Diffusion furnace capable of improving temperature precision

Abstract

The utility model discloses a diffusion furnace capable of improving temperature precision, which comprises a fixed shell, a heating device, a binding post and a temperature measuring device, and is characterized in that the heating device sequentially comprises a reflecting plate layer with a circular cross section, an armored heating wire layer arranged around the reflecting plate layer and a uniform heat plate layer from outside to inside; the reflecting plate layer reflects heat of the armored heating wire layer to the heat uniformizing plate layer, and the heat uniformizing plate layer radiates heat of the armored heating wire layer and the reflecting plate layer to the center of the diffusion furnace. The armored heating wire layer emits energy of far infrared rays to the periphery, one part of the energy is directly emitted to the heat uniformizing plate layer, the other part of the energy of the far infrared rays is reflected and gathered to the heat uniformizing plate layer through the reflecting plate layer, and then the heat uniformizing plate layer radiates uniform far infrared ray energy to the center of the diffusion furnace. The temperature difference in the diffusion furnace can reach + / -0.5 DEG C, the temperature precision in the diffusion furnace is improved, most of energy generated by the armored heating wire layer towards the periphery can be gathered on the heat uniformizing plate layer, and heat energy loss is reduced.

Description

Technical Field

[0001] The utility model relates to the technical field of photovoltaic semiconductor manufacturing equipment, and can be applied to semiconductor and photovoltaic diffusion furnaces or various heating devices and diffusion furnaces, in particular to a diffusion furnace capable of improving temperature accuracy. Background Art

[0002] Diffusion furnaces are used for diffusion, oxidation, annealing, alloying and sintering processes in industries such as large-scale integrated circuits, discrete devices, power electronics, optoelectronic devices and optical fibers. The main purpose of the diffusion process is to dope semiconductor wafers under high temperature conditions, that is, to diffuse elements such as phosphorus and boron into silicon wafers, thereby changing and controlling the type, concentration and distribution of impurities in the semiconductor in order to establish different electrical characteristic areas.

[0003] The heating device in the existing diffusion furnace generates heat by energizing the heating wire to process and sinter the components in the diffusion furnace; the heat generated by the heating wire is diffused in all directions, and the heat received in the diffusion furnace will cause heat loss and form temperature errors in the diffusion furnace. Although the existing technology can reduce the temperature error by setting independent temperature control zones, it still cannot further solve the problem of heat loss and improve temperature accuracy. Summary of the invention

[0004] In view of this, an object of the present invention is to provide a diffusion furnace capable of improving temperature accuracy.

[0005] In order to solve the above technical problems, the technical solution of the utility model is: a diffusion furnace capable of improving temperature accuracy, comprising a fixed outer shell, a heating device installed in the fixed outer shell, a terminal arranged outside the fixed outer shell and electrically connected to the heating device, and a temperature measuring device for detecting the temperature in the diffusion furnace, wherein the heating device comprises, from the outside to the inside, a reflecting plate layer with a circular cross-section, an armored heating wire layer and a uniform heat plate layer arranged around the reflecting plate layer, the reflecting plate layer reflects the heat of the far-infrared rays of the armored heating wire layer to the uniform heat plate layer, and the uniform heat plate layer gathers the heat of the far-infrared rays of the armored heating wire layer and the reflecting plate layer and radiates it evenly toward the center of the diffusion furnace.

[0006] Preferably, a heat-insulating layer is further provided between the fixed shell and the heating device, and the heat-insulating layer is clamped between the reflective plate layer and the fixed shell.

[0007] Furthermore, a mounting bottom plate layer is provided between the thermal insulation layer and the reflective plate layer, the outer surface of the mounting bottom plate layer fixes the thermal insulation layer and the fixed outer shell, and the inner surface of the mounting bottom plate layer fixes the heating device.

[0008] Preferably, a vacuum cavity is formed between the reflective plate layer and the heat uniforming plate layer of the heating device, and the armored heating wire layer is arranged in the vacuum cavity.

[0009] Preferably, the armored heating wire layer includes heating wire groups stacked up and down and arranged in a staggered manner.

[0010] Preferably, the temperature measuring device is a thermocouple arranged in the diffusion furnace.

[0011] The technical effects of the utility model are mainly reflected in the following aspects: the armored heating wire layer emits far-infrared energy in all directions, a part of which is directly emitted to the uniform heating plate layer, and the other part is reflected by the reflection plate layer and concentrated on the uniform heating plate layer. The uniform heating plate layer then radiates uniform far-infrared energy to the center of the diffusion furnace, so that the temperature difference in the diffusion furnace can reach ±0.5°C, which improves the temperature accuracy in the diffusion furnace, and most of the energy generated by the armored heating wire layer in all directions can be concentrated on the uniform heating plate layer, reducing the loss of heat energy. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 It is a structural schematic diagram of the utility model;

[0013] Figure 2 It is a schematic diagram of the cross-sectional structure of the utility model;

[0014] Figure 3 For this utility model Figure 2 A magnified schematic diagram of part A.

[0015] 1-fixed shell; 2-heating device; 21-reflecting plate layer; 22-armored heating wire layer; 23-heat uniform plate layer; 24-vacuum cavity; 3-temperature measuring device; 4-insulation layer; 5-installation bottom plate layer. Implementation

[0016] The specific implementation modes of the present invention are further described below in conjunction with the accompanying drawings to make the technical solutions of the present invention easier to understand and grasp. Example

[0017] according to Figure 1-3As shown, a diffusion furnace capable of improving temperature accuracy comprises a fixed outer shell 1, a heating device 2 installed in the fixed outer shell 1, a terminal arranged outside the fixed outer shell 1 and electrically connected to the heating device 2, and a temperature measuring device 3 for detecting the temperature in the diffusion furnace. The heating device 2 of the existing diffusion furnace generates heat by energizing the heating wire and transfers heat to its surroundings. During this process, part of the heat of the heating wire can be transferred to the center of the diffusion furnace, and the other part of the heat will be absorbed and consumed by the outer wall of the diffusion furnace such as the insulation layer 4 and the fixed outer shell 1. This part of the consumed heat will cause a large error in the working temperature of the diffusion furnace, and the energy loss will also be greatly increased.

[0018] Therefore, in the present application, the heating device 2 includes, from the outside to the inside, a reflective plate layer 21 with a circular cross-section, an armored heating wire layer 22 arranged around the reflective plate layer 21, and a uniform heat plate layer 23. The armored heating wire layer 22 can be powered on to generate heat and radiate far-infrared heat to the surrounding areas. Part of the far-infrared heat is directly radiated to the uniform heat plate layer 23, and the other part is reflected from the reflective plate layer 21 by the concave mirror focusing principle to concentrate the far-infrared rays emitted by the armored heating wire layer 22 to the reflective plate layer 21 onto the uniform heat plate layer 23. The uniform heat plate layer 23 concentrates the two parts of heat from the armored heating wire layer 22 and the far-infrared heat from the reflective plate layer 21 and radiates them evenly toward the center of the diffusion furnace, so that the temperature difference in the diffusion furnace can reach ±0.5°C, and the loss of heat energy can be reduced.

[0019] In order to further improve the thermal efficiency, an insulation layer 4 is further provided between the fixed shell 1 and the heating device 2. The insulation layer 4 is clamped between the reflective plate layer 21 and the fixed shell 1. The heat lost on the reflective plate layer 21 of the heating device 2 is reduced, and the overall temperature of the heating device 2 can be kept constant.

[0020] The reflective plate layer 1 of the heating device 2 needs to remain circular to ensure that the principle of concave mirror focusing can be achieved. An installation base layer 5 is also arranged between the thermal insulation layer 4 and the reflective plate layer 21. The outer surface of the installation base layer 5 fixes the thermal insulation layer 4 and the fixed outer shell 1, and the inner surface of the installation base layer 5 fixes the heating device 2. The installation base layer 5 can fix the shape of the reflective plate layer 21.

[0021] The armored heating wire layer 22 emits far-infrared rays after being energized. The far-infrared rays transfer energy by thermal radiation in a vacuum environment without the participation of an intermediate medium, which can also improve the efficiency of energy transfer. Therefore, a vacuum cavity 24 is formed between the reflective plate layer 21 and the uniform heat plate layer 23 of the heating device 2, and the armored heating wire layer 22 is arranged in the vacuum cavity 24.

[0022] The armored heating wire layer 22 includes heating wire groups stacked up and down and arranged staggered, which can fill the gaps between the respective heating coils to provide stable far-infrared energy.

[0023] The temperature measuring device 3 is a thermocouple arranged in the diffusion furnace. Each group of the thermocouples can be arranged as two K-type armored thermocouples, and the temperature measuring area thereof is located in the center.

[0024] Working principle:

[0025] A portion of the energy generated by the far-infrared rays emitted by the armored heating wire layer 22 when it is powered on is directly radiated to the heat-distributing plate layer 23, and the other portion is concentrated and reflected to the heat-distributing plate layer 23 through the reflective plate layer 21. The heat-distributing plate layer 23 radiates the concentrated heat evenly toward the center of the diffusion furnace, which can not only improve the temperature accuracy of the diffusion furnace, but also reduce heat loss.

Claims

1. A diffusion furnace capable of improving temperature accuracy, comprising a fixed housing, a heating device installed in the fixed housing, a terminal arranged outside the fixed housing and electrically connected to the heating device, and a temperature measuring device for detecting the temperature in the diffusion furnace, characterized in that: The heating device includes, from the outside to the inside, a reflective plate layer with a circular cross-section, an armored heating wire layer arranged around the reflective plate layer, and a uniform heat plate layer. The reflective plate layer reflects the heat of the far-infrared rays of the armored heating wire layer to the uniform heat plate layer, and the uniform heat plate layer gathers the heat of the far-infrared rays of the armored heating wire layer and the reflective plate layer and radiates it evenly toward the center of the diffusion furnace.

2. A diffusion furnace capable of improving temperature accuracy according to claim 1, characterized in that: A heat-insulating layer is also provided between the fixed shell and the heating device, and the heat-insulating layer is clamped between the reflecting plate layer and the fixed shell.

3. A diffusion furnace capable of improving temperature accuracy according to claim 2, characterized in that: A mounting bottom plate layer is also arranged between the heat-insulating layer and the reflective plate layer. The outer surface of the mounting bottom plate layer fixes the heat-insulating layer and the fixed outer shell, and the inner surface of the mounting bottom plate layer fixes the heating device.

4. A diffusion furnace capable of improving temperature accuracy according to claim 1, characterized in that: A vacuum cavity is formed between the reflective plate layer and the heat-distributing plate layer of the heating device, and the armored heating wire layer is arranged in the vacuum cavity.

5. A diffusion furnace capable of improving temperature accuracy according to claim 1, characterized in that: The armored heating wire layer includes heating wire groups which are stacked up and down and arranged in a staggered manner.

6. A diffusion furnace capable of improving temperature accuracy according to claim 1, characterized in that: The temperature measuring device is a thermocouple arranged in the diffusion furnace.

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