JPS6333275B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a heating apparatus for baking photoresist or similar materials in the manufacturing process of semiconductor devices, for example.

As is well known, photoetching technology is frequently used in manufacturing semiconductor devices. For example, when forming a semiconductor element on the surface of a semiconductor wafer (wafer), or when drawing out electrodes or forming wiring from the semiconductor element, photoresist is applied to the wafer surface and baked to harden. Then, partial exposure, development, and post-baking are performed to form a mask, and this mask is used to partially etch the insulating film, wiring layer, etc.

Among the photoresist film forming operations, a photoresist baking process is performed for the purpose of improving the photosensitivity of the photoresist and the adhesion between the wafer and the photoresist.

Currently, the mainstream method of photoresist baking processing is a method using infrared radiation or a method using hot air, but in these photoresist baking processes, the photoresist film is hardened from the surface, so the internal solvent evaporates. This increases the baking time. In addition, since a large number of wafers are processed in order to shorten the processing time per wafer, the processing space becomes large and cleaning becomes difficult, making it difficult to perform baking processing in a clean atmosphere. The disadvantage is that it tends to become large.

For this reason, dielectric heating methods using microwaves have been considered, but when projecting microwaves from above the surface of the object to be processed, an aluminum (Al) film that reflects the microwaves is applied to the entire surface of the object to be processed. If the resistivity value is extremely small, or if the object to be processed is a Si wafer, the wafer temperature induced by microwave dielectric heating will not rise to a predetermined temperature.

Further, for the same microwave output, if the microwave reflective film (aluminum film, etc.) partially remains, the induced temperature value of the wafer, which is the object to be processed, varies depending on the remaining amount. In addition, when the specific resistance value of the wafer, which is the object to be processed, changes, the induced wafer temperature value also changes, making it impossible to obtain a uniform and highly accurate baking effect. It has not yet been put into practical use.

Therefore, an object of the present invention is to provide a baking (heating) device that can perform highly accurate and uniform baking and has a short processing time.

In order to achieve such an object, the present invention includes a support body configured of an object that supports a semiconductor wafer and whose temperature is raised by microwave dielectric heating, and a microwave projection section that generates heat on the support body. In the heating device, the microwave projection section is arranged to project microwaves to the back side of the mounting surface of the support on which the semiconductor wafer is placed, and the microwave A shield plate is provided to prevent waves from leaking to the mounting surface side, and further,
The present invention is provided with a temperature monitoring system that controls the amount of microwave radiation while monitoring the temperature of the semiconductor wafer.

1 and 2 show a schematic perspective view and a sectional view of a microwave hot plate type photoresist baking apparatus of the present invention. As shown in FIG. 1, this apparatus sets a cartridge 2 containing a plurality of wafers 1 that have been subjected to photoresist coating or development, and a loader section 3 that supplies the wafers 1 one by one. A wafer transfer section 4 that transfers the wafers, a baking section 5 that bakes the photoresist of the transferred wafers 1 by microwave dielectric heating, an unloader section 6 that stores the baked wafers 1 one by one in the cartridge 2, and a wafer 1 A control unit 7 that detects temperature, controls the amount of microwave output, and controls a series of operations.
It consists of This device is usually installed inside a clean bench. Further, as shown in FIG. 2, nitrogen gas 9 is supplied to the furnace body 8 through the following route. Nitrogen gas 9 is supplied through a supply pipe 10 in the _A1 direction, passed through a filter 11 and purified,
Nitrogen is supplied to the nitrogen supply chamber 12 in the _A2 direction. The nitrogen gas 9 led to the nitrogen supply chamber 12 is passed through the mesh shield plate A13 with laminar flow function to A ₃ ,
It is evenly supplied to the furnace body 8 in the A ₃ ′ direction. The atmosphere inside the furnace body 8 is cleaned by nitrogen gas 9, and the mesh shield plate _B14 is
Laminar flow is maintained because it flows evenly in the A ₄ ' direction. Furthermore, the nitrogen gas 9 is the mesh shield plate C.
15 is guided in the _A5 direction, and exhausted from the exhaust chamber 16 and the exhaust pipe 17 in the _A6 direction.

The wafer 1 is automatically supplied to the upper surface of the wafer support 18. In the case of the wafer support 18, the wafer 1 is attracted to the surface of the wafer support 18 in order to apply a vacuum 20 from the direction _B1 through the support shaft 19. In addition, the wafer support 18
is made of a material that can be heated by microwave dielectric heating.

On the other hand, microwaves are generated by a magnetron 21, propagated through a waveguide 22, a coaxial cable 23, and an antenna 24, and guided into the furnace body 8. The magnetron 21, waveguide 22, coaxial cable 23, and antenna 24 constitute a microwave projection section. The antenna 24 has a microwave shield section A25, and the microwaves generated from the antenna 24 are projected onto the wafer support 18 from below (back side) of the wafer support 18. The microwave is
As a result of being shielded by the mesh shield plate B14 having a microwave shielding function disposed around the wafer support, the micro particles are prevented from leaking to the mounting surface side of the wafer support 18.
As a result, the amount of microwaves projected onto the mounting surface side of the wafer support 18, that is, above the wafer 1, is reduced. Thereby, the wafer 1 is heated to a predetermined temperature by heat conduction using the microwave dielectrically heated wafer support 18 as a heat source. As a result, regardless of whether the wafer 1 is made of aluminum or other material that reflects microwaves or not, the wafer 1 can be heated to a predetermined temperature and a good photoresist bake can be achieved. processing becomes possible.

The heating temperature uniformity of the wafer 1 is maintained by the rotation motor 26.
, the wafer support 18 is rotated, and the rotation center position X ₁ of the wafer support 18 and the antenna 24 are
The optimum heating temperature can be obtained by eccentrically setting the installation position X ₂ and by determining the correlation between the rotational speed of the wafer support 18 and the eccentricity.

In order to accurately control the temperature of the wafer 1, a radial temperature sensor 28 passes through a finder 27 that blocks microwaves and transmits infrared rays.
The temperature of the wafer 1 is measured, and according to the measurement result, the temperature is processed by the temperature control unit 29, the control deviation amount is transmitted to the overall control unit 30, and the amount of power supplied from the magnetron power control unit 31 to the magnetron 21 is controlled, Control the temperature of the wafer 1. These constitute a temperature monitoring system. Therefore, even if the heat transfer efficiency from the wafer support 18 to the wafer 1 changes, feedback control is performed by the closed loop configuration of the radial temperature sensor 28, the control unit 7, and the magnetron 21, and the temperature of the wafer 1 is maintained. can be maintained with high accuracy.

When the wafer 1 is processed at a predetermined temperature for a predetermined time,
The microwave power is then cut off and the wafer support 18
The vacuum 20 is turned off, and the wafer 1 is automatically transferred.

For shielding microwaves to the outside, mesh seal plate A13 and mesh shield plate C1 are used.
5. It is cut off by a microwave shield part A25 and a microwave shield part B32.

As described above, by applying the present invention to the semiconductor device manufacturing process, it is possible to provide high-speed photoresist baking processing in a dust-free atmosphere, and it is expected to improve product yield as well as to save energy. Moreover, by simplifying and downsizing the device, it is expected that the reliability and space efficiency of the device will be improved.

Further, the present invention can also be applied to cure baking of a semiconductor protective film using resin (polyimide), dehydration baking treatment in a wafer processing process, and the like.

As described above, according to the present invention, photoresist and similar materials can be baked in less than 1/50 of the time required by conventional methods, and can be baked while maintaining a uniform and highly accurate temperature. Moreover, the device structure can be simplified.

[Brief explanation of drawings]

Fig. 1 is a perspective view showing the appearance of the device of the present invention;
The figure is an internal sectional view of the main part. 1...Wafer, 2...Cartridge, 3...Loader section, 4...Wafer transfer section, 5...Bake section,
6... Unloader section, 7... Control section, 8... Furnace body, 9... Nitrogen gas, 10... Supply pipe, 11
...Filter, 12...Nitriding supply chamber, 13...Mesh shield plate A, 14...Mesh shield plate B, 15...Mesh shield plate C, 16...
Exhaust chamber, 17... Exhaust pipe, 18... Wafer support, 19... Support shaft, 20... Vacuum,
21... Magnetron, 22... Waveguide, 23...
... Coaxial cable, 24 ... Antenna, 25 ... Microwave shield part A, 26 ... Rotating motor, 2
7...Finder, 28...Radial temperature sensor,
29... Temperature control section, 30... Overall control section, 31
...Magnetron power control section, 32...Microwave shield section B.

Claims (1)

[Claims] 1. A support consisting of an object that supports a semiconductor wafer and whose temperature is raised by microwave dielectric heating;
and a microwave projection section that generates heat on the support, the microwave projection section being arranged to project microwaves onto the back side of the mounting surface of the support on which the semiconductor wafer is placed. established,
and a shield plate is disposed around the support to prevent microwaves from leaking to the mounting surface side,
The heating apparatus further includes a temperature monitoring system that controls the amount of microwave radiation while monitoring the temperature of the semiconductor wafer.