US3822111A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Apparatus for pulling up semiconductor crystals
Assignee: Sony Corp
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Filing: 1973-01-29
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Granted: 1974-07-02
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Expires: 1993-01-29
Abstract
Abstract Apparatus for controlling the diameter of a crystal pulled from a semiconductor melt in a crucible including a float which has a shape substantially similar to the crystal and which is pulled from a liquid filled tub in synchronism with the pulling up of the crystal, and an electronic circuit for comparing the weight of the float with the weight of the crystal during the pull up operation. The rate at which the crystal is pulled up and the temperature of the crucible are controlled as a function of the relative weights of the float and the crystal as they are being pulled up.
Inventors
- 👤 T Suzuki
- 👤 K Hoshi
- 👤 Y Tamate
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 09:50
CPC Classifications
C; C30; C30B; C30B15/00; C30B15/20; C30B15/22; C30B15/28; Y; Y10; Y10T; Y10T117/00; Y10T117/10; Y10T117/1004; Y10T117/1008; Y10T117/1024; Y10T117/1032; Y10T117/106; Y10T117/1064; Y10T117/1072
Claims Analysis
Total Claims: 42
Claim 1
Independent Claim
109 words
Apparatus for producing a semiconductor crystal comprising: a. a crucible containing a melt of the semiconductor; b. a tub filled with a liquid; c. a float immersed in the liquid of the tub; d. means for simultaneously pulling up a growing crystal from the crucible and for removing the float from the liquid; e. comparator means for comparing the weights of the crystal and the float and for producing an output signal representative of the weight difference between the crystal and the float; and f. control means responsive to the output signal of the comparator means for controlling the speed at which the crystal and float are pulled up.
Claim 2
Dependent Claim
109 words
Apparatus for producing a semiconductor crystal comprising: a. a crucible containing a melt of the semiconductor; b. a tub filled with a liquid; c. a float immersed in the liquid of the tub; d. means for simultaneously pulling up a growing crystal from the crucible and for removing the float from the liquid; e. comparator means for comparing the weights of the crystal and the float and for producing an output signal representative of the weight difference between the crystal and the float; and f. control means responsive to the output signal of the comparator means for controlling the speed at which the crystal and float are pulled up.
Claim 3
Dependent Claim
28 words
Apparatus for producing a semiconductor crystal as recited in claim 1 wherein the float has the desired shape of the crystal to be pulled up from the crucible.
Claim 4
Dependent Claim
22 words
Apparatus for producing a semiconductor crystal as recited in claim 1 wherein the control means includes means for vertically moving the crucible.
Claim 5
Dependent Claim
23 words
Apparatus for producing a semiconductor crystal as recited in claim 1 wherein the control means further controls the heating temperature of the crucible.
Claim 6
Dependent Claim
60 words
Apparatus for producing a semiconductor crystal as recited in claim 1 wherein the means for pulling up the crystal and the float includes a vertically movable member, and wherein the comparator means includes a first weight detector connected between the vertically movable member and the crystal and a second weight detector connected between the vertically movable member and the float.
Claim 7
Dependent Claim
28 words
Apparatus for producing a semiconductor crystal as recited in claim 1 further comprising means for rotating the crucible and the crystal in opposite directions relative to each other.
Claim 8
Dependent Claim
101 words
Apparatus for producing a semiconductor crystal as recited in claim 1 wherein the control means includes means for sensing the length of the crystal and for producing a first output signal representative of the length of the crystal, means for sensing the weight of the crystal and for producing a second output signal representative of the crystal weight, and means responsive to the first and second output signals for controlling the rate of response of the control means as a function of the rate of change of the second Signal with respect to the rate of change of the first signal.
Claim 9
Dependent Claim
30 words
Apparatus for producing a semiconductor crystal as recited in claim 1 wherein the tub is fed with a continuous supply of liquid for maintaining the liquid level constant in height.
Claim 10
Dependent Claim
25 words
Apparatus for producing a semiconductor crystal as recited in claim 1 wherein the tub and the crucible have interior hollow shapes which are substantially identical.
Claim 11
Dependent Claim
26 words
Apparatus for producing a semiconductor crystal as recited in claim 1 wherein the tub is lifted up for maintaining the height of the liquid level constant.
Claim 12
Dependent Claim
29 words
Apparatus for producing a semiconductor crystal as recited in claim 1 further comprising means for heating the crucible and means for rotating the crucible relative to the heating means.
Claim 13
Dependent Claim
37 words
Apparatus for producing a semiconductor crystal as recited in claim 1 further comprising: a. means for heating the crucible; b. a furnace for enclosing the crucible and the heating means; and c. means for cooling the furnace.
Claim 14
Dependent Claim
47 words
Apparatus for producing a semiconductor crystal as recited in claim 12 further comprising: a. means for sensing the temperature of the furnace and for producing a control signal representative of the furnace temperature and b. means for controlling the cooling means in accordance with the control signal.
Claim 15
Dependent Claim
108 words
Apparatus for producing a semiconductor crystal comprising: a. a crucible containing a melt of the semiconductor; b. a tub filled with a liquid; c. a float immersed in the liquid of the tub; d. means for simultaneously pulling up a growing crystal from the crucible and for removing the float relative to the liquid in the tub; e. comparator means for comparing the weights of the crystal and the float and for producing an output signal representative of the weight difference between the crystal and the float; and f. control means responsive to the output signal of the comparator means for controlling the shape of the growing crystal.
Claim 16
Dependent Claim
108 words
Apparatus for producing a semiconductor crystal comprising: a. a crucible containing a melt of the semiconductor; b. a tub filled with a liquid; c. a float immersed in the liquid of the tub; d. means for simultaneously pulling up a growing crystal from the crucible and for removing the float relative to the liquid in the tub; e. comparator means for comparing the weights of the crystal and the float and for producing an output signal representative of the weight difference between the crystal and the float; and f. control means responsive to the output signal of the comparator means for controlling the shape of the growing crystal.
Claim 17
Dependent Claim
28 words
Apparatus for producing a semiconductor crystal as recited in claim 14 wherein the float has the desired shape of the crystal to be pulled up from the crucible.
Claim 18
Dependent Claim
22 words
Apparatus for producing a semiconductor crystal as recited in claim 14 wherein the control means includes means for vertically moving the crucible.
Claim 19
Dependent Claim
39 words
Apparatus for producing a semiconductor crystal as recited in claim 14 wherein the means for controlling the shape of the growing crystal includes means for controlling the speed at which the growing crystal and the float are pulled up.
Claim 20
Dependent Claim
140 words
Apparatus for producing a semiconductor crystal as recited in claim 17 wherein the control means includes means for generating a control signal representative of the variation of the weight of the growing crystal due to the increase in its length, a reference source for supplying a reference signal, comparator means for comparing the control signal with the reference signal and for generating an output signal representative of the difference between the control signal and the reference signal, and means responsive to the comparator output signal for vertically moving the crucible at a controlled speed such that the ratio of the pull-up speed of the growing crystal to the lift speed of the crucible equals the ratio of the cross-sectional area of the crucible to the cross-sectional area of the crystal, taken at the surface of the melt in the crucible.
Claim 21
Dependent Claim
23 words
Apparatus for producing a semiconductor crystal as recited in claim 14 wherein the control means further controls the heating temperature of the crucible.
Claim 22
Dependent Claim
60 words
Apparatus for producing a semiconductor crystal as recited in claim 14 wherein the means for pulling up the crystal and the float includes a vertically movable member, and wherein the comparator means includes a first weight detector connected between the vertically movable member and the crystal and a second weight detector connected between the vertically movable member and the float.
Claim 23
Dependent Claim
30 words
Apparatus for producing a semiconductor crystal as recited in claim 20, wherein the first and second weight detectors comprise strain gages constructed of adjacent portions of the same silicon wafer.
Claim 24
Dependent Claim
18 words
Apparatus for producing a semiconductor crystal as recited in claim 14, further comprising means for rotating the crucible.
Claim 25
Dependent Claim
19 words
Apparatus for producing a semiconductor crystal as recited in claim 14, further comprising means for rotating the growing crystal.
Claim 26
Dependent Claim
28 words
Apparatus for producing a semiconductor crystal as recited in claim 14 further comprising means for rotating the crucible and the crystal in opposite directions relative to each other.
Claim 27
Dependent Claim
82 words
Apparatus for producing a semiconductor crystal as recited in claim 14, further comprising a hermetically sealed furnace surrounding the crucible and wherein the means for pulling up the growing crystal includes a rotatable, hollow outer shaft, a rotatable, crystal pulling, inner shaft, the outer shaft having a portion which extends into the furnace and means for effecting a hermetic seal between the outer shaft and the inner shaft, the inner shaft being freely movable in a vertical direction within the outer shaft.
Claim 28
Dependent Claim
53 words
Apparatus for producing a semiconductor crystal as recited in claim 14 further comprising a heater disposed about the periphery of the crucible and an insulator surrounding the heater and having a predetermined spaced relationship with it for preventing the radiation of heat outwardly and for reflecting the radiated heat inwardly upon the crucible.
Claim 29
Dependent Claim
85 words
Apparatus for producing a semiconductor crystal as recited in claim 14 wherein the growing crystal pulling up means further comprises a vertically movable frame, a support for the growing crystal and suspension means connected between the frame and the crystal support for reducing rotational friction of the crystal support, the suspension means including a vertically mounted rod having a flared end, a bearing holder encompassing the flared end of the rod, and bearings within the holder which ride on the flared portion of the rod.
Claim 30
Dependent Claim
56 words
Apparatus for producing a semiconductor crystal as recited in claim 14 wherein the ratio of cross-sectional area of the float, at any given longitudinal position, to the cross-sectional area of the crystal at a corresponding longitudinal position is substantially equal to the ratio of the specific gravities of the liquid in the tub and the crystal.
Claim 31
Dependent Claim
111 words
Apparatus for producing a semiconductor crystal as recited in claim 14 and further comprising means for generating separate output signals representative of the weights of the growing crystal and of the float, means for comparing the output signals and generating a representative output signal, processing means responsive to the comparator output signal for generating first, second and third control signals, means responsive to the first control signal for controlling the temperature of the melt within the crucible, means responsive to the second control signal for controlling the speed at which the growing crystal is pulled up and means responsive to the third signal for lifting the crucible at a controlled speed.
Claim 32
Dependent Claim
147 words
Apparatus for producing a semiconductor crystal as recited in claim 29 further comprising diameter adjuster means for generating a signal corresponding to a predetermined diameter of the growing crystal, a zero adjuster means having two inputs and an output, one of the inputs being supplied with the signal representative of the weight of the float and the other input being supplied with the signal from the diameter adjuster means so that the output of the diameter adjuster means is superposed upon the output of the zero adjuster means, and wherein the comparator means includes a polarization error amplifier having one input supplied with the signal representative of the weight of the growing crystal and another input which is supplied with the output from the zero adjuster means, the zero adjuster means including means for initially adjusting the output of the pOlarization error amplifier to be substantially zero.
Claim 33
Dependent Claim
105 words
Apparatus for producing a semiconductor crystal as recited in claim 14 wherein the control means includes programmed source means for producing a variable control signal in response to the length of the growing crystal, the programmed relationship between the length of the growing crystal and the magnitude of the variable control signal being such that the magnitude is zero until the length of the growing crystal is a predetermined fraction of its desired finished length, the magnitude thereafter increasing proportionally with the length of the growing crystal, and menas responsive to the magnitude of the variable control signal for controlling the temperature of the melt.
Claim 34
Dependent Claim
99 words
Apparatus for producing a semiconductor crystal as recited in claim 14, wherein the control means further comprises means for generating a control signal representative of the difference in the set cross-sectional area of the float and the physical cross-sectional area of the growing crystal, means for comparing the control signal with a programmed reference signal and for generating an output signal when the control signal exceeds a predetermined value, means for differentiating the output signal with respect to the length of the growing crystal, and means responsive to the differentiated output signal for controlling the temperature of the melt.
Claim 35
Dependent Claim
101 words
Apparatus for producing a semiconductor crystal as recited in claim 14 wherein the control means includes means for sensing the length of the crystal and for producing a first output signal representative of the length of the crystal, means for sensing the weight of the crystal and for producing a second output signal representative of the crystal weight, and means responsive to the first and second output signals for controlling the rate of response of the control means as a function of the rate of change of the second signal with respect to the rate of change of the first signal.
Claim 36
Dependent Claim
30 words
Apparatus for producing a semiconductor crystal as recited in claim 14 wherein the tub is fed with a continuous supply of liquid for maintaining the liquid level constant in height.
Claim 37
Dependent Claim
25 words
Apparatus for producing a semiconductor crystal as recited in claim 14 wherein the tub and the crucible have interior hollow shapes which are substantially identical.
Claim 38
Dependent Claim
26 words
Apparatus for producing a semiconductor crystal as recited in claim 14 wherein the tub is lifted up for maintaining the height of the liquid level constant.
Claim 39
Dependent Claim
28 words
Apparatus for producing a semiconductor crystal as recited in claim 14 further comprising means for lowering the tub to remove the float from the liquid in the tub.
Claim 40
Dependent Claim
29 words
Apparatus for producing a semiconductor crystal as recited in claim 14 further comprising means for heating the crucible and means for rotating the crucible relative to the heating means.
Claim 41
Dependent Claim
37 words
Apparatus for producing a semiconductor crystal as recited in claim 14 further comprising: a. means for heating the crucible; b. a furnace for enclosing the crucible and the heating means; and c. means for cooling the furnace.
Claim 42
Dependent Claim
47 words
Apparatus for producing a semiconductor crystal as recited in claim 39 further comprising: a. means for sensing the temperature of the furnace and for producing a control signal representative of the furnace temperature and b. means for controlling the cooling means in accordance with the control signal.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-07-01 | 1977-12-31 | 1978-07-02 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-07-01 | 1981-12-31 | 1982-07-02 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-07-01 | 1985-12-31 | 1986-07-02 | $7700.00 | Window Closed / Lapsed |