testing thickness of phosphorosilicate glass and polycrystalline silicon synchronously on line - Google Patents

Abstract

The invention relates to a device for testing the thickness of phosphorosilicate glass and polycrystalline silicon synchronously on line. The device comprises an insulating substrate and three test units, wherein each test unit comprises a phosphorosilicate glass layer and four-probe polycrystalline silicon resistor test bridges; the phosphorosilicate glass layer is fixed to the top surface of the insulating substrate and is etched to form grooves which are parallel to each other, and steps are formed between the grooves; polycrystalline silicon resistor stripes ascend the steps on the phosphorosilicate glass layer; in a first test unit, the polycrystalline silicon resistor stripe is parallel to the X-axis direction of a cartesian coordinate system; and a second test unit and a third test unit are provided with two four-probe polycrystalline silicon resistor test bridges respectively, and included angles beta 1 and beta 2 are formed between the polycrystalline silicon resistor stripes and an X axis of the cartesian coordinate system respectively. According to the device, the polycrystalline silicon ascends a plurality of steps formed by the phosphorosilicate glass, and the thickness of the phosphorosilicate glass and the polycrystalline silicon is tested by testing five polycrystalline silicon resistors in three groups.

Description

An online synchronous testing device for the thickness of phosphosilicate glass and polysilicon

technical field

The invention provides a testing device for the geometrical parameters of a micro-electromechanical device, in particular to an online synchronous testing device for the thickness of phosphosilicate glass and polysilicon.

Background technique

The geometric parameters of MEMS devices are the most basic parameters of the device. By measuring the geometric parameters online, the shape and size of the device can be obtained, and the process error of the manufacturing process can be monitored in real time. Polysilicon is an important and basic material for manufacturing microelectromechanical device structures. It is usually produced by chemical vapor deposition (CVD), and the required pattern is formed by photolithography. Phosphosilicate glass (PSG) is an important sacrificial layer material. When making a movable structure, the thickness of the PSG layer is used to define the longitudinal movement range of the movable structure. Therefore, structural materials and sacrificial layer materials are often directly stacked in the manufacturing process, and the thickness parameters of these materials are very important for the structure of MEMS devices. Manufacturers of micro-electromechanical products hope to be able to conduct online testing through general-purpose measuring instruments in the process line to reflect the influence of the process on geometric parameters in a timely manner. Therefore, online testing without leaving the processing environment and using general-purpose equipment has become a necessity for process monitoring means.

Contents of the invention

Technical problem: The present invention provides an online synchronous testing device for the thickness of phosphosilicate glass and polysilicon. The online synchronous testing device uses polysilicon to climb multiple steps made of phosphosilicate glass, and passes three groups of five polysilicon resistance tests. , and then realize the test of the thickness of phosphosilicate glass and polysilicon.

Technical scheme: in order to solve the above technical problems, the technical scheme adopted in the present invention is:

An online synchronous testing device for the thickness of phosphosilicate glass and polysilicon, the testing device includes an insulating substrate, and three testing units, a first testing unit, a second testing unit and a third testing unit fixed on the top surface of the insulating substrate, in,

Each test unit includes a phosphosilicate glass layer and a four-probe polysilicon resistance test bridge. The four-probe polysilicon resistance test bridge includes a polysilicon resistance bar and four test electrodes connected to the polysilicon resistance bar; A metal block; the phosphosilicate glass layer is fixed on the top surface of the insulating substrate; the phosphosilicate glass layer is etched into grooves parallel to each other, and steps are formed between the grooves; the polysilicon resistance strip is covered on the phosphosilicate glass layer, and the polysilicon The resistance strip climbs the steps on the phosphosilicate glass layer;

In the first test unit, the number of the four-probe polysilicon resistance test bridge is one, the polysilicon resistance strip is parallel to the X-axis direction of the Cartesian coordinate system, and the test electrodes in the four-probe polysilicon resistance test bridge are located in the phosphorus silicon the sides of the steps on the glass floor;

In the second test unit, the number of four-probe polysilicon resistance test bridges is two, and two four-probe polysilicon resistance test bridges share two test electrodes, wherein the polysilicon in one four-probe polysilicon resistance test bridge The resistance strip climbs over the steps on the phosphosilicate glass layer, and the polysilicon resistance strip in the other four-probe polysilicon resistance test bridge is a plane; the polysilicon resistance strip is arranged obliquely, and forms a β ₁ with the X-axis of the Cartesian coordinate system Angle, β ₁ is greater than 0 degrees and less than 90 degrees;

In the third test unit, the number of four-probe polysilicon resistance test bridges is two, and two four-probe polysilicon resistance test bridges share two test electrodes, wherein the polysilicon in one four-probe polysilicon resistance test bridge The resistance strip climbs over the steps on the phosphosilicate glass layer, and the polysilicon resistance strip in the other four-probe polysilicon resistance test bridge is a plane; the polysilicon resistance strip is arranged obliquely, and forms a β ₂ with the X-axis of the Cartesian coordinate system The included angle, β ₂ is greater than 0 degrees and less than 90 degrees, and β ₂ and β ₁ are not equal.

Beneficial effect: Compared with the prior art, the present invention has the beneficial effect that the online synchronous testing of the thickness of phosphosilicate glass and polysilicon can be realized. In the technical solution, three test units, the first test unit, the second test unit and the third test unit, are fixed on the top surface of the insulating substrate. Each test unit includes a phosphosilicate glass layer and a four-probe polysilicon resistance test bridge. The phosphosilicate glass layer is etched into grooves parallel to each other, and steps are formed between the grooves; and the polysilicon resistance strip climbs over the phosphosilicate glass layer. steps. In the first test unit, the polysilicon resistance strip is parallel to the X-axis direction of the Cartesian coordinate system. In the second test unit and the third test unit, two four-probe polysilicon resistance test bridges are overlapped respectively, wherein the polysilicon resistance strip in one four-probe polysilicon resistance test bridge climbs over the steps on the phosphosilicate glass layer, The polysilicon resistance strip in another four-probe polysilicon resistance test bridge is a plane. An angle _β1 is formed between the polysilicon resistance strip in the second test unit and the X-axis of the Cartesian coordinate system. An angle _β2 is formed between the polysilicon resistance strip in the third test unit and the X-axis of the Cartesian coordinate system, and _β2 is not equal to _β1 . Using the four-probe method, by testing three groups of five four-probe polysilicon resistance test bridges, and combining the angle between the polysilicon resistance strip and the x-axis in the Cartesian coordinate system, the thickness of phosphosilicate glass and polysilicon can be obtained. The test equipment has low requirements, and the test can be completed by ordinary current sources and digital voltmeters, and the test process and test parameter values are stable. The processing is synchronized with the MEMS device, and there is no special processing requirement. The parameters are extracted by electrical excitation and electrical measurement, which fully meets the requirements of online testing.

Description of drawings

Fig. 1 is a schematic structural diagram of the first test unit in the present invention.

Fig. 2 is an A-A sectional view in Fig. 1 .

Fig. 3 is an enlarged cross-sectional view of a single step in the present invention.

Fig. 4 is a schematic structural diagram of a four-probe polysilicon resistance testing bridge in the present invention.

Fig. 5 is a schematic structural diagram of the second testing unit in the present invention.

Fig. 6 is a schematic structural diagram of the third testing unit in the present invention.

In the figure there are: first test unit 1, second test unit 2, third test unit 3, phosphosilicate glass layer 4, four-probe polysilicon resistance test bridge 5, insulating substrate 6, first test electrode 101, second Test electrode 102, third test electrode 103, fourth test electrode 104, fifth test electrode 201, sixth test electrode 202, seventh test electrode 203, eighth test electrode 204, ninth test electrode 205, tenth test electrode 206, the eleventh test electrode 301, the twelfth test electrode 302, the thirteenth test electrode 303, the fourteenth test electrode 304, the fifteenth test electrode 305, the sixteenth test electrode 306, the groove 401, the step 402 , a polysilicon resistance strip 501, a test electrode 502, and a metal block 503.

Detailed ways

The following is a detailed description of the embodiments of the present invention. This embodiment is implemented on the premise of the technical solution of the present invention, and detailed implementation methods and specific operating procedures are provided, but the protection scope of the present invention is not limited to the following implementation example.

As shown in Fig. 1 to Fig. 6, a kind of online synchronous test device of the thickness of phosphosilicate glass and polysilicon of the present invention, this test device comprises insulating substrate 6, and the first test unit 1 that is fixed on the top surface of insulating substrate 6 , the second test unit 2 and the third test unit 3 three test units. Each test unit includes a phosphosilicate glass layer 4 and a four-probe polysilicon resistance test bridge 5, and the four-probe polysilicon resistance test bridge 5 includes a polysilicon resistance strip 501 and four test electrodes 502 connected to the polysilicon resistance strip 501; A metal block 503 is fixed in each test electrode 502; the phosphosilicate glass layer 4 is fixed on the top surface of the insulating substrate; the phosphosilicate glass layer 4 is etched into grooves 401 parallel to each other, and steps 402 are formed between the grooves 401; The polysilicon resistance strip 501 covers the phosphosilicate glass layer 4 , and the polysilicon resistance strip 501 climbs over the step 402 on the phosphosilicate glass layer 4 . In the first test unit 1, the quantity of the four-probe polysilicon resistance test bridge 5 is one, the polysilicon resistance bar 501 is parallel to the X-axis direction of the Cartesian coordinate system, and the test electrode 502 in the four-probe polysilicon resistance test bridge 5 is located at Two sides of the step 402 on the phosphosilicate glass layer 4 . In the second test unit 2, the quantity of the four-probe polysilicon resistance test bridge 5 is two, and the two four-probe polysilicon resistance test bridges share two test electrodes, wherein the polysilicon resistance in one four-probe polysilicon resistance test bridge The strip climbs over the step 402 on the phosphosilicate glass layer 4, and the polysilicon resistance strip in the other four-probe polysilicon resistance test bridge is a plane; the polysilicon resistance strip 501 is arranged obliquely, and is formed between the X-axis of the Cartesian coordinate system. β ₁ included angle, β ₁ is greater than 0 degrees and less than 90 degrees. In the third test unit 3, the quantity of the four-probe polysilicon resistance test bridge 5 is two, and the two four-probe polysilicon resistance test bridges share two test electrodes, wherein the polysilicon resistance in one four-probe polysilicon resistance test bridge The strip climbs over the step 402 on the phosphosilicate glass layer 4, and the polysilicon resistance strip in the other four-probe polysilicon resistance test bridge is a plane; the polysilicon resistance strip 501 is arranged obliquely, and is formed between the X-axis of the Cartesian coordinate system. β ₂ angle, β ₂ is greater than 0 degrees and less than 90 degrees, and β ₂ and β ₁ are not equal.

In the first test unit, the four test electrodes are respectively the first test electrode 101, the second test electrode 102, the third test electrode 103, and the fourth test electrode 104, and each test electrode is provided with a metal block 503, the second test electrode A test electrode 101 and the second test electrode 102 are located on one side of the polysilicon resistance strip 501, the third test electrode 103 and the fourth test electrode 104 are located on the other side of the polysilicon resistance strip 501, and the groove 401 is located between the first test electrode 101 and the polysilicon resistance strip 501. Between the second test electrodes 102, the first test electrode 101 and the second test electrode 102 are symmetrical to each other along the center line of the polysilicon resistance strip 501, and the connection point between the first test electrode 101 and the polysilicon resistance strip 501 and the second test electrode 102 The connection point with the polysilicon resistance strip 501 is between the connection point between the third test electrode 103 and the polysilicon resistance strip 501 and the connection point between the fourth test electrode 104 and the polysilicon resistance strip 501; the first test electrode 101 and the polysilicon resistance strip 501 The minimum distance from the connection point to the groove 401 and the minimum distance from the connection point of the second test electrode 102 to the polysilicon resistance strip 501 to the groove 401 are respectively equal to half of the pitch of the groove 401 .

In the second test unit, the six test electrodes are respectively the fifth test electrode 201, the sixth test electrode 202, the seventh test electrode 203, the eighth test electrode 204, the ninth test electrode 205 and the tenth test electrode 206, each One test electrode is provided with a metal block 503, the fifth test electrode 201, the sixth test electrode 202 and the seventh test electrode 203 are located on one side of the polysilicon resistance bar 501, the eighth test electrode 204, the ninth test electrode 205 and the first test electrode Ten test electrodes 206 are located on the other side of the polysilicon resistor strip 501 . The groove 401 is located between the fifth test electrode 201 and the sixth test electrode 202 , and the polysilicon resistance strip 501 between the sixth test electrode 202 and the seventh test electrode 203 is a smooth plane. The connection point between the fifth test electrode 201 and the polysilicon resistance strip 501 and the connection point between the sixth test electrode 202 and the polysilicon resistance strip 501 are located at the connection point between the eighth test electrode 204 and the polysilicon resistance strip 501 and the connection point between the ninth test electrode 205 and the polysilicon resistance strip 501. Between the connection points of the resistive strip 501. The connection point between the ninth test electrode 205 and the polysilicon resistance strip 501 and the connection point between the tenth test electrode 206 and the polysilicon resistance strip 501 are located at the connection point between the sixth test electrode 202 and the polysilicon resistance strip 501 and the connection point between the seventh test electrode 203 and the polysilicon resistance strip 501. Between the connection points of the resistive strip 501. The minimum distance from the connection point of the fifth test electrode 201 and the polysilicon resistance strip 501 to the groove 401, and the minimum distance from the connection point of the sixth test electrode 202 and the polysilicon resistance strip 501 to the groove 401 are respectively equal to half of the pitch of the groove 401 .

In the third test unit, the six test electrodes are the eleventh test electrode 301, the twelfth test electrode 302, the thirteenth test electrode 303, the fourteenth test electrode 304, the fifteenth test electrode 305 and the tenth test electrode. Six test electrodes 306, each test electrode is provided with a metal block 503, the eleventh test electrode 301, the twelfth test electrode 302 and the thirteenth test electrode 303 are located on one side of the polysilicon resistance strip 501, the fourteenth test electrode The electrode 304 , the fifteenth test electrode 305 and the sixteenth test electrode 306 are located on the other side of the polysilicon resistance strip 501 . The groove 401 is located between the eleventh test electrode 301 and the twelfth test electrode 302 , and the polysilicon resistance strip 501 between the twelfth test electrode 302 and the thirteenth test electrode 303 is a smooth plane. The connection point of the eleventh test electrode 301 and the polysilicon resistance bar 501 and the connection point of the twelfth test electrode 302 and the polysilicon resistance bar 501 are located at the connection point of the fourteenth test electrode 304 and the polysilicon resistance bar 501 and the fifteenth test Between the connection point of the electrode 305 and the polysilicon resistance strip 501 . The junction of the fifteenth test electrode 305 and the polysilicon resistance strip 501 and the junction of the sixteenth test electrode 306 and the polysilicon resistance strip 501 are located at the junction of the twelfth test electrode 302 and the polysilicon resistance strip 501 and the thirteenth test Between the connection point of the electrode 303 and the polysilicon resistance strip 501 . The minimum distance from the connection point of the eleventh test electrode 301 and the polysilicon resistance strip 501 to the groove 401, and the minimum distance from the connection point of the twelfth test electrode 302 and the polysilicon resistance strip 501 to the groove 401 are respectively equal to the groove 401 pitch half of.

The device can be manufactured using basic micro-electromechanical processing technology. The fabrication process of the test structure is described below with a typical two-layer polysilicon MEMS surface processing technology.

Select an N-type semiconductor silicon wafer, thermally grow a silicon dioxide layer with a thickness of 100 nanometers, and deposit a layer of silicon nitride with a thickness of 500 nanometers through a low-pressure chemical vapor deposition process to form an insulating substrate 6 . A low-pressure chemical vapor deposition process is used to deposit a layer of 300nm polysilicon and N-type heavy doping to make the layer of polysilicon a conductor, and a part of the test electrode is formed by etching through a photolithography process. A phosphosilicate glass layer 4 with a thickness of 2000 nanometers was deposited by using a low pressure chemical vapor deposition process, and a part of the test electrode and the groove 401 were formed by a photolithography process. Deposit a layer of polysilicon with a thickness of 1500 nanometers by using a low-pressure chemical vapor deposition process, carry out N-type heavy doping on the polysilicon, and form polysilicon resistance strips 501 and test electrodes by photolithography, that is, the first test electrode 101 to the sixteenth test electrode 306 . A metal block 503 is formed on the test electrode using a lift-off process. Finally, the structure is released by etching the phosphosilicate glass layer 4 .

Using the online synchronous testing device with the above structure, the measurement adopts the four-probe method, through the testing of three groups of five four-probe polysilicon resistance test bridges, combined with the included angle between the polysilicon resistance strip 501 and the x-axis in the Cartesian coordinate system, Phosphosilicate glass and polysilicon thicknesses are available. The thickness of the phosphosilicate glass refers to the thickness of the phosphosilicate glass layer 4 . The polysilicon thickness refers to the thickness of the polysilicon resistance strip 501 . The specific test process is:

Step 1: Measure the resistance between the first test electrode 101 and the second test electrode 102 in the first test unit by using the four-probe method known in the art, denoted as R ₁ . The specific process is: apply a constant current between the third test electrode 103 and the fourth test electrode 104, measure the voltage between the first test electrode 101 and the second test electrode 102, and the ratio of the voltage to the current is the resistance R ₁ .

Step 2: Measure the resistance between the fifth test electrode 201 and the sixth test electrode 202 in the second test unit by using the four-probe method known in the art, denoted as R ₂ . The specific process is: apply a constant current between the eighth test electrode 204 and the ninth test electrode 205, measure the voltage between the fifth test electrode 201 and the sixth test electrode 202, and the ratio of the voltage to the current is the resistance R ₂ .

Step 3: Measure the resistance between the ninth test electrode 205 and the tenth test electrode 206 in the second test unit by using the four-probe method known in the art, denoted as _RA . The specific process is: apply a constant current between the sixth test electrode 202 and the seventh test electrode 203, measure the voltage between the ninth test electrode 205 and the tenth test electrode 206, and the ratio of the voltage to the current is the resistance _RA .

Step 4: Measure the resistance between the eleventh test electrode 301 and the twelfth test electrode 302 in the third test unit by using the four-probe method known in the art, which is denoted as R ₃ . The specific process is: apply a constant current between the fourteenth test electrode 304 and the fifteenth test electrode 305, measure the voltage between the eleventh test electrode 301 and the twelfth test electrode 302, and the ratio of the voltage to the current is Resistor _R3 .

Step 5: Measure the resistance between the fifteenth test electrode 305 and the sixteenth test electrode 306 in the third test unit by using the four-probe method known in the art, denoted as _RB . The specific process is: apply a constant current between the twelfth test electrode 302 and the thirteenth test electrode 303, measure the voltage between the fifteenth test electrode 305 and the sixteenth test electrode 306, and the ratio of the voltage to the current is Resistor R _B .

Step 6: Using the equation group (1), the thickness of phosphosilicate glass and polysilicon can be obtained:

$\left\{\begin{array}{c}\mathrm{<span\; class="notranslate">\; sin</span>}\mathrm{<span\; class="notranslate">\; \&alpha;</span>}<span\; class="notranslate">\; =</span>\frac{{\mathrm{<span\; class="notranslate">\; t</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; t</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}}{{\mathrm{<span\; class="notranslate">\; S</span>}}_{\mathrm{<span\; class="notranslate">\; 3</span>}}}\\ \mathrm{<span\; class="notranslate">\; x</span>}<span\; class="notranslate">\; =</span>{\mathrm{<span\; class="notranslate">\; S</span>}}_{\mathrm{<span\; class="notranslate">\; 3</span>}}<span\; class="notranslate">\; \&Center\; Dot;</span>\mathrm{<span\; class="notranslate">\; cos</span>}\mathrm{<span\; class="notranslate">\; \&alpha;</span>}<span\; class="notranslate">\; +</span>\frac{{\mathrm{<span\; class="notranslate">\; t</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}}{\mathrm{<span\; class="notranslate">\; sin</span>}\mathrm{<span\; class="notranslate">\; \&alpha;</span>}}\\ {\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; no</span>}<span\; class="notranslate">\; \&Center\; Dot;</span><span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; S</span>}}<span\; class="notranslate">\; \&Center\; Dot;</span>\frac{\mathrm{<span\; class="notranslate">\; 2</span>}{\mathrm{<span\; class="notranslate">\; S</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}}{\mathrm{<span\; class="notranslate">\; W</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; S</span>}}<span\; class="notranslate">\; \&CenterDot;</span>\frac{{\mathrm{<span\; class="notranslate">\; S</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 2</span>}\mathrm{<span\; class="notranslate">\; x</span>}}{\mathrm{<span\; class="notranslate">\; W</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; S</span>}}<span\; class="notranslate">\; \&Center\; Dot;</span>\frac{\mathrm{<span\; class="notranslate">\; 2</span>}{\mathrm{<span\; class="notranslate">\; the\; s</span>}}_{\mathrm{<span\; class="notranslate">\; 3</span>}}}{\mathrm{<span\; class="notranslate">\; W</span>}}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; 4</span>}\mathrm{<span\; class="notranslate">\; \&lambda;</span>}<span\; class="notranslate">\; \&CenterDot;</span>{\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; S</span>}}<span\; class="notranslate">\; \&Center\; Dot;</span>\frac{{\mathrm{<span\; class="notranslate">\; t</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}}{\mathrm{<span\; class="notranslate">\; W</span>}}<span\; class="notranslate">\; )</span>\\ {\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; no</span>}<span\; class="notranslate">\; \&Center\; Dot;</span><span\; class="notranslate">\; (</span>\frac{{\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; S</span>}}}{{\mathrm{<span\; class="notranslate">\; L</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}}<span\; class="notranslate">\; \&Center\; Dot;</span>\frac{\mathrm{<span\; class="notranslate">\; 2</span>}{\mathrm{<span\; class="notranslate">\; S</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}}{\mathrm{<span\; class="notranslate">\; cos</span>}{\mathrm{<span\; class="notranslate">\; \&beta;</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}}<span\; class="notranslate">\; +</span>\frac{{\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; A</span>}}}{{\mathrm{<span\; class="notranslate">\; L</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}}<span\; class="notranslate">\; (</span>\frac{{\mathrm{<span\; class="notranslate">\; S</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}}{\mathrm{<span\; class="notranslate">\; cos</span>}{\mathrm{<span\; class="notranslate">\; \&beta;</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 2</span>}\mathrm{<span\; class="notranslate">\; x</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; +</span>\frac{{\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; A</span>}}}{{\mathrm{<span\; class="notranslate">\; L</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}}<span\; class="notranslate">\; \&CenterDot;</span>\frac{\mathrm{<span\; class="notranslate">\; 2</span>}{\mathrm{<span\; class="notranslate">\; S</span>}}_{\mathrm{<span\; class="notranslate">\; 3</span>}}}{\mathrm{<span\; class="notranslate">\; cos</span>}{\mathrm{<span\; class="notranslate">\; \&beta;</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; 4</span>}\mathrm{<span\; class="notranslate">\; \&lambda;</span>}<span\; class="notranslate">\; \&Center\; Dot;</span>{\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; S</span>}}<span\; class="notranslate">\; \&Center\; Dot;</span>\frac{{\mathrm{<span\; class="notranslate">\; t</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}}{\mathrm{<span\; class="notranslate">\; W</span>}}<span\; class="notranslate">\; )</span>\\ {\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; 3</span>}}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; no</span>}<span\; class="notranslate">\; \&CenterDot;</span><span\; class="notranslate">\; (</span>\frac{{\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; B</span>}}}{{\mathrm{<span\; class="notranslate">\; L</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}}<span\; class="notranslate">\; \&CenterDot;</span>\frac{\mathrm{<span\; class="notranslate">\; 2</span>}{\mathrm{<span\; class="notranslate">\; S</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}}{\mathrm{<span\; class="notranslate">\; cos</span>}{\mathrm{<span\; class="notranslate">\; \&beta;</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}}<span\; class="notranslate">\; +</span>\frac{{\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; B</span>}}}{{\mathrm{<span\; class="notranslate">\; L</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}}<span\; class="notranslate">\; \&CenterDot;</span><span\; class="notranslate">\; (</span>\frac{{\mathrm{<span\; class="notranslate">\; S</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}}{\mathrm{<span\; class="notranslate">\; cos</span>}{\mathrm{<span\; class="notranslate">\; \&beta;</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 2</span>}\mathrm{<span\; class="notranslate">\; x</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; +</span>\frac{{\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; B</span>}}}{{\mathrm{<span\; class="notranslate">\; L</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}}<span\; class="notranslate">\; \&Center\; Dot;</span>\frac{\mathrm{<span\; class="notranslate">\; 2</span>}{\mathrm{<span\; class="notranslate">\; S</span>}}_{\mathrm{<span\; class="notranslate">\; 3</span>}}}{\mathrm{<span\; class="notranslate">\; cos</span>}{\mathrm{<span\; class="notranslate">\; \&beta;</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; 4</span>}\mathrm{<span\; class="notranslate">\; \&lambda;</span>}<span\; class="notranslate">\; \&Center\; Dot;</span>{\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; S</span>}}<span\; class="notranslate">\; \&CenterDot;</span>\frac{{\mathrm{<span\; class="notranslate">\; t</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}}{\mathrm{<span\; class="notranslate">\; W</span>}}<span\; class="notranslate">\; )</span>\end{array}\right.$

In the equation group (1), t ₁ represents the thickness of the polysilicon resistance strip 501 . t ₂ represents the thickness of the phosphosilicate glass layer 4 . α represents the inclination angle of the sidewall of the groove 401 . S ₃ represents the length of the sidewall of the groove 401 . x represents the horizontal distance from the top of the groove 401 to the bottom of the groove 401 . n is the number of steps of each test unit, and in this test device, the number of steps of the three test units is the same. R ₁ represents the resistance between the first test electrode 101 and the second test electrode 102 in the first test unit. R _S represents the sheet resistance of the polysilicon resistor strip 501 . S ₂ represents the distance between the test electrode and the groove 401 . W represents the length of the polysilicon resistance strip 501 along the y-axis direction of the Cartesian coordinate system. S ₁ represents the length of the top of the groove 401 along the x-axis direction of the Cartesian coordinate system. _β1 represents the angle between the polysilicon resistance strip in the second test unit and the X-axis of the Cartesian coordinate system. λ is the correction factor of the corner resistance, and its value is 0.5. R ₂ represents the resistance between the fifth test electrode 201 and the sixth test electrode 202 in the second test unit. _RA represents the resistance between the ninth test electrode 205 and the tenth test electrode 206 in the second test unit. L ₁ represents the length of the polysilicon resistance strip between the ninth test electrode 205 and the tenth test electrode 206 along the direction that makes an angle β ₁ with the x-axis of the Cartesian coordinate system. _β2 represents the angle formed between the polysilicon resistance strip in the third test unit and the X-axis of the Cartesian coordinate system. R ₃ represents the resistance between the eleventh test electrode 301 and the twelfth test electrode 302 in the third test unit. _RB represents the resistance between the fifteenth test electrode 305 and the sixteenth test electrode 306 in the third test unit. L ₂ represents the length of the polysilicon resistance strip between the fifteenth test electrode 305 and the sixteenth test electrode 306 along the direction that makes an angle β ₂ with the x-axis of the Cartesian coordinate system.

There are five unknowns in equation (1): t ₁ , t ₂ , x, S ₃ and α. Therefore, all unknown parameters can be found. make

$\mathrm{<span\; class="notranslate">\; A</span>}<span\; class="notranslate">\; =</span>\frac{{\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; A</span>}}}{{\mathrm{<span\; class="notranslate">\; L</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}}<span\; class="notranslate">\; \&Center\; Dot;</span>\frac{{\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; B</span>}}}{{\mathrm{<span\; class="notranslate">\; L</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}}<span\; class="notranslate">\; \&Center\; Dot;</span>\mathrm{<span\; class="notranslate">\; W</span>}<span\; class="notranslate">\; \&Center\; Dot;</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; cos</span>}{\mathrm{<span\; class="notranslate">\; \&beta;</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; cos</span>}{\mathrm{<span\; class="notranslate">\; \&beta;</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; )</span>$

$\mathrm{<span\; class="notranslate">\; B</span>}<span\; class="notranslate">\; =</span>\frac{{\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; B</span>}}}{{\mathrm{<span\; class="notranslate">\; L</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}}<span\; class="notranslate">\; \&Center\; Dot;</span>{\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; S</span>}}<span\; class="notranslate">\; \&Center\; Dot;</span>\mathrm{<span\; class="notranslate">\; cos</span>}{\mathrm{<span\; class="notranslate">\; \&beta;</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; \&CenterDot;</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; cos</span>}{\mathrm{<span\; class="notranslate">\; \&beta;</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; )</span>$

$\mathrm{<span\; class="notranslate">\; C</span>}<span\; class="notranslate">\; =</span>\frac{{\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; A</span>}}}{{\mathrm{<span\; class="notranslate">\; L</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}}<span\; class="notranslate">\; \&Center\; Dot;</span>{\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; S</span>}}<span\; class="notranslate">\; \&Center\; Dot;</span>\mathrm{<span\; class="notranslate">\; cos</span>}{\mathrm{<span\; class="notranslate">\; \&beta;</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; \&Center\; Dot;</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; cos</span>}{\mathrm{<span\; class="notranslate">\; \&beta;</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; )</span>$

and end up with:

${\mathrm{<span\; class="notranslate">\; t</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; =</span>\frac{\mathrm{<span\; class="notranslate">\; W</span>}}{\mathrm{<span\; class="notranslate">\; 4</span>}\mathrm{<span\; class="notranslate">\; n\&lambda;</span>}{\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; S</span>}}}<span\; class="notranslate">\; \&Center\; Dot;</span>\frac{{\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; \&CenterDot;</span>\mathrm{<span\; class="notranslate">\; A</span>}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; \&Center\; Dot;</span>\mathrm{<span\; class="notranslate">\; B</span>}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; 3</span>}}<span\; class="notranslate">\; \&Center\; Dot;</span>\mathrm{<span\; class="notranslate">\; C</span>}}{\mathrm{<span\; class="notranslate">\; A</span>}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; B</span>}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; C</span>}}$

t ₂ =S ₃ ·sinα+t ₁

The invention is based on the principle of four probes and the principle of resistance change caused by polysilicon covering grooves, and adopts a four-probe test method to simultaneously obtain the thickness of the phosphorosilicate glass layer and the thickness of the polysilicon layer. The test device uses a simple DC current source as the excitation source, and uses ordinary voltage test equipment to complete all the excitation and test processes.

Claims (1)

1. the on-line synchronous testing arrangement of a phosphorosilicate glass and polysilicon thickness, it is characterized in that, this testing arrangement comprises dielectric substrate (6) and is fixed on first test cell (1) of dielectric substrate (6) end face, the second test cell (2) and (3) three test cells of the 3rd test cell, wherein

Each test cell comprises phosphorosilicate glass layer (4) and four point probe polysilicon resistance test bridge (5), and four point probe polysilicon resistance test bridge (5) comprises a polysilicon resistance bar (501) and is connected to four test electrodes (502) on polysilicon resistance bar (501); In each test electrode (502), fix a metal derby (503), phosphorosilicate glass layer (4) is fixed on dielectric substrate end face; Phosphorosilicate glass layer (4) is etched to the groove (401) being parallel to each other, and forms step (402) between groove (401); It is upper that polysilicon resistance bar (501) covers phosphorosilicate glass layer (4), and the step (402) ascended on phosphorosilicate glass layer (4) of polysilicon resistance bar (501);

In described the first test cell (1), the quantity of four point probe polysilicon resistance test bridge (5) is one, polysilicon resistance bar (501) is parallel with the X-direction of cartesian coordinate system, and test electrode (502) in four point probe polysilicon resistance test bridge (5) is positioned at the both sides of the step (402) on phosphorosilicate glass layer (4);

In described the second test cell (2), the quantity of four point probe polysilicon resistance test bridge (5) is two, two four point probe polysilicon resistance test bridges share two test electrodes, wherein, the step (402) that polysilicon resistance bar in a four point probe polysilicon resistance test bridge is ascended on phosphorosilicate glass layer (4), the polysilicon resistance bar in another four point probe polysilicon resistance test bridge is plane; Polysilicon resistance bar (501) is and is in tilted layout, and and the X-axis of cartesian coordinate system between form β ₁angle, β ₁be greater than 0 degree and be less than 90 degree;

In the 3rd described test cell (3), the quantity of four point probe polysilicon resistance test bridge (5) is two, two four point probe polysilicon resistance test bridges share two test electrodes, wherein, the step (402) that polysilicon resistance bar in a four point probe polysilicon resistance test bridge is ascended on phosphorosilicate glass layer (4), the polysilicon resistance bar in another four point probe polysilicon resistance test bridge is plane; Polysilicon resistance bar (501) is and is in tilted layout, and and the X-axis of cartesian coordinate system between form β ₂angle, β ₂be greater than 0 degree and be less than 90 degree, and β ₂with β ₁unequal.