Heat treatment apparatus and accurate temperature measurement method for semiconductor workpiece

Abstract

To provide a heat treatment apparatus and accurate temperature measurement method for a semiconductor workpiece.SOLUTION: The heat treatment apparatus comprises: heating elements; an upper cover plate and a lower cover plate; a reaction chamber defined by the upper cover plate, the lower cover plate and a reaction chamber body; a workpiece support element; an infrared emitter located at one end of the upper cover plate; and an infrared reflection sensor located at the other end of the upper cover plate, and an infrared transmission sensor located at the other end of the lower cover plate. The infrared emitter and the infrared reflection sensor are located at a side of the upper cover plate facing the reaction chamber, and the infrared transmission sensor is located at a side of the lower cover plate facing the reaction chamber. The infrared emitter is located on a sidewall of a first end of the reaction chamber body, and the infrared reflection sensor and the infrared transmission sensor are located on a sidewall of the other end of the reaction chamber body. The heat treatment apparatus can accurately measure the temperature of the surface of a semiconductor workpiece, control the temperature at different locations, and improve the temperature control precision.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] TECHNICAL FIELD This disclosure relates to the field of semiconductor processing, and more particularly, to the field of thermal processing of semiconductor workpieces. [Background technology]

[0002] Typically, the heat treatment process of semiconductor workpieces requires a heating temperature of about 400℃~1200℃. In the rapid thermal treatment process, the semiconductor workpieces are usually heat treated by a double-sided heating method using a light array. In the heat treatment process, it is very important to measure the temperature of the workpiece reliably and accurately. Summary of the Invention [Problem to be solved by the invention]

[0003] The present disclosure provides a thermal processing apparatus for semiconductor workpieces and a method for high accuracy temperature measurement. [Means for solving the problem]

[0004] According to one aspect of the present disclosure, there is provided a thermal processing apparatus for a semiconductor workpiece, the thermal processing apparatus comprising: one or more heating elements for heating the semiconductor workpiece; An upper cover plate and a lower cover plate; a reaction chamber defined by the upper cover plate, the lower cover plate and a reaction chamber body; a workpiece support element for supporting the semiconductor workpiece; at least one infrared emitter located at a first end of the top plate; at least one reflective infrared sensor located at a second end of the top cover plate and at least one transmissive infrared sensor located at a second end of the bottom cover plate, wherein the first end and the second end face each other; The at least one infrared emitter and the at least one reflective infrared sensor are respectively located on a side of the upper cover plate facing the reaction chamber, and the at least one transmissive infrared sensor is located on a side of the lower cover plate facing the reaction chamber; The at least one infrared emitter is located on a sidewall at a first end of the reaction chamber body, and the at least one reflective infrared sensor and the at least one transmissive infrared sensor are located on a sidewall at a second end of the reaction chamber body.

[0005] According to another aspect of the present disclosure, there is provided a method for high accuracy temperature measurement for a semiconductor workpiece, the method comprising: placing a semiconductor workpiece on a workpiece support element within a reaction chamber of a thermal processing apparatus; placing an upper cover plate and a lower cover plate; emitting infrared radiation toward the semiconductor workpiece on a side of the top cover plate facing the semiconductor workpiece with at least one infrared emitter; receiving and measuring an amount of infrared radiation of a first portion reflected by a surface of the semiconductor workpiece with at least one reflective infrared sensor, and receiving and measuring an amount of infrared radiation of a second portion transmitted by the surface of the semiconductor workpiece with at least one transmissive infrared sensor; determining a reflectance and a transmittance of the semiconductor workpiece at a location based on the amount of infrared radiation of a first portion and the amount of infrared radiation of a second portion at the same location, and calculating an emissivity of the semiconductor workpiece based on the reflectance and the transmittance; and calculating a temperature of the surface of the semiconductor workpiece at the same location based on the emissivity.

[0006] It should be understood that the contents of this section are not intended to identify key features of the embodiments of the present disclosure, nor are they intended to limit the scope of the present disclosure. Other features of the present disclosure will be readily apparent from the following specification.

[0007] The drawings are for a better understanding of the present technical solution and are not intended to limit the present disclosure. [Brief description of the drawings]

[0008] [Figure 1] FIG. 2 is a top view of a heat treatment apparatus according to an embodiment of the present disclosure. [Diagram 2] 1 is a cross-sectional view of a heat treatment apparatus according to an embodiment of the present disclosure. [Diagram 3] FIG. 2 is a schematic diagram showing a partition of a light module in a heat treatment apparatus according to an embodiment of the present disclosure. [Figure 4] 1 is a schematic diagram showing positions of an infrared emitter, a reflective infrared sensor, and a transmissive infrared sensor in a heat treatment apparatus according to an embodiment of the present disclosure. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] Hereinafter, exemplary embodiments of the present disclosure will be described with reference to the drawings, and various details of the embodiments of the present disclosure will be included in the description to facilitate understanding, but these should be considered as merely illustrative. Therefore, those skilled in the art should recognize that various changes and modifications can be made to the embodiments described herein without departing from the scope and spirit of the present disclosure. Similarly, in the following description, descriptions of well-known functions and structures are omitted for clarity and conciseness.

[0010] The heat treatment process of the semiconductor workpiece described in the present disclosure may be, for example, a rapid thermal annealing process. Because different materials (e.g., Si, SiO2, SiN, etc.) on a semiconductor workpiece such as a wafer have different optical absorption coefficients, when the surface of the semiconductor workpiece is heated using a single-sided radiation method, a pattern effect occurs, and therefore, in order to reduce the problem of uneven heating of the wafer caused by the pattern effect, a double-sided heating method is usually used.

[0011] Meanwhile, in the rapid thermal annealing process, non-contact measurement methods are used to measure the temperature of the semiconductor workpiece. Due to the installation of the heating element (e.g., light module) used for double-sided heating of the wafer, the semiconductor workpiece is completely covered by the radiation of the heating element, but the light emitted from the heating element is reflected and transmitted by the semiconductor workpiece, which hinders the temperature measurement of the semiconductor workpiece by the non-contact measurement method. This effect is particularly noticeable when the emissivity of the wafer is low.

[0012] Semiconductor workpieces are typically transparent in the infrared band at normal workpiece temperatures and do not emit significant blackbody radiation. Conventional radiation measurement methods have a large error in the measurable blackbody radiation emitted by the workpiece at temperatures below 750° C., making it difficult to measure the temperature of a semiconductor workpiece.

[0013] Heat Treatment Equipment

[0014] According to one aspect of the present disclosure, there is provided a thermal processing apparatus for a semiconductor workpiece, the thermal processing apparatus comprising: one or more heating elements for heating the semiconductor workpiece; An upper cover plate and a lower cover plate; a reaction chamber defined by the upper cover plate, the lower cover plate and a reaction chamber body; a workpiece support element for supporting the semiconductor workpiece; at least one infrared emitter located at a first end of the top plate; at least one reflective infrared sensor located at a second end of the top cover plate and at least one transmissive infrared sensor located at a second end of the bottom cover plate, wherein the first end and the second end face each other; the at least one infrared emitter and the at least one reflective infrared sensor are respectively located on a side of the top cover plate facing the semiconductor workpiece, and the at least one transmissive infrared sensor is located on a side of the bottom cover plate facing the reaction chamber; The at least one infrared emitter is located on a sidewall at a first end of the reaction chamber body, and the at least one reflective infrared sensor and the at least one transmissive infrared sensor are located on a sidewall at a second end of the reaction chamber body.

[0015] Specifically, as shown in Figures 1 and 2, a heat treatment apparatus according to one embodiment of the present disclosure includes a top plate 1, a bottom plate 11, an upper heating light module 3, a lower heating light module 12, an upper cover plate 4, a lower cover plate 13, a reaction chamber body 5, a workpiece support element (e.g., a quartz support plate 9 and an ejector pin 8), an infrared emitter 6 and a reflective infrared sensor 2 provided at both ends on the inside of the upper cover plate 4, a transmissive infrared sensor 10 provided on the inside of the lower cover plate, and a reaction chamber door 14.

[0016] The above-mentioned infrared emitter 6, reflective infrared sensor 2, and transmissive infrared sensor 10 may each be one or more, and may, for example, include infrared emitters (601, 602, 603, 604, 605), reflective infrared sensors (201, 202, 203, 204, 205), and transmissive infrared sensors (1001, 1002, 1003, 1004, 1005), as shown in FIG. 1, respectively.

[0017] Specifically, the upper and lower cover plates of the present invention can both be made of high hydroxyl quartz, which can completely filter out the infrared light with a wavelength of 2.7 μm emitted from the heating light module, and reduce the impact of the radiation from the heating light module on the temperature of the semiconductor workpiece.

[0018] In the heat treatment apparatus of the present invention, at least one infrared emitter 6 is provided on the end of the top cover plate 4 facing the inside of the semiconductor workpiece, and the infrared emitter 6 can radiate infrared light with a wavelength of 2.3 μm and / or 2.7 μm to the semiconductor workpiece. According to one specific embodiment, five infrared emitters 601, 602, 603, 604, 605 may be provided.

[0019] Based on the above structure, the 2.7 μm wavelength infrared light from the heating light module is filtered by the top cover plate made of high hydroxyl quartz material, so that the 2.7 μm wavelength infrared light in the reaction chamber only comes from the thermal radiation from the infrared emitter and the workpiece, which is advantageous for more accurate control of the temperature of the semiconductor workpiece, especially for measuring the temperature of the semiconductor workpiece under working conditions where the emissivity of the semiconductor workpiece is low.

[0020] In the current specification of the heat treatment equipment, two temperature detection points are used, and the configuration of four temperature zones is controlled by program simulation, but the temperature measurement and controlled zones cannot meet the needs for temperature control of semiconductor workpieces (e.g., wafers) in more advanced processes. With reference to Figures 1 and 3, the present invention uses five sets of temperature measurement units (including an infrared emitter, a reflective infrared sensor, and a transmissive infrared sensor), and can control seven temperature zones to heat the wafer by program simulation.

[0021] Furthermore, as shown in FIG. 3, the top light module and the bottom light module are each divided into seven sub-groups, the reaction chamber between the door side and the wafer is divided into two equal spaces, and the area close to the wafer is divided into five temperature measurement sites T1-T5.

[0022] 4, the angles of the infrared emitter 6 (α), the reflective infrared sensor 2 (β), and the transmissive infrared sensor 10 (γ) with respect to the vertical axis of the semiconductor workpiece 7 (or the vertical axis of the reaction chamber) may be 30° to 60°, for example, 45°. Here, the infrared emitter 6 and the transmissive infrared sensor 10 are on the same straight line.

[0023] The above-mentioned infrared emitter, reflective infrared sensor, and transmissive infrared sensor jointly constitute a semiconductor workpiece emissivity measurement system that is not affected by a heating tube, and is thus advantageous for accurately measuring the temperature of a semiconductor workpiece, particularly in the range of 400°C to 750°C.

[0024] High precision temperature measurement method

[0025] In accordance with another aspect of the present invention, there is provided a method for high accuracy temperature measurement for a semiconductor workpiece, the method comprising: placing a semiconductor workpiece on a workpiece support element within a reaction chamber of a thermal processing apparatus; placing an upper cover plate and a lower cover plate; emitting infrared radiation toward the semiconductor workpiece on a side of the top cover plate facing the semiconductor workpiece with at least one infrared emitter; receiving and measuring an amount of infrared radiation of a first portion reflected by a surface of the semiconductor workpiece with at least one reflective infrared sensor, and receiving and measuring an amount of infrared radiation of a second portion transmitted by the surface of the semiconductor workpiece with at least one transmissive infrared sensor; determining a reflectance and a transmittance of the semiconductor workpiece at a same location based on the amount of infrared radiation of a first portion and the amount of infrared radiation of a second portion at the same location, and calculating an emissivity of the semiconductor workpiece based on the reflectance and the transmittance; and calculating a temperature of the surface of the semiconductor workpiece at the same location based on the emissivity.

[0026] According to a specific embodiment, the high-precision temperature measuring method of the present invention includes the steps of: setting up an upper cover plate 4 and a lower cover plate 14 made of high hydroxyl quartz material to filter the infrared light with a wavelength of 2.7 μm emitted from the heating light module; setting up an infrared emitter 6 with a wavelength of 2.7 μm on the inside of the upper cover plate made of high hydroxyl quartz material to emit the infrared light with a wavelength of 2.7 μm to the wafer 7; and setting up a reflective infrared sensor 2 with a wavelength of 2.7 μm and a transmissive infrared sensor 10 with a wavelength of 2.7 μm in the reflection and transmission directions corresponding to the infrared light. The reflective infrared sensor 2 can measure the reflectance of the wafer to the infrared light with a wavelength of 2.7 μm, and the transmissive infrared sensor 10 can measure the transmittance of the wafer to the infrared light with a wavelength of 2.7 μm. The infrared emitter 6, the reflective infrared sensor 2, and the transmissive infrared sensor 10 together form a wafer emissivity measurement system independent of the heating light module, from which the temperature of the surface of the wafer can be calculated.

[0027] In addition, two transmission type infrared sensors (pyrometers) 10 mounted on the bottom of the reaction chamber on the outer side of the bottom cover plate 13 away from the wafer also operate at 2.3 μm wavelength to measure the backside temperature of the wafer outside the working conditions where the wafer has low emissivity.

[0028] Specifically, infrared light with a wavelength of 2.7 μm emitted from an infrared emitter 6 is modulated by a chopper to become pulsed light, and when the pulsed light with a wavelength of 2.7 μm is irradiated onto a semiconductor workpiece (wafer) 7, the reflected portion is received by a 2.7 μm reflective infrared sensor 2, and the transmitted portion is received by a 2.7 μm transmissive infrared sensor 9. Calculation is made based on the following formula (1).

[0029]

number

[0030] The sum of the emissivity, reflectivity, and transmittance of an object is set to 1, and the real-time reflectivity ρ and transmittance τ of the wafer are determined by the 2.7 μm reflective infrared sensor 2 and the 2.7 μm transmissive infrared sensor 10, and the emissivity ε of the wafer is calculated. The reflectivity ρ is the ratio between the intensity of the reflected light detected by the reflective infrared sensor and the intensity of the infrared light emitted by the infrared emitter, and the transmittance τ is the ratio between the intensity of the transmitted light detected by the transmissive infrared sensor and the intensity of the infrared light emitted by the infrared emitter.

[0031] In addition, the above-mentioned reflective infrared sensor 2 and reflective infrared sensor 10 can also receive infrared light thermally radiated from the upper and lower surfaces of the wafer, and the radiated light can be distinguished in frequency from the light radiated from the infrared emitter 6. The following blackbody radiation equation (2) is obeyed.

[0032]

number

[0033] Calculate the front and back temperatures of the wafer, where I wafer is the received infrared thermal radiation of the wafer, h is Planck's constant, c is the speed of light, k is Boltzmann's constant, λ is the radiation wavelength, and ε is the emissivity of the wafer.

[0034] When the wafer enters the rapid thermal processing chamber and starts to be heated, the 2.7μm infrared emitter 6, the 2.7μm reflective infrared sensor 2, and the 2.7μm transmissive infrared sensor 9 continuously measure the reflectance, emissivity, and transmittance of the wafer. The temperature measurement result obtained by this measurement can provide a reference temperature in the wafer temperature range of 250-400℃, and at this time, the rising state of the wafer temperature can be monitored in real time. When the process temperature reaches 400-750℃, the 2.7μm infrared emitter 6, the 2.7μm reflective infrared sensor 2, and the 2.7μm transmissive infrared sensor 9 can accurately calculate the wafer temperature, which is helpful for closed-loop control of the wafer temperature. When the wafer process temperature is higher than 750℃, the above 2.7μm infrared emitter 6, the 2.7μm reflective infrared sensor 2, and the 2.7μm transmissive infrared sensor can measure the wafer temperature by the conventional method.

[0035] According to the above method of the present invention, the stability of temperature measurement and control of the heat treatment equipment can be improved under such working conditions as the semiconductor workpiece has low emissivity (<0.3), the emissivity of the semiconductor workpiece changes rapidly (e.g., there is a polysilicon layer on the wafer, which undergoes phase transition during heating), etc. Also, the measurement range of the semiconductor workpiece temperature can be as low as 250°C.

[0036] Preferably, the accurately measurable temperature of the semiconductor workpiece is within the range of 400°C to 750°C.

[0037] Referring to FIG. 3, the heat treatment apparatus of the present invention has two sets of heating light arrays arranged vertically, i.e., a top light module and a bottom light module, and each heating light array is divided into four sets (shown in light gray to dark gray), and the space from the door side of the reaction chamber to the wafer is divided into two symmetrical parts, and the area from the center of the reaction chamber to the center of the wafer is divided into five temperature measurement areas T1 to T5.

[0038] For example, according to the method of the present invention, a plurality of infrared emitters may be installed, and a plurality of reflective infrared sensors and a plurality of transmissive infrared sensors may also be installed. In this way, the number of temperature measurement sites is increased, the range of measurable temperatures is expanded, and the temperature measurement accuracy is improved. According to the measured temperatures of various sites of the semiconductor workpiece, the light modules corresponding to the sites can be individually controlled, thereby realizing precise temperature control and making the deviation of the temperature control within ±1°C.

[0039] It should be understood that various forms of the above process can be used by rearranging, adding, or deleting steps. For example, but not limited to, each step described in this disclosure can be performed in parallel, sequentially, or in a different order, as long as the desired results of the technical solutions disclosed in this disclosure can be achieved.

[0040] The above specific embodiments do not limit the scope of the present disclosure. It is understood by those skilled in the art that various modifications, combinations, subcombinations and substitutions are possible according to design requirements and other factors. Any modifications, equivalent substitutions, improvements, etc. made within the principle of the present disclosure shall all be included in the protection scope of the present disclosure.

Claims

1. 1. A thermal processing apparatus for a semiconductor workpiece, comprising: one or more heating elements for heating the semiconductor workpiece; An upper cover plate and a lower cover plate; a reaction chamber defined by the upper cover plate, the lower cover plate and a reaction chamber body; a workpiece support element for supporting the semiconductor workpiece; at least one infrared emitter located at a first end of the top plate; at least one reflective infrared sensor located at a second end of the top cover plate and at least one transmissive infrared sensor located at a second end of the bottom cover plate, wherein the first end and the second end are opposed to each other; The at least one infrared emitter and the at least one reflective infrared sensor are respectively located on a side of the upper cover plate facing the reaction chamber, and the at least one transmissive infrared sensor is located on a side of the lower cover plate facing the reaction chamber; the at least one infrared emitter is located on a sidewall of a first end of the reaction chamber body, and the at least one reflective infrared sensor and the at least one transmissive infrared sensor are located on a sidewall of a second end of the reaction chamber body; 13. A heat treatment apparatus for a semiconductor workpiece comprising:

2. the at least one infrared emitter emits infrared radiation at one or both of the wavelengths of 2.3 microns and 2.7 microns; 2. The thermal processing apparatus for a semiconductor workpiece of claim 1.

3. the at least one infrared emitter, the at least one reflective infrared sensor, and the at least one transmissive infrared sensor are in equal numbers; 3. The heat treatment apparatus for semiconductor workpieces according to claim 1 or 2.

4. The infrared emitter and the corresponding transmission type infrared sensor are on the same line.

3. The heat treatment apparatus for semiconductor workpieces according to claim 1 or 2.

5. The upper cover plate and the lower cover plate are each made of high-hydroxyl quartz.

3. The heat treatment apparatus for semiconductor workpieces according to claim 1 or 2.

6. The infrared emitter, the reflective infrared sensor, and the transmissive infrared sensor each have an equal angle with the vertical axis of the reaction chamber body, the angle being preferably 30-60°, and most preferably 45°; 3. The heat treatment apparatus for semiconductor workpieces according to claim 1 or 2.

7. It is possible to accurately measure the temperature of a semiconductor workpiece in the range of 400 to 750°C.

3. The heat treatment apparatus for semiconductor workpieces according to claim 1 or 2.

8. 1. A high accuracy temperature measurement method for a semiconductor workpiece, comprising: placing a semiconductor workpiece on a workpiece support element within a reaction chamber of a thermal processing apparatus; placing an upper cover plate and a lower cover plate; emitting infrared radiation by at least one infrared emitter toward the semiconductor workpiece on a side of the top cover plate facing the reaction chamber; receiving and measuring an amount of infrared radiation of a first portion reflected by a surface of the semiconductor workpiece with at least one reflective infrared sensor, and receiving and measuring an amount of infrared radiation of a second portion transmitted by the surface of the semiconductor workpiece with at least one transmissive infrared sensor; determining a reflectance and a transmittance of the semiconductor workpiece at a same location based on the amount of infrared radiation of a first portion and the amount of infrared radiation of a second portion at the same location, and calculating an emissivity of the semiconductor workpiece based on the reflectance and the transmittance; and calculating a temperature of the surface of the semiconductor workpiece at the same location based on the emissivity.

1. A method for high precision temperature measurement for a semiconductor workpiece, comprising:

9. the temperature of the semiconductor workpiece is within the range of 400° C. to 750° C.; 9. The method for high accuracy temperature measurement according to claim 8.

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