JPH0425729A - Temperature measuring instrument - Google Patents
Temperature measuring instrumentInfo
- Publication number
- JPH0425729A JPH0425729A JP2132193A JP13219390A JPH0425729A JP H0425729 A JPH0425729 A JP H0425729A JP 2132193 A JP2132193 A JP 2132193A JP 13219390 A JP13219390 A JP 13219390A JP H0425729 A JPH0425729 A JP H0425729A
- Authority
- JP
- Japan
- Prior art keywords
- temperature
- opening
- measured
- infrared rays
- closing
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
- 230000005855 radiation Effects 0.000 claims abstract description 29
- 238000010521 absorption reaction Methods 0.000 claims abstract description 28
- 230000007246 mechanism Effects 0.000 abstract description 25
- 229920002120 photoresistant polymer Polymers 0.000 abstract description 25
- 239000004065 semiconductor Substances 0.000 abstract description 24
- 230000003287 optical effect Effects 0.000 abstract description 20
- 238000005259 measurement Methods 0.000 abstract description 11
- 235000012431 wafers Nutrition 0.000 description 31
- 238000010438 heat treatment Methods 0.000 description 12
- 238000009529 body temperature measurement Methods 0.000 description 11
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 description 8
- 229910052710 silicon Inorganic materials 0.000 description 8
- 239000010703 silicon Substances 0.000 description 8
- 238000000034 method Methods 0.000 description 6
- 239000010408 film Substances 0.000 description 5
- 239000000463 material Substances 0.000 description 4
- 238000002834 transmittance Methods 0.000 description 4
- 230000008569 process Effects 0.000 description 3
- PCHJSUWPFVWCPO-UHFFFAOYSA-N gold Chemical compound [Au] PCHJSUWPFVWCPO-UHFFFAOYSA-N 0.000 description 2
- 239000010931 gold Substances 0.000 description 2
- 229910052737 gold Inorganic materials 0.000 description 2
- 239000011810 insulating material Substances 0.000 description 2
- 238000009413 insulation Methods 0.000 description 2
- 238000007747 plating Methods 0.000 description 2
- 229920000178 Acrylic resin Polymers 0.000 description 1
- 239000004593 Epoxy Substances 0.000 description 1
- 239000004642 Polyimide Substances 0.000 description 1
- 238000000862 absorption spectrum Methods 0.000 description 1
- NIXOWILDQLNWCW-UHFFFAOYSA-N acrylic acid group Chemical group C(C=C)(=O)O NIXOWILDQLNWCW-UHFFFAOYSA-N 0.000 description 1
- 229910052782 aluminium Inorganic materials 0.000 description 1
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 1
- 230000008901 benefit Effects 0.000 description 1
- 230000008859 change Effects 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 239000000428 dust Substances 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 229910052751 metal Inorganic materials 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- 229920000647 polyepoxide Polymers 0.000 description 1
- 229920001721 polyimide Polymers 0.000 description 1
- 229920001296 polysiloxane Polymers 0.000 description 1
- 229920005749 polyurethane resin Polymers 0.000 description 1
- 229920000915 polyvinyl chloride Polymers 0.000 description 1
- 239000004800 polyvinyl chloride Substances 0.000 description 1
- 230000009467 reduction Effects 0.000 description 1
- 230000004044 response Effects 0.000 description 1
- 238000004544 sputter deposition Methods 0.000 description 1
- 239000010409 thin film Substances 0.000 description 1
Landscapes
- Radiation Pyrometers (AREA)
- Exposure Of Semiconductors, Excluding Electron Or Ion Beam Exposure (AREA)
Abstract
Description
【発明の詳細な説明】 [発明の目的] (産業上の利用分野) 本発明は、温度測定装置に関する。[Detailed description of the invention] [Purpose of the invention] (Industrial application field) The present invention relates to a temperature measuring device.
(従来の技術)
一般に、被測定体の温度を測定する温度測定装置として
は、従来から熱電対等の温度センサーを被測定体に接触
さ″せて測定する温度測定装置と、例えば被測定体から
放射される赤外線等を測定してその放射量から被測定体
の温度を算出する温度測定装置とがある。(Prior Art) In general, temperature measuring devices that measure the temperature of a measured object have conventionally been divided into temperature measuring devices that measure the temperature of a measured object by bringing a temperature sensor such as a thermocouple into contact with the measured object, and There is a temperature measurement device that measures emitted infrared rays and calculates the temperature of a measured object from the amount of radiation.
これらの装置のうち、後者の装置は、ステファン・ボル
ツマンの法則を利用したもので、温度Tと射出能Eおよ
び放射率εとの関係を表わす次式、T−(E/(70ε
)”
を用いて被測定体の温度を算出するものであるが、実際
の測定においては、射出能Eおよび放射、率εを正確に
知る手段がないためこれらの推定値E′ε′を用いて、
次式によって温度T−を推定する。Of these devices, the latter device utilizes the Stefan-Boltzmann law, and is expressed by the following equation, T-(E/(70ε
)” is used to calculate the temperature of the object to be measured, but in actual measurements, these estimated values E′ε′ are used because there is no way to accurately know the emissivity E and the radiation rate ε. hand,
The temperature T- is estimated by the following equation.
T=−(E−/σ0ε−、l/4
なお、これらの式において、σ0はステファンボルツマ
ン定数[4,88X10−’ (Kcal/ 12hK
’ )]を示している。T=-(E-/σ0ε-, l/4 In these equations, σ0 is the Stefan Boltzmann constant [4,88X10-' (Kcal/ 12hK
')] is shown.
この温度測定装置によれば、被測定体に非接触で温度を
測定することができる。According to this temperature measuring device, the temperature can be measured without contacting the object to be measured.
(発明が解決しようとする課題)
しかしながら、上記説明の従来の温度測定装置のうち、
熱電対等の温度センサーを被測定体に接触させて測定す
る温度測定装置では、温度センサーを接触させることが
できない部位の温度を測定することができないという問
題がある。(Problem to be Solved by the Invention) However, among the conventional temperature measuring devices described above,
Temperature measuring devices that measure temperature by bringing a temperature sensor such as a thermocouple into contact with a measured object have a problem in that it is not possible to measure the temperature of a portion that cannot be brought into contact with the temperature sensor.
例えば加熱板上に半導体ウェハを載置して、この半導体
ウェハ表面に塗布されたフォトレジストのベーキングを
行うベーキング装置では、フォトレジストの温度を検出
して加熱温度を制御することが好ましい。For example, in a baking device that places a semiconductor wafer on a heating plate and bakes a photoresist coated on the surface of the semiconductor wafer, it is preferable to control the heating temperature by detecting the temperature of the photoresist.
しかしながら、半導体ウェハ表面に塗布されたフォトレ
ジストに温度センサーを接触させることができない(フ
ォトレジスト膜を破損させてしまう)ため、例えば加熱
板内に熱電対等の温度センサーを埋設しておき加熱板の
温度からフォトレジストの温度を推定している。ところ
が、このような方法では正確なフォトレジストの温度を
検知することができないという問題がある。However, since it is not possible to bring a temperature sensor into contact with the photoresist coated on the surface of a semiconductor wafer (this would damage the photoresist film), for example, a temperature sensor such as a thermocouple is buried inside the heating plate. The temperature of the photoresist is estimated from the temperature. However, this method has a problem in that it is not possible to accurately detect the temperature of the photoresist.
また、被測定体から放射される赤外線等を測定し、その
放射量からステファン・ボルツマンの法則を利用して被
測定体の温度を算出する従来の温度測定装置では、被測
定体に非接触で温度を測定することができるので、上述
したベーキング装置の場合でも直接フォトレジストの温
度を測定することができる。In addition, conventional temperature measurement devices that measure infrared rays etc. emitted from a measured object and calculate the temperature of the measured object using the Stefan-Boltzmann law from the amount of radiation do not make contact with the measured object. Since the temperature can be measured, the temperature of the photoresist can be directly measured even in the case of the above-mentioned baking device.
しかしながら、この場合例えばシリコンウェハおよびフ
ォトレジストは、赤外線に対する透過率が高いので、加
熱板からの赤外線を主として測定し、この加熱板の温度
を測定することになり、正確なシリコンウェハおよびフ
ォトレジストの温度は測定することができないという問
題かある。また、この装置では正確に知ることのできな
い放射率の設定を行う必要が有るという問題もある。However, in this case, for example, silicon wafers and photoresists have high transmittance to infrared rays, so the infrared rays from the heating plate are mainly measured and the temperature of this heating plate is measured. The problem is that temperature cannot be measured. Another problem with this device is that it is necessary to set the emissivity, which cannot be accurately known.
本発明は、かかる従来の事情に対処してなされたもので
、放射率の設定が不要で、かつ、非接触でより正確に被
測定体の温度を測定することのできる温度測定装置を提
供しようとするものである。The present invention has been made in response to such conventional circumstances, and aims to provide a temperature measuring device that does not require emissivity settings and can more accurately measure the temperature of a measured object without contact. That is.
[発明の構成]
(課題を解決するための手段)
すなわち本発明は、被測定体の吸収特性から求めた複数
の吸収ピーク波長における放射量を測定する手段と、こ
の手段に入射する放射を、前記被測定体からの放射と、
放射率既知のリファレンスからの放射とに切替る手段と
、前記複数の吸収ピーク波長における前記被測定体から
の放射量と前記リファレンスからの放射量との差から前
記被測定体の温度を算出する手段とを具備したことを特
徴とする。[Structure of the Invention] (Means for Solving the Problems) That is, the present invention provides a means for measuring the amount of radiation at a plurality of absorption peak wavelengths determined from the absorption characteristics of an object to be measured, and a method for measuring radiation incident on the means. radiation from the object to be measured;
means for switching to radiation from a reference whose emissivity is known; and calculating the temperature of the object to be measured from the difference between the amount of radiation from the object to be measured and the amount of radiation from the reference at the plurality of absorption peak wavelengths. It is characterized by comprising means.
(作 用)
上記構成の本発明の温度測定装置では、被測定体の吸収
特性から求めた複数の吸収ピーク波長において放射量の
測定を行う。すなわち、被測定体の放射率と吸収率は等
しいので、吸収率の高い波長(吸収ピーク波長)、すな
わち放射率の高い波長において放射量を測定する。(Function) In the temperature measuring device of the present invention having the above configuration, the amount of radiation is measured at a plurality of absorption peak wavelengths determined from the absorption characteristics of the object to be measured. That is, since the emissivity and absorption rate of the object to be measured are equal, the amount of radiation is measured at a wavelength with high absorption rate (absorption peak wavelength), that is, a wavelength with high emissivity.
また、被測定体からの放射量と放射率既知のリファレン
スからの放射量とを切替えて測定し、これらの放射量の
差から被測定体の温度を算出する。Further, the radiation amount from the object to be measured and the amount of radiation from a reference whose emissivity is known are switched and measured, and the temperature of the object to be measured is calculated from the difference between these amounts of radiation.
したがって、非接触で正確に被測定体の温度を測定する
ことができ、かつ、放射率の設定も不要とすることがで
きる。Therefore, the temperature of the object to be measured can be accurately measured without contact, and there is no need to set the emissivity.
(実施例)
以下、本発明の温度測定装置を半導体ウェハの表面にレ
ジスト液塗布後のベーキング工程における温度測定に適
用した実施例を図面を参照して説明する。(Example) Hereinafter, an example in which the temperature measuring device of the present invention is applied to temperature measurement in a baking process after applying a resist solution to the surface of a semiconductor wafer will be described with reference to the drawings.
ベーキング装置1には、上面に半導体ウェハ2を載置可
能に構成された発熱板3が設けられている。この発熱板
3には、加熱手段として例えば抵抗加熱ヒータ4が設け
られており、この抵抗加熱ヒータ4には、温度制御器5
によって抵抗加熱ヒータ4に供給する電力を制御可能に
構成された電源6が接続されている。The baking apparatus 1 is provided with a heat generating plate 3 on which a semiconductor wafer 2 can be placed. This heating plate 3 is provided with a resistance heater 4 as a heating means, for example, and this resistance heater 4 is equipped with a temperature controller 5.
A power source 6 configured to be able to control the electric power supplied to the resistance heater 4 is connected thereto.
上記発熱板3は、断熱材7を有する筐体8内に収容され
ている。また、後述する温度測定装置10で半導体ウェ
ハ2からの放射を測定するために、例えばこの筐体8の
天井部には、温度測定装置10によって測定する波長領
域の電磁波(例えば赤外線)の透過度の高い材質からな
るウィンド9が設けられている。The heat generating plate 3 is housed in a casing 8 having a heat insulating material 7. In addition, in order to measure radiation from the semiconductor wafer 2 with a temperature measuring device 10 to be described later, for example, the ceiling of the housing 8 is provided with a transmittance of electromagnetic waves (for example, infrared rays) in the wavelength range to be measured by the temperature measuring device 10. A window 9 made of a high quality material is provided.
なお、発熱板3の半導体ウェハ2載置面には、例えばス
パッタリング等で金属薄膜を形成する等により、鏡面仕
上を施しである。これは、発熱板3からの赤外線が後述
する温度測定に与える影響を軽減するためである。この
ように発熱板3表面から放射される赤外線を減少させて
も、半導体ウェハ2は赤外線の透過率が高く、もともと
放射による加熱ではなく主として熱伝導による加熱が行
われているので、半導体ウェハ2の加熱効率の減少は僅
かである。Note that the surface of the heat generating plate 3 on which the semiconductor wafer 2 is placed is given a mirror finish by, for example, forming a metal thin film by sputtering or the like. This is to reduce the influence of infrared rays from the heat generating plate 3 on temperature measurement, which will be described later. Even if the infrared rays emitted from the surface of the heat generating plate 3 are reduced in this way, the semiconductor wafer 2 has a high transmittance of infrared rays, and since heating is primarily performed by thermal conduction rather than by radiation, the semiconductor wafer 2 The reduction in heating efficiency is slight.
上記ベーキング装置1のウィンド9の上部には、温度測
定装置10が設けられている。この温度測定装置10に
は、発熱板3の上に載置された半導体ウェハ2の表面に
被着されたフォトレジスト2aあるいは半導体ウェハ2
自身から放射される電磁波例えば赤外線を検出可能に構
成された赤外線検出器11として例えば波長依存性のな
いサーモバイル型受光素子が設けられている。A temperature measuring device 10 is provided above the window 9 of the baking device 1. This temperature measuring device 10 includes a photoresist 2a attached to the surface of a semiconductor wafer 2 placed on a heat generating plate 3 or a semiconductor wafer 2 placed on a heat generating plate 3.
As the infrared detector 11 configured to be able to detect electromagnetic waves emitted from itself, such as infrared rays, for example, a thermomobile type light receiving element without wavelength dependence is provided.
また、この赤外線検出器11とウィンド9との間には、
上記赤外線を収束させて赤外線検出器11に入射させる
ための光学系12が設けられている。この光学系12は
、例えば鏡筒13内の天井部に下向きに設けられた凸面
鏡14と、この凸面鏡14に対向する如く設けられた中
央部に開口を有する凹面鏡15、およびこの凹面鏡15
の下部に設けられた環状の遮光板16等から構成されて
いる。Moreover, between this infrared detector 11 and the window 9,
An optical system 12 is provided to converge the infrared rays and make them enter the infrared detector 11. This optical system 12 includes, for example, a convex mirror 14 provided facing downward on the ceiling in a lens barrel 13, a concave mirror 15 having an opening in the center and provided opposite to this convex mirror 14, and this concave mirror 15.
It is composed of an annular light shielding plate 16 provided at the lower part of the screen.
なお、遮光板16は複数段けられ、ラビリンス構造によ
り、静止空気層を形成し、空気の対流によるごみの付着
や温度変動を防止するよう構成されている。The light shielding plates 16 are arranged in multiple stages and have a labyrinth structure to form a still air layer to prevent dust from adhering to the light and temperature fluctuations due to air convection.
そして、図示矢印で示す如く、ウィンド9を通して鏡筒
13内に入射する赤外線から、遮光板16によって迷光
成分を除去し、この赤外線を凹面鏡15の開口を通過さ
せた後凸面鏡14で凹面鏡15へ反射し、凹面鏡15で
赤外線検出器11に収束させる。As shown by the arrow in the figure, stray light components are removed from the infrared rays that enter the lens barrel 13 through the window 9 by the light shielding plate 16, and after passing through the opening of the concave mirror 15, the infrared rays are reflected by the convex mirror 14 to the concave mirror 15. Then, the concave mirror 15 focuses the infrared light onto the infrared detector 11 .
上記光学系12とウィンド9との間には、例えばロータ
リーソレノイド17によって回動するリファレンス板1
8によって、ウィンド9から光学系12(したがって赤
外線検出器11)に入射する赤外線を断続的に遮断(チ
ョッピング)する第1の開閉機構19が設けられている
。A reference plate 1 rotated by a rotary solenoid 17, for example, is provided between the optical system 12 and the window 9.
8, a first opening/closing mechanism 19 is provided which intermittently cuts off (chops) infrared rays incident on the optical system 12 (therefore, the infrared detector 11) from the window 9.
この第1の開閉機構19のリファレンス板18は、少な
くとも光学系12側の面18aが放射率既知の材料から
構成されている。つまり、この第1の開閉機構19が閉
じている時には、赤外線検出器11にリファレンス板1
8の面18a(放射率既知の材料)からの赤外線および
光学系12の各部位、例えば凸面鏡14、凹面鏡15、
遮光板16等からの赤外線が入射し、一方、第1の開閉
機構19が開いている時には、赤外線検出器11にウィ
ンド9を通過した被測定体(半導体ウエノ12およびフ
ォトレジスト2a)からの赤外線および光学系12の各
部位、例えば凸面鏡14、凹面鏡15、遮光板16等か
らの赤外線が入射するよう構成されている。At least the surface 18a of the reference plate 18 of the first opening/closing mechanism 19 facing the optical system 12 is made of a material with a known emissivity. In other words, when the first opening/closing mechanism 19 is closed, the reference plate 1 is connected to the infrared detector 11.
Infrared rays from the surface 18a (material with known emissivity) of 8 and various parts of the optical system 12, such as the convex mirror 14, the concave mirror 15,
When infrared rays from the light shielding plate 16 and the like are incident, and on the other hand, the first opening/closing mechanism 19 is open, infrared rays from the object to be measured (semiconductor wafer 12 and photoresist 2a) that have passed through the window 9 are detected by the infrared detector 11. The optical system 12 is configured such that infrared rays from each part of the optical system 12, such as the convex mirror 14, the concave mirror 15, and the light shielding plate 16, are incident.
したがって、後述する温度算出時には、上記第1の開閉
機構19が開いている時の赤外線測定信号から、閉じて
いる時の赤外線測定信号を差し引くことにより、例えば
光学系12等からの雑音成分を除去し、精度良く温度測
定を行うことができるよう構成されている。Therefore, when calculating the temperature described later, by subtracting the infrared measurement signal when the first opening/closing mechanism 19 is closed from the infrared measurement signal when the first opening/closing mechanism 19 is open, noise components from, for example, the optical system 12 are removed. However, it is configured to be able to measure temperature with high accuracy.
なお、□リファレンス板18の面18aを構成する放射
率既知の材料としては、放射率が経時的に変化しに<<
、かつ、赤外線の放射量ができる限り少ないものが好ま
しい。したがって、リファレンス板18の面18aは、
例えば金めつき等により鏡面仕上げすることが好ましい
が、例えばアルミニウム面等とすることもできる。Note that the material for which the surface 18a of the □reference plate 18 is made has a known emissivity, and the emissivity does not change over time.
, and one that emits as little infrared rays as possible is preferable. Therefore, the surface 18a of the reference plate 18 is
For example, it is preferable to have a mirror finish by gold plating, but it is also possible to use an aluminum surface, for example.
また、上述した如く、例えば金め9き等による鏡面仕上
げを実施すれば、通常の測定では、このリファレンス板
18の面18gからの放射は無視できる程度に小さくす
ることができる。したがって、第1の開閉機構19が開
いている時の赤外線測定信号から、閉じている時の赤外
線測定信号を差し引いた信号をそのまま用いて被測定体
の温度を算出することもできる。また、このリファレン
ス板18に熱電対等の接触型の温度検出器を設け、この
温度検出器によって測定された温度と既知の放射率から
、リファレンス板18の面18aがらの放射量を算出し
、上記信号の差に加算して補正するようにすれば、さら
に測定精度を向上させることができる。Furthermore, as described above, if a mirror finish is applied, for example, by gold plating, the radiation from the surface 18g of the reference plate 18 can be reduced to a negligible level in normal measurements. Therefore, the temperature of the object to be measured can also be calculated using a signal obtained by subtracting the infrared measurement signal when the first opening/closing mechanism 19 is closed from the infrared measurement signal when the first opening/closing mechanism 19 is open. Further, a contact type temperature detector such as a thermocouple is provided on this reference plate 18, and the amount of radiation from the surface 18a of the reference plate 18 is calculated from the temperature measured by this temperature detector and the known emissivity. By adding to the signal difference and correcting it, the measurement accuracy can be further improved.
さらに、上記光学系12と赤外線検出器11との間には
、光学系12から赤外線検出器11に入射する赤外線を
断続的に遮断(チョッピング)する第2の開閉機構20
が設けられている。この第2の開閉機構20は、例えば
モータ21と、このモータ21によって回動する円板状
の開閉板22と、この開閉板22の対称位置に設けられ
、それぞれ異なった波長(後述するλ1とλ2)の赤外
線を選択的に透過する複数例えば2つの狭帯域バンドパ
スフィルタ23.24等から構成されている。Further, between the optical system 12 and the infrared detector 11, there is a second opening/closing mechanism 20 that intermittently blocks (chops) infrared rays incident on the infrared detector 11 from the optical system 12.
is provided. This second opening/closing mechanism 20 is provided with, for example, a motor 21, a disk-shaped opening/closing plate 22 rotated by the motor 21, and a symmetrical position of the opening/closing plate 22. It is composed of a plurality of, for example, two narrowband bandpass filters 23 and 24 that selectively transmit infrared rays of λ2).
つまり、この第2の開閉機構20の開閉板22を回転さ
せることにより、赤外線検出器11には、チョッピング
されたλ1の波長の赤外線と、チョッピングされたλ2
の波長の赤外線とが交互に入射するよう構成されている
。したがって、赤外線検出器11の出力信号はパルス状
の信号となり、後述する温度算出時には、例えばこれら
のパルス状の信号の平均をとることにより、電気的な雑
音の低減を図るよう構成されている。That is, by rotating the opening/closing plate 22 of the second opening/closing mechanism 20, the infrared detector 11 receives chopped infrared rays with a wavelength of λ1 and chopped infrared rays with a wavelength of λ2.
The structure is such that infrared rays of wavelengths of 1 and 2 are incident alternately. Therefore, the output signal of the infrared detector 11 is a pulse-like signal, and when calculating the temperature described later, for example, these pulse-like signals are averaged to reduce electrical noise.
そして、赤外線検出器11の出力を、増幅器25によっ
て増幅し、この増幅された信号に基いて温度算出器26
によって被測定体(半導体ウェハ2およびフォトレジス
ト2 a、 )の温度を算出するよう構成されている。Then, the output of the infrared detector 11 is amplified by the amplifier 25, and based on this amplified signal, the temperature calculator 26
The device is configured to calculate the temperature of the object to be measured (semiconductor wafer 2 and photoresist 2 a, ).
なお、この温度算出器26によって算出された温度信号
は、温度制御器5にフィードバックされるよう構成され
ており、この温度測定結果に基づいて温度制御器5によ
り電源6を制御し、半導体ウェハ2あるいはフォトレジ
スト2aが所定温度となるように抵抗加熱ヒータ4に供
給する電力を調節する。The temperature signal calculated by the temperature calculator 26 is configured to be fed back to the temperature controller 5, and the temperature controller 5 controls the power supply 6 based on the temperature measurement result, and the semiconductor wafer 2 Alternatively, the power supplied to the resistance heater 4 is adjusted so that the photoresist 2a reaches a predetermined temperature.
上記構成の温度測定装置10では、次のようにしてフォ
トレジスト2aあるいは半導体ウェハ2の温度の測定を
行う。The temperature measuring device 10 having the above configuration measures the temperature of the photoresist 2a or the semiconductor wafer 2 in the following manner.
すなわち、まず第1の開閉機構19のロータリーソレノ
イド17を所定の速度で駆動し、リファレンス板18を
所定の速度で回転させることにより、光学系12の入口
部分で赤外線をチョッピングするとともに、第2の開閉
機構20のモータ21により開閉板22を上記第1の開
閉機構19と例えば同期させて回転し、光学系12の出
口部分で赤外線をチョッピングする。That is, by first driving the rotary solenoid 17 of the first opening/closing mechanism 19 at a predetermined speed and rotating the reference plate 18 at a predetermined speed, the infrared rays are chopped at the entrance of the optical system 12, and the second The opening/closing plate 22 is rotated by the motor 21 of the opening/closing mechanism 20 in synchronization with the first opening/closing mechanism 19, and the infrared rays are chopped at the exit portion of the optical system 12.
そして、前述した如く、第1の開閉機構19の開閉時の
信号の差をとることにより、光学的な雑音成分の影響を
除去するとともに、第2の開閉機構20の開閉により得
られたパルス状の信号の平均をとることにより、電気的
な雑音を低減した被測定体(半導体ウェハ2およびフォ
トレジスト2a)からの赤外線の測定信号を波長λ1、
λ2について得、この信号に基いて次のようにして温度
を算出する。As described above, by taking the difference between the signals when the first opening/closing mechanism 19 opens and closes, the influence of optical noise components can be removed, and the pulse shape obtained by opening and closing the second opening/closing mechanism 20 can be removed. By taking the average of the signals, the infrared measurement signal from the object to be measured (semiconductor wafer 2 and photoresist 2a) with reduced electrical noise is converted to wavelength λ1,
λ2, and based on this signal, the temperature is calculated as follows.
周知のように、ブランクの法則では、黒体がらの電磁波
(主に赤外線)の単色射出能E は、bλ
Ebλ”C1”λ−5/ [exp (C2/λT)
−1]ただし
λ :波長(m)
T 二ケルビン温度(K)
C1:定数−3,2179X 10−” (Kcal
・m 2/ h )C2:定数−1,4388XIO
−Xl0−2(と表すことができる。As is well known, according to Blank's law, the monochromatic emission power E of electromagnetic waves (mainly infrared rays) from a black body is bλ Ebλ"C1"λ-5/ [exp (C2/λT)
-1] However, λ: Wavelength (m) T Kelvin temperature (K) C1: Constant -3,2179X 10-" (Kcal
・m2/h)C2: Constant -1,4388XIO
-Xl0-2 (can be expressed as
そこで、上記ブランクの法則を用いて波長λ1、λ2に
おける単色射出能の推定値E −およびλ1
E22′を表すと、η1とη2をそれぞれ赤外線検出器
11の波長λ1、λ2に対する効率、K1、K2を波長
λ1、λ2に対するゲインとして、E ′ 璽
ε
λ1 λ1 °に1 °η1 ・C,−λ1−5
/ [exp (C2/λ+T) −1−]−ελ1
・K1 ・f(λ1.T)
Eλ2゛−ελ2争に2φη2・cl・λ2−5/ [
exp (C2/λ2T)−11−ελ2・K2・f
(λ2.T)
となる。ここで、
ε λ 1 8 K 1 ・ η 1 − ε
拳 K2− η 2λ 2
となるように増幅器25のゲインに、、K2を較正して
おき、両式の比をとると、
E −/E “−f(λ1.T)λ1 λ
2
/f (λ2.T)
となる。Therefore, if we express the estimated monochromatic output power E - and λ1 E22' at wavelengths λ1 and λ2 using Blank's law, then η1 and η2 are the efficiency of the infrared detector 11 at wavelengths λ1 and λ2, K1, K2 As the gain for wavelengths λ1 and λ2, E'
ε λ1 λ1 1 °η1 ・C, -λ1-5
/ [exp (C2/λ+T) −1−]−ελ1
・K1 ・f(λ1.T) Eλ2゛−ελ2 and 2φη2・cl・λ2−5/ [
exp (C2/λ2T)-11-ελ2・K2・f
(λ2.T). Here, ε λ 1 8 K 1 ・η 1 − ε
Calibrate K2 to the gain of the amplifier 25 so that it becomes K2- η 2λ 2 , and take the ratio of both equations: E −/E “−f(λ1.T) λ1 λ
2/f (λ2.T).
温度算出器26は、例えばNEWTON −RAPHS
ON法等の数値解析によって上式から温度Tを算出する
。The temperature calculator 26 is, for example, NEWTON-RAPHS.
The temperature T is calculated from the above equation by numerical analysis such as the ON method.
上記のゲインに、 、K2の較正は以下のようにして容
易に達成することができる。Calibration of the above gains, K2, can be easily accomplished as follows.
例えば、まず実用上測定対象とする放射の波長範囲にお
いてη1*η2なるような、すなわち赤外線検出器11
の効率に波長依存性がなく、効率η1とη2とが十分の
精度で等しくなるようなもの例えばサーモバイル型受光
素子を選択する。For example, first, in the wavelength range of the radiation to be measured in practice, η1*η2, that is, the infrared detector 11
For example, a thermomobile type light receiving element is selected whose efficiency has no wavelength dependence and whose efficiencies η1 and η2 are equal with sufficient accuracy.
次に、予め測定した被測定体の吸収スペクトルから波長
λ1、λ2における単色放射率ελ1、ελ2を求める
。これらのελ1 λ2を用い、 ε
てゲインに1とに2の比が、
K + / K 2 ”Fε /ε
λ2 λ1
となるようにに1とに2を設定する。この場合に1とに
2の比は赤外線検出器11の種類とは無関係に被測定体
の光物性のみから定まるという大きなメリットがある。Next, monochromatic emissivities ελ1 and ελ2 at wavelengths λ1 and λ2 are determined from the previously measured absorption spectrum of the object to be measured. Using these ελ1 λ2, set the gain to 1 and 2 so that the ratio of 1 to 2 becomes K + / K 2 "Fε /ε λ2 λ1. In this case, 1 and 2 are set for the gain. There is a great advantage that the ratio is determined only from the optical properties of the object to be measured, regardless of the type of infrared detector 11.
また、効率η1、η2がともに既知の場合には、K +
/ K 2冒ε η2/ελ1η1λ2
のように、K1とに2を設定してもよい。Furthermore, if both the efficiencies η1 and η2 are known, K +
K1 and K1 may be set to 2, as shown in the following formula: /K2 εη2/ελ1η1λ2.
一方、キルヒホッフの法則によれば、全ての物体の射出
能と吸収率の比は等しく、その値は黒体の射出能に等し
い。すなわち、いろいろな物体の射出能をE、、K2.
・・・・・・El、吸収率をφ1゜φ2.・・・・・・
φ。とし、黒体の射出能をE1吸収率をφとすると、次
式が成立つ。On the other hand, according to Kirchhoff's law, the ratio of emission power and absorption rate of all objects is equal, and its value is equal to the emission power of a black body. That is, the ejection powers of various objects are expressed as E, , K2.
...El, absorption rate φ1゜φ2.・・・・・・
φ. If the blackbody emission power and E1 absorption rate are φ, then the following equation holds true.
E、/φ+−E2/φ2−・・・・・・・・・−E/φ
−Eこれを変形すると、
E1/E−φ、、E2/E−φ2゜
・・・・・・、E、/E−φ。E, /φ+-E2/φ2-・・・・・・・・・-E/φ
-E If you transform this, E1/E-φ,, E2/E-φ2゜..., E, /E-φ.
となるが、 EIl/E−ε、(放射率) であるから、 ε1−φ1.ε2−φ2.・・・・・・、ε、−φ。However, EIl/E-ε, (emissivity) Because it is, ε1−φ1. ε2−φ2. ......, ε, -φ.
となり、全ての物体の放射率は同物体の吸収率に等しい
事が導出される。したがって、温度測定を行う場合は、
被測定体の放射率の高い、すなわち吸収率の高い波長(
吸収ピーク波長)の赤外線を測定することにより、被測
定体の背景からの赤外線放射の影響の少ない精度の良い
温度測定を実現することができる。Therefore, it is derived that the emissivity of every object is equal to the absorption rate of the same object. Therefore, when making temperature measurements,
The wavelength at which the measured object has a high emissivity, that is, a high absorption rate (
By measuring infrared rays at the absorption peak wavelength), it is possible to realize highly accurate temperature measurement with less influence of infrared radiation from the background of the object to be measured.
ここで、縦軸を透過率、横軸を波長とした第2図のグラ
フおよび第3図のグラフは、それぞれシリコンウェハお
よびシリコンウェハ上に厚さ約5μmのフォトレジスト
膜を形成した場合の赤外線に対する吸収特性を示してい
る。第2図のグラフに示されるように、シリコンウェハ
は、波長的9μmと約16μmに吸収ピークを有し、第
3図のグラフに示されるように、この場合のフォトレジ
スト膜(フォトレジストの種類によって異なる)は、例
えば波長的3μmと約7μm等に幾つかの吸収ピークを
有する。Here, the graphs in Figure 2 and Figure 3, where the vertical axis is the transmittance and the horizontal axis is the wavelength, show the infrared rays when a silicon wafer and a photoresist film with a thickness of approximately 5 μm are formed on the silicon wafer, respectively. It shows the absorption characteristics for As shown in the graph of FIG. 2, the silicon wafer has absorption peaks at wavelengths of 9 μm and 16 μm, and as shown in the graph of FIG. has several absorption peaks at wavelengths of 3 μm and about 7 μm, for example.
そこで、この実施例では、半導体ウェハ(シリコンウェ
ハ)2の温度を測定する場合は、λ1およびλ2を波長
9μmおよび16μmとして温度測定を行う。また、フ
ォトレジスト2aの温度を測定する場合は、λ1および
λ2を3μmおよび7μmとして温度測定を行う。Therefore, in this embodiment, when measuring the temperature of the semiconductor wafer (silicon wafer) 2, temperature measurement is performed with wavelengths λ1 and λ2 of 9 μm and 16 μm. Further, when measuring the temperature of the photoresist 2a, temperature measurement is performed with λ1 and λ2 set to 3 μm and 7 μm.
なお、前述した増幅器25のゲインに、 、K2の較正
は、予め半導体ウェハ2の温度を測定する場合と、フォ
トレジスト2aの温度を測定する場合とで、それぞれ別
々に行っておく必要がある。Note that the aforementioned gain of the amplifier 25, K2, needs to be calibrated separately in advance for measuring the temperature of the semiconductor wafer 2 and for measuring the temperature of the photoresist 2a.
すなわち、この実施例では、被測定体(半導体ウェハ2
またはフォトレジスト2a)の赤外線吸収ピーク波長に
対応する2種類の波長λ1、λ2の赤外線の放射量をそ
れぞれ測定し、これらの測定値から温度を算出するので
、放射率の高い波長における放射量を測定することによ
り、測定精度の向上を図ることができるとともに、第1
の開閉機構19および第2の開閉機構20によって、光
学的な雑音および電気的な雑音を低減した精度の高い測
定信号を得ることができるので、被測定体の温度を非接
触で正確に測定することができる。That is, in this embodiment, the object to be measured (semiconductor wafer 2
Alternatively, the amount of infrared radiation at two wavelengths λ1 and λ2 corresponding to the infrared absorption peak wavelength of photoresist 2a) is measured, and the temperature is calculated from these measured values, so the amount of radiation at wavelengths with high emissivity can be calculated. By measuring, the measurement accuracy can be improved and the first
The opening/closing mechanism 19 and the second opening/closing mechanism 20 make it possible to obtain highly accurate measurement signals with reduced optical noise and electrical noise, so the temperature of the object to be measured can be accurately measured without contact. be able to.
また、従来のように、放射率の設定を行う必要もない。Further, there is no need to set the emissivity as in the conventional case.
さらに、加熱板3に鏡面仕上が施しであるので、加熱板
3から赤外線検出器11、に入射する赤外線量を減少さ
せることができ、半導体ウェハ2およびフォトレジスト
2aのより正確な温度を測定することができる。Furthermore, since the heating plate 3 has a mirror finish, the amount of infrared rays incident on the infrared detector 11 from the heating plate 3 can be reduced, allowing more accurate temperature measurement of the semiconductor wafer 2 and photoresist 2a. be able to.
したがって、フォトレジスト2aあるいは半導体ウェハ
2の正確な温度に基いて、電源6から抵抗加熱ヒータ4
に供給する電力の制御を行うことができ、フォトレジス
ト2aの温度を所望の温度に保持して良好なベーキング
処理を行うことができる。Therefore, based on the accurate temperature of the photoresist 2a or the semiconductor wafer 2, the resistance heater 4 is connected to the power source 6.
The temperature of the photoresist 2a can be maintained at a desired temperature and a good baking process can be performed.
なお、上記実施例では、半導体ウエノ\2のべ一キング
工程におけるシリコンウェハ、フォトレジストの温度側
一定を行う場合の例について説明したが、本発明の温度
測定装置は、他の被測定体の温度測定にも応用可能で例
えば、ポリイミド系およびシリコン系絶縁膜、絶縁用フ
ェス、イオン感応用ポリ塩化ビニル膜、およびエポキシ
、アクリル、ポリウレタン樹脂等、吸収ピーク波長を有
するものであればいずれにも適用が可能である。In the above embodiment, an example was explained in which the temperature side of the silicon wafer and photoresist in the baking process of semiconductor wafer \2 is kept constant, but the temperature measuring device of the present invention It can also be applied to temperature measurements, such as polyimide and silicone insulation films, insulation boards, ion-sensitized polyvinyl chloride films, and epoxy, acrylic, and polyurethane resins, as long as they have an absorption peak wavelength. Applicable.
[発明の効果]
上述のように、本発明の温度測定装置によれば、放射率
の設定が不要で、かつ、非接触で正確に被測定体の温度
を測定することができる。[Effects of the Invention] As described above, according to the temperature measuring device of the present invention, it is not necessary to set the emissivity, and the temperature of the object to be measured can be accurately measured without contact.
第1図は本発明の一実施例の温度測定装置の構成を示す
図、第2図はシリコンウェハの赤外線に対する吸収特性
を示すグラフ、第3図はシリコンウェハ上に厚さ約5μ
mのフォトレジスト膜を形成した場合の赤外線に対する
吸収特性を示すグラフである。
1・・・・・・ベーキング処理、2・・・・・・半導体
ウェハ、2a・・・・・・フォトレジスト、3・・・・
・・加熱板、4・・・・・・抵抗加熱ヒータ、5・・・
・・・温度制御器、6・・・・・・電源、7・・・・・
・断熱材、8・・・・・・筐体、9・・・・・・ウィン
ド、10・・・・・・温度測定装置、11・・・・・・
赤外線検出器、112・・・・・・光学系、13・・・
・・・鏡筒、14・・・・・・凸面鏡、15・・・・・
・凹面鏡、16・・・・・・遮光板、17・・・・・・
ロータリーソレノイド、18・・・・・・リファレンス
板、19・・・・・・第1の開閉機構、20・・・・・
・第2の開閉機構、21・・・・・・モータ、22・・
・・・・開閉板、23.24・・・・・・フィルター
25・・・・・・増幅器、26・・・・・・温度算出器
。
第1
図Fig. 1 is a diagram showing the configuration of a temperature measuring device according to an embodiment of the present invention, Fig. 2 is a graph showing the infrared absorption characteristics of a silicon wafer, and Fig. 3 is a graph showing the infrared absorption characteristics of a silicon wafer.
3 is a graph showing absorption characteristics for infrared rays when a photoresist film of m is formed. 1...Baking treatment, 2...Semiconductor wafer, 2a...Photoresist, 3...
...Heating plate, 4...Resistance heater, 5...
...Temperature controller, 6...Power supply, 7...
・Insulating material, 8... Housing, 9... Window, 10... Temperature measuring device, 11...
Infrared detector, 112...Optical system, 13...
... Lens tube, 14 ... Convex mirror, 15 ...
・Concave mirror, 16... Light shielding plate, 17...
Rotary solenoid, 18... Reference plate, 19... First opening/closing mechanism, 20...
・Second opening/closing mechanism, 21...Motor, 22...
...Opening/closing plate, 23.24...Filter
25...Amplifier, 26...Temperature calculator. Figure 1
Claims (1)
波長における放射量を測定する手段と、この手段に入射
する放射を、前記被測定体からの放射と、放射率既知の
リファレンスからの放射とに切替る手段と、 前記複数の吸収ピーク波長における前記被測定体からの
放射量と前記リファレンスからの放射量との差から前記
被測定体の温度を算出する手段とを具備したことを特徴
とする温度測定装置。(1) A means for measuring the amount of radiation at a plurality of absorption peak wavelengths determined from the absorption characteristics of the object to be measured, and a means for measuring the amount of radiation at a plurality of absorption peak wavelengths determined from the absorption characteristics of the object to be measured; radiation, and means for calculating the temperature of the object to be measured from the difference between the amount of radiation from the object to be measured and the amount of radiation from the reference at the plurality of absorption peak wavelengths. Characteristic temperature measuring device.
Priority Applications (1)
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JP02132193A JP3093239B2 (en) | 1990-05-22 | 1990-05-22 | Semiconductor wafer heat treatment apparatus and heat treatment method |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP02132193A JP3093239B2 (en) | 1990-05-22 | 1990-05-22 | Semiconductor wafer heat treatment apparatus and heat treatment method |
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Publication Number | Publication Date |
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JPH0425729A true JPH0425729A (en) | 1992-01-29 |
JP3093239B2 JP3093239B2 (en) | 2000-10-03 |
Family
ID=15075575
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Cited By (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPH10115557A (en) * | 1996-10-15 | 1998-05-06 | Nippon Avionics Co Ltd | Method and apparatus for temperature correction of infrared sensor as well as infrared thermography using two-dimensional infrared sensor |
JP2005536049A (en) * | 2002-08-13 | 2005-11-24 | ラム リサーチ コーポレーション | Method and apparatus for in-situ monitoring of substrate temperature by emitted electromagnetic radiation |
Families Citing this family (1)
Publication number | Priority date | Publication date | Assignee | Title |
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WO2013148066A1 (en) * | 2012-03-30 | 2013-10-03 | Applied Materials, Inc. | Laser noise elimination in transmission thermometry |
-
1990
- 1990-05-22 JP JP02132193A patent/JP3093239B2/en not_active Expired - Fee Related
Cited By (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPH10115557A (en) * | 1996-10-15 | 1998-05-06 | Nippon Avionics Co Ltd | Method and apparatus for temperature correction of infrared sensor as well as infrared thermography using two-dimensional infrared sensor |
JP2005536049A (en) * | 2002-08-13 | 2005-11-24 | ラム リサーチ コーポレーション | Method and apparatus for in-situ monitoring of substrate temperature by emitted electromagnetic radiation |
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