JPS59121821A - Set-up means for heater - Google Patents

Abstract

PURPOSE:To obtain a convenient set-up means for heater offering sufficient auxiliary heating effects by providing a holding member for holding an flat object to be heated by gravity being in contact with it and a heating source arranged to be combined with and separable from said holding member for heating periphery or adjacency of periphery of the object to be heated. CONSTITUTION:A wafer 1 is held by its own gravity at four minute areas by four projections 34 of a holding member 3. When this wafer 1 is heated by light irradiation with light of a plane light source, or in advance of this irradiation, electric power to be applied to a heating source 2 is adjusted within a range 400-1,300W, for example, for lightening. Thus periphery 1c or adjacency of periphery 1b of the wafer 1 is auxiliarily heated in order that the temperature on periphery 1c of adjacency of periphery 1b of the wafer 1 becomes nearly same as that of pipe wall of the heating source 2 in the temperature zone over about 500 deg.C. By the auxiliary heating of the heating source 2, a difference of temperature between a central part 1a and the periphery 1c or the adjacency of periphery 1b becomes extremely small thereby making the overall temperature of the wafer 1 uniform. Accordingly, generation of warpage large enough to cause disorder in the following processes as well as ''slip line'' can be prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a heater assembly used when, for example, a flat object to be heated, such as a semiconductor wafer, is irradiated with light and heated in a light irradiation furnace.

Recently, as a method for introducing impurities into semiconductor wafers (hereinafter simply referred to as "Ueno--"), since the impurity concentration and junction depth can be precisely controlled, impurities are turned into ions and accelerated. - ion implantation methods have been used. In this ion implantation method, the crystalline state of the wafer surface changes after the ions are implanted and becomes rough, so in order to eliminate this roughness and create a good surface condition, approximately 100
It is often necessary to heat the wafer to a temperature of 0'C or higher, and this heat treatment must be done in a short time so that the concentration distribution of the implanted impurity in the depth direction does not change due to thermal diffusion. It won't happen.

Furthermore, in order to improve productivity, rapid heating and rapid cooling of Ueno is required.

In addition to such heat treatment, there are knee processes that require heating in semiconductor manufacturing, such as impurity diffusion processes, chemical vapor deposition processes, heat treatment processes for electrical activation, and A heat treatment process is required to nitride or oxidize the surface layer of the silicon wafer, and when performing these processes, rapid heating and rapid cooling of the wafer is required in the same way as described above.

In response to these demands, a light irradiation furnace that heats wafers with light has recently been developed, and this light irradiation furnace can raise the temperature to 1000°C to 1400°C in just a few seconds. .

By the way, when performing heat treatment on a wafer, for example, single crystal silicon, by simply irradiating it with light, the temperature is raised to a processing temperature of around 1150°C within a short period of several seconds, and then maintained at this processing temperature. During heating and processing, a relatively large temperature difference occurs between the outer periphery or near the outer periphery of the wafer and the center, and this temperature difference can cause problems for the wafer in subsequent processing steps. It was found that large "warping" and damage called "slip line" could occur.

This is because the thickness of the wafer is usually very thin, around 0.5 tm, and depending on the temperature distribution in the thickness direction, the relaxation time is on the order of 10-3 seconds, so it is actually not bad. Impact) Although the temperature distribution in the direction along the surface of the wafer does not necessarily affect the wafer surface, even if the wafer surface is irradiated with light at a uniform irradiation energy density, Since the heat dissipation from the center of the wafer is considerably larger than that from the center of the wafer, when the temperature rises, the temperature at or near the outer circumference of the wafer cannot follow the temperature at the center of the wafer. Even if the wafer is heated to the processing temperature, the temperature at or near the wafer's periphery does not reach the temperature at the center of the wafer, and as a result, the temperature at or near the wafer's center becomes lower than the temperature at the center of the wafer. This is because it becomes considerably low.

If a large "warp" occurs in the wafer in this way, it will disrupt the pattern image in subsequent processing steps, such as photo-etching, and this will cause trouble, and if "slip lines" occur, the wafer itself cannot be used as a semiconductor material. If it becomes worthless, it will cause a serious loss.

Under these circumstances, means have been proposed for additionally heating the outer periphery or the vicinity of the outer periphery of the ball.

In this method, the surface of the wafer is primarily heated by light irradiation from a light source such as a halogen lamp, while the outer periphery or the vicinity of the wafer is auxiliarily heated by a heating source such as a lamp or heater. It is a means of heating ueno while heating it.

The present invention relates to a heater assembly with a novel configuration that employs such an auxiliary heating means, which can obtain a sufficient auxiliary heating effect, and can also heat the object to be heated with a simple configuration. The purpose is to provide a convenient heater assembly in which the holder for holding the object to be heated can be easily separated. A holder for holding an object to be heated by gravity in contact with the object, and a heating source that mainly heats the outer periphery or the vicinity of the outer periphery of the object, which is provided in separable combination with the holder. At the point.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the invention will now be described with reference to the drawings, in which a semiconductor wafer is heated by light irradiation.

FIG. 1 is an explanatory view of a wafer (indicated by a dashed line) l placed in a light irradiation furnace, viewed from above, and FIG. 2 is an explanatory view of FIG. 1, viewed from the side. Although not shown, there are power consumptions of 1150 yen above and below the wafer 1, respectively.
A surface light source consisting of 12 W rod-shaped halogen light bulbs arranged close to each other on one plane is disposed, and this surface light source makes the irradiation energy density uniform on the surface of the wafer 1 and the surface temperature of the wafer 1. Approximately 1 at the center 1a of
The wafer 1 is irradiated with light so that the temperature reaches 150°C. The total power consumption of the surface light source for light irradiation is about 28 KW, and the wafer l is disc-shaped with a diameter of 4 inches and a thickness of 0.4 m, and is made of single crystal silicon implanted with boron ions. be.

Reference numeral 2 denotes a heating source such as a halogen light bulb or an infrared light bulb, which includes a quartz glass enclosure 21 consisting of an annular portion 23 and moving arms 24 extending in one direction from both ends of the annular portion 230. A filament 22 is provided inside the envelope 21, and a portion of the filament 22 located within the annular portion 23 of the envelope 21 is a light emitting portion.
The portion located within the arm portion 24 is a non-light emitting portion. 25 is a filament supporter, 26 is a metal foil such as molybdenum,
27 is an external lead. The heat source 2 is disposed, for example, on the lower surface side or the upper surface side (in this example, the lower surface side) of the wafer 1 so as to mainly heat the outer peripheral portion 1c or the outer peripheral portion 1b-i of the wafer 1.

Reference numeral 3 denotes a holder for the wafer 1 which is combined with the heating source 2 to constitute a heater assembly;
An arc-shaped ring part 31 that contacts the outer periphery of the annular part 23 of the enclosure 21 and surrounds this outer periphery from the outside; A hooking portion 32 extends from the top and is bent to contact the upper outer periphery of the sealing body 21 of the heating source 2; For example, a protrusion 3 that comes into contact with a micro-area part located at least one part toward the center from the outer peripheral part IC.
4 and a stopper 36 provided at the outer end 35 of each hook 32. .

The holder 3 is supported by the own weight of the holder 3 by the four hooks 32 being hooked to the enclosure 21 of the heating source 2 in the vertical direction.In the horizontal direction, the holder 3 is supported by its own weight. is supported with the arc-shaped ring portion 31 contacting and surrounding the outer periphery of the annular portion 23 of the enclosure 21: /'L,
The holder 3 and the heat source 2 are integrally constructed so that they can be used for a long time.

With the above configuration, the wafer 1 is heated in the following manner. That is, when the wafer 1 held by its own weight in four small areas by the four protrusions 34 of the holder 3 is irradiated with light from the surface light source 2 to heat it, or prior to this light irradiation, the heating source 2 When the power applied to the wafer 1 is adjusted in the range of 400W to 1300W for lighting, the temperature at the outer circumference 1c or near the outer circumference 1b of the wafer 1 and the temperature of the tube wall of the heating source 2 are approximately 500W.
The outer periphery IC or the outer periphery 0 part 1b of the wafer 1 is additionally heated so that the temperature is almost the same within the temperature range of .degree. C. or higher.

According to the above embodiment, main heating is performed by irradiating both sides of the wafer 1 with light from the surface light source from above and below. 1c or the area near the outer periphery 1b is heated supplementarily, and as a result, the temperature difference between the central area 1a and the outer periphery 1 or the area 1b near the outer periphery becomes extremely small, and the wafer 1
This makes it possible to equalize the overall temperature of the process, thereby preventing the occurrence of large U-shaped cracks that may cause problems in later processing steps, as well as preventing the occurrence of "slip lines." . Since the holder 3 is provided to be separable from the heating source 2, it is easy to remove only the holder 3 and clean it. It is also possible to prevent the light irradiation atmosphere from being contaminated, and as a result, the wafer 1 can be heated satisfactorily. And only the heating source 2 or the holder 3
It is also possible to replace only one part independently, which is economical since the cost required for replacement is lower than when both parts are integrally fixed inseparably.

When the heating source 2 is provided with the moving arm 24 as in the above embodiment, the heater assembly of the present invention can be easily attached to an automatic moving mechanism that moves the heater assembly of the present invention forward and backward within the light irradiation furnace. . That is, the light irradiation atmosphere is normally required to be clean, and it is necessary to prevent the components of the automatic movement mechanism from entering the light irradiation furnace for reasons such as preventing light shielding. Since only the heater assembly can be placed in the light irradiation furnace, there is no need to use a special structure as an automatic movement mechanism, and a simple structure can be used. As in the above embodiment, it is preferable that the wafer 1 is held in a small area located one inch or more in the center from the outer peripheral IC of the wafer 1. In this case, the protrusion of the holder 3 of the wafer 1 is At the contact part with the part 34, the holder 3 is removed from the contact part.
Even if there is heat loss due to heat conduction, the temperature drop due to this is small and does not cause "warpage" or "slip lines".

In the above, it is preferable that the height L of the heater assembly is as small as possible. In this case, the area of the entrance and exit of the light irradiation furnace can be reduced, and stable heating can be achieved without disturbing the atmospheric condition inside the light irradiation furnace. can be processed.

The wafer 1 is held by the holder 3 with at least 2 minute areas, so that the wafer 1 can be held stably.
It is sufficient if there are at least two locations, but it is practically preferable that the area of each of the minute area portions of the wafer 1 is within 0.5tIr1B2. Further, the shape of the projection 34 of the holder 3 can be changed in various ways, and the entire shape may be bent along an arc, or the tip may be rounded or pointed. good. The heating source 2 is not limited to self-heating material as in the above embodiment, but may be made of a high-melting point metal whose temperature increases upon exposure to light, for example.

Further, as shown in FIG. 3, in the holder 3, the protruding part 34 is not provided, but the hooking part 32 is formed so that its tip is inclined downward.
c may be held. The structure of the holder 3 is as shown in FIG. As shown in the figure, the hook part 32 is not brought into direct contact with the annular part 23 of the heat source 2, and only the ring part 31 is brought into contact with the diagonally upper part of the annular part 23, so that the ring part 31 is supported in the vertical and horizontal directions. It may also be a configuration.

Although one embodiment of the present invention has been described above, the present invention is not limited thereto, and includes, for example, processes that require heating in semiconductor manufacturing, such as an impurity diffusion process, a chemical vapor deposition process, and an ion implantation layer. The present invention can be widely applied to a process for recovering crystal defects, a heat treatment process for electrical activation, and a heat treatment process for oxidizing the surface layer of a silicon wafer.

As described above, according to the present invention, it is possible to obtain a sufficient auxiliary heating effect, and the object to be heated can be held with a simple structure, and the holder for holding the object to be heated can be easily attached. It is possible to provide a convenient heater assembly that can be separated individually.

[Brief explanation of the drawing]

1 and 2 are an explanatory plan view and an explanatory longitudinal front view showing one embodiment of the present invention, respectively, and FIGS. 3 to 5 are an explanatory longitudinal front view showing main parts of other embodiments, respectively. It is a diagram. 1... Semiconductor wafer la... Central portion 1b... Near outer periphery IC...
··The outer periphery

Claims (1)

[Scope of Claims] 1) A holder for holding a flat object to be heated by gravity in contact therewith, and a holder provided in separable combination with this holder, mainly the outer periphery or outer periphery of the object to be heated. 1. A heater assembly comprising: a heating source that heats the vicinity; 2) the holder is integrally formed of quartz glass;
A ring portion extending along an arc, a plurality of hook portions fixed to the ring portion that are hooked to the heating source, and each of these hook portions contacts the object to be heated and holds it under the influence of gravity. 2. The heater assembly according to claim 1, further comprising a protrusion for holding the heater. 3) The first aspect of the present invention is characterized in that the heat source has a long moving arm extending in one direction from a part thereof.
The heater assembly according to item 1 or 2.