JPH0334091B2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a heating power supply device suitable for heating polycrystalline semiconductor rods used in the manufacture of semiconductor devices, and more specifically, to The present invention relates to a heating power supply device which can simultaneously heat a polycrystalline semiconductor rod with a balanced predetermined ratio of current and can change the heating voltage continuously and over a wide range.

[Conventional technology]

When producing high-purity silicon used in semiconductor devices, normally multiple undeposited high-purity silicon rods are fixed to graphite electrodes in a device with a quartz bell jar placed over a base plate, and then the silicon is placed on this carrier. Silicon has been deposited by thermal decomposition of a gaseous mixture of hydrogen and trichlorosilane. Since this rod-shaped carrier has a negative resistance peculiar to semiconductors, the following problems occur during the heating process.

The first problem is a heating control problem caused by the heating characteristics of the rod-shaped carrier from the initial heating to the end of the reaction.

At the initial heating stage, the rod-shaped carrier exhibits high resistance, and a high voltage is required to energize it, as shown in FIG. However, the diameter of the rod-shaped carrier at this stage is still small and the heat dissipation surface is narrow, so the reaction proceeds with a small current. When the temperature of the rod-shaped carrier rises above a predetermined temperature as the reaction progresses, its resistance drops significantly and high pressure is no longer necessary. Furthermore, as the reaction progresses, the rod-shaped carrier becomes thicker and its resistance gradually decreases, so it is necessary to gradually lower the voltage even after reaching the reaction temperature. However, as the reaction progresses, the heat dissipation surface becomes wider, so the amount of heat dissipation increases, and it is necessary to gradually increase the amount of current.

In this way, as the precipitation reaction progresses, the voltage required for energization must be decreased in accordance with the resistance change accompanying the heating reaction, and the current must be gradually increased in accordance with the degree of growth of the rod-shaped carrier. The operation is extremely complicated and difficult, and also causes an increase in the scale of the power supply device.

The second problem is a problem caused by variations in heating that occur when a plurality of rod-shaped carriers are heated at the same time.

When heating a plurality of rod-shaped carriers at the same time, it is difficult to heat all the rod-shaped carriers to a uniform temperature due to the influence of radiant heat and the like. If the heating temperature varies during the process of connecting multiple rod-shaped carriers in parallel, the electrical resistance of the carrier heated at a higher temperature decreases, and the current concentrates on the carrier with lower electrical resistance. This accelerates the heating of the carrier, further lowering its electrical resistance, and ultimately only one carrier is heated and the others are not.

Therefore, polycrystalline semiconductor rods such as high-purity silicon are heated in the form of a plurality of rods connected in series. However, when a plurality of polycrystalline semiconductor rods are connected in series, the load resistance becomes even greater at the initial stage of heating, and a particularly high voltage is required. Further, as described above, a large current is required when the resistance is low in the latter stage of heating. If a single power supply were to simultaneously satisfy these requirements, the scale of the power supply would be enormous.

Therefore, efforts are being made to downsize power supplies by combining multiple power supplies.As shown in Figure 6, two main power supplies with large current capacity that can be switched in series and parallel are used. The semiconductor rods L ₁ to _{L o} are initially heated by connecting T _n and one auxiliary power supply T _s with high voltage capacity in series, and only the main power supply T _n is used in series mode during the middle stage of heating. However, there are some that use only the main power supply T _n in parallel mode at the end of heating. In addition, other devices include, for example,
There is also a device that switches the power supply by -△ switching (Japanese Patent Application Laid-open No. 80284/1984).

[Problem to be solved by the invention]

However, the former heating power supply device requires a plurality of power transformers, and its capacity is still large, resulting in a large price and space requirement. Moreover, with this power supply,
Not only does it take time to switch the power source, but the current temporarily stops when switching, causing sudden changes in electromagnetic force and temperature, which can lead to quality defects in the semiconductor rods that become the product. Furthermore, the latter power supply device does not have a large difference in effectiveness compared to the former power supply device.

The present invention solves all the problems of the conventional devices described above, and its purpose is to make it possible to continuously adjust the load voltage by cleverly combining multiple thyristor units and multiple transformers. It is an object of the present invention to provide a heating power supply device that can simultaneously and stably heat objects having negative resistance such as semiconductors in parallel, which has been considered impossible in the past.

[Means to solve the problem]

The heating power supply device of the present invention according to claim 1 includes a power transformer and a group of anti-parallel thyristor units each including a plurality of anti-parallel thyristors whose input sides are respectively connected to locations where the voltages on the secondary side of the power transformer are different. , the input side is connected in parallel to the output side of the group of anti-parallel thyristor units, and the input sides are connected in parallel so that the currents flowing through the individual secondary coils are balanced at a predetermined ratio, and the individual secondary coils on the output side It is characterized by comprising a balanced transformer group consisting of a plurality of transformers each having a plurality of heated objects connected in series to each end of the coil.

In the heating power supply device of the present invention according to claim 2, the balanced transformer group includes a small current/high voltage balanced transformer group exclusively used for startup, and a group of small current/high voltage balanced transformers that are operated continuously from the small current/high voltage balanced transformer group. The small current/high voltage balanced transformer group is assembled with a dedicated anti-parallel thyristor unit connected to the high voltage point on the secondary side of the power transformer. It is characterized by being combined.

[Effect]

In the heating power supply device of the present invention according to claim 1, a plurality of anti-parallel thyristors in the anti-parallel thyristor group are sequentially connected to a power transformer from a high voltage side to a low voltage side, and the anti-parallel thyristors connected to the power transformer are By controlling the firing angle, the output voltage can be changed continuously. Furthermore, the voltage range that each anti-parallel thyristor bears becomes smaller, the anti-parallel thyristor group becomes smaller, and the output voltage range is expanded.

Furthermore, the output voltage of the anti-parallel thyristor group is applied equally to multiple heated objects, each of which is connected in series with a plurality of transformers whose secondary currents are balanced. ing. Therefore, even though a plurality of objects to be heated are connected in parallel, each object to be heated is supplied with a specific voltage arbitrarily adjusted by a group of anti-parallel thyristor units.
A predetermined ratio of current balanced by the plurality of transformers is applied regardless of the resistance of each heated object. As a result, even if the objects to be heated are polycrystalline semiconductor rods made of high-purity silicon or the like having negative resistance, the objects to be heated are simultaneously and uniformly heated in a state where the objects are connected in parallel.

In the heating power supply device of the present invention as set forth in claim 2, a small current/high voltage balanced transformer group dedicated to startup is provided independently together with an anti-parallel thyristor unit. As a result, when the object to be heated is a polycrystalline semiconductor rod, the initial heating that exhibits unique current/voltage characteristics is handled by the small-capacity dedicated device mentioned above, and the capacity of the balance transformer group and anti-parallel thyristor unit that takes over is can be significantly reduced. Furthermore, since there is almost no temperature difference between the objects to be heated during initial heating, the dedicated device does not require the same level of control precision as the equipment that will succeed it.

〔Example〕

Hereinafter, the present invention will be explained in detail based on embodiments shown in the drawings.

FIG. 1 is a circuit diagram showing the main circuit of an example of the heating power supply device of the present invention.

The main circuit comprises one power transformer MT, a group of antiparallel thyristor units X, a balancing transformer BT, and a group of low current/high voltage balancing transformers BST.
The anti-parallel thyristor unit group X consists of m+1 anti-parallel thyristor unit groups X ₀ , X ₁ , X ₂ . . . X _n . The balanced transformer group BT consists of n transformers BT ₁ , BT ₂ ...XT _o of normal configuration corresponding to the semiconductors L ₁ , L ₂ ...L _o that are heated objects, and the primary coil in each transformer One end of P is the input side of the balanced transformer group BT, and one end of the secondary coil S with the same polarity as the primary coil P is the output side of the balanced transformer group BT. The small current/high voltage balanced transformer group BST is
It consists of n transformers BST _{1 , BST 2} .

A plurality of taps TP ₁ , TP _{2 .} . . TP _n having different voltages are provided on the secondary side of the power transformer MT. The voltage of each tap is TP ₁ (v)＞TP ₂ (v)＞…＞TP _n
(v). Tap TP ₁ , TP ₂
...TP _n is connected to the input sides of a plurality of thyristor units X ₁ , X ₂ , ...X _n combined in antiparallel, respectively. X ₁ of each thyristor unit,
X ₂ ,...X _n output side is combined into one at _point P, and multiple transformers PT _{1 ,} BT ₂ ...BT _o
One ends (input side) of the primary windings P are connected in parallel. The other end of the primary winding P is connected to one end of the secondary winding S of the adjacent balancing transformers BT ₁ , BT ₂ . . . BT _o so as to have opposite polarity. The other end of the secondary winding S is connected to one terminal ₁ , ₂ ...n into which the semiconductor rods L1, L2... _Lo are inserted. The other terminals ₁ ', ₂ '...n' into which the semiconductor rods L1, L2...L _o are inserted are connected to the ground wire L'.

Terminal 1- into which each semiconductor rod L ₁ , L ₂ ...L _o is inserted
Between 1', 2-2'... between n-n', there are multiple small current/high voltage transformers BST ₁ , BST ₂ ... dedicated for startup.
Each secondary winding S of BST _o is connected respectively. Small current/high voltage transformer BST ₁ , BST ₂ …BST _o
The primary windings P are connected in series with forward polarity. One end of each winding P is connected to the tap TP ₁ on the high voltage side of the power transformer MT with a thyristor unit X ₁ .
It is connected to the output side of the thyristor unit _X0 , which is connected separately from the _thyristor unit Connected at ₂ points.

Note that CT is a current transformer used for automatic control described later, and is provided on the output side of the transformer _BT1 .

The operation and operation of the heating power supply main circuit having the above configuration are as follows.

In the first step, currents I 1 , I ₂ ...I _{o of the same magnitude and increasing continuously are passed through the semiconductor rods L 1 , L 2 ...L o without using an electromagnetic} contactor or the like. ₁ ,
L ₂ ...Grow L _o . For this reason, at the start,
Thyristor unit X ₀ through magnetic contactor MC
and BST ₁ , a small current/high voltage transformer dedicated to startup.
BST ₂ ... In the circuit with the primary winding P of BST _o , the phase of the thyrist unit X ₀ is controlled and the semiconductor rods L ₁ , L ₂
…Apply voltage E ₀ to _Lo .

At this time, if the resistances of the semiconductor rods L ₁ , L ₂ ...L _o are equal, the small current/high voltage transformers BST ₁ , BST ₂
…The currents I ₁ , I ₂ … I _o flowing to the secondary side of BST _o are: I ₁ = I ₂ … = I _o (N _p /N _s ) I ₀ (N _p : number of primary turns, N _s : 2 (next number of turns), and the voltage applied to the primary side is E ₀ /n. In addition, if the resistances of the semiconductors L ₁ , L ₂ ...L _o are different, such as R ₁ ≠R ₂ ...≠R _o , each of the small current/high voltage transformers BST ₁ , BST ₂ ...BST _o The next-side impedance is (N _p /N _s ) ² R ₁ , (N _p /N _s ) ² R ₂ ... (N _p /N _s ) _Ro . As a result, each primary winding P has (N _p /N _s )R ₁ I ₀ , (N _p /N _s )R ₂ I ₀ ...(N _p /N _s )R _o I ₀ The following voltages are generated in each secondary winding S: (N _p /N _s )R ₁ I ₀ , (N _p /N _s )R ₂ I ₀ ... (N _p /N _s )R _o I ₀ A voltage is induced. As a result, the semiconductor rod L ₁ ,
The current flowing through L ₂ ...L _o is I ₁ = 1/R ₁ (N _p /N _s ) R ₁ I ₀ , I ₂ = 1/R ₂ (N _p /N _s ) R ₂ I ₀ ... I _o = 1/R ₁ (N _p /N _s ) R _o I ₀ , and in this case, as in the case where the resistance values of the semiconductor bars are equal, I ₁ = I ₂ ...I _o = (N _p /N _s ) I It becomes ₀ .

Therefore, by adjusting the firing angle of the thyristor unit _X0 to control _I0 , it is possible to control the voltage applied to each semiconductor bar while balancing the current flowing through each semiconductor bar. It is.

The first step above requires high voltage, but compared to the case where semiconductor bars are connected in series,
The voltage is much lower and the current is very small. Therefore, the small current/high voltage transformer BST ₁ ,
BST ₂ ...The capacity of BST _o and thyristor unit X ₀ is small. In addition, there is almost no difference in temperature or precipitation reaction between the semiconductor bars at this stage, so the current
No particular problem arises even if I ₁ , I ₂ ...I _o are constant.

In the first step, the semiconductors L ₁ , L _{2 .} . . , the current flowing through the semiconductor rods L _{1 ,} L _{2 .} . . _Lo is transferred to _a circuit consisting of thyristor units X _{1 ,} X ₂ .

In the second step, first, thyristor unit X ₂ is fully fired and X ₁ is phase controlled.
A voltage E ₁ having a waveform shown in FIG. 2a is generated between P ₁ and P ₂ to supply a current I ₀ ' to a group of balanced transformers consisting of transformers BT ₁ , BT ₂ . . . BT _n . Semiconductor L ₁ , L ₂
...If the currents flowing through L _o are I ₁ , I ₂ ...I _o , then if each current is balanced, the currents flowing through each primary winding P and secondary winding S of each transformer are equal, and the currents flowing through each transformer are equal. Therefore, the magnetomotive forces cancel each other out and no electromotive force is generated in the respective primary windings P and secondary windings S of each transformer. However, if I ₁ ≠I ₂ ≠...≠I _o , each A magnetomotive force is generated in each of the primary winding P and secondary winding S of the transformer, producing an electromotive force, and as a result, the current in each semiconductor bar increases if the current is small, and decreases if the current is large. Operate.

That is, between both terminals of each semiconductor rod L ₁ , L ₂ ...L _o ,
In other words, the voltages e ₁ , e ₂ ...e _o applied between the terminals 1-1', 2-2'... n-n' change the resistance of each semiconductor bar by R ₁ , R ₂ ...R, respectively. _o and also transformer BT ₁ ,
The voltages V ₁ , V ₂ ...V _o induced in BT ₂ ...BT _n are respectively V ₁ = K (I _o - I ₁ ), V ₂ = K (I ₁ - I ₂ )... V _o = K
Assuming (I _o-1 − I _o ) (where K is a constant and a value determined by the design of the transformer), e ₁ = [E ₁ + K (I _o − I ₂ )], e ₂ =
[E ₁ +K (I ₁ - I ₂ )], e ₃ = [E ₁ + K (I ₂ - I ₃ )]...e _o
=
[E ₁ +K(I _o-1 −I _o )].

This is because, in general, when designing a transformer, the transformer induced voltage V is expressed as V=4.44f·N·A·B×10 ^-8 .

Here, f = frequency N = number of turns (primary side) A = core cross-sectional area B = magnetic flux density f, N, and A are constants determined by design, B refers to the magnetic flux density in the core, and primary side current I ₁ The difference between B and secondary current I ₂ is proportional to B. Therefore, V=4.44f・N・A・S(I ₁ −I ₂ )×10 ^-8
=K(I ₁ −I ₂ ) S: Constant of proportionality. On the other hand _, since E ₁ is the voltage output from _the thyristors X ₁ , X _{2 . . .} It becomes an addition, and e _o =E ₁ +V _o = [E ₁ +K(I _o-1 4-I _o )].

_{Therefore , the respective currents I 1 , I 2 .} (I ₁ - I ₂ )]... I _o = 1/R _o [E ₁ + K (I _o-1 - I _o )], and each current is determined by the current and voltage of the adjacent semiconductor bar, and sequentially, I ₁ = E ₁ + KI _o /1 + R ₁ , I ₂ = E ₁ + KI ₁ /1 + R ₂ ...I _o = E ₁ +
KI _o-1 /1 + R _o .

As a result, for example, if I _o increases, I ₁ increases at the same time, and the current in each semiconductor bar follows I _o in sequence,
If K is equal between each transformer, I ₁ = I ₂ =...
= I will settle down with _o . Moreover, if K is not equal, I ₁ , I _{2 .} . . I _o will be balanced at that ratio. In other words, if we control the phase angle of the thyristor unit X ₁ to change E ₁ and control I _o , we get
I ₁ , I ₂ ...I _o-1 sequentially according to the ratio of K between each transformer
will be controlled in a balanced manner.

In this case, the voltage width controlled by the thyristor units X ₁ and X ₂ is Tp ₁ (v) to Tp ₂ (v), and as the diameter of each semiconductor rod increases due to growth and the resistance decreases, the voltage control width changes. Tp ₁ (v) to Tp ₂ (v) are too high, so next, voltage control is performed using taps Tp ₂ and Tp ₂₊₁ . The voltage at this time is Tp ₂
(v) to Tp ₂₊₁ (v), so that the thyristor unit X ₂₊₁ is fully fired and the phase of X ₂ is controlled. After that, the taps are lowered one after another, and finally the taps Tp _n+1 , T _pn
is controlled by thyristor units X _n-1 and X _n connected to obtain a voltage E ₁ having the waveform shown in FIG. 2b,
In the end, E ₁ is controlled up to Tp ₁ (v). Further, the current I ₀ ' is increased over time by a program or manually.

In the second step above, a large current is required, but the voltage has already dropped significantly, so the transformer
BT ₁ , BT ₂ ...BT _o and thyristor unit X ₁ ,
X ₂ ...X _n has a small capacity.

By the way, why does the above current (I ₁ , I ₂ ...I _o )
The reason why it is necessary to control the ratio is because the precipitation growth reaction differs depending on the installation position of the semiconductor rod.

Generally, when a large number of semiconductor rods are deposited and grown at the same time, the cooling means of the apparatus is provided on the wall of the quartz Bergier furnace that covers the semiconductor rods. Therefore, a temperature difference occurs between the area close to the bell gear furnace wall and the furnace core due to the difference in the amount of heat released, resulting in a difference in the precipitation rate. That is, while the furnace core grows relatively quickly, the growth of the furnace wall is delayed. This growth rate is due to the initial heating (first step) where the amount of heat radiation itself is small.
This is not a problem, but it cannot be ignored in the second step, and it becomes more noticeable as the number of simultaneous deposits increases. Therefore, when growing a large number of semiconductor rods at the same time, in order to maintain uniform precipitation growth for all semiconductor rods, a predetermined correlation should be established between the currents in areas where the precipitation growth is slow and areas where the precipitation growth is fast. Therefore, it is necessary to control it.

FIG. 3 is a block diagram for controlling the main circuit shown in FIG. 1. The signal from the program setting device or manual setting device 12 and the current from the detection unit 11 of the current transformer CT are converted into effective values, the outputs are compared, and the error amount is amplified by the DC amplifier 13. Then, when the MC is turned on, that is, when the semiconductor bar heating starts, the output of the DC amplifier 13 is applied to the phase pulse regulator 23, and the pulse transformer 24
The current flowing through the semiconductor rod is controlled by adjusting the phase angle of _the thyristor unit _X0 .

Next, when the electromagnetic contactor MC is cut off, the output of the DC amplifier 13 becomes equal to the number of thyristor units (X ₁ ~
X _n ) and the same number of shift circuits 14, 15, 16
The output signal of the shift circuit 14 changes sequentially from 0 to α in proportion to the amount of the setting signal from the program setting device or manual setting device 12.
The output signal of the shift circuit 15 transitions from 0 to α ₁ and the output signal of the shift circuit 16 transitions from 0 to α ₁ . Therefore, the pulse signals of the phase pulse regulators 17, 18, 19 sequentially shift from 0 to 180°, and the thyristor units X ₁ ,
_{X 2 ... _ _ _ _ _} As mentioned above, the voltage E ₁ is Tp ₁ (v)→Tp ₂ (v)…→
This results in a change to Tp _n (v) and an increase in current.

FIG. 4 is a circuit diagram showing another embodiment of the present invention,
The transformers BT ₁ , BT ₂ , . . . BT _o and terminals 1-1', 2-2', .

In the main circuit, transformers BT ₁ and BT ₂ are connected at point P ₁ to the same anti-parallel thyristor unit group as described above.
...One end of each secondary winding P of BT _o is connected.
The other end of each secondary winding P is connected to one connection terminal ₁ , ₂ ...n of the semiconductor rods L1, L2... _Lo .
The other connection terminals 1', 2'...n' of each semiconductor bar are connected to the ground line L' as in the circuit of FIG.
Furthermore, between terminals 1 and 1', between terminals 2 and 2', and between n and n', there are small current/high voltage transformers BST ₁ , which are used only for startup.
BST ₂ …BST _o and anti-parallel thyristor unit
X ₀ etc. are also connected. And each transformer BT ₁ ,
Each primary winding S of BT ₂ ...BT _o is connected in series in a loop with forward polarity.

In the main circuit, when voltage _{E 1} is supplied by power transformer MT and anti-parallel thyristor units X _{1 , X 2 .} . .
If the resistance of L _o is equal, the current flowing through each semiconductor bar is I ₁ = I ₂ =... = I _o = N _p /N _s I _p (N _p : number of primary turns, N _s : number of secondary turns). Become. I _p is the balanced transformer BT ₁ ,
BT ₂ ... Current flowing through each primary winding P of BT _o , with supply voltage E ₁ , resistance R ₁ of semiconductor rods L ₁ , L ₂ ... _Lo ,
It is obtained from R ₂ ...R _o and the voltages e ₁ , e ₂ ...e _o as follows.

I _p =1/n・N _s /N _p・(I ₁ +I ₂ …I _o ) =1/n・N _s /N _p・(e ₁ /R ₁ +e ₂ /R ₂ +…+e _o /R _o ) = 1/n・N _s /N _p・[(E ₁ −e ₁ /R ₁ )′ + (E ₁ −e ₂ /R ₂ )…+(E ₁ −e _o ′/R _o ) However, , e ₁ ′, e ₂ ′…e _o ′ are transformers BT ₁ , BT ₂ …
This is the secondary voltage of BT _o .

In addition, the resistances R ₁ , R ₂ ... of each semiconductor rod L ₁ , L ₂ ...L _o
If _Ro is different such as R ₁ ≠ R ₂ ≠…≠ _Ro , the primary impedance of each transformer BT ₁ , BT ₂ ...BT _o is sequentially as follows: ((N _p /N _s ) ² R ₁ , (N _p /N _s ) ² R ₂ ... (N _p /N _s ) ² _Ro , and the voltage induced in each primary winding P is also equivalently sequential (N _p /N _s ) ² R ₁ , (N _p /N _s ) ² R ₂ ... (N _p /N _s ) ² _Ro.On the other hand, each secondary winding S of the transformer BT ₁ , BT ₂ ...BT _o has the above Only the voltage necessary to induce the primary winding P is applied, and each secondary voltage is e ₁ ′=(N _p /N _s )R ₁ I _p , e ₂ ′=(N _p /N _s ) R ₂ I _p ... e ₁ ′ = (N _p / N _s ) R _o I _p.Then , the semiconductor rods L ₁ , L ₂ ... which are loads are
_Lo has the remaining voltages (E ₁ −e ₁ ′), (E ₁ −e ₂ ′)…(E ₁
−e _o ′) will be applied, so
The currents I ₁ , I ₂ ... I _o flowing through each semiconductor bar are: I ₁ = 1/R ₁ (N _p /N _s ) R ₁ I _p = (N _p /N _s ) I _p I ₂ = 1/R ₂ (N _p / N _s ) R ₂ I _p = (N _p / N _s ) I _p … I _o = 1/R _o (N _p / N _s ) R _o I _p = (N _p / N _s ) I From the _above , I ₁ = I ₂ =...I _o = (N _p /N _s ) I _p .

That is, in the main circuit as well, semiconductors L ₁ ,
The currents I _{1 ,} I 2 ...I _o flowing through L ₂ ...L _o are kept constant regardless of their respective resistance values R ₁ , R ₂ ...R _o .

At startup, a small current/high voltage transformer exclusively for startup
BST ₁ , BST ₂ …Due to the action of BST _o, the above current I ₁ ,
I ₂ ... I _o are balanced as described in the circuit of Figure 1.

The balanced transformer group adopted in the circuit shown in Figure 1 and the fourth
The advantages and disadvantages of the balanced transformer group adopted in the circuit shown in the figure are as follows.

When performing a relatively small-scale precipitation reaction, when the precipitation growth of each semiconductor is almost uniform and there is no need to adjust the precipitation rate depending on the location of the semiconductor rod during the reaction, it is easy to design a balanced transformer. Furthermore, the balanced transformer group of FIG. 4 is advantageous because it is easy to maintain. On the other hand, if it is necessary to control precipitation growth during the reaction as described above, the balanced transformer group shown in FIG. 1 must be used. Therefore, in actual operation, it is reasonable to use the balancing transformer groups shown in FIGS. 1 and 4 as appropriate based on the scale of operation and the like.

Further, even in the case of a large-scale precipitation reaction, there is almost no difference in the precipitation state of each semiconductor rod during initial heating. Therefore, it is desirable that the small current/high voltage transformer used exclusively for startup be a transformer with a simple structure as in both of the above embodiments.

In addition, if you are willing to increase the scale of the transformer, you can use small current/high voltage transformers BST ₁ and BST ₂ exclusively for startup.
...BST _o , and the transformer BT ₁ , which takes over operation from the transformer and continues operation up to high current and low voltage.
It is possible to combine BT ₂ ...BT _o into a set of balanced transformers.

In addition, a small current/high voltage transformer is used exclusively for startup.
The anti-parallel thyristor unit X ₀ combined with BST ₁ , BST _{2 .} . . BST _o may be omitted, and the anti-parallel thyristor unit X ₁ may be shared.

Furthermore, the balanced transformer group is not limited to the circuit shown in FIG. 1 and the circuit shown in FIG. .

〔Effect of the invention〕

In the heating power supply device of the present invention as set forth in claim 1, even if the object to be heated is a polycrystalline semiconductor bar made of high-purity silicon or the like having negative resistance, the object can be connected in parallel and heated evenly. Therefore, the voltage applied to the object to be heated is significantly reduced, and the power supply voltage is reduced. Further, only one power transformer is required, and its capacity is relatively small. Therefore, it is possible to increase the number of objects to be heated, and heating economy is significantly improved.

Furthermore, since the voltage applied to the heated object can be continuously varied over a wide range, the heating accuracy for the heated object is improved, and the control mechanism using the thyristor unit is simple. Therefore,
Together with the miniaturization of the power transformer, the scale and cost of the entire power supply device are significantly reduced.

In the heating power supply device of the present invention as set forth in claim 2, the scale of the entire power supply device is further reduced by expanding the balance transformer group and the anti-parallel thyristor unit at the time of startup.

[Brief explanation of drawings]

Fig. 1 is a circuit diagram showing an example of the main circuit in a heating power supply device embodying the present invention, Figs. FIG. 3 is a control block diagram of the main circuit, FIG.
The figure is a voltage/current characteristic diagram when heating and growing a semiconductor rod, and FIG. 6 is a circuit diagram showing the main circuit of a conventional heating power supply device. In the figure, _Tn : main power supply, _Ts : auxiliary power supply, MT: power transformer, X: anti-parallel thyristor unit group,
X ₀ to _{X n} : Anti-parallel thyristor unit, BT: Balanced transformer group, BT ₁ to _{BT o} : Transformer, BST: Small current/high voltage balanced transformer group, BST ₁ to BST _o : Small transformer dedicated for startup Current/high voltage transformer, CT: current transformer,
MC: Electromagnetic contactor, L ₁ ~ _{L o} : Semiconductor bar, 11: Detector, 12: Setting device, 13: DC amplifier, 14 ~
16: Shift circuit, 17-19: Phase pulse adjuster, 20-22, 24: Pulse transformer, 23:
Phase pulse regulator.

Claims (1)

[Claims] 1. A power transformer, a group of anti-parallel thyristor units each including a plurality of anti-parallel thyristors whose input sides are respectively connected to locations where the voltages on the secondary side of the power transformer differ, and the anti-parallel thyristor units. The input side is connected in parallel to the output side of the group, and the currents flowing through the individual secondary coils are interconnected so that they are balanced at a predetermined ratio. 1. A heating power supply device comprising a balance transformer group consisting of a plurality of transformers each having a heating body connected in series. 2 The balanced transformer group generates a small current exclusively for startup.
It is divided into a high-voltage balanced transformer group and a balanced transformer group that continues operation following the low-current/high-voltage balanced transformer group, and the low-current/high-voltage balanced transformer group is 2. The heating power supply device according to claim 1, wherein the heating power supply device is combined with a dedicated anti-parallel thyristor unit connected to a high voltage point on the secondary side of a power transformer.