JP2003007603A - Substrate heating equipment and method of manufacturing part - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the product quality and yield of a polarizable substrate by destaticizing the substrate. SOLUTION: The heating section 300 of substrate heating equipment is provided with discharging sections 401 and 402, which respectively spray cationic and anionic gases upon both surfaces of the substrate 11 for destaticizing the electrostatically charged substrate 11.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a substrate heating apparatus and a component manufacturing method which are effective for obtaining a surface acoustic wave element by forming comb-shaped electrodes on a piezoelectric substrate, for example.

[0002]

2. Description of the Related Art Surface acoustic wave (SAW) elements are in widespread demand as signal filters for electrical and electronic equipment. For example, it is used as an intermediate frequency filter for televisions, video cassette recorders, etc., an intermediate frequency filter for mobile phones, etc.

A piezoelectric substrate made of quartz, lithium niobate (LNB), lithium tantalate (LTO) or the like is used as the base substrate of the surface acoustic wave device. Comb-shaped electrodes are formed on the piezoelectric substrate. The comb-shaped electrode is formed by forming aluminum (Al), titanium (Ti), etc. on the piezoelectric substrate by a sputtering method and then etching the film. Patterning of such electrodes begins with forming a pattern of resist.

This manufacturing process is briefly described below from the cleaning process, and is also called a photolithography process. Substrate loading → Washing treatment → Divided bake treatment → Resist coating treatment → Prebake treatment → Exposure treatment → Post-exposure bake treatment → Development treatment → Washing treatment → Post bake treatment → Cooling treatment. Here, in the baking process, heating is performed on a part in the process of being manufactured.

FIG. 4 is shown for explaining the problems in the post-baking process in the above-mentioned processing steps. In the semi-finished product 100 in the process of manufacture, an electrode material 12 (a film such as aluminum) is formed on a piezoelectric substrate 11 serving as a base, and a resist film 13 is patterned on the upper surface of the electrode material 12. .

The semi-finished product 100 in the process of manufacturing is left on the hot plate 200 and heated. This allows
The semi-finished product being manufactured is dried so that it can be transferred to the next processing step.

[0007]

Here, the present inventor
Attention was paid to the pyroelectricity of the piezoelectric substrate 11. Piezoelectric substrate 11
Is polarized inside the substrate even at room temperature. Therefore, the front and back surfaces of the substrate are charged so as to cancel the polarization inside the substrate. That is, the front surface of the substrate is negatively charged, and the back surface of the substrate is positively charged.

This phenomenon becomes significantly large at the baking temperature of 90 ° C. to 130 ° C. in the photolithography process. The surface charge of the substrate heated to 130 ° C., which is a general post-baking temperature, is −10 kV or higher.

This charge accumulation phenomenon causes the substrates to be charged with polarities separately on the front and back sides. The charges charged by heating the substrate return to the initial polarization state when the substrate temperature returns to room temperature, but a discharge phenomenon may occur during heating. The discharge phenomenon occurs between the surface of the substrate and another substance or inside the substrate. When such a discharge phenomenon occurs, the substrate itself is cracked, broken, and the pattern is damaged.

As a well-known method as a countermeasure against static electricity, a static elimination treatment by an ionizer can be mentioned. This method is effective for a semiconductor Si (silicon) substrate whose charge is fixed to either positive or negative, and a liquid crystal glass substrate, but is not suitable as a static elimination method when the substrate is a piezoelectric substrate. .

Therefore, an object of the present invention is to provide a substrate heating apparatus and a part manufacturing method capable of eliminating the charge on a polarizable substrate to improve the product quality and yield.

[0012]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention provides a substrate heating unit for removing one side of the substrate and one side of the other side of the substrate in order to eliminate the charge of the substrate. A discharge part for spraying the positive ion gas and the negative ion gas is provided.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows an embodiment of the present invention, and schematically shows a heating section 300 of a heating device for performing a baking process. The heating unit 300 has a box shape,
For example, the semi-finished product 100 in the process of manufacturing can be placed on the hot plate 310 by opening the front lid (not shown). This placement work is performed by, for example, a robot. When the semi-finished product 100 is placed on the hot plate 310, the substrate 11 of the semi-finished product 100 is heated.

Although the drawing shows only one heating unit 300, in reality, the heating unit is gradually moved to the heating unit having a high heating temperature through the heating steps of a plurality of heating units such as the first stage and the second stage. , The work is done so that sudden thermal shock is not applied. And again, when it is cooled rapidly, it is a semi-finished product 10
Since a thermal shock is applied to 0, the work of gradually moving to a place where the heating temperature is low is performed.

In the semi-finished product 100, an electrode material 12 (a film of aluminum or the like) is formed on a piezoelectric substrate 11 serving as a base, and a resist film 13 is patterned on the upper surface of the electrode material 12. Showing things. Here, the resist film 13 is formed by screen printing, for example. And the heated hot plate 31
By mounting the semi-finished product 100 on the 0, the semi-finished product 100 is heated by the heater temperature of the hot plate 310, and the resist film 13 is coined. That is, when the semi-finished product 100 is left on the hot plate 310 for a certain period of time, the substrate temperature becomes substantially equal to the plate temperature. A heater is built in the hot plate 310 and can be heated by energizing.

In this apparatus, the heating unit 3 is used for this heating.
00, a discharge unit (discharge port) for spraying inert gas of positive ions and negative ions to one surface (upper surface) and the other surface (lower surface) of the substrate in order to eliminate the charge of the substrate. ) 401 and 402 are provided. Ion and negative ion gases are argon (Ar) gas and nitrogen gas (N ₂ ).

Further, in this apparatus, a plurality of openings 311 are formed in the hot plate 310 so that the above-mentioned gas effectively acts on the substrate 11. When the semi-finished product 100 is placed on the hot plate 310, the semi-finished product 100 has an opening 311.
It is preferable to design so that 1 can be closed. Also, in the figure, the upper surface side and the lower surface side of the hot plate 310 are shown as communicating with each other, but in reality,
The space on the upper surface side and the space on the lower surface side may be partitioned with the hot plate 310 as a boundary. This is to prevent the gases from being mixed.

According to the heating device as described above, it is possible to discharge an inactive gas, which is independent of the front and back, to the polarized substrate 11 to remove electricity. Positive ions are ejected to the upper surface of the substrate charged to the negative side, and negative ions are ejected to the lower surface of the substrate charged to the positive side. As a result, the effect of static elimination is obtained, and the electric discharge that occurs conventionally is suppressed. That is, unlike the conventional case, the discharge phenomenon does not occur between the substrate surface and another substance or in the substrate. In addition, it is possible to prevent the electric discharge phenomenon from causing the substrate itself to crack, break, or damage the pattern. Therefore, it is possible to improve product quality and yield.

In the above-mentioned embodiment, the discharge port for the inert gas is installed right above the substrate and right below the substrate. However, gases having opposite ionic polarities are separately sprayed on the front and back of the substrate. Can be configured as. Therefore, the direction of the discharge port is not limited to the direction shown in the figure. The discharge port may be installed diagonally or laterally of the heating unit 300.

Further, the example of FIG. 1 shows a simple example in which an electrode material (aluminum film) 12 is formed on a piezoelectric substrate 11 and a resist film 13 is patterned thereon. However, actually, as shown in FIG. 2, for example, a large number of surface acoustic wave elements 1a, 1b, 1c, 1d, ... Are formed on the wafer 10, and the wafer 10 corresponds to the semi-finished product 100.

The present invention is not limited to the above embodiment. As shown in FIG. 3, the gas discharge part 411,
412 may also be attached. As a result, waste of argon gas and nitrogen gas can be eliminated. That is, after the argon gas and the nitrogen gas are discharged, the gas discharge part 41
1, 412 is used for suction.

The above description is based on the premise that the step of performing the static elimination treatment is the step of performing the baking treatment after the resist application. However, the static elimination means or the static elimination step of the present invention is not limited to the above steps. In short, any of these can be applied to the step of heating and drying the substrate.

[0024]

As described above, according to the present invention,
The charge on the substrate having polarizability can be eliminated to improve product quality and yield.

[Brief description of drawings]

FIG. 1 is a basic configuration diagram of a heating device according to an embodiment of the present invention.

FIG. 2 is a diagram showing an example of a semi-finished product processed by the heating device of the present invention.

FIG. 3 is a diagram showing another example of the heating device according to the present invention.

FIG. 4 is an explanatory view shown for explaining a problem when the piezoelectric substrate is heated.

[Explanation of symbols]

11 ... Piezoelectric substrate, 12 ... Electrode material (aluminum film), 13 ... Resist film, 300 ... Heating part, 310 ... Hot plate, 311 ... Opening, 401, 402 ... Gas discharge part.

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) H01L 21/30 571 (72) Inventor Mitsuo Hirota 8 Shinsita-cho, Isogo-ku, Yokohama-shi, Kanagawa Stock company F term in Toshiba Yokohama office (reference) 5F046 KA04 KA07 KA10 LA18 5J097 AA27 AA32 HA10

Claims (7)

[Claims] 1. A substrate heating unit is provided with a discharge unit for spraying positive ion gas and negative ion gas onto one surface and the other surface of the substrate, respectively, in order to remove static charges on the substrate. Substrate heating device characterized by. 2. The substrate heating apparatus according to claim 1, wherein the substrate heating unit has a box shape for housing the substrate. 3. The substrate heating unit includes a transfer unit that transfers a plate on which the substrate is placed.
1. The substrate heating device described in 1. 4. The substrate heating device according to claim 1, wherein the substrate constitutes a surface acoustic wave element. 5. The substrate heating apparatus according to claim 1, wherein the positive ion gas and the negative ion gas are argon gas and nitrogen gas. 6. The substrate heating unit is a device for cleaning the substrate,
2. The substrate heating device according to claim 1, wherein the substrate heating device is arranged close to either the resist coating device or the exposure device. 7. A component manufacturing method including a heating step of heating an intermediate processed semi-finished product while sequentially moving the base substrate to a processing section in order to form an element on the surface of the base substrate, The heating step includes a step of spraying a positive ion gas and a negative ion gas to one surface and the other surface of the intermediate processed semi-finished product, respectively, in order to remove the electrostatic charge. Method.