Temperature control method for semiconductor process

Abstract

To provide a temperature control method for a semiconductor process.SOLUTION: The method includes the steps for providing, in a first process device, a first measurement point of a first point distribution for measuring a temperature within the first process device, and providing, in a second detection device, a second measurement point of a second point distribution for measuring a target parameter. The first point distribution includes a concentric dot array with non-uniform radial spacing. The second point distribution includes a concentric dot array corresponding to the first point distribution. The method of the present invention monitors the uniformity of the process for the entire semiconductor workpiece and can accurately compensate for the process temperature.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present invention relates to the field of semiconductor manufacturing, and more particularly to temperature control methods for semiconductor processing. [Background technology]

[0002] In semiconductor processing, rapid thermal annealing process is usually used, and rapid thermal annealing equipment usually includes atmospheric pressure annealing equipment and low pressure annealing equipment. In semiconductor manufacturing, according to different applications, the temperature range of thermal annealing process is usually between 200℃~1250℃, which is a high temperature process equipment. Temperature is an important parameter in rapid annealing equipment, especially in advanced manufacturing processes, the temperature deviation is usually required to be less than 1℃. Summary of the Invention [Problem to be solved by the invention]

[0003] The present invention provides a temperature control method for semiconductor processing that can monitor process uniformity across an entire semiconductor workpiece and accurately compensate for process temperature. [Means for solving the problem]

[0004] According to one aspect of the present invention, there is provided a method of temperature control for semiconductor processing, the method comprising: providing a first distribution of first measurement points in a first process device to measure a temperature in the first process device; providing a second distribution of second measurement points at a second detection device for measuring the target parameter; the first distribution of points includes an array of concentric dots that are not equally spaced radially; The second point distribution includes a concentric array of dots corresponding to the first point distribution.

[0005] 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.

[0006] The accompanying drawings are provided for a better understanding of the present invention and are not intended to limit the present invention. [Brief description of the drawings]

[0007] [Figure 1] FIG. 2 is a schematic diagram showing partitions and temperature detection areas of a heat lamp in a heat treatment device. [Diagram 2] 1 is a distribution diagram of measurement points of a target parameter on a measuring machine stand according to the prior art; [Diagram 3] FIG. 4 is a distribution diagram of measurement points according to an embodiment of the present invention. [Figure 4] 1 is a flow chart schematic of a temperature control method according to one embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] 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.

[0009] In practical application, with the increasing number of wafers passing through the reaction chamber of the thermal annealing equipment, the temperature sensor (e.g., pyrometer) of the equipment may be misaligned or dirty, which will affect the accuracy of temperature measurement. Meanwhile, the aging of the heat lamp in the thermal annealing equipment will also affect the actual temperature in the reaction chamber. Therefore, in order to produce acceptable wafers by the equipment, it is necessary to keep the process temperature in the reaction chamber in a stable range (e.g., the temperature deviation is less than 1°C) by performing temperature compensation within the temperature range allowed for the thermal annealing equipment.

[0010] In a heat treatment process (i.e., a thermal annealing process), the annealing process typically utilizes a sensor (e.g., a pyrometer) to detect the temperature in a reaction chamber according to the heating area in the heat treatment device. After the heat treatment process is completed, the semiconductor workpiece (e.g., a wafer) is transferred to a detector table to detect target parameters for the heat-treated semiconductor workpiece. Based on the test results of the target parameters, it is determined whether parameter compensation is required for the heat treatment process table.

[0011] The semiconductor workpieces are detected on two different machines, and the radii of the concentric circles for measuring the sheet resistivity and oxide thickness on the wafer do not match the radii for controlling the lamp partitions, so that the difference in the measurement point distribution on the two machines leads to inaccuracies in the temperature compensation calculation and is prone to deviations in the temperature compensation value. In actual application, the calculation must be repeated many times to reduce the temperature compensation error, which will have a negative impact on production efficiency.

[0012] As shown in Fig. 1, in a thermal processing apparatus, multiple heating elements are generally used for heating, for example, a semiconductor workpiece (e.g., a wafer) to be processed is heated by full surface radiation using a top lamp module and a bottom lamp module. In the prior art, each lamp module is divided into multiple zones, for example, four zones Z1, Z2, Z3, and Z4, around the central axis of the wafer, and these zones are controlled separately. Temperature measurements T1 and T2 are made for the temperature in the reaction chamber by providing a sensor, for example, a pyrometer.

[0013] As shown in Fig. 2, in a conventional detection device (measuring machine table), the measurement points are usually provided as five concentric circles (removing 3 mm from the edge) with a center point and equal intervals (29.4 mm). For example, in the case of measurements in the manufacture of 12-inch wafers, 49-point measurement or 121-point measurement is currently common. In the case of 49-point measurement, there are five concentric circles with a center point and equal intervals, and in the case of 121-point measurement, there are five concentric circles with a center point and equal intervals.

[0014] As can be seen from Figures 1 and 2 above, the radius of the partition in the lamp module of the heat treatment apparatus does not match the radius of the concentric circle of the measurement point on the measuring machine table, so the compensation data obtained based on the detection results of the measuring machine table cannot accurately correspond to the control process parameters of the heat treatment apparatus (e.g., the lamp power), which results in compensation errors and an increase in the number of compensations, and reduces the efficiency of the process.

[0015] According to one aspect of the present invention, a temperature control method for semiconductor processing is provided, comprising the steps of: providing, in a first processing tool, first measurement points of a first point distribution for measuring a temperature in the first processing tool; and providing, in a second detection tool, second measurement points of a second point distribution for measuring a target parameter, wherein the first point distribution comprises a concentric dot array having unequal radial spacing, and the second point distribution comprises a concentric dot array corresponding to the first point distribution.

[0016] According to one specific embodiment, the temperature control method includes: acquiring a process temperature of each point of the test target semiconductor workpiece in the first point distribution under standard process conditions in the first process device; Detecting a target parameter corresponding to the process temperature of the semiconductor workpiece to be tested in the second detection device, and determining a correspondence relationship between the process temperature and the target parameter; detecting a target parameter of the semiconductor workpiece under test in the second detection device and comparing the measured value of the target parameter of the semiconductor workpiece under test with a set standard range of the target parameter; calculating a deviation value of the target parameter when the measured value of the target parameter of the semiconductor workpiece to be tested exceeds the set standard range; and calculating a temperature deviation value in each heating region from the deviation value of the target parameter according to the correspondence relationship. Determining the correspondence between the process temperature and the target parameter refers to determining the rate of change based on the amount of change in the corresponding target parameter measured by the second detection device when the process temperature in the first process device changes by 1°C.

[0017] According to one specific embodiment, under standard rapid annealing process conditions, such as a low pressure of 1 to 760 Torr, a process temperature of 200 to 1200°C, a process gas containing oxygen gas, nitrogen gas, oxygen gas and nitrogen gas, or oxygen gas and hydrogen gas, and a total air flow rate of 1 to 60 slm, when the process temperature detected on the annealing machine table changes by 1°C, the change in sheet resistivity of the test wafer detected on the measuring machine table is 2 Ω cm -2 If the rate of change is 2 Ω cm -2 °C -1 Here, the standard value of the wafer sheet resistivity is 160 Ω cm -2and after the test wafer is subjected to rapid annealing under predetermined conditions on the annealing machine table, the sheet resistivity of the annealed wafer detected on the measuring machine table is 170 Ω cm -2 If so, the temperature value to be compensated is calculated as follows:

[0018]

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[0019] According to another embodiment, the thickness change of the oxide film on the wafer surface can be detected on the measuring machine stage, and the thickness change associated with a unit temperature change can be taken as the thickness change rate. The deviation value of the oxide film thickness on the wafer surface to be tested from a set standard thickness value is tested and calculated, and the deviation value is divided by the thickness change rate to obtain the temperature compensation value.

[0020] Specifically, in rapid thermal annealing equipment, the wafer rotates during the process, and in annealing equipment for wafers 12 inches or larger, in particular, it is necessary to control the heat lamps in separate regions in order to maintain uniformity in the annealing temperature of the wafer, and the power for each region is controlled separately, thereby adjusting the temperature uniformity.

[0021] Specifically, as shown in Figures 3 and 4, the temperature control method of the present invention may include a step of setting a measurement point, a step of determining a correspondence relationship between the temperature of a first process device and a target parameter measured by a second detection device, and a step of compensating the parameter.

[0022] Specifically, the step 100 of providing measuring points may include providing a first distribution of points in a first process tool (e.g., a thermal annealing tool) and providing a second distribution of points in a second detection tool (e.g., a detection machine stage for detecting sheet resistivity or oxide thickness). Here, the center point of the first distribution of points and the center point of the heating element (e.g., a top heating lamp module and a bottom heating lamp module) of the first process tool are on the same vertical line. Furthermore, by setting the radius of the concentric circles of the distribution of points according to the area partition of the heating element, the concentric circles of the distribution of points respectively correspond to the corresponding areas of the heating element, that is, the intervals of the concentric circles of the distribution of points in the first process tool are not equal.

[0023] According to an embodiment, as shown in FIG. 3, the semiconductor workpiece is a 12-inch wafer, and the heat treatment process is a rapid thermal annealing process. In this case, the rapid thermal annealing apparatus includes a plurality of heat lamp modules (e.g., a top heat lamp module and a bottom heat lamp module) and includes a plurality of heating zones (e.g., six heating zones). According to the above temperature control method, a first point distribution is provided, which typically includes a center point and six concentric circles with unequal intervals. Furthermore, the intervals between adjacent concentric circles are 25 mm, 35 mm, 20 mm, 30 mm, 10 mm, and 27 mm from the center point to the edge in sequence (i.e., the radii are 25 mm, 60 mm, 80 mm, 110 mm, 120 mm, and 147 mm in sequence), with 3 mm removed from the edge. In this case, the second point distribution on the detector table is set to include a center point and six concentric circles with unequal intervals, and the intervals between adjacent concentric circles may be 25 mm, 35 mm, 20 mm, 30 mm, 10 mm, and 27 mm (i.e., the radii are 25 mm, 60 mm, 80 mm, 110 mm, 120 mm, and 147 mm, respectively) from the center point to the edge, with 3 mm removed from the edge. That is, the second point distribution completely corresponds to the first point distribution, so that the measurement data by the detector table can more accurately reflect the uniformity of the heat treatment process.

[0024] According to another embodiment, in the rapid thermal annealing process of the wafer, the first process device (thermal annealing device) may include multiple heating elements, for example, a top heating lamp module and a bottom heating lamp module, and the heating lamp module may be divided into four regions (see, for example, FIG. 1). The size of each region can be adjusted according to specific process conditions. According to the region partition of the heating lamp module, the first point distribution of the first process device may include a center point and three concentric circles, and accordingly, on the wafer, the intervals between adjacent concentric circles from the center point to the edge may be 60 mm, 50 mm, and 37 mm in sequence (i.e., the radii are 60 mm, 110 mm, and 147 mm in sequence), with 3 mm removed from the edge. In this process device, the machine base does not directly test the process temperature, but measures the current and voltage values, etc., by sensors, and obtains the temperature value through calculation. As the equipment is used or becomes dirty, the sensor readings are subject to drift and error, causing the temperature sensed by the process equipment to be inaccurate.

[0025] In the second detection device, a second point distribution is performed, and the measurement points of the second point distribution correspond one-to-one to the first point distribution, i.e., the second point distribution includes a center point and a plurality of concentric circles with different intervals. The second detection device can be used to physically detect the sheet resistivity or oxide thickness of the semiconductor workpiece. Specifically, the average value of the parameter data measured for the measurement points on the same concentric circle is the measured value of the parameter in the region.

[0026] According to one embodiment, in a rapid thermal annealing process for a 12-inch wafer, the positions of the four regions of the annealing device corresponding to the wafer are 0, 60 mm, 110 mm, and 147 mm, respectively. Therefore, in the measurement, the radii of the concentric circles are adjusted to 60 mm, 110 mm, and 147 mm. The data of the multiple concentric circles are individually analyzed and calculated to preset compensation values ​​for temperature. The measurements of the other concentric circles may be adjusted as necessary, thereby serving to monitor the process.

[0027] Specifically, the number of points on the same concentric circle of the above point distribution may be set according to the needs of the process, and may be, for example, a 49-dot array or a 121-dot array. For example, when the semiconductor workpiece to be processed is a 12-inch wafer, the first point distribution includes a central point and a concentric 49-dot array or a 121-dot array with distances of 25 mm, 60 mm, 80 mm, 110 mm, 120 mm, and 147 mm extending radially outward from the central point, respectively.

[0028] Step 110 of determining the correspondence relationship may include determining a rate of change from an amount of change in a target parameter (e.g., sheet resistivity or oxide film thickness) measured by the second detection device when the process temperature in the first process device changes by 1°C.

[0029] According to one specific embodiment, in a first process device (thermal annealing device), the process temperature of each point of the semiconductor workpiece (wafer) under test in a first point distribution (e.g., a central point and three concentric circles) is obtained (detected by a standard sensor) under standard process conditions. Then, in a second detection device (i.e., a measuring machine table), a target parameter (e.g., sheet resistivity or oxide film thickness) of the semiconductor workpiece (wafer) under test is detected according to the measurement points of a second point distribution corresponding to the first point distribution, and a correspondence relationship between the process temperature and the target parameter is determined. As described above, this correspondence relationship refers to determining the rate of change from the amount of change of the corresponding target parameter (i.e., sheet resistivity or oxide film thickness) measured by the second detection device when the process temperature in the first process device changes by 1°C.

[0030] According to one embodiment, in a rapid thermal annealing process, the above target parameter may be the sheet resistivity or the surface oxide thickness of the wafer, and the rate of change with respect to the process temperature in the first process equipment may be 2.

[0031] 4, the above temperature control method further includes step 120 of comparing the measured value of the target parameter with a set standard range of the target parameter, step 130 of determining whether the measured value of the target parameter exceeds the set standard range, step 140 of calculating the deviation value of the measured value of the target parameter with respect to the standard range if the measured value exceeds the set standard range, and step 150 of calculating and setting the temperature compensation value of the corresponding heating zone based on the calculated deviation value and the above correspondence relationship, and performing temperature compensation for each heating zone. If the measured value does not exceed the set standard range, step 120 of detecting and comparing the target parameter is continued for the wafer after thermal annealing without performing temperature compensation.

[0032] According to one embodiment, the temperature compensation step is performed by adjusting the power of the heating elements of each heating zone.

[0033] According to the temperature control method of the present invention, the temperature compensation accuracy is improved by using the accurate test parameters of the subsequent detector to perform temperature compensation for the process treatment machine without accurate temperature measurement according to a predetermined correspondence. Specifically, in the method of the present invention, the measurement points of the detector are set to include a center point and unequal-spaced concentric circles, and these concentric circles correspond one-to-one with the heating areas of the process equipment, thus accurately reflecting the changes of the process conditions and accurately adjusting the process.

[0034] Taking a rapid thermal annealing device as an example, the heating lamp is divided into four heating zones, and the heating power can be adjusted and controlled individually for one or more zones during the process to achieve uniformity. For equipment for large-scale mass production, during the maintenance period of one equipment, due to the aging of the lamp and the drift of the precise temperature of the temperature measurement point, it is necessary to pre-set the temperature compensation value for each heating zone to make the temperature uniform. The positions corresponding to the wafers in the four zones are 0 mm, 60 mm, 110 mm, and 147 mm, respectively. Therefore, in the measurement, the radii of the concentric circles of the measurement points are adjusted to 60 mm, 110 mm, and 147 mm. The data of these concentric circles are individually analyzed and calculated, and the compensation value for the temperature is pre-set. In addition, the measurement values ​​of other concentric circles can also be set and can be adjusted appropriately according to the needs of the process, thereby achieving the purpose of monitoring the entire process, improving the stability of the process, and promoting production efficiency.

[0035] 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.

[0036] The above specific embodiments do not limit the scope of protection of the present disclosure. Those skilled in the art can understand 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 gist of the present disclosure are all intended to be included in the scope of protection of the present disclosure.

Claims

1. 1. A temperature control method for semiconductor processing, comprising: providing a first distribution of first measurement points in a first process tool to measure a temperature in the first process tool; providing a second distribution of second measurement points at a second detection device for measuring the target parameter; the first distribution of points includes an array of concentric dots that are not equally spaced radially; 11. A temperature control method for a semiconductor process, comprising: the second point distribution including a concentric dot array corresponding to the first point distribution.

2. The concentric circles of the first point distribution correspond one-to-one to the heating regions of the first process device, and the concentric circles of the measurement dot array correspond to the plurality of heating regions, respectively. The temperature control method according to claim 1 .

3. The temperature control method includes: acquiring a process temperature of each point of the test target semiconductor workpiece in the first point distribution under standard process conditions in the first process device; detecting a target parameter corresponding to the process temperature of the semiconductor workpiece to be tested in the second detection device, and determining a correspondence relationship between the process temperature and the target parameter; detecting a target parameter of the semiconductor workpiece under test in the second detection device and comparing the measured value of the target parameter of the semiconductor workpiece under test with a set standard range of the target parameter; calculating a deviation value of the target parameter when the measured value of the target parameter of the semiconductor workpiece to be tested exceeds the set standard range; calculating a temperature deviation value in each heating region from the deviation value of the target parameter according to the correspondence relationship; and performing temperature compensation for each of the heating regions based on a temperature deviation value in each of the heating regions. The temperature control method according to claim 2 .

4. The temperature compensation is performed by adjusting the power of the heating elements of each heating zone. The temperature control method according to claim 3.

5. The target parameter is the sheet resistivity or the thickness of a surface oxide film of the semiconductor workpiece; The temperature control method according to claim 1 or 2.

6. The target parameter is the sheet resistivity or the thickness of a surface oxide film of the semiconductor workpiece; The temperature control method according to claim 3 or 4.

7. the first process tool is a rapid thermal anneal tool and the semiconductor workpiece being processed is a wafer; The temperature control method according to any one of claims 1 to 4.

8. The rapid thermal annealing apparatus includes a plurality of heat lamp modules and includes a plurality of heating zones; The temperature control method according to claim 7.

9. determining the correspondence relationship between the process temperature and the target parameter includes determining a change rate from an amount of change in the target parameter measured by the second detection device when the process temperature in the first process device changes by 1° C. The temperature control method according to claim 6.

10. the target parameter is a sheet resistivity or a thickness of a surface oxide film of a wafer, and a rate of change with respect to a process temperature in the first process device is 2; The temperature control method according to claim 9.

11. When the semiconductor workpiece to be processed is a 12-inch wafer, the first point distribution includes a center point and a concentric 49-dot array or a 121-dot array extending radially outward from the center point at distances of 25 mm, 60 mm, 80 mm, 110 mm, 120 mm, and 147 mm, respectively; The temperature control method according to any one of claims 1 to 4.

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