Insulation system and substrate processing apparatus

Examples of an insulation system include a digital isolator for receiving supply of a first power supply on an input side thereof and receiving supply of a second power supply on an output side thereof, and an output adjusting unit for receiving supply of the second power supply, directly outputting an output of the digital isolator when a voltage of the second power supply is larger than a predetermined voltage, and stopping data output irrespective of the output of the digital isolator when the voltage of the second power supply is smaller or equal to the predetermined voltage.

TECHNICAL FIELD

Examples are described which relate to an insulation system and a substrate processing apparatus using the same.

BACKGROUND

At present, a signal insulation method based on a photo-coupler has been widely used in systems requiring electrical insulation such as industrial equipment or medical equipment. However, it has become difficult in systems using photo-couplers to cope with recent high speed operations due to problems such as low data rate, duty ratio deterioration, etc. Therefore, the foregoing method has been replaced by an insulation method using a digital isolator that can solve these problems.

For example, an ADS board is used to control reactor-related AIO, DIO at a cycle of 50 msec. In an ADS board, a photo-coupler is used as an insulating element of DO. When a photo-coupler is used as an insulating element of Fast ADS developed for the purpose of further high-speed driving, a 50% duty ratio of DO cannot be obtained. Therefore, a digital isolator which enables the 50% duty ratio even under high speed driving can be adopted. The output side of the digital isolator may fall into an indefinite state in a power supply unstable state or the like at a power-on time, power cut-off time or the like. Such an indefinite state may impair reliability or safety.

SUMMARY

Some examples described herein may address the above-described problems. Some examples described herein may provide an insulation system and a substrate processing apparatus that can enhance reliability.

In some examples, an insulation system includes a digital isolator for receiving supply of a first power supply on an input side thereof and receiving supply of a second power supply on an output side thereof, and an output adjusting unit for receiving supply of the second power supply, directly outputting an output of the digital isolator when a voltage of the second power supply is larger than a predetermined voltage, and stopping data output irrespective of the output of the digital isolator when the voltage of the second power supply is smaller or equal to the predetermined voltage.

DETAILED DESCRIPTION

An insulation system and a substrate processing apparatus according to an embodiment will be described with reference to the drawings. The same or corresponding constituent elements are represented by the same reference numerals, and duplicative descriptions thereof may be omitted.

FIG. 1is a diagram showing an example of an insulation system. The insulation system10includes an insulating unit11having a digital isolator, an output unit14and a controller12. The respective configurations of these units will be described hereunder.

In the insulating unit11, for example, a digital isolator is used as an insulating element between an input and an output. The right and left sides of the insulating unit11with respect to a broken line at the center of the insulating unit11are electrically insulated from each other, but data communication can be performed between the right and left sides. In a conventional system using a photo-coupler, the data rate may be limited to about 10 Mbps, and also the duty ratio may deteriorate to around 20% due to high-speed operations. On the other hand, the digital isolator can realize a high data rate of, for example, 100 Mbps or more, and an excellent duty ratio of, for example, about 50%. The digital isolator can be configured by one or plural ICs, for example.

This digital isolator receives supply of a first power supply Vdd1on an input side thereof, and also receives supply of a second power supply Vdd2on an output side thereof. A ground terminal GND1on the input side of the digital isolator and a ground terminal GND2on the output side of the digital isolator are different from each other.FIG. 2is a diagram showing an example of a truth table of the digital isolator. When power supply by the first power supply Vdd1and the second power supply Vdd2is being normally performed, L level is output as an output Vo_Tmp for an input Vin of L level, and H level is output as an output Vo_Tmp for an input Vin of H level.

The digital isolator has, for example, a well-known fail-safe output function, so that the output Vo_Tmp is settled even when the first power supply Vdd1is cut off. When power supply is not performed by the first power supply Vdd1, but power supply is normally performed by the second power supply Vdd2, in this example, the output Vo_Tmp is fixed to L level, but it may be fixed to H level. On the other hand, when the second power supply Vdd2is cut off, the output Vo_Tmp falls into an indefinite state. When the output Vo_Tmp is used while the indefinite state is left, a next-state connection system may malfunction unintentionally, so that reliability and safety may be impaired.

FIG. 3is a diagram showing an example of a truth table of the output unit14. When the signal level of the control terminal14bis L, the output Vo_Tmp is directly output as an output Vout. On the other hand, when the signal level of the control terminal14bis H, signal passage from the output Vo_Tmp to the output Vout is not allowed, and the output Vout is set to an electrically insulated or high-impedance state. Accordingly, it may be said that this output unit14is an output unit having an enable terminal for enabling or disenabling signal passage.

The controller12may adopt various configurations for reflecting the voltage state of the second power supply Vdd2in the control terminal14bof the output unit14. The signal level of the control terminal14bis changed according to whether the voltage of the second power supply Vdd2is normal or abnormal, whereby it is possible to determine whether the signal passage in the output unit14is enabled or disenabled.

The output Vout of the output unit14which is an output of the insulation system is settled at all times by the output unit14and the controller12described above even when the output Vo_Tmp of the insulating unit11is in an indefinite state, which prevents malfunction and enhances reliability and safety.

In the insulation system10ofFIG. 1, the controller12and the output unit14constitutes an output adjusting unit16. The output adjusting unit16receives supply of the second power source Vdd2. The output adjusting unit directly outputs the output of the digital isolator when the voltage of the second power supply Vdd2is larger than a predetermined voltage, but stops data output irrespective of the output of the digital isolator when the voltage of the second power supply Vdd2is smaller or equal to the predetermined voltage. The operation as described above can be realized by various circuit configurations different from the configuration including the controller12and the output unit14ofFIG. 1. For example, dedicated hardware or CPU (which is also called as Central Processing Unit, a central processor, a processing device, a calculation device, a microprocessor, a microcomputer, a processor, DSP or the like) for executing a program stored in a memory may be adopted.

FIG. 4is a diagram showing an example of a configuration of the insulation system10. In this example, the output unit14is a 3-state buffer. A 3-state buffer circuit is a circuit that can take both of High/Low level states or a high-impedance (Hi-Z) state as the output state. The controller12includes a first resistor R1and a second resistor R2which are connected in series to the second power supply Vdd2and the ground terminal GND2. Furthermore, a switching element Q1having a gate connected to a middle point between the first resistor R1and the second resistor R2is provided. A middle point between the second power supply Vdd2and the first resistor R1, and the drain of the switching element Q1are connected to each other by a third resistor R3. The source of the switching element Q1is connected to the ground terminal GND2.

The controller12illustrated inFIG. 4switches the connection of the control terminal14bto the second power supply Vdd2or the ground terminal GND2according to the state of the second power supply Vdd2. That is, the control terminal14bis set to an H-level state or an L-level state. The controller12illustrated inFIG. 4is configured so that when the voltage of the second power supply Vdd2becomes larger than a predetermined voltage, the switching element Q1is turned on to connect the ground terminal GND2to the control terminal14b, whereas when the voltage of the second power supply Vdd2becomes smaller or equal to the predetermined value, the switching element Q1is turned off to connect the control terminal14bto the second power supply Vdd2via a resistor. More specifically, when the second power supply Vdd2is surely powered, the switching element Q1is turned on with a voltage Vtr divided by the first and second resistors R1and R2, and the output is connected to the ground terminal GND2. On the other hand, when the second power supply Vdd2is in an unpowered state, a power-on transient state or a cut-off transient state and thus a voltage is not normally supplied, the output of the controller12is connected to the second power supply Vdd2via the third resistor R3.

Next, an example of the operation of the insulation system10illustrated inFIG. 4will be described.

(A) Normal Operation

FIG. 5is a timing chart showing an example of the normal operation. When both the first power supply Vdd1and the second power supply Vdd2are normally powered, a signal is transmitted from the input Vin to the output Vout at a high data rate and an excellent duty ratio. At this time, the switching element Q1is turned on, and the control terminal14bis connected to the ground terminal GND2.

(B) When First Power Supply Vdd1is Indefinite

FIG. 6Ais a timing chart showing an example of the operation when the first power supply Vdd1is indefinite at the power-on time. The first power supply Vdd1is unpowered during the period from the left end till a time t1inFIG. 6A. The output Vout is fixed by the fail-safe output function of the digital isolator. In this example, the output Vout is fixed to L level.

The period from the time t1to t2inFIG. 6Ais a transient period during which the first power supply Vdd1transitions from the L level to the H level. At the initial time of this period, the output Vout is fixed to L level by the fail-safe output function in the same as the unpowered period. When a time t_vdd has come, the voltage of the first power supply Vdd1reaches the operation voltage of the digital isolator, and the operation is switched to the normal operation. At this time, the state of the input Vin is output from the output Vout.

The period from the time t2to the right end inFIG. 6Ais a period during which the first power supply Vdd1normally supplies power. In this period, the signal of the input Vin is output from the output Vout. The operation at the power-on time of the first power supply Vdd1has been described with reference toFIG. 6A.FIG. 6Bis a timing chart showing an operation when the first power supply Vdd1is cut off. The operation at the cut-off time corresponds to an operation obtained by reversely progressing the operation at the power-on time. That is, when the time has passed the time t1and reached the time t_vdd, the voltage of the first power supply Vdd1decreases to the operation voltage of the digital isolator, and at this timing, the output Vout is fixed to the L level by the fail-safe output function.

(C) When Second Power Supply Vdd2is Indefinite

FIG. 7Ais a timing chart showing an example of the operation when the second power supply Vdd2is indefinite at the power-on time. During the period from the left end to a time t1inFIG. 7A, the second power supply Vdd2is unpowered. In this period, the output Vo_tmp of the digital isolator has fallen into an indefinite state as shown in the truth table ofFIG. 2. In this case, in the controller12ofFIG. 4, Vtr divided from the second power supply Vdd2is also unpowered, so that the switching element Q1is turned off. As a result, the control terminal14bis connected to the second power source Vdd2via the third resistor R3, and likewise unpowered. Accordingly, the control terminal14bis set to the H level, and the output Vout is set to an electrically insulated or high-impedance state. Under the insulated or high-impedance state, the output Vout is neither High nor Low, and set to substantially the same state as if it is separated from an output circuit inside an output terminal.

The period from the time t1to the time t2inFIG. 7Ais a transient period during which the second power supply Vdd2transitions from the L level to the H level. At the initial time of this period, that is, from the time t1till the time t_vdd at which the voltage of the second power supply Vdd2has reached the operation voltage of the digital isolator, the voltage of the second power supply Vdd2increases, but the indefinite state of the output Vo_tmp continues as in the case of the unpowered state. In the controller12, Vtr increases according to the increase of the second power supply Vdd2, but is smaller than a threshold value of the switching element Q1, so that the switching element Q1maintains an off-state. Accordingly, the output Vout maintains the electrically insulated or high-impedance state.

When the time has reached the time t_vdd and the voltage of the second power supply Vdd2becomes larger than the operation voltage of the digital isolator, the state of the input Vin is output from the output Vo_tmp. When the input Vin is at the H level, the output Vo_tmp increases as in the case of the voltage of the second power supply Vdd2. However, by setting the threshold value where the switching element Q1switches state to be larger than the operation voltage of the digital isolator, the switching element Q1is kept in an off-state for a while after the time has reached the time t_vdd. Accordingly, the output Vout maintains the electrical insulation or high-impedance for a certain period after the time has reached the time t_vdd.

Thereafter, when the time t_tr has come, Vtr becomes larger than the threshold value of the switching element Q1, and the switching element Q1is turned on. As a result, the control terminal14bis connected to the ground terminal GND2, and the state of the output Vo_tmp is output to the output Vout. That is, the input Vin is output to the output Vout. Thereafter, when the time t2has come, the voltage of the second power supply Vdd2has reached the H level. During a period subsequent to the time t2, the signal is transmitted from the input Vin to the output Vout.

As described above, the insulated or high-impedance state of the Vout is not released immediately after the time has reached the time t_vdd and the indefinite state of the output Vo_tmp has been dissolved, but the switching element Q1is turned on after a certain period has elapsed from the time t_vdd and the time t_tr has come. By the processing as described above, the insulated or high-impedance state of Vout can be prevented from being released under the indefinite state of the output Vo_tmp even when the indefinite state of the output Vo_tmp is extended a little due to fluctuation of the operation.

The operation at the time of the second power supply Vdd2is turned on has been described with reference toFIG. 7A.FIG. 7Bis a timing chart showing the operation when the second power supply Vdd2is cut off. The operation at the cut-off time corresponds to an operation obtained by reversely progressing the operation at the power-on time. That is, when the time has passed the time t1and reached the time t_tr, the output Vout is set to an electrically insulated or high-impedance state. Thereafter, when the time has reached the time t_vdd and the voltage of the second power supply Vdd2has decreased to the operation voltage of the digital isolator, the output Vo_tmp falls into an indefinite state.

According to the operation described in the foregoing (A) to (C), the output Vout of the insulation system10has been never set to an indefinite state, and the state thereof is always settled, and in particular, the insulation system10falls into an insulated state without outputting unless the second power supply Vdd2is substantially surely powered. Therefore, the malfunction can be prevented, and reliability and safety can be enhanced. Furthermore, not only at the power-on time and the power cut-off time, but also when another abnormality such as instantaneous voltage drop or the like occurs in the second power supply Vdd2, it is expected that they can be dealt with.

FIG. 8is a diagram showing an example of the operation when instantaneous voltage drop occurs in the second power supply Vdd2. Vo_tmp falls into the indefinite state from the time t_vdd till the next time t_vdd, but the reliability of the insulation system may be enhanced by setting the output Vout to the insulated or high-impedance state before the period begins and after the period ends.

FIG. 9is a diagram showing another example of the circuit of the controller12. The controller12ofFIG. 9prevents chattering to stabilize the operation. This controller12has a constant current circuit20connected to the second power supply Vdd2. The output of the constant current circuit20is input as Vref to a negative-side input of a comparator22. Vtr is applied to a positive-side input of the comparator22. The output of the comparator22is connected to the gate of the switching element Q1.FIG. 10is a diagram showing an example of a configuration of the constant current circuit20ofFIG. 9. As shown inFIG. 10, the constant current circuit20may be configured by using an operational amplifier.

Vtr and Vref may be given by the following expressions.
Vtr=Vdd2×R2/(R1+R2)
Vref=Iref×R4

At the power-on time of the second power supply Vdd2, when Vtr>Vref+Vhys is satisfied, the output Voc of the comparator22is set to H level, and the switching element Q1is turned on. As a result, the output unit14outputs the output Vo_temp from the output Vout.

On the other hand, at the power cut-off time of the second power supply Vdd2, when Vtr<Vref−Vhys is satisfied, the output Voc of the comparator22is set to L level, and the switching element Q1is turned off. As a result, the output Vout is set to the insulated or high-impedance state.

FIG. 11is a diagram showing a voltage waveform at the power-on time. When the voltage of the second power supply Vdd2increases, increase of Vref stops, and converges to a certain value. However, Vtr continues to increase. When Vtr reaches a threshold value Vth1represented by Vref+Vhys, the comparator22turns on the switching element Q1. On the other hand, when the voltage of the second power supply Vdd2decreases, the decrease of Vref stops, and converges to a certain value. However, Vtr continues to decrease. When Vtr reaches a threshold value Vth2represented by Vref-Vhys, the comparator22turns off the switching element Q1.

Accordingly, the controller12ofFIGS. 9 and 10connects the control terminal14bto the ground when the voltage of the second power supply Vdd2becomes larger than a predetermined first threshold value, and connects the control terminal14bto the second power supply Vdd2via a resistor when the voltage of the second power supply Vdd2becomes smaller than a second threshold value smaller than the first threshold value. The switching element Q1is controlled by using the different threshold values at the power-on time and the power cut-off time respectively, which prevents chattering to stabilize the operation for example when the second power supply Vdd2fluctuates or the like.

FIG. 12is a diagram showing an example of the substrate processing apparatus. The substrate processing apparatus includes a module controller40, an IO board41, and a device46. The module controller40is, for example, Transfer Module Controller (TMC) or Process Module Controller (PMC). The IO board41receives an instruction from the module controller40, and controls the device46. The IO board41is configured by connecting CPU42and DO (Digital Output) circuit44via the insulation system10. The insulation system10is an insulation system having any configuration described above. The first power supply Vdd1and the ground terminal GND1are used at CPU42and the primary side of the digital isolator, and the second power supply Vdd2and the ground terminal GND2are used at the DO circuit44and the secondary side of the digital isolator.

The device46corresponds to various devices operating based on an instruction from the IO board41. For example, the device46is a gas supply device for supplying gas to a substrate. In this case, ON/OFF of the gas supply device is controlled based on an instruction from the IO board41.

The device46may be, for example, an RF generator for subjecting a substrate to plasma processing. In this case, ON/OFF of the RF generator is controlled based on an instruction from the IO board41. Another device used for substrate processing or the like may be used as the device46. Highly-reliable control having no indefinite state can be realized by the insulation system10described above.