TWI471463B - Measurement and compensation system for ingot growth and method thereof - Google Patents

Description

Crystal growth measurement compensation system and method thereof

A compensation system and method thereof, especially a measurement and compensation system for crystal growth.

Polycrystalline germanium materials are widely used in consumer electronics products, such as the solar cell industry, because of their high production speed and low cost. Polycrystalline germanium materials are produced by means of casting, and all of the germanium raw materials are melted in a large scale. By slow cooling, crystals containing crystal grains of different lattice directions are formed.

Conventional polycrystalline germanium growth furnaces can be roughly divided into three types: the first is a casting method in which the melt and the crystallization process are carried out in different crucibles; the second melting and crystallization process is carried out in the same crucible; and the third electromagnetism without using antimony Casting method.

Directional solidification (DSS) is the mainstream of polycrystalline germanium in the market. For polycrystalline crystal growth furnaces using tantalum, the process is limited by the physical properties of tantalum, the difference of raw materials, the thermal field of casting furnace. The degree of aging, the degree of aging of the temperature-controlled thermocouple of the foundry furnace, and other variations of the casting furnace itself cause a large variation in crystal growth conditions, resulting in unstable quality of the crystals produced each time. Generally speaking, the long crystal velocity affects the degree of impurity precipitation such as impurities, and also affects the crystal growth structure. Since the conventional directional solidification method of the polycrystalline crucible casting furnace does not have the function of monitoring the long-speed change of the crystal in real time, it is increased. Variations in process stability.

One of the objects of the present invention is to provide a crystal growth measurement compensation system capable of real-time monitoring of the growth rate or crystal change of the crystal growth, and timely compensation, so that the conditions for crystal growth are optimized. Under the parameters, to ensure the uniformity of the quality of the crystal.

The embodiment of the present invention provides a crystal growth measurement and compensation system, comprising: a control unit storing a predetermined crystal growth data; a crystal growth rate measuring unit coupled to the control unit, having at least one quartz rod; a casting unit coupled to the control unit, the motor unit having at least one turn and a pair of temperature control modules; wherein the crystal growth rate measuring unit is mounted on the top of the crucible, the quartz rod is relatively The raft is moved, whereby the crystal growth rate measuring unit measures the crystal growth data in the crucible, and the control unit can compensate the crystal growth in the casting unit according to the predetermined crystal growth data.

Embodiments of the present invention provide a crystal growth measurement compensation method, including the following steps:

1. A control unit for storing a predetermined crystal growth data, a crystal growth rate measuring unit coupled to the control unit, and a casting unit coupled to the control unit;

2. performing a crystal growth step: melting one seed crystal and a plurality of crystal growth materials by using one of the casting units;

3. Performing a measuring step: using a quartz rod of the crystal growth rate measuring unit to move relative to the crucible, wherein the crystal growth rate measuring unit measures the crystal growth data of the crystal growth step;

4. Performing an alignment step: using the control unit to compare the crystal growth data of the crystal growth step with the predetermined crystal growth data;

5. Performing a compensation step: controlling the casting unit with the control unit to compensate for crystal growth data for adjusting the crystal growth step.

In a specific embodiment, the crystal growth rate measuring unit can be an electronically controlled or manually operated unit.

The invention has the following beneficial effects: the invention mainly uses the crystal growth rate measuring unit to monitor the speed of crystal growth and the melting of the material in real time, and uses the computer to compare the actual growth conditions and the optimized growth conditions. The difference, and then the actual growth conditions are adjusted and compensated to optimize the growth conditions, in order to avoid the problem of unstable crystal quality caused by variations in various production conditions.

For a better understanding of the features and technical aspects of the present invention, reference should be made to the accompanying drawings.

The invention mainly provides a crystal growth measurement compensation system, which can detect crystal growth data in a casting unit by using a crystal growth rate measuring unit, and grow the measured crystal growth data and a predetermined crystal growth input in a control computer. The data is compared to ensure the control of the growth conditions to improve the stability of the process. It should be noted that the predetermined crystal growth data and the measured crystal growth data may include a relatively diverse and extensive data, such as the long crystal speed, the melting speed of the crystal growth material, and the like, and the present invention does not limit the crystal. Types (such as single crystal, polycrystalline), long crystal processes (such as mono-like (multi-crystalline silicon solar cells), multi-crystalline silicon solar cells, etc.) or the application of various types of crystal growth furnaces, and the following are directional solidification of polycrystalline germanium The process (DSS) illustrates the invention.

Please refer to FIG. 1 and FIG. 3 , which are functional block diagrams and schematic diagrams of the crystal growth measurement compensation system 1 of the present invention, which include a control unit 11, a crystal growth rate measuring unit 12 and a casting unit 13; wherein the control unit 11 stores The control unit 11 can be a computer having a processor, a storage module 111, a display module, and the like. The storage module 111 is configured to store the predetermined crystal growth data and control the data. Unit 11 can be used to calculate the alignment and output signals to achieve control effects.

The crystal growth rate measuring unit 12 and the casting unit 13 are electrically coupled to the control unit 11, respectively. In other words, the control unit 11 can output signals to control the operation of the crystal growth rate measuring unit 12 and the casting unit 13, and can also receive the crystal. The crystal growth data in the casting unit 13 measured by the growth rate measuring unit 12.

As shown in FIG. 1 , FIG. 3 and FIG. 3A , in the first embodiment of the present invention, the crystal growth rate measuring unit 12 is a unit for automatically detecting crystal growth data during the crystal growth process, and the crystal growth rate is measured. The unit 12 has a driving module 121 coupled to the control unit 11, a quartz rod clamping module 122 coupled to the driving module 121, and a quartz rod 123 fixed to the quartz rod clamping module 122; The crystal growth rate measuring unit 12 is preferably installed in the casting unit 13, so that the quartz rod 123 can be moved into the casting unit 13 to measure the crystal growth data in the casting unit 13 by the height difference, and the crystal growth rate is The measuring unit 12 can return the measured crystal growth data to the control unit 11 for data comparison operation; the driving module 121 can be a linear lead screw, a cylinder, a linear motor or the like.

Furthermore, the casting unit 13 has at least one 坩埚133 and a temperature control module corresponding to the 坩埚133, such as the heating module 131, the cooling module 132 and the furnace wall cooling module 134, the heating module 131, the cooling module 132 and The position of the furnace wall cooling module 134 corresponds to the 坩埚133; the 坩埚133 is a kind of accommodating seed crystal and a plurality of crystal growth materials (for example: sapphire (Al ₂ O ₃ ), bismuth (Si), calcium fluoride (CaF) ₂ ) A container of sodium iodide (NaI) or other halide group salt crystals, etc., which may have a shape such as a D shape, a circular shape or the like. As shown in FIG. 3, the crucible 133 is located above the cooling module 132. The cooling module 132 can be a support member, and the material thereof can be graphite (C), tungsten (W), molybdenum (Mo), niobium (Nb), Made of high melting point metal of lanthanum (La), tantalum (Ta), yttrium (Re) or alloys thereof or other high temperature resistant ceramic materials, the outer shape thereof may also have a structure such as heat radiating fins; and in a variant embodiment The interior of the cooling module 132 may have a hollow portion to mount the cooling flow passage 1321 to utilize the flow of cooling fluid in the cooling flow passage 1321, such as helium (He), neon (Ne), hydrogen (H) or cooling liquid, via The hollow portion cools the crucible 133; likewise, the furnace wall cooling module 134 also has a cooling fluid to provide a cooling function. In addition, the casting unit 13, such as a polycrystalline crucible casting furnace, has a hole at the top thereof, such as a Pyrometer-Dipping tunnel, a TC-1 tunnel, an OT or the like, and the quartz rod 123 can insert the quartz rod 123 through the tunnel. And have its end face contact with the wafer, the surface of the material or the crucible 133.

The heating module 131 can be a heater such as a thermocouple positioned substantially at the crucible 133 to heat the crystal growth material in the crucible 133 together with the seed crystal to a temperature substantially higher than the melting temperature of the crystal growth material. For example, the crystal growth feedstock is heated to a temperature in the range of from about 1100 °C to 2400 °C. While heating, the bottom of the crucible 133 is cooled by flowing the fluid through the cooling flow path 1321 so that the nucleation layer remains intact and incompletely melted, and when the molten material is homogenized, the seed crystal can be started. growing up.

Therefore, after the growth of the seed crystal is started, the crystal growth measurement compensation system 1 of the present invention can perform the following steps to instantly monitor and adjust the growth parameters of the crystal, such as the long crystal speed, the melting speed of the crystal growth material, In order to compensate the actual growth parameters of the crystal to the predetermined crystal growth data set by the operator:

Step 1: Perform a measurement step in which the quartz rod 123 of the crystal growth rate measuring unit 12 is moved relative to the crucible 133 to measure the crystal growth data of the crystal growth step. In the embodiment, the crystal growth rate measuring unit 12 is installed above the crucible 133, and the control unit 11 can output a signal to the driving module 121 of the crystal growth rate measuring unit 12, and the driving module 121 can control the quartz. The rod clamping module 122 drives the quartz rod 123 to move vertically with respect to the crucible 133; when the bottom of the quartz rod 123 contacts the melted crystal material, the crucible 133 or the wafer surface, the quartz rod clamping module 122 can be The distance moved by the distance (i.e., the height difference in which the quartz rod 123 moves) is converted into data such as the long crystal velocity and the melting speed of the crystal growth material.

On the other hand, the storage module 11 of the control unit 11 further stores a measured frequency data, and the driving module 121 can programmatically drive the quartz rod clamping module 122 and the quartz rod 123 according to the measured frequency data. For example, the operator can input and store the measurement frequency data in the storage module 111 of the control unit 11 according to different crystal growth stages in advance, for example, can be set higher in a key stage of the crystal growth process. The frequency measurement action, such as setting the measurement every 15 minutes between the crystal growth time of about 25 to 40 hours, and the other stable growth process for each hour.

Step 2: Performing an alignment step, the control unit 11 compares the crystal growth data of the crystal growth step with the predetermined crystal growth data. Specifically, in this step, the operator may input and store the maximum allowable deviation value between the actual crystal growth data and the predetermined crystal growth data in advance in the storage module 111 of the control unit 11, and the control unit 11 may actually The growth data is compared with a curve of the predetermined crystal growth data to check whether the deviation value between the actual crystal growth data and the predetermined crystal growth data is greater than the maximum allowable deviation value, as described above, in this step, the control unit 11 The actual crystal long-speed, the melting rate of the crystal growth material and the like can be compared with the data of the long-speed crystal of the storage module 111 and the melting speed of the crystal growth material.

Step 3: Perform a compensation step: control the casting unit 13 by the control unit 11 to compensate for the crystal growth data of the crystal growth step. In a specific embodiment, the crystal growth rate measuring unit 12 can be an electronically controlled or manually operated unit; and in a preferred embodiment, the crystal growth data and the predetermined crystal growth data of the crystal growth step of the second step When the deviation value is greater than the maximum allowable deviation value input by the operator, the control unit 11 can control the temperature control module of the casting unit 13, such as the heating module 131, the cooling module 132, the furnace wall cooling module 134 or the insulation. The cage opening degree, etc., compensates the crystal growth data of the crystal growth step until the difference between the two is less than the maximum allowable deviation value. Specifically, when the melting speed of the crystal growth material is too slow, the control unit 11 can control the heating module 131 of the casting unit 13 to increase the heating power thereof, or simultaneously reduce the cooling module 132 and the furnace wall cooling module 134. Cooling speed (such as reducing the flow rate or temperature of the cooling fluid, etc.) to increase the temperature profile of the crucible 133; and if the crystal long speed is too slow, the control unit 11 can control the heating module 131 of the casting unit 13 to reduce its heating power, or At the same time, the cooling rate of the cooling module 132 is increased (such as increasing the flow rate or temperature of the cooling fluid), or the opening of the insulating cage is opened; thereby, the long speed of the crystal or the melting speed of the long crystal material can be Controlled according to predetermined crystal growth data.

In one embodiment, the temperature of the heating module 131 can be controlled to ±10 degrees, the cooling liquid flow rate can be controlled to ±20 LPM, and the cooling gas flow rate can be controlled to ±50 LPM.

Referring to FIG. 2, a second embodiment of the present invention is shown, wherein the difference from the first embodiment is that the crystal growth rate measuring unit 12' of the embodiment is a method for manually driving the quartz rod 123. The crystal growth data of the crystal growth step were measured. In other words, in the present embodiment, the operator directly drives the quartz rod 123 to measure the height of the target object. When the quartz rod 123 moves, the optical travel can be measured by optical, magnetic or electrical signals, for example, when quartz is used. When the rod 123 is in contact with the dip or the ingot, the quartz rod 123 can immediately send a signal due to the contact, and the signal is detected, and the position measurement is performed at the same time to prevent the quartz rod 123 from contacting the soup for too long. The ingot generates a sticking phenomenon, and the operator inputs the height data into the control unit 11, and the control unit 11 can convert the crystal long-speed and long-crystal raw materials according to the data input thereto (that is, the height difference of the movement of the quartz rod 123). Information such as the speed of the melt. Similarly, the control unit 11 can compare the actual crystal growth data with the predetermined crystal growth data, and accordingly control the casting unit 13 to perform the compensation step.

In summary, the present invention achieves at least the following objectives:

1. When the present invention is applied to a polycrystalline germanium long crystal process, the long-speed or crystal change of the growth of each crystal germanium can be monitored in real time.

2. The present invention can utilize the stylized design, editing and definition of the driving module to drive the quartz rod to measure the time and position, as the measurement of the long crystal speed and the melting of the material in different unit time.

3. The invention can input the optimized crystal growth and the melting speed of the feed into the control unit in advance, and can adjust the polycrystalline furnace immediately when the actual speed change measured by the crystal growth rate measuring unit deviates from the input value. A device that affects the change in crystal velocity (such as the temperature control device described above) is compensated to control the crystal growth and the rate at which the material is melted, thereby achieving uniformity in the quality of the grown crystal.

4. The crystal growth rate measuring unit of the present invention can control the movement of the quartz rod in an automatic, semi-automatic or manual manner, and thus has a very wide range of applications.

The above description is only a preferred embodiment of the present invention, and is not intended to limit the scope of the present invention, and the equivalents of the present invention are intended to be included within the scope of the present invention.

1. . . Crystal growth measurement compensation system

11. . . control unit

111. . . Storage module

12. . . Crystal growth rate measuring unit

12’. . . Crystal growth rate measuring unit

121. . . Drive module

122. . . Quartz rod clamping module

123. . . Quartz rod

13. . . Casting unit

131. . . Heating module

132. . . Cooling module

1321. . . Cooling runner

133. . . crucible

134. . . Furnace wall cooling module

1 is a functional block diagram of a crystal growth measurement compensation system according to a first embodiment of the present invention.

2 is a functional block diagram of a crystal growth measurement compensation system according to a second embodiment of the present invention.

3 is a schematic view of a crystal growth measurement compensation system according to a first embodiment of the present invention.

Fig. 3A shows an enlarged view of a portion A in Fig. 3.

1. . . Crystal growth measurement compensation system

12. . . Crystal growth rate measuring unit

121. . . Drive module

122. . . Quartz rod clamping module

123. . . Quartz rod

13. . . Casting unit

131. . . Heating module

132. . . Cooling module

1321. . . Cooling runner

133. . . crucible

134. . . Furnace wall cooling module

Claims (11)

A crystal growth measurement compensation system includes: a control unit storing a predetermined crystal growth data; a crystal growth rate measuring unit coupled to the control unit, having a driving module and a quartz rod clamping mold And the at least one quartz rod, the driving module is coupled to the control unit, the quartz rod clamping module is coupled to the driving module, the quartz rod is clamped to the quartz rod clamping module; and a coupling The casting unit connected to the control unit has at least one cymbal and a corresponding temperature control module for accommodating a crystal growth material; wherein the crystal growth rate measuring unit is mounted on the raft The driving module is configured to drive the quartz rod clamping module to drive the quartz rod to move the quartz rod relative to the crucible, and when the bottom of the quartz rod contacts the crystal crucible, the crystal growth material or the crucible, The quartz rod clamping module measures the crystal growth data in the crucible according to the distance moved by the quartz rod, and the control unit can compensate the crystal growth in the casting unit according to the predetermined crystal growth data. The crystal growth measurement compensation system of claim 1, wherein the control unit further stores a measurement frequency data, and the driving module sequentially drives the quartz rod clamping mode according to the measurement frequency data. Group and the quartz rod. The crystal growth measurement compensation system of claim 2, wherein the control unit has at least one storage module, and the predetermined crystal growth data and the measurement frequency data are stored in the storage module. The crystal growth measurement compensation system according to claim 1, wherein the temperature control module comprises at least a pair of heating modules corresponding to the crucible and a corresponding cooling module and a furnace wall cooling module. The crystal growth measurement compensation system according to claim 1, wherein the crystal growth measurement compensation system is applied to a single crystal process. A crystal growth measurement compensation method includes the following steps: providing a control unit for storing a predetermined crystal growth data, a crystal growth rate measuring unit coupled to the control unit, and a casting unit coupled to the control unit, The crystal growth rate measuring unit has a driving module, a quartz rod clamping module and at least one quartz rod. The driving module is coupled to the control unit, and the quartz rod clamping module is coupled to the driving module. a quartz rod is clamped to the quartz rod clamping module; performing a crystal growth step: melting one seed crystal and a plurality of crystal growth materials by using one of the casting units; performing a measuring step: using the a driving module of the crystal growth rate measuring unit drives the quartz rod holder to drive the quartz rod to move the quartz rod relative to the crucible, and when the bottom of the quartz rod contacts the crystal crucible, the crystal growth material or the坩埚, the quartz rod clamping module measures the crystal growth data of the crystal growth step according to the distance moved by the quartz rod; and performs an alignment step: using the control unit to grow the crystal growth step Crystal growth data with the predetermined data than crystal growth; and performing a compensation step of: using the control unit controls the casting unit, The crystal growth data of the crystal growth step is adjusted to compensate. The crystal growth measurement compensation method according to claim 6, wherein in the measuring step, the driving module drives the quartz rod clamping module to vertically move relative to the crucible to measure the Crystal growth data for the long crystal step. The crystal growth measurement compensation method according to claim 7, wherein the control unit further stores a measurement frequency data, wherein the control unit controls the driving mode according to the measurement frequency data. a group to programmatically drive the quartz rod clamping module and the quartz rod. The crystal growth measurement compensation method according to claim 6, wherein the control unit further stores a maximum allowable deviation value, and in the comparing step, the crystal growth data of the crystal growth step and the predetermined crystal growth data The compensation step is performed when the deviation value between the deviations is greater than the maximum allowable deviation value. The crystal growth measurement compensation method according to claim 9, wherein in the compensating step, the heating unit, a cooling module and a furnace wall cooling module of the casting unit are controlled by the control unit. At least one of them is used to compensate for the crystal growth data of the crystal growth step. The crystal growth measurement compensation method according to claim 6, wherein in the measuring step, the movement of the quartz rod is controlled in an automatic, semi-automatic or manual manner.