JP2014055335A - Vacuum film deposition apparatus, and temperature control method and apparatus for evaporation source therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a vacuum film deposition apparatus which can provide stable vapor deposition while crystal sensors are being switched and a temperature control method and apparatus for its evaporation source.SOLUTION: A vacuum film deposition apparatus which vapor-deposits vapor deposition materials from a vapor deposition source onto a substrate surface in vacuum includes a crucible housing the vapor deposition sources therewithin, a heater for heating the crucible, a power supply unit for supplying heating power to the heater, and a control unit for controlling output power form the power supply unit, A crystal sensor is disposed close to the vapor deposition source, the crystal sensor generating rate signals showing the evaporation rate of the vapor deposition material. During a predetermined period after the crystal sensor is switched, the power supply unit is controlled so that the power which was supplied from the power supply unit to the heater during a predetermined period immediately before the crystal sensor was switched is maintained. In other periods, power to be supplied from the power supply unit to the heater is controlled based on the rate signal from the crystal sensor showing the evaporation rate of the vapor deposition material.

Description

  The present invention relates to a vacuum film forming apparatus for evaporating an organic EL material or the like on a large substrate for a display device such as an organic EL device or a liquid crystal display, and in particular, the evaporation rate of an evaporation material from an evaporation source is constant. The present invention relates to an evaporation source temperature control method and apparatus using a rate detection crystal sensor (so-called AT-cut crystal resonator) for performing physical vapor deposition (PVC) by heating a vapor deposition material while controlling the vapor deposition material to be kept at a constant value.

  In a vacuum film forming apparatus for depositing an organic EL material or the like on a large substrate for a display device, the above-described AT is generally used in order to control the evaporation rate of the evaporation material from the evaporation source to be constant. A crystal sensor for rate detection using a crystal which is a cut crystal resonator is widely used. Since such a crystal sensor detects the evaporation rate (rate) by the fluctuation of the frequency of the natural vibration accompanying the increase in the mass of the vapor deposition material deposited on the surface of the crystal, which is a vibrator, the sensor has a relatively short life, and therefore As is also known from Patent Document 1 below, a plurality of crystals are mounted in one sensor, and the crystals are automatically replaced when their lifetime approaches.

  Further, a method for operating a vacuum deposition apparatus using such a crystal sensor is already known in Patent Document 2 below.

JP 2003-139505 A JP 2007-138193 A

  As described above, the crystal sensor has a relatively short lifetime, and therefore, a plurality of crystals are mounted in the sensor, and when the crystal approaches its lifetime, it is automatically replaced. Yes. However, at that time, that is, when mechanically switching to a new crystal by a contactor, a time when the sensor cannot detect the rate temporarily occurs, and it takes about several minutes until the output stabilizes. Problems such as necessary were pointed out. Also, since the crystal sensor is sensitive to temperature, its output is not stable until the temperature of the sensor itself saturates, so when switching to a new crystal, the output from the sensor (reading) Cannot be trusted.

  Therefore, the present invention has been achieved in view of the above-described problems in the prior art, and the above-described crystal sensor is used as a means for monitoring and controlling the deposited film thickness. Even when switching the sensor crystal, instability due to individual crystal differences is eliminated, stable temperature control of the evaporation source is possible, and organic EL materials, etc. are stabilized on a large substrate for a relatively long time. An object of the present invention is to provide a vacuum film forming apparatus capable of performing vapor deposition and a temperature control method and apparatus for the evaporation source.

  In order to achieve the above-mentioned object of the present invention, according to the present invention, first, a vacuum film forming apparatus for depositing a deposition member from a deposition source on a substrate surface in a vacuum, the deposition source being deposited inside A crucible for storing the source, a heater for heating the crucible, a power supply unit for controlling heating power to the heater, and a control unit for controlling output power from the power supply unit, and In the case where a crystal sensor that generates a rate signal indicating the evaporation rate of the vapor deposition member is disposed in the vicinity of the vapor deposition source, in a predetermined period after the switching of the crystal sensor, the control unit performs a predetermined period immediately before the switching. The power supply unit is controlled so as to hold the power supplied from the power supply unit to the heater in the period, and in other periods, the vapor deposition unit from the crystal sensor Based on the rate signal indicative of the rate of evaporation, the vacuum deposition apparatus is provided for controlling the power supplied to the heater from the power supply unit.

  According to the present invention, in addition to the vacuum film forming apparatus, the heating power to the heater for heating the crucible is controlled in a vacuum film forming apparatus for depositing a vapor deposition member from a vapor deposition source on the substrate surface in a vacuum. In a predetermined period after the switching of the crystal sensor that generates a rate signal indicating the evaporation rate of the vapor deposition member, the electric power supplied to the heater in the predetermined period immediately before the switching is a temperature control method of the evaporation source. Evaporation source temperature control method for controlling power supply to hold, and during other periods, controlling power supply to the heater based on a rate signal indicating the evaporation rate of the vapor deposition member from the crystal sensor However, in vacuum, the heating power to the heater for heating the crucible is controlled in a vacuum film forming apparatus that deposits a deposition member from a deposition source on the substrate surface. An evaporation source temperature control device comprising: a power supply unit that controls heating power to the heater; and a control unit that controls output power from the power supply unit, and in proximity to the evaporation source. Then, in the case where a crystal sensor that generates a rate signal indicating the evaporation rate of the vapor deposition member is disposed, in a predetermined period after the switching of the crystal sensor, the control unit performs the power operation in a predetermined period immediately before the switching. The power supply unit is controlled to hold the power supplied from the supply unit to the heater, and in other periods, the power is based on a rate signal indicating the evaporation rate of the vapor deposition member from the crystal sensor. An evaporation source temperature control device for controlling electric power supplied from a supply unit to the heater is provided.

  In addition, according to the present invention, in the vacuum film forming apparatus, the temperature control method and apparatus for the evaporation source thereof, in a predetermined period after the switching of the crystal sensor, the control unit performs a predetermined process immediately before the switching. It is preferable to calculate an average value of the electric power supplied from the electric power supply unit to the heater in the period, and control the electric power to be the calculated average electric power value.

  According to the present invention described above, the above-described crystal sensor is used as a means for monitoring and controlling the deposited film thickness. However, even when switching the crystal of the rate detection crystal sensor, instability due to individual crystal individual differences is achieved. Eliminating and enabling stable temperature control of the evaporation source, and a vacuum film forming apparatus capable of stably depositing an organic EL material or the like on a large substrate over a relatively long time, and its evaporation source The temperature control method and apparatus can be realized.

It is a figure which shows an example of the organic EL device manufacturing apparatus using the film-forming apparatus which becomes one embodiment of this invention in the one part. It is a figure which shows the structure of the process (film-forming) chamber provided with the film-forming apparatus for vapor-depositing organic EL material in the inside with the conveyance chamber of the organic EL device manufacturing apparatus mentioned above. It is a figure which shows the structure of the film-forming apparatus centering on the vapor deposition source mentioned above. It is a figure which shows the detailed structure of the crystal sensor which comprises the film-forming apparatus mentioned above. It is a figure which shows the use condition in the film-forming apparatus of the crystal sensor mentioned above. It is a figure which shows an example of the frequency-power characteristic of the film-forming apparatus mentioned above. It is a flowchart figure which shows temperature control of the evaporation source including the power hold function in the film-forming apparatus mentioned above.

  Hereinafter, a film forming apparatus according to an embodiment of the present invention, particularly a film forming apparatus for depositing an organic EL material on a large substrate for an organic EL device will be described in detail with reference to the accompanying drawings. .

  First, attached FIG. 1 shows an example of an organic EL device manufacturing apparatus using a film forming apparatus according to an embodiment of the present invention as a part thereof. In general, a load cluster 3 that carries a substrate 6 to be processed (work), four clusters (A to D) that respectively process the substrate 6, and between adjacent clusters or between the cluster A and the load cluster 3. Furthermore, it is comprised from a total of five delivery chambers 4 installed between the next process (for example, sealing process).

  The load cluster 3 receives the substrate 6 from the load lock chamber 31 having the gate valve 10 and maintaining the vacuum in front and back, and the substrate 6 from the load lock chamber 31, and carries the substrate 6 into the delivery chamber 4a. It consists of a robot 5R. Each load lock chamber 31 and each delivery chamber 4 have a gate valve 10 in the front and rear thereof, and by controlling the opening and closing of the gate valve 10, while maintaining the internal vacuum, the load cluster 3 or the next The substrate 6 is delivered to a cluster or the like.

  Each cluster (A to D) includes a transfer chamber 2 having a single transfer robot 5 and two processing chambers that receive a substrate from the transfer robot 5 and perform predetermined processing (arranged vertically in the drawing). 1 (subscripts a to d indicate clusters, and subscripts u and d indicate upper and lower sides). A gate valve 10 is provided between the transfer chamber 2 and the processing chamber 1.

  Next, FIG. 2 attached is a processing (film formation) chamber including a part of the above-described organic EL device manufacturing apparatus, in particular, a transfer chamber 2 and a film forming apparatus for depositing an organic EL material therein. 1 is shown. Here, a vacuum deposition chamber 1bu for forming an EL layer on the substrate 6 by depositing a light emitting material in a vacuum is shown as a configuration of the processing chamber.

  As shown in the figure, the vacuum deposition chamber 1bu is roughly divided into a deposition unit 7 for evaporating the light emitting material and depositing it on the substrate 6, an alignment unit 8 for depositing on a necessary part of the substrate 6, and a transfer chamber 2. The substrate 6 is transferred to and from the transfer robot 5, and the processing transfer unit 9 is configured to move the substrate 6 to the vapor deposition unit 7. Here, the schematic structure of the vapor deposition part 7, the alignment part 8, and the process delivery part 9 is demonstrated.

  The alignment unit 8 and the processing delivery unit 9 are each provided with two systems, a right R line and a left L line. The processing delivery unit 9 can deliver the substrate 6 without interfering with the comb-like hand 52 of the transfer robot 5 and has a substrate chuck 91 having means for fixing the substrate 6, and rotates the substrate chuck 91. Hand turning drive means 92 for moving the substrate 6 upright to the alignment unit 8. As a means for fixing the substrate 6, for example, electromagnetic adsorption or a clip is used in consideration of being in a vacuum.

  The alignment unit 8 includes a shadow mask 81 including a mask 81m and a frame 81f, and an alignment driving unit 83 for aligning the substrate 6 and the shadow mask 81 with an alignment mark on the substrate (not shown). .

  The vapor deposition part 7 has the evaporation source 71 and the evaporation source drive means (not shown) for moving the said vapor deposition source to an up-down direction. The evaporation source 71 is filled with a light emitting material that is a vapor deposition material, and the vapor deposition material is heated to control the vaporized organic EL material at a stable vaporization rate.

  Subsequently, FIG. 3 attached shows the configuration of the film forming apparatus centering on the above-described vapor deposition source 71. As shown in the figure, the vapor deposition source 71 has a plurality of nozzles 711 on its side wall surface. The crucible 714 containing the organic EL material 713 is provided inside the casing 712 formed with a heater 715 around the crucible. The heater 715 is supplied with, for example, power from a commercial power supply via a power supply unit 210 whose output power is controlled by the control unit 200. The power supply unit 210 includes, for example, a power element such as an IGBT, and the control unit 200 includes a CPU including a memory. The control unit 200 includes the vapor deposition. From the power supply unit 210 based on an output signal (a so-called rate signal indicating the evaporation rate of the vapor deposition material) described below provided near the source 71 or a temperature signal from a temperature sensor (not shown). Electric power for heat generation is controlled and supplied to the heater 71 of the vapor deposition source 71.

  Next, FIG. 4 attached here shows the detailed structure of the above-described crystal sensor 300. Inside the crystal sensor cover 310 shown in FIG. 4A, a holder 320 shown in FIG. A plurality of (in this example, 12) crystals 321 and 321 are mounted. Then, the crystal is sequentially switched by rotating the holder 320 in increments of 30 degrees. That is, the crystal sensor cover 310 is provided with one opening 311, and by rotating the holder 220, one crystal is selected as the crystal sensor, and the deposit is deposited on the crystal sensors other than the selected one. It is physically shielded from flying.

  Further, FIG. 5 shows a use state of the above-described crystal sensor 200 (FIG. 5A is a top view, FIG. 5B is a side view), and reference numeral 716 in FIG. An angle limiting plate is provided at the tip for limiting the emission of the organic EL material. As is clear from these figures, the evaporated organic EL material radiated from the nozzle 711 of the vapor deposition source 71 is vapor deposited on the surface of the crystal disposed in the opening 311 of the crystal sensor cover 310, thereby vapor deposition material. A rate signal indicative of the evaporation rate of the crystal is detected and is automatically replaced as the crystal approaches its lifetime. Specifically, the holder 320 rotates and a new crystal 321 is disposed in the opening 311 of the sensor cover 310. However, as described above, a time during which the sensor cannot detect the rate value occurs, and it takes about several minutes until the output is stabilized.

  Therefore, in the present invention, after the sensor switching (switching to a new crystal), the deposition is performed with the film thickness in the most recent period until the crystal sensor is stabilized, so the evaporation source heater power at the latest is maintained. Aside (power hold function at the time of sensor switching), vapor deposition is performed with the electric power.

  That is, in the present invention, (1) it is known from the experimental results that if the power is constant, it can be vapor-deposited with the same film thickness. (2) However, there is a change in the amount of vapor due to the remaining amount of the material to be vapor-deposited. It is impossible to control the deposition of organic EL materials and the like stably with the same power at all times for a long time. (3) The power decreases with the decrease in the material (see attached FIG. 6). In consideration of frequency-power characteristics), when switching to a new crystal mechanically by a contactor, a stable vapor deposition is realized by temporarily using a power hold function.

  Next, the temperature control of the evaporation source including the power hold function at the time of sensor switching according to the present invention described above will be described in detail below with reference to the flowchart shown in FIG. The power hold function is executed at predetermined intervals by the CPU constituting the control unit 200 shown in FIG. 3 according to software stored in the internal memory.

  When the apparatus starts its operation, it is first determined whether or not there is a sensor switch (switch to a new crystal) (step S71). As a result, when it is determined that the sensor is not switched (see “NO” in the figure), the thermoelectric which measures the normal operation, that is, the rate value which is a detection signal from the crystal sensor and the temperature in the crucible. Based on the temperature from the temperature sensor or the like, a power Pi to be supplied to the heater 71 of the vapor deposition source 71 for heat generation is calculated so as to obtain a desired vapor deposition rate of the organic EL material (step S72). The electric power Pi is supplied to the heater 71 by controlling the electric power supply unit 210 so that the calculated supply electric power Pi is supplied to the heater 71 (step S73). Thereafter, the calculated supply power Pi is temporarily stored (saved) in, for example, an internal memory of the CPU (step S74). Here, “i” is a natural number that is equal to or greater than 1 and equal to or less than “n”, and increases sequentially with each storage, and “n” is a natural number equal to or greater than 2.

On the other hand, if it is determined as a result of the determination in step S71 that the sensor has been switched (see “YES” in the figure), the following control using the power hold function is performed. That is, the following equation to calculate the average value P _A of the power P supplied to the heater of the evaporation source before switching (step S75).

Note that “n” is a natural number of 1 or more, and an average value P _AV of the electric power P supplied to the heater within a predetermined period immediately before the sensor switching is obtained by the formula, and thereafter regardless rate value from the sensor, the average value P _AV of the sought power P is to be supplied to the heater, for controlling the power supply unit 210 (step S76). Even after that, the operation is repeated until a predetermined time “τ” elapses after the sensor is switched (see “NO” in the figure). Then, when a predetermined time “τ” has elapsed (see “YES” in the figure), the processing is terminated.

  That is, according to the power hold function described above, the average power supplied to the heater of the evaporation source is considered (stored) together with the resonance frequency and power of the crystal sensor (frequency, power, and slope in FIG. 6). Therefore, even during the period until the correct rate value comes out from the newly switched crystal sensor (that is, until it becomes stable), the individual difference of the crystals constituting the sensor is eliminated (reduced), It is possible to stably deposit an EL material or the like.

In the above operation, the switching of the sensor may be, for example, the time point when the rate value change (differential value) from the crystal sensor becomes zero (0). Since the output of about a minute has an unstable period, the above-mentioned predetermined time “τ” is set to about 30 minutes, and “n” for calculating the average value P _AV of the power P is the same. Furthermore, it may be set as appropriate so that an average value for a period of about 30 minutes can be calculated.

  DESCRIPTION OF SYMBOLS 1 ... Processing (film-forming) chamber, 6 ... Substrate, 7 ... Evaporation part, 71 ... Evaporation source, 711 ... Nozzle, 713 ... Organic EL material, 714 ... Crucible, 715 ... Heater, 200 ... Control part, 210 ... Power supply 300, crystal sensor

Claims (6)

A vacuum film forming apparatus for depositing a vapor deposition member from a vapor deposition source on a substrate surface in a vacuum, the vapor deposition source including a crucible for accommodating the vapor deposition source therein, a heater for heating the crucible, and the heater A power supply unit for controlling the heating power of the gas and a control unit for controlling the output power from the power supply unit, and in the vicinity of the vapor deposition source, generates a rate signal indicating the evaporation rate of the vapor deposition member In the one where the crystal sensor is arranged,
In a predetermined period after the switching of the crystal sensor, the control unit controls the power supply unit so as to hold the power supplied from the power supply unit to the heater in a predetermined period immediately before the switching. ,
In the other period, the vacuum film forming apparatus controls power supplied from the power supply unit to the heater based on a rate signal indicating an evaporation rate of the vapor deposition member from the crystal sensor.   2. The vacuum film forming apparatus according to claim 1, wherein, in a predetermined period after the switching of the crystal sensor, the control unit is supplied from the power supply unit to the heater in a predetermined period immediately before the switching. A vacuum film forming apparatus characterized in that an average value of electric power is calculated and controlled so as to be the calculated average electric power value. An evaporation source temperature control method for controlling heating power to a heater for heating a crucible in a vacuum film forming apparatus for depositing an evaporation member from an evaporation source on a substrate surface in vacuum,
In a predetermined period after the switching of the crystal sensor that generates a rate signal indicating the evaporation speed of the vapor deposition member, the supply power is controlled so as to hold the electric power supplied to the heater in the predetermined period immediately before the switching,
In the other period, the power supply to the heater is controlled based on a rate signal indicating the evaporation rate of the vapor deposition member from the crystal sensor.   4. The temperature control method for an evaporation source according to claim 3, wherein in a predetermined period after the switching of the crystal sensor, an average of the electric power supplied from the power supply unit to the heater in the predetermined period immediately before the switching. A temperature control method for an evaporation source, characterized in that a value is calculated, and control is performed so that the calculated average power value is obtained. An evaporation source temperature control device for controlling heating power to a heater for heating a crucible in a vacuum film forming apparatus for depositing a deposition member from a deposition source on a substrate surface in vacuum, the heating power for the heater A crystal sensor that generates a rate signal indicating the evaporation rate of the vapor deposition member in the vicinity of the vapor deposition source, and a power supply unit that controls the power supply, and a control unit that controls the output power from the power supply unit In the arrangement,
In a predetermined period after the switching of the crystal sensor, the control unit controls the power supply unit so as to hold the power supplied from the power supply unit to the heater in a predetermined period immediately before the switching. ,
In other periods, the temperature control of the evaporation source is characterized in that the power supplied from the power supply unit to the heater is controlled based on a rate signal indicating the evaporation rate of the vapor deposition member from the crystal sensor. apparatus.   6. The temperature control apparatus for an evaporation source according to claim 5, wherein, in a predetermined period after the switching of the crystal sensor, the control unit supplies the heater from the power supply unit in a predetermined period immediately before the switching. A vacuum film forming apparatus characterized in that an average value of the calculated power is calculated and controlled so as to be the calculated average power value.

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