Description

AIR PRESSURE PIVOTING PICKER FOR TRANSFERRING SEMICONDUCTOR DEVICES

Technical Field

[1] The present invention relates to a picker for transferring semiconductor devices by suction, and more particularly, to an air pressure pivoting picker for transferring semiconductor devices capable of pivoting a direction of a semiconductor device sucked to a picker.

[2]

Background Art

[3] A semiconductor device having undergone a packaging process is tested, sorted according to each level of the test, and then transferred to a consumer by a packing process. In order to test and sort the semiconductor device, as shown in FIG. 1, the semiconductor device has to be transferred into a test socket of a burn-in board (BIB) 120 or a test dut board (TDB) from a tray 100, or has to be transferred in an opposite direction to the test socket.

[4] As shown in FIG. 1 , the semiconductor device is transferred on a process line showing a moving line of a picker. The test socket 125 for inserting a semiconductor device is disposed on the BIB (or the TDB) with an angle of 90° with respect to a semiconductor package disposed on the tray 100. Accordingly, a semiconductor device has to be rotated in an angle of 90° when being transferred.

[5] In order to rotate the semiconductor device, various methods have been proposed in the conventional art. The methods include transferring a semiconductor device after rotating the BIB 120° by 90° for alignment, rotating a buffer after transferring a semiconductor device to the buffer, and rotating a tray. However, the methods have the following problems. When the BIB 120 is used, an additional rotating device has to be provided, and a rotating space is necessary in a sorting device with consideration of a rotation radius of the BIB 120 (or the TDB). When the buffer is used, an additional rotating device has to be provided and the sorting device has an increased volume due to the buffer. When the tray is rotated, the above problems occur.

[6] In order to solve the problems, a method for rotating a cylinder body of a picker by

90 has been proposed. However, the method has a problem that a gap between neighboring cylinders is increased since a rotation radius of the cylinder has to be considered according to a size of the cylinder. The method is not suitable when a pitch between semiconductor devices to be transferred is small.

[7] Accordingly, the present inventors provide an air pressure pivoting picker for

transferring semiconductor devices by pivoting not a cylinder body but a picker shaft which sucks a semiconductor device. [8]

Disclosure of Invention

Technical Problem

[9] Therefore, it is an object of the present invention to provide an air pressure pivoting picker capable of pivoting a picker shaft.

[10] It is another object of the present invention to provide an air pressure pivoting picker capable of implementing a small pitch between neighboring semiconductor devices by pivoting a picker shaft.

[11] It is still another object of the present invention to provide an air pressure pivoting picker module capable of rotating a semiconductor device without rotating a tray, or a burn-in board, or a test-dut board.

[12] It is yet still another object of the present invention to provide an air pressure pivoting picker capable of compactizing an entire structure of a device for sorting a semiconductor device because no additional device for rotating the burn in board, the test dut board, or the tray rotating device is necessary.

[13] These object of the present invention may be achieved by the present invention decribed in the following.

[14]

Technical Solution

[15] To achieve these objects, there is provided an air pressure pivoting picker, comprising: a cylinder body; a pivot shaft disposed to penetrate through the cylinder body, having a vacuum passage therein, and having a pivot guide recess on a surface thereof; a first air pressure pivoting port for injecting compressed air into a first air pressure pivoting chamber formed near the pivot shaft; a second air pressure pivoting port for injecting compressed air into a second air pressure pivoting chamber formed near the pivot shaft; a ball retainer having a sealing portion for dividing the first and the second air pressure pivoting chambers from each other, having a ball holder on a circumference thereof in correspondence with the pivot guide recess, encompassing the pivot shaft, and up-down moving by the compressed air; a ball being received in the ball holder and up-down moving together with the ball retainer, the ball being engaged with the pivot guide recess, for rotating the pivot shaft by being moved in upper and lower directions; a ball linear guide encompassing the pivot shaft and the ball retainer, the ball linear guided being formed with a linear guide groove at a position corresponding to the ball holder of the ball retainer, for guiding the ball to be linearly moved in upper and lower directions; and a stopper coupled onto a circumference of

the pivot shaft thus to be rotated together with the pivot shaft, for stopping the pivot shaft being rotated by being contacted with a stopper mounting portion formed at a lower portion of the cylinder body.

[16] The cylinder body comprises a first guide shaft having a first air pressure passage therein, and disposed to penetrate through the cylinder body; a second guide shaft having a second air pressure passage therein, and disposed to penetrate through the cylinder body; a cylinder guide coupled to the first and the second guide shafts; a first air pressure chamber formed near the first guide shaft inside the cylinder body; a second air pressure chamber formed near the second guide shaft inside the cylinder body; and a sealing portion for dividing the first and the second air pressure chambers from each other, wherein the cylinder body is up-down moved by compressed air introduced into the first or the second air pressure passage.

[17] The cylinder body may further comprise a sensor for sensing a position of the ball retainer, and a sensing hole may be formed at the ball linear guide in correspondence with the sensor. A pad 17a may be further provided at a position of the stopper mounting portion 17 contacting the stopper 24.

[18] A rotation bearing for smoothly rotating the pivot shaft may be installed at an upper portion inside a moving sector of the ball retainer. A spacer 19 may be installed at a lower portion of the rotation bearing, thereby preventing damage of the rotation bearing due to repeated collision between the rotation bearing and the ball retainer.

[19] Reference will now be made in detail to the preferred embodiments of the present invention, examples of which are illustrated in the accompanying drawings.

[20]

Brief Description of the Drawings

[21] FIG. 1 is a schematic view showing that a semiconductor device is transferred to a burn-in board from a tray by a picker module;

[22] FIG. 2 is a perspective view of an air pressure pivoting picker according to the present invention;

[23] FIG. 3 is a sectional view of the air pressure pivoting picker taken along line A-A ¹ in FIG. 2, showing that a pivot shaft is not rotated and a cylinder body is disposed at an upper portion;

[24] FIG. 4 is a sectional view of the air pressure pivoting picker, showing that the pivot shaft is rotated and the cylinder body is disposed at a lower portion;

[25] FIG. 5 is a perspective view of a ball retainer of the air pressure pivoting picker according to the present invention;

[26] FIG. 6 is a perspective view of a ball linear guide of the air pressure pivoting picker according to the present invention;

[27] FIG. 7 is a perspective view of a pivot shaft of the air pressure pivoting picker according to the present invention;

[28] FIG. 8 is an unfolded view taken along line B-B' and C-C in FIG. 7, showing a moving path of a ball on a surface of the pivot shaft when the pivot shaft is pivoted;

[29] FIG. 9 is a bottom perspective view of the air pressure pivoting picker according to the present invention, showing a stopper may be seen, and FIG. 10 is a schematic view showing an operation of the stopper; and

[30] FIG. 11 is a conceptual view showing an enhanced moving path of the ball on a surface of the pivot shaft in FIG. 8.

[31]

Mode for the Invention

[32] FIG. 2 is a perspective view of an air pressure pivoting picker according to the present invention.

[33] As shown in FIG. 2, the air pressure pivoting picker according to the present invention comprises a cylinder body 10, a pivot shaft 20, and a cylinder guide 30. First and second air pressure pivoting ports 11, 12 for supplying compressed air to provide a rotation driving force for the pivot shaft are formed at the cylinder body 10. The cylinder body 10 is coupled to the cylinder guide 30 by first and second guide shafts 31, 33 so as to be up-down moved. The first and the second guide shafts 31, 33 are installed to penetrate through the cylinder body. The cylinder body 10 is up-down moved by compressed air supplied to first and second air pressure passages 32, 34 respectively formed in the first and the second guide shafts.

[34] A vacuum passage 21 is formed in the pivot shaft 20, and a sucking pad 22 is coupled to a lower end of the pivot shaft 20. Once inside of the pivot shaft is become vacuum as an additional vacuum pipe (not shown) is connected to an upper end of the vacuum passage 21, a semiconductor device 100 is adhered to the sucking pad 22 by a vacuum force. If the semiconductor device is transferred to a desired position and then the vacuum state inside the pivot shaft is removed, the semiconductor device is separated from the sucking pad. In the present invention, the pivot shaft 20 may be rotated and a detailed rotating mechanism thereof will be explained.

[35] The cylinder guide 30 is a 'U' -shaped member, and has first and second guide shafts 31, 33. The first and the second guide shafts 31, 33 are disposed to penetrate through the cylinder body 10, thereby guiding the cylinder body 10 to be up-down moved. The first and the second guide shafts 31, 33 are respectively provided with first and second air pressure passages 32, 34 therein. The cylinder body 10 is up-down moved by an air pressure applied to the first and the second air pressure passages 32, 34. A detailed explanation of the up-down motion of the cylinder body 10 will be

explained.

[36] FIG. 3 is a sectional view of the air pressure pivoting picker taken along line A-A' in FIG. 2, showing that a pivot shaft 20 is not rotated and a cylinder body 10 is disposed at an upper portion; and FIG. 4 is a sectional view of the air pressure pivoting picker, showing that the pivot shaft 20 is rotated and the cylinder body 10 is disposed at a lower portion.

[37] As shown in FIGs. 3 and 4, the pivot shaft 20 is disposed to penetrate through the cylinder body 10. First and second air pressure pivoting chambers 11a, 12a are formed near the pivot shaft 20. The pivot shaft is disposed in a ball retainer 13 having a sealing portion 13a for dividing the first and the second air pressure pivoting chambers from each other. As shown in FIG. 5, a ball holder 13b for receiving a ball 14 is formed at a lower portion of the ball retainer 13. A ball linear guide 15 formed with a linear guide groove 15a in correspondence with the ball holder 13b in FIG. 6 is installed to encompass the ball retainer 13. The first and the second air pressure pivoting chambers 11a, 12a are respectively connected to the first and the second air pressure pivoting ports 11, 12 for supplying compressed air.

[38] As shown in FIG. 7, a pivot guide recess 23 is formed on a surface of the pivot shaft

20. The ball 14 received in the ball holder 13b of the ball retainer 13 is guided to be up-down moved by the linear guide groove 15a of the ball linear guide 15.

[39] Referring to FIG. 3, the first air pressure pivoting port 11 guides compressed air supplied from outside to the first air pressure pivoting chamber 11a. The second air pressure pivoting port 12 guides compressed air supplied from outside to the second air pressure pivoting chamber 12a. The first and the second air pressure pivoting chambers 11a, 12a are divided from each other by the sealing portion 13a circumferentially formed at the ball retainer, and have a hermetic structure.

[40] When the sealing portion 13a dividing the first and the second air pressure pivoting chambers 11a, 12a from each other receives a force by supplied compressed air, the ball retainer 13 is up-down moved with encompassing the pivot shaft 20. When compressed air is supplied from the first air pressure port 11, the first air pressure pivoting chamber 1 Ia is expanded. As the sealing portion 13a receives a force downwardly by the expansion pressure, the ball retainer 13 is lowered. When compressed air is supplied from the second air pressure port 12, the ball retainer 13 is upwardly moved. The ball holder 13b for receiving the balll4 is formed outside the ball retainer. The ball 14 is received in the ball retainer 14 and is up-down moved in the linear guide groove 15a of the ball linear guide 15, thereby guiding the ball retainer 13 to be up-down moved.

[41] As the ball retainer 13 is up-down moved, the ball 14 is up-down moved together with the ball retainer 13. Here, a linear-motion of the ball 14 in upper and lower

directions is guided by the linear guide groove 15a of the ball linear guide 15 that encompasses the ball retainer 13. The perspective view for the ball linear guide 15 is shown in FIG. 6.

[42] One or more balls and one or more ball holders may be used. In the preferred embodiment, three balls and three ball holders are disposed on a circumference of the ball retainer 13 with an angle of 120°therebetween. FIG. 3 shows only one of the balls 14. The perspective view for the ball retainer 13 is shown in FIG. 5.

[43] As shown in FIG. 7, a pivot guide recess 23 is formed on a surface of the pivot shaft

20 in correspondence with a sector where the ball 14 performs a linear-motion. Accordingly, when the ball 14 is linearly-moved in upper and lower directions, the pivot shaft 21 is rotated at its own position along a moving path of the pivot guide recess 23. That is, the ball 14 is positioned at the ball holder 13b of the ball retainer 13, and is received in the linear guide groove 15a of the ball linear guide 15 and in the pivot guide recess 23 of the pivot shaft 20. Accordingly, when the ball retainer 13 is up- down moved, the ball 14 is up-down moved thus to pass a moving path of the pivot guide recess 23 of the pivot shaft 20. As a result, the pivot shaft 20 is rotated at its own position.

[44] A sensor 16 for sensing a position of the ball retainer 13 that up-down moves may be installed at the cylinder body 10. A sensing hole 15b may be formed in correspondence with the sensor of the ball linear guide 15, thereby sensing a position of the ball retainer. By sensing a current position of the ball retainer, a rotated angle of the semiconductor device vacuum-sucked to the sucking pad 22 may be checked.

[45] Referring to FIG. 3, when compressed air is introduced into the first air pressure pivoting port 11 , the compressed air flows into the first air pressure pivoting chamber thus to downwardly push the sealing portion 13a. Accordingly, the ball retainer 13 performs a linear motion in a downward direction, and the ball 14 is guided by the ball linear guide recess 15a of the ball linear guide 15. Since the ball 14 passes the pivot guide recess 23 of the pivot shaft 20 while moving downward, the pivot shaft is rotated. FIG. 4 shows a rotated state of the pivot shaft.

[46] The pivot guide recess 23 formed on a surface of the pivot shaft 20 is formed in a curved line in correspondence with the ball 14. FIG. 8 is a partial unfolded portion of the pivot shaft, which shows the pivot guide recess corresponding to a moving sector of the ball 14 in upper and lower directions.

[47] As shown in FIG. 8, three balls 14 move along a moving path of the pivot guide recess23. As the ball performs a linear-motion in upper and lower directions, the pivot shaft is rotated along a moving path of the ball. It is assumed that an upper dead point of the ball 14 is B, a lower dead point of the ball 14 is C, and a horizontal distance between the upper dead point B and the lower dead point C is 1/4 of a circumference

of the pivot shaft 20. Here, when the ball 14 performs a linear motion from the upper dead point to the lower dead point or from the lower dead point to the upper dead point, the pivot shaft is rotated by an angle of 90°. The number of the balls and a rotation angle of the pivot shaft may be modified by adjusting a moving path of the pivot guide recess.

[48] In the present invention, a direction of the semiconductor device can be converted by rotating the pivot shaft, and a pitch between neighboring semiconductor devices can be decreased more than in the conventional method in which the cylinder is rotated. According to the conventional method for rotating the cylinder, a rotation radius of the cylinder is required with consideration of a size of the cylinder, and thus it is impossible to obtain a pitch less than the rotation radius of the cylinder. However, in the present invention, smaller pitch can be obtained since not a rotation radius of the cylinder but a thickness of the cylinder is considered.

[49] As aforementioned, the ball retainer 13 performs a linear- motion in upper and lower directions, and the pivot shaft 20 performs a rotation motion. A rotation bearing 18 for smoothly rotating the pivot shaft may be installed at an upper portion of a moving sector of the ball retainer 13. When the ball retainer 13 repeatedly collides with the rotation bearing 18 while moving up-down, the rotation bearing 18 may be damaged. In order to prevent the damage of the rotation bearing 18, a spacer 19 may be installed at a lower portion of the rotation bearing 18. A material of the spacer 19 is not limited to a specific one. But, the spacer 19 is preferably formed of metal having high strength such as reinforced steel.

[50] The pivot shaft is rotated when the pivot guide recess 23 of the pivot shaft passes the ball 14. As shown in FIG. 8, if a curved path of the pivot guide recess is aligned to be 90° when the pivot shaft is rotated by an angle of 90°, a force for stopping the pivot guide recess is applied to the end of the curved path when the pivot guide recess is rotated. Accordingly, repeated rotation and stop of the pivot shaft may cause abrasion of the pivot guide recess. As a result, the pivot shaft is not smoothly rotated but is fluctuated.

[51] In order to solve the problem, a stopper 24 is installed near the pivot shaft so as to be rotated together with the pivot shaft. Also, a stopper mounting portion 17 is installed at a lower portion of the cylinder body so as to stop a rotation of the stopper 24. Although the stopper mounting portion 17 may be separately formed from the cylinder body 10 as in drawing, the stopper mounting portion 17 may be integrally formed with the cylinder body 10.

[52] FIG. 9 is a view showing the stopper 24. A pad 17a is disposed at a contact portion between the stopper mounting portion 17 and the stopper 24, thereby absorbing impact from the stopper 24. The material for the pad 17a is not limited to any one. However,

the pad 17a is preferably formed of reinforced rubber or ure thane having characteristic for easily absorbing impact.

[53] FIG. 10 is a conceptual view showing an operation of the stopper.

[54] As shown in FIG. 10, the stopper 24 is rotated together with the pivot shaft 20.

When the pivot shaft 20 is rotated in an arrowed direction, the stopper 24 is rotated together with the pivot shaft 20. When a first mounting portion 24a of the stopper 24 comes in contact with the pad 17a of the stopper mounting portion 17, the rotation of the stopper 24 is stopped and thereby the rotation of the pivot shaft 20 is stopped. Here, when the pivot shaft 20 is rotated in an opposite direction to the arrowed direction, the stopper is rotated until a second mounting portion 24b of the stopper 24 is stopped by contacting the pad 17a.

[55] As shown in FIG. 11, the curved path of the pivot shaft is formed to have a margin of +1° not in an angle of exact 90°. That is, the pivot guide recess is formed so that the pivot shaft can be rotated by an angle of 92°. When the pivot shaft is stopped after being rotated, a force is not applied to the pivot guide recess but a stopping force by the stopper 24 is applied to the pivot guide recess. Accordingly, the pivot guide recess is prevented from being damaged.

[56] Hereinafter, an up-down motion of the cylinder body 10 will be explained with reference to FIGs. 3 and 4.

[57] The first and the second guide shafts 31, 33 connected to the cylinder guide 30 are disposed to penetrate through the cylinder body 10. The first and the second air pressure passages 32, 34 are respectively disposed in the first and the second guide shafts 31, 33. The first and the second air pressure passages 32, 34 are respectively connected to the first and the second air pressure chambers 35, 36, thereby respectively supplying compressed air applied from outside to the first and the second air pressure chambers 35, 36.

[58] The first and the second air pressure chambers 35, 36 are divided from each other by the sealing portion 31a disposed on a circumference of the first guide shaft. The sealing portion 31a is formed near the first guide shaft 31 thus to implement a hermetic configuration of the chambers, and enables the cylinder body 10 to be up-down moved by compressed air.

[59] FIG. 3 shows that the cylinder body 10 has moved in an upper direction. When compressed air is introduced into the second air pressure passage 34, the compressed air is introduced into the second air pressure chamber 36. The compressed air does not flow by the sealing portion 31a, but downwardly pushes the cylinder body 10 by its repulsive force. Accordingly, the cylinder body 10 is lowered, as shown in FIG. 4.

[60] On the contrary, when compressed air is introduced into the first air pressure passage 32, the compressed air is introduced into the first air pressure chamber 35.

Under a state that the first air pressure chamber 35 having a hermetic structure by the sealing portion 31a is filled with compressed air, if compressed air is continuously introduced into the first air pressure chamber 35, the first air pressure chamber 35 has an increased volume and the cylinder body 10 is upwardly moved.

[61] The cylinder body 10 is up-down moved as compressed air is supplied to the first and second air pressure passages.

[62] It will also be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit or scope of the invention. Thus, it is intended that the present invention cover modifications and variations of this invention provided they come within the scope of the appended claims and their equivalents.

[63]