KR20010051371A - Heat processing method and heat processing apparatus - Google Patents

Abstract

PURPOSE: A heating treatment apparatus is provided to prevent the generation of an irregularity in the line widths of a pattern consisting of a coating film on a substrate. CONSTITUTION: A sensor part(64) for measuring the thickness of a resist film on the surface of a wafer(W) is movably provided in a post exposure baking device(44) and the measurement is measured during a heating treatment on the wafer(W). The set temperature of a heater(62) which is built in a heating plate(61) is adjusted from the correlation between the previously found step and the final line width of a pattern consisting of a coating film on the substrate after continuous treatments on the substrate so that the step is confined within the prescribed extent.

Description

Heat treatment method and heat treatment device {HEAT PROCESSING METHOD AND HEAT PROCESSING APPARATUS}

The present invention relates to a heat treatment method and a heat treatment apparatus for a substrate.

For example, in a photolithography process in a semiconductor device manufacturing process, a resist coating process for forming a resist film on a wafer surface, an exposure process in which a wafer is irradiated with a pattern, and a wafer is heated to improve a post-exposure pattern shape. The heat treatment, after which the development treatment for developing the wafer is performed. Each processing apparatus which performs these processes is arranged as one system except the exposure processing apparatus, and comprises the coating and developing processing system.

Here, whether or not a predetermined wafer is manufactured by the coating and developing processing system is performed by inspecting and measuring the line width of the circuit pattern formed on the wafer surface after a series of processing. The line width measuring instrument for measuring the line width is provided separately outside the coating and developing processing system, and the worker carries the manufactured wafer to the line width measuring instrument to perform the line width measurement.

However, since the line width measurement of the wafer is performed after a series of treatments, and the worker transfers the wafer to the line width measuring instrument in the coating and developing processing system, even if an abnormality occurs in the line width of the wafer, for example, exposure is performed. It takes time to correct the heating time after the treatment. In addition, since many wafers were manufactured in the meantime, many defective products which deviated from the specification of predetermined | prescribed line width were manufactured.

During the heat treatment after the exposure treatment, a step is formed in the film thickness of the coating film on the wafer surface between the exposed exposed portion and the unexposed portion, but according to the inventor's knowledge, the step and the series of processing described above It was found that there was a consistent correlation between the line widths of later wafers.

The present invention has been made in view of this point, and during the heat treatment after the exposure treatment, the step of measuring the thickness of the coating film thickness on the surface of the wafer correlated with the line width is measured so that the step is immediately heated so that the step is in a predetermined range. It aims to correct the time.

BRIEF DESCRIPTION OF THE DRAWINGS The top view which shows the external appearance of the application | coating development system provided with the post exposure baking apparatus which concerns on 1st Embodiment.

Figure 2 is a front view of the coating and developing treatment system of Figure 1;

3 is a rear view of the coating and developing treatment system of FIG.

4 is an explanatory view of a longitudinal section of a post exposure baking apparatus according to the first embodiment;

5 is an explanatory diagram of a cross section of a post exposure baking apparatus according to the first embodiment;

Fig. 6 is a flowchart showing a process of heat treatment performed by the post exposure baking apparatus according to the first embodiment.

7 is an explanatory diagram of a film thickness step of a resist film on a wafer surface formed by heat treatment;

8 is an explanatory diagram showing an example of a correlation between a step difference formed on a wafer surface and a final line width;

9 is an explanatory view of a partitioned plate of the post exposure baking apparatus according to the second embodiment;

10 is an explanatory diagram in the case where a protective member is attached to a sensor unit for measuring a step height on a wafer surface;

11 is a plan view of a plate with radially partitioned regions;

12 is a plan view of a plate with concentrically and radially partitioned regions;

<Explanation of symbols for main parts of drawing>

1: Coating development processing system 2: Cassette station

3: processing station 4: interface unit

5: cassette holder 7,50: wafer carrier

8: conveying path 13: main conveying device

15,17: resist coating apparatus 16,18: developing apparatus

30,40,43: Cooling device 31: Advice device

32: alignment device 33,42: extension device

34,35: prebaking device 41: extension cooling device

36,37,46,47: Post Baking Device 44,45: Post Exposure Baking Device

51: peripheral exposure apparatus 52: exposure apparatus

60: casing 61,81: plate

62,82a, 82b, 82c: Heater 64: Sensor

63, 83a, 83b, 83c: heater control device 66: arm

67,68 rail 69: main controller

70: exhaust port 71: supply port

72: lifting pin 73: through hole

74: support pins 81a, 81b, 81c: partitioned area

90: protection member C: cassette

W: Semiconductor Wafer G1, G2, G3, G4, G5: Processing device group

In view of the above object, the heat treatment method of the present invention is a method of heat treating a substrate after exposing the substrate having a coating film, wherein the coating film thickness of the substrate surface is at least once during the heat treatment of the substrate. It has a process of measuring the level difference.

The heat treatment apparatus of the present invention also has a step measuring means capable of measuring a step of the thickness of the coating film on the surface of the substrate during the heat treatment.

According to the present invention, for example, the heating temperature or the heating time are corrected as necessary based on the measured value of the step correlated with the line width of the pattern formed by a series of substrate treatments to maintain the step within a predetermined range. Can be. As a result, the final line width after a series of substrate treatments is suppressed within a predetermined range. It is also possible to adjust the heating temperature and the heating time for each partitioned area. The correction may be performed only when the measured value of the step is not within the range of a preset allowable value.

Embodiment of the Invention

EMBODIMENT OF THE INVENTION Hereinafter, preferable embodiment of this invention is described.

1 is a plan view of a coating and developing treatment system 1 having a post exposure baking apparatus as a heat treatment apparatus according to the present embodiment, FIG. 2 is a front view of a coating and developing treatment system 1, and FIG. 3 is a coating and developing treatment. Back view of the system 1.

As shown in FIG. 1, the coating and developing processing system 1 carries out 25 wafers W from the outside in the cassette unit to the coating and developing system 1 from the outside, or with respect to the cassette C. As shown in FIG. A cassette station 2 for carrying in and out of the wafer W, a processing station 3 formed by arranging various processing apparatuses for carrying out a predetermined process in a single sheet during the coating and developing process step, and the processing station 3 ), And has an arrangement in which the interface unit 4 for exchanging the wafer W is integrally connected with the exposure apparatus 52 provided adjacent to the cross-section.

The cassette station 2 is free to place a plurality of cassettes C in a line in the X direction (up and down direction in FIG. 1) at a predetermined position on the cassette placing table 5 serving as a placing unit. Then, a wafer carrier 7 which can be transported with respect to the cassette array direction (X direction) and the wafer array direction (Z direction; vertical direction) of the wafer W accommodated in the cassette C is along the transport path 8. It is installed freely to move and can selectively access each cassette (C).

As will be described later, the wafer carrier 7 is configured to be accessible to the alignment apparatus 32 and the extension apparatus 33 belonging to the third processing apparatus group G3 on the processing station 3 side.

In the processing station 3, a main transporting device 13 is provided at the center thereof, and various processing devices are arranged in multiple stages around the main transporting device 13 to form a processing device group. In the coating and developing processing system 1, four processing apparatus groups G1, G2, G3, and G4 are arranged, and the first and second processing apparatus groups G1 and G2 are developed processing systems 1. The third processing apparatus group G3 is disposed adjacent to the cassette station 2, and the fourth processing apparatus group G4 is disposed adjacent to the interface unit 4. Further, as an option, the fifth processing device group G5 indicated by the broken lines can be arranged separately on the back side.

In the first processing apparatus group G1, as shown in FIG. 2, two kinds of spinner type processing apparatuses, for example, a resist coating apparatus 15 for applying and processing a resist to a wafer W and a wafer W ) Is developed in two stages sequentially from below. Similarly, in the case of the second processing apparatus group G2, the resist coating apparatus 17 and the developing processing apparatus 18 are laminated | stacked in two steps sequentially from the bottom.

As shown in FIG. 3, the third processing apparatus group G3 includes a cooling apparatus 30 for cooling the wafer W, an advice apparatus 31 for enhancing fixability of the resist liquid and the wafer W, Alignment device 32 for aligning wafer W, extension device 33 for waiting wafer W, prebaking devices 34 and 35 for drying process of thinner solvent after resist coating, and after developing treatment The post-baking apparatuses 36 and 37 which heat-process are laminated | stacked in 8 steps, for example from the bottom.

In the fourth processing apparatus group G4, for example, the cooling device 40, the extension cooling device 41, the extension device 42, the cooling device 43, and the exposure treatment which naturally cool the wafer W on which it is placed. Post-exposure baking apparatuses 44 and 45 and post-baking apparatuses 46 and 47 according to the present embodiment, which are subjected to the subsequent heat treatment, are stacked in, for example, eight stages from the bottom.

The wafer carrier 50 is provided in the center part of the interface part 4. The wafer carrier 50 is constituted freely by movement in the X direction (up and down direction in FIG. 1), Z direction (vertical direction) and rotation in the θ direction (rotation direction around the Z axis). The extension / cooling device 41, the extension device 42, the peripheral exposure apparatus 51, and the exposure apparatus 52 shown by the broken line which belong to group G4 are comprised so that it can access.

Next, the structure of the post exposure baking apparatus 44 which concerns on this embodiment is demonstrated.

In the post exposure baking device 44, as shown in FIG. 4, the disk-shaped plate 61 with the thickness which mounts and heats the wafer W is provided. The plate 61 has a heater 62 serving as a heat source at the time of heating, and the heater temperature of the heater 62 is controlled by the heater controller 63.

On the other hand, on the upper side of the wafer W, two sensor units 64 for measuring the level difference on the surface of the wafer W are supported by the arm 66. The sensor unit 64 is configured to detect the film thickness of the resist film on the surface of the wafer W by the LED light, and the difference in the film thickness measured by the two sensor units 64 is the wafer W. It is recognized as the film thickness step of the surface of the.

Moreover, the arm 66 on which the sensor part 64 is supported is attached to the rail 67 extended in the Y direction (up-down direction in FIG. 5), as shown in FIG. The image is movable. Moreover, the rail 67 is attached to the two rails 68 provided along the wall of the casing 60, and becomes free to move to a X direction (left-right direction in FIG. 5). Therefore, the sensor unit 64 attached to the arm 66 is movable in the X and Y directions.

The measured value of the film thickness step | step of the surface of the wafer W measured by the sensor part 64 mentioned above is sent to the main control unit 69, as shown in FIG. The main controller 69 stores in advance a predetermined heating temperature and a predetermined timing, for example, a tolerance value of a step on the surface of the wafer W after 20 seconds from the start of heating. When the measured value of the step is not within the allowable range, the heater control device 63 is configured.

The exhaust port 70 for exhausting the inside of the casing 60 is provided in the lower surface of the casing 60. On the other hand, a supply port 71 is provided on the upper surface of the casing 60. When a predetermined gas, for example, clean air or nitrogen gas is supplied from the supply port 71, a down flow is formed in the casing 60. do.

In addition, the post-exposure baking apparatus 44 is provided with a lifting pin 72 for supporting and lifting the wafer W when carrying in and out of the wafer W. The through-hole 73 formed in the plate 61 is provided. Can penetrate through. Further, on the plate 61, proximity pins 74 for supporting the wafer W during the heat treatment are provided at three locations on the same circumference.

Next, the operation of the post exposure baking apparatus 44 as the heat treatment apparatus configured as described above will be described together with the process of the coating and developing treatment of the wafer W performed by the coating and developing treatment system 1.

First, the wafer carrier 7 takes out one unprocessed wafer W from the cassette C and carries it into the alignment apparatus 32 belonging to the 3rd processing apparatus group G3. Subsequently, the alignment of the wafer W, which has been completed as the alignment device 32, is performed by the main transport device 13, the advance device 31, the cooling device 30, the resist coating device 15 or 17, and the prebaking. It is conveyed to the apparatus 33 or 34 one by one, and a predetermined process is performed. Thereafter, the wafer W is conveyed to the extension cooling device 41.

Subsequently, the wafer W is taken out from the extension cooling device 41 by the wafer carrier 50, and then passed through the peripheral exposure apparatus 51 to the exposure apparatus 52. After the exposure process is completed, the wafer W is conveyed to the extension device 42 by the wafer carrier 50, and then held by the main transport device 13. Subsequently, the wafer W is conveyed to the post exposure baking device 44 or 45.

Next, the operation of the wafer W in the post exposure baking device 44 will be described according to the flow of FIG. 6.

First, the wafer W after the pretreatment is completed is carried into the post exposure baking apparatus 44 by the carrier 50, and is taken up by the lifting pins 72 that are raised and waiting in advance. The wafer W descends as the lifting pin 72 descends, and is supported by the support pin 74 on the plate 61. At this time, the heating of the wafer W is started by the plate 61 previously heated to a predetermined temperature. In addition, during the heat treatment, the above-described downflow is always formed in the casing 60 in order to exhaust the solvent and the like generated on the wafer surface.

Next, the two sensor units 64 move to a predetermined position on the wafer W by the arm 66 and wait. These sensor portions 64 irradiate LED light to the wafer surface at a predetermined timing, for example, 20 seconds from the start of heating, and expose portions and minnow formed on the resist film on the surface of the wafer W as shown in FIG. The step d of the film thickness with the miner is measured. The measured value is sent to the main controller 69 and compared with the allowable value of the step of the wafer surface previously stored in the storage unit of the main controller 69.

Here, the allowable value of the step difference on the surface of the wafer W is determined from the correlation between the step level of the wafer W surface during the heat treatment and the final line width required by the experiment or the like. As this correlation, for example, as shown in Fig. 8, there is a relationship in which the final line width also decreases as the step becomes smaller. The value of the step corresponding to the boundary value of the allowable range of the final line width becomes the allowable value of the step and is stored in the main controller 69 in advance.

The main controller 69 sends the data to the heater control device 63 when the measured value of the step is not within the allowable value of the step stored in advance, and the heater control device 63 sends the heater (based on the sent data). Adjust the set temperature in 62). For example, when the measured value of the step is larger than the allowable value of the step, the setting temperature of the heater 62 is lowered. On the contrary, when the measured value of the step is smaller than the allowable value of the step, the adjustment is made to raise the set temperature of the heater 62. . On the other hand, when the measured value of the step is within the range of the allowable value of the step, no data is sent to the heater control device 63, and the set temperature of the heater 62 is maintained as it is.

Thereafter, the sensor unit 64, which has completed the step measurement, is retracted from the upper surface of the wafer W by the arm 66 to a predetermined position. The wafer W is then heated to an appropriate temperature for a predetermined time.

After the heat treatment is completed, the wafer W is supported by the lifting pins 72 again, rises, is turned over to the wafer carrier 7, and then carried out from the post exposure baking apparatus 44.

According to the above embodiment, during the heat treatment of the post exposure baking apparatus 44, the step part of the film thickness of the resist film on the surface of the wafer W is measured by the sensor part 64, and the set temperature of the heater 62 is immediately changed. By correcting at an appropriate temperature, the occurrence of so-called defective products of the wafer W is reduced, and as a result, the production yield is improved. In addition, since the set temperature of the heater 62 is suppressed by the minimum control necessary only when the measured step is not within the range of a preset allowable value, the work efficiency is improved.

In addition, since the sensor unit 64 is movable by the arm 66, it is possible to move to a position suitable for the step measurement and measure the step difference. Furthermore, since the down flow is formed in the casing 60, the sensor unit 64 can be prevented from being contaminated by the solvent generated in the wafer W or the like.

Next, the post exposure baking apparatus 44 which has a plate partitioned as 2nd Embodiment is demonstrated. As shown in FIG. 9, the plate 81 of the post exposure baking apparatus 44 in this 2nd Embodiment is divided in concentric shape, and the heater 82a is divided into the partitioned area 81a, 81b, 81c. And 82b and 82c are built in, respectively. Each of these heaters 82a, 82b, and 82c is configured to be individually controlled by the heater control devices 83a, 83b, and 83c. Furthermore, each heater control device 83a, 83b, 83c is connected to one main controller 69, which is based on the step measured by the sensor unit 64. , 83b, 83c).

In the post exposure baking apparatus 44 which concerns on 2nd Embodiment, the wafer W is carried in by the conveyance body 50 similarly to the post exposure baking apparatus 44 which concerns on 1st Embodiment, and the plate After being placed on the support pin 74 on the 81, it is heated by the heaters 82a, 82b, 82c for each region. During the heat treatment, the wafers W may be moved by the sensor unit 64 at different timings, for example, after 20 seconds in the region 81a, 30 seconds in the region 81b, and 40 seconds in the region 81c. ) The level difference of the surface is measured. These measured values are sent to the main control unit 69, and the main control unit 69 compares the allowable values of the steps stored in advance for each area. As in the first embodiment, data is sent to the respective heater control devices 83a, 83b, 83c only when the measured value of the step difference in each area is not within the allowable range, and the heaters 82a, 82b, 82c are provided. The set temperature of is adjusted for each area.

According to this second embodiment, since the step formed on the surface of the wafer W for each of the divided regions 81a, 81b, 81c of the plate 81 is measured, and the heating temperature is adjusted for each region, the same wafer ( The nonuniformity of the final line width in W) is suppressed, and the uniformity in surface inside the wafer W is maintained.

In the above embodiment, the plate 81 has regions 81a, 81b, 81c partitioned concentrically, but as shown in FIG. 11, the plate 81 has a region 81d radially partitioned. The present invention is applicable even if it is. As shown in Fig. 12, finer adjustments can be made by combining the concentric circles and the radial shapes so as to individually control the heating temperature and the heating time for the more subdivided regions 81e and 81f.

Here, in the above-described embodiment, the step may be measured again at the end of the heat treatment to confirm whether or not the appropriate step is formed from the correlation with the final line width. In addition, although the set temperature of the heater was adjusted based on the measured value of the step, the heating time may be adjusted instead.

In addition, in the above-mentioned embodiment, although the downflow was formed so that the sensor part 64 might not be polluted by the solvent etc. which evaporate from the wafer W, as shown in FIG. 10, the protection member which covers the sensor part 64 ( 90) may be provided.

In the above step measurement, more accurate measurement can be performed by using a dedicated test wafer or a substrate having a test pattern advantageous for step measurement. The control based on the step measurement of the test wafer is preferably performed after processing between the lots of the wafer and a predetermined number of production wafers.

Moreover, in the said embodiment, although the heating temperature and heating time at the time of the post-exposure heat processing were controlled based on the data when the level | step difference was measured, you may instead control the developing time of the developing process which is post-processing. .

Although the above-described embodiment relates to a wafer processing system in a lithography process of a semiconductor wafer device manufacturing process, it can be applied to a processing system of a substrate other than a semiconductor wafer, for example, an LCD substrate.

According to the method of the present invention, since the film thickness step of the coating film on the surface of the substrate is measured during the heat treatment of the substrate, it is unnecessary to stop the processing of the substrate in order to measure the step. And based on the result, since the heat treatment temperature and the heat time of a board | substrate can be controlled during a process, a defective product reduces and a production yield is improved. By controlling the heating temperature or the heating time based on the measured value of the level difference of the substrate surface, the film thickness level of the coating film on the surface of the substrate during the heat treatment is maintained within a predetermined range. As a result, the final line width of the substrate correlated with the step is kept within a predetermined range, thereby reducing defective products and improving production yield. By controlling the heating temperature or the heating time of the substrate only when the measured value of the film thickness step of the coating film on the substrate surface exceeds a preset allowable value, unnecessary control is suppressed and the working efficiency is improved. When the film thickness step of the coating film on the substrate surface is measured for each area of the partitioned plate, the step of a more detailed range on the substrate can be measured. In addition, since the nonuniformity of the step generated between the regions in the same plate is also corrected, the uniformity of the line width in the same substrate surface is improved.

According to the apparatus of the present invention, since the heat treatment apparatus has a step measuring device, it is not necessary to provide a device for measuring the step difference separately, and the cost can be reduced. In addition, during the heat treatment, for example, the heating temperature and the like can be controlled and corrected based on the measured value of the step, so that defective products are reduced and the production yield is improved as compared with when the step measuring device is installed separately. Since the sensor portion of the step measuring means is free to move on the substrate, the sensor portion can measure the film thickness step of the coating film on the surface of the substrate at an optimal position on the substrate. Having a protective member covering the sensor portion prevents contamination of the sensor portion, thereby improving the protection environment of the sensor portion. If the exhaust port is provided below the substrate, since the solvent and the like evaporated during the heat treatment are exhausted to the lower side of the substrate, contamination of the sensor portion provided above the substrate can be prevented.

In addition, embodiment mentioned above was disclosed as the intention to make clear the technical content of this invention to the last, and this invention is not limited to such specific example and is interpreted, and changes variously in the range described in the spirit and Claim of this invention. It can be.

Claims (20)

After exposing a substrate having a coating film, the substrate is heat treated. And a step of measuring a film thickness step of the coating film on the surface of the substrate at least once during the heat treatment of the substrate. The heat treatment method according to claim 1, further comprising a step of controlling the heating temperature of the substrate based on the measured value of the film thickness step of the coating film after measuring the film thickness step of the coating film on the substrate surface. The heat treatment method according to claim 1, further comprising a step of controlling the heating time of the substrate based on the measured value of the film thickness step of the coating film after measuring the film thickness step of the coating film on the substrate surface. The heating treatment method according to claim 2, wherein the control is performed only when the measured value is not within a range of a preset allowable value. 4. The heating treatment method according to claim 3, wherein the control is performed only when the measured value is not within a range of a preset allowable value. A method of heat-treating a substrate having a coating film and then heating the substrate by a heat treatment apparatus capable of heating each partitioned area, And a step of measuring a film thickness step of the coating film on the surface of the substrate for each of the partitioned regions at least once during the heat treatment. 7. The process according to claim 6, wherein the step of controlling the heating temperature of the substrate in each of the divided regions is measured based on the measured value of the film thickness difference of the coating film on the substrate surface after measuring the film thickness difference of the coating film on the substrate surface. Eggplant heat treatment method. 7. The process according to claim 6, wherein the step of controlling the heating time of the substrate for each of the divided regions is measured based on the measured value of the film thickness step of the coating film on the substrate surface after measuring the film thickness step of the coating film on the substrate surface. Eggplant heat treatment method. 8. The heating treatment method according to claim 7, wherein the control is performed for each of the divided regions only when the measured value exceeds a preset allowable value. 9. The heating treatment method according to claim 8, wherein the control is performed for each of the divided regions only when the measured value exceeds a preset allowable value. As a heat treatment apparatus which heats the said board | substrate after exposing the board | substrate which has a coating film, And a step measuring means capable of measuring a film thickness step of the coating film on the surface of the substrate during heat processing. The heat treatment apparatus according to claim 11, wherein the step measuring means has a sensor part for measuring a film thickness step of the coating film, and the sensor part is movable on the substrate. The heat treatment apparatus according to claim 12, further comprising a protective member covering the sensor unit. 12. The heat treatment apparatus according to claim 11, further comprising an exhaust port for exhausting the inside of the heat treatment apparatus, wherein the exhaust port is disposed below the substrate. 12. The heat treatment apparatus according to claim 11, further comprising a plate on which the substrate is placed and heated, wherein the plate is individually temperature-controlled for each partitioned area. 12. The heat treatment apparatus according to claim 11, further comprising a plate on which the substrate is placed and heated, wherein the plate is capable of adjusting a heating time individually for each partitioned area. The heat treatment apparatus according to claim 15, wherein the plate is partitioned into concentric circles. 18. The heat treatment apparatus according to claim 17, wherein the plate is further radially partitioned. The heat treatment apparatus according to claim 16, wherein the plate is partitioned into concentric circles. The heat treatment apparatus according to claim 19, wherein the plate is further radially partitioned.