WO2009082119A2

WO2009082119A2 - Apparatus and method for controlling heating lamp

Info

Publication number: WO2009082119A2
Application number: PCT/KR2008/007468
Authority: WO
Inventors: Sang Hyun Ji; Ki Nam Kim; Dae Yong Lee
Original assignee: Kornic Systems Corp.
Priority date: 2007-12-26
Filing date: 2008-12-17
Publication date: 2009-07-02
Also published as: KR20090069907A; WO2009082119A3

Abstract

Disclosed is an apparatus for controlling heating lamps, which can detect rapid deterioration or burnout of specific heating lamp(s) used in rapid thermal processing equipment. The apparatus includes a heating lamp group(30) divided into a plurality of sub-groups each including a plurality of individual heating lamps bundled in parallel, a power controller(51) to apply power to each sub-group, and a current meter(41) to measure current applied to the sub-group. Upon initial use of the lamps, an initial input current value is measured by the current meter and is fed back to the power controller. Then, during implementation of a thermal process, an in-process input current value is measured by the current meter and is fed back to the power controller. The power controller outputs an alarm signal if a difference between the initial input current value and the in-process input current value exceeds a predetermined criterion value range.

Description

APPARATUS AND METHOD FOR CONTROLLING HEATING

LAMP

Technical Field

[1] The present invention relates to an apparatus for controlling heating lamps and a method for controlling heating lamps, and more particularly, to an apparatus and method for controlling heating lamps, wherein deterioration or burnout of any specific one of a great number of heating lamps used in, for example, rapid thermal processing equipment can be rapidly detected, assuring uniformity in heat supply. Background Art

[2] Rapid thermal processing equipment, used in fabrication of semiconductor devices or

LCD devices, is designed to heat a substrate using heating lamps. Conventionally, a variety of installation structures have been proposed, wherein a plurality of heating lamps is installed to achieve uniform heating throughout a substrate. However desirable an installation structure is, there is a problem in uniformly heating a substrate because individual heating lamps emit different amounts of heat after extended use due to a difference in lifespan or deterioration rate thereof.

[3] FIG. 1 is a view illustrating conventional rapid thermal processing equipment. As shown in FIG. 1, a heating lamp group 30 consists of a plurality of individual heating lamps 31 to 36. The heating lamp group 30 is provided to heat an object to be heated, i.e. a target object 10. A temperature meter 20 is provided to measure a temperature of the target object 10 and in turn, the temperature measured by the temperature meter 20 is fed back to a power controller 50. The power controller 50 controls electric power applied to the heating lamp group 30 upon receiving a feedback signal of the temperature meter 20, to allow the target object 10 to reach a desired user input temperature.

[4] When the heating lamp group 30 is used for an extended time, a specific one of the individual heating lamps 31 to 36 may deteriorate or burn out prior to the others. For this reason, a lamp performance monitor 40 is provided to monitor deterioration or burnout of the individual heating lamps 31 to 36.

[5] FIG. 2 is a view illustrating a method for monitoring the performance of a heating lamp. As shown in FIG. 2, a Current Transformer (CT) 41 is used as the lamp performance monitor 40. Also, a Silicon Controlled Rectifier (SCR) 52, advantageous to control rapid heating, is used as a main component of the power controller 50.

[6] When the individual heating lamps 31 and 32 are initially mounted, current applied to the individual heating lamps 31 and 32 is measured in real time via the current transformer 41. FIG. 3 is a graph illustrating an initial input current value. Here, the initial input current value represents a value measured upon initial use of each heating lamp 31 or 32, i.e. before deterioration of the heating lamp 31 or 32. The initial input current value is stored in a power control board 51. The current applied to the heating lamp 31 or 32 is measured in real time via the current transformer 41 even during implementation of a thermal process. An input current value acquired during implementation of the thermal process (hereinafter, it is referred to as an in-process input current value) is fed back to the power control board 51.

[7] Repetitive implementation of the thermal process causes deterioration in the individual heating lamps 31 and 32, resulting in a difference between the initial input current value and the in-process input current value. If the difference between the initial input current value and the in-process input current value gradually increases and exceeds a predetermined criterion value, the power control board 51 sends an alarm signal to a main controller 60.

[8] As described above, in the prior art, the current transformer 41 is installed to correspond to each of the individual heating lamps 31 and 32. This arrangement is advantageous to indicate which one of the individual heating lamps 31 and 32 is damaged. However, due to the fact that degradation of temperature uniformity occurs even if any specific one of the several individual heating lamps is damaged, it is more important to know whether or not damage to the lamps occurs, rather than to know which lamp is damaged. This is because damage to the lamps can be easily confirmed through visual inspection in most cases and also, can be confirmed via a simple method, for example, by turning on the lamps using low power.

[9] In the above-described prior art, the lamps correspond to the power control boards in a one-to-one ratio in such a manner that malfunction of equipment must be unconditionally determined without reference to any criterion value if no current flows through the equipment, and therefore, the current transformer 11 must be installed on a per individual lamp basis, causing complex overall configuration and high maintenance costs.

Disclosure of Invention Technical Problem

[10] Therefore, the present invention has been made in view of the above problems, and it is an object of the present invention to provide an apparatus and method for controlling heating lamps, wherein the presence of damaged lamp(s) can be immediately detected, as in the prior art, even with a reduced number of current transformers and also, which lamp is damaged can be determined relatively quickly. Technical Solution [11] In accordance with an aspect of the present invention, the above and other objects can be accomplished by the provision of a heating lamp control apparatus comprising: a heating lamp group divided into a plurality of sub-groups each including a plurality of individual heating lamps bundled in parallel; a power controller to apply power to each sub-group; and a current meter provided between each sub-group and the power controller, to measure current applied to the sub-group, wherein an initial input current value, which is measured by the current meter upon initial use of the lamps, is fed back to and stored in the power controller and then, an in-process input current value, which is measured by the current meter during implementation of a thermal process, is fed back to and stored in the power controller, whereby the power controller outputs an alarm signal if a difference between the initial input current value and the in-process input current value exceeds a predetermined criterion value range.

[12] The power controller may include a Silicon Controlled Rectifier (SCR), and te current meter may take the form of a current transformer.

[13] In accordance with another aspect of the present invention, there is provided a heating lamp control method comprising: bundling a plurality of individual lamps into a plurality of sub-groups, each of which contains some of the plurality of individual lamps bundled in parallel to receive power together; applying power to each subgroup, to acquire an initial input current value on a per sub-group basis; measuring current applied to each sub-group during implementation of a thermal process, to acquire an in-process input current value; and comparing the initial input current value with the in-process input current value and outputting an alarm signal if a difference between the initial input current value and the in-process input current value exceeds a predetermined criterion value range.

Advantageous Effects

[14] According to the various aspects of the present invention as described above, it is unnecessary to provide each lamp with a current transformer that is used to monitor deterioration of the lamp. This can simplify the overall configuration of equipment and also, assures convenience in maintenance thereof. Further, the deteriorated lamp can be conveniently detected by inspecting a specific group of lamps, rather than inspecting all lamps of the specific group one by one. Such a convenient detection of deterioration and damage of the lamp(s) can assure uniform and stable implementation of a thermal process. Brief Description of the Drawings

[15] The above and other objects, features and other advantages of the present invention will be more clearly understood from the following detailed description taken in conjunction with the accompanying drawings, in which: [16] FIG. 1 is a view illustrating conventional rapid thermal processing equipment;

[17] FIG. 2 is a view illustrating a method for monitoring the performance of a lamp;

[18] FIG. 3 is a graph illustrating initial input current values of lamps;

[19] FIG. 4 is a view illustrating an apparatus for controlling heating lamps in accordance with the present invention;

[20] FIG. 5 is a graph illustrating initial input current values of lamps in FIG. 4;

[21] FIG. 6 is a graph illustrating in-process input current values of lamps in FIG. 4; and

[22] FIG. 7 is a flow chart illustrating a method for controlling heating lamps in accordance with the present invention. Best Mode for Carrying Out the Invention

[23] Now, a preferred embodiment of the present invention will be described in detail with reference to the accompanying drawings. In the drawings, only characteristic components of the present invention are illustrated, in order to prevent repeated description of the prior art. The following embodiment has been described only for a better understanding of the present invention, and those skilled in the art will appreciated that various modifications to the embodiment are possible, without departing from the scope and spirit of the invention as disclosed in the accompanying claims.

[24] FIG. 4 is a view illustrating an apparatus for controlling heating lamps in accordance with the present invention, and FIG. 7 is a flow chart illustrating a method for controlling heating lamps in accordance with the present invention. Referring to FIGS. 4 and 7, first, the heating lamp group 30 is divided into a plurality of sub-groups 30a and 30b (Sl). In this case, each of the sub-groups 30a and 30b includes a plurality of individual heating lamps 31, 32 and 33; 34, 35 and 36, the individual heating lamps of each sub-group being bundled in parallel and adapted to receive power from the SCR 52 associated therewith. Each sub-group 30a or 30b is provided with the current transformer 41, which is used to measure current applied to the associated sub-group.

[25] Under the assumption that all the individual heating lamps 31, 32 and 33 of the subgroup 30a are initially normal, initial input current values as shown in the graph of FIG. 5 are acquired on a per sub-group basis, more particularly, with respect to the sub-group 30a, via the current transformer 41 (S2). The initial input current values are stored in the power control board 51 associated with the sub-group 30a.

[26] Then, the current transformer 41 measures values of in-process input current applied to each sub-group 30a or 30b even during implementation of a thermal process, and feeds back the in-process input current values to the power control board 51 (S3). In FIG. 6, a graph curve a is caused when all three lamps of the sub-group are normal, a graph curve b is caused when one lamp is damaged, and a graph curve c is caused when two lamps are damaged. Accordingly, as will be appreciated with reference to FIG. 6, the greater the number of damaged lamp, the smaller the flow of current. If any one lamp is not completely damaged, but is slightly deteriorated, it is expected that the resulting in-process input current value is located between the graph curve "a" and the graph curve "b".

[27] The power control board 51 compares the in-process input current value with the initial input current value (S4). If a difference between the in-process input current value and the initial input current value exceeds predetermined criterion value ranges (as designated by reference letters a , b and c in FIG. 6), the power control board 51 sends an alarm signal to the main controller 60, so as to inform damage to the lamp(s) (S5). If the difference is within the predetermined criterion value ranges, the power control board 51 allows the thermal process to be continuously implemented (S6). Here, the criterion value ranges, designated by reference letters a , b and c , may be determined by an inspector.

[28] Note that the present invention provides no function to directly detect which lamp is damaged. However, bundling the lamps into the sub-groups has the effect of allowing the inspector to concentrate detection of abnormal lamp(s) on a specific suspect subgroup, enabling convenient and rapid detection of the presence of damaged lamp(s). Furthermore, concentrating the inspector s attention on the suspect sub-group allows the inspector to easily detect the abnormal lamp(s) even with the naked eye.

[29] Also, note that it is not always desirable to control the supply of power on a per lamp basis because this limits power control to an excessively localized region, resulting in inter-region temperature differences. Accordingly, as occasion demands, it may be desirable to control power on a per group basis. This power control is further desirable, in particular, to detect deterioration of lamps on a per group basis as described in the present invention.

[30] Although the preferred embodiment of the present invention has been disclosed for illustrative purposes, those skilled in the art will appreciate that various modifications, additions and substitutions are possible, without departing from the scope and spirit of the invention as disclosed in the accompanying claims.

Claims

[1] A heating lamp control apparatus comprising: a heating lamp group divided into a plurality of sub-groups each including a plurality of individual heating lamps bundled in parallel; a power controller to apply power to each sub-group; and a current meter provided between each sub-group and the power controller, to measure current applied to the sub-group, wherein an initial input current value, which is measured by the current meter upon initial use of the lamps, is fed back to and stored in the power controller and then, an in-process input current value, which is measured by the current meter during implementation of a thermal process, is fed back to and stored in the power controller, whereby the power controller outputs an alarm signal if a difference between the initial input current value and the in-process input current value exceeds a predetermined criterion value range.

[2] The heating lamp control apparatus according to claim 1, wherein the power controller includes a Silicon Controlled Rectifier (SCR), to apply power to each sub-group via the SCR.

[3] The heating lamp control apparatus according to claim 1, wherein the current meter takes the form of a current transformer.

[4] A heating lamp control method comprising: bundling a plurality of individual lamps into a plurality of sub-groups, each of which contains some of the plurality of individual lamps bundled in parallel to receive power together; applying power to each sub-group, to acquire an initial input current value on a per sub-group basis; measuring current applied to each sub-group during implementation of a thermal process, to acquire an in-process input current value; and comparing the initial input current value with the in-process input current value and outputting an alarm signal if a difference between the initial input current value and the in-process input current value exceeds a predetermined criterion value range.