KR101892894B1 - An Apparatus for Grinding a Surface of a Lead Frame - Google Patents

Abstract

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lead frame surface polishing apparatus, and more particularly, to a lead frame surface polishing apparatus that polishes an epoxy molding compound (EMC) coated on a lead frame of a semiconductor to form a uniform coated surface . The lead frame surface polishing apparatus comprises a transfer unit (12) for transferring a lead frame having a coated surface to be polished; A balance spindle module (11) disposed below the transfer unit (12) and arranged to be able to contact the surface of the lead frame; A contact spindle unit 14 disposed above the transfer unit 12; A Z axis module 17 for up and down movement of the contact spindle unit 14; And an abrasive belt rotated by the contact spindle unit 14. [

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a lead frame,

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lead frame surface polishing apparatus, and more particularly, to a lead frame surface polishing apparatus that polishes an epoxy molding compound (EMC) coated on a lead frame of a semiconductor to form a uniform coated surface .

The lead frame functions as a conductor for connecting the semiconductor chip to an external circuit, and simultaneously functions as a frame for fixing the semiconductor package to the electronic circuit board. An epoxy molding compound (EMC) may be coated to protect the semiconductor chip disposed in the lead frame or the lead frame from the external environment. During the coating process, the lead frame may be partially overcoated. Such an overcoated portion may reduce the surface uniformity level of the lead frame surface and may cause defects in the semiconductor package, so that the overcoated portion needs to be polished.

Prior art related to a semiconductor lead frame is disclosed in Patent Publication No. 10-1999-0002969. The prior art includes a first step of exposing a coin to be electrolytically polished using a mask; A second step of applying a predetermined potential between the coining portion and the machining electrode; A third step of spraying an electrolytic polishing solution on the exposed coin part to perform electrolytic polishing; And a fourth step of separating the mask from the lead frame after electrolytic polishing is performed on the coinning portion.

Japanese Patent Application Laid-Open No. 10-2006-0112307 discloses a patterning process for integrally forming a plurality of leads on a prepared base material and a tip connecting portion interconnecting the ends of the leads. And a step of pressing the lead frame by using a mold having a predetermined shape, wherein a cutting process for cutting the leading end connecting portion and a setting process for forming a step up and down with respect to a lead frame portion are performed simultaneously A method of manufacturing a lead frame including a lead frame punching molding process to be performed is disclosed.

The technique related to the lead frame disclosed in the prior art does not disclose a method of making the surface of the lead frame uniform, or has a problem that a complicated process condition is required. The thickness of the lead frame may be, for example, 100 to 300 占 퐉, and the EMC coating thickness may be 60 to 70 占 퐉. There is a need for a grinding method which has high reliability and which is not complicated in the process and can be controlled precisely at the same time in order to uniformly form the coating thickness of the lead frame having such a thickness level. The prior art does not disclose a technique or method suitable for such conditions.

The present invention has been made to solve the problems of the prior art and has the following purpose.

Prior Art 1: Patent Publication No. 10-1999-0002969 (published by Samsung Aviation Industrial Co., Ltd., Jan. 15, 1999) Leadframe and leadframe electrolytic polishing method Prior Art 2: Patent Publication No. 10-2006-0112307 (Samsung Techwin Co., Ltd., published on October 31, 2006) Method of manufacturing lead frame and press working device for lead frame applied thereto

SUMMARY OF THE INVENTION It is an object of the present invention to provide a lead frame surface grinding apparatus capable of forming a uniformly coated surface of a lead frame by automatically setting the grinding conditions of the grinding belt.

According to a preferred embodiment of the present invention, the lead frame surface grinding apparatus comprises a transfer unit for transferring a lead frame having a coated surface to be polished; A balance spindle module disposed below the transfer unit and arranged to be able to contact the surface of the lead frame; A contact spindle unit disposed above the transfer unit; A Z-axis module for up-and-down movement of the contact spindle unit; And an abrasive belt rotated by the contact spindle unit.

According to another preferred embodiment of the present invention, a tension unit for adjusting the tension of the abrasive belt and a drive roller unit for rotating the contact spindle unit are further included.

According to another preferred embodiment of the present invention, the polishing apparatus further comprises a detection unit for measuring the warp and tension of the abrasive belt.

According to another preferred embodiment of the present invention, the polishing belt is vertically moved by a moving block coupled to the shaft block, and the moving block moves up and down along a linear guide disposed at four corners of the hexahedron- do.

The lead frame surface grinding apparatus according to the present invention permits the overcoating of the coated surface of the lead frame to be eliminated while enhancing the reliability by mechanical polishing and machining. Further, the lead frame surface grinding apparatus according to the present invention has a built-in type spindle, which improves the operating precision. The lead frame surface grinding apparatus according to the present invention is capable of constant speed and variable speed while allowing tension or skew to be automatically adjusted. In addition, the leadframe surface device according to the present invention has the advantage of being able to apply one or more belts.

Figs. 1A, 1B and 1C show a front view, a plan view and a side view, respectively, of an embodiment of a surface grinding apparatus according to the present invention.
Fig. 2 shows an embodiment of the structure of the transfer unit applied to the surface grinding apparatus according to the present invention.
FIG. 3 shows an embodiment of a vertical module applied to a surface grinding apparatus according to the present invention.
4 shows an embodiment of a polishing module applied to a surface polishing apparatus according to the present invention.
5A and 5B illustrate an example of a position adjustment process of the polishing module in the surface polishing apparatus according to the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail with reference to the embodiments shown in the accompanying drawings, but the present invention is not limited thereto. In the following description, components having the same reference numerals in different drawings have similar functions, so that they will not be described repeatedly unless necessary for an understanding of the invention, and the known components will be briefly described or omitted. However, It should not be understood as being excluded from the embodiment of Fig.

Figs. 1A, 1B and 1C show a front view, a plan view and a side view, respectively, of an embodiment of a surface grinding apparatus according to the present invention.

Referring to Figs. 1A, 1B and 1C, the surface polishing apparatus 10 includes a transfer unit 12 for transferring a lead frame having a coating surface to be polished; A balance spindle module (11) disposed below the transfer unit (12) and arranged to be able to contact the surface of the lead frame; A contact spindle unit 14 disposed above the transfer unit 12; A Z axis module 17 for up and down movement of the contact spindle unit 14; And an abrasive belt (GV) rotated along the contact spindle unit (14).

The surface polishing apparatus 10 according to the present invention may have a function of adjusting the thickness of the coating surface of the lead frame and the thickness adjustment may be performed by adjusting the average thickness of the coating surface and the surface uniformity level such as average roughness ≪ / RTI > The surface of the leadframe may be made of a protective coating of synthetic resin material, for example an epoxy molding compound (EMC). The surface of the lead frame can be coated with various protective coatings or other purposes, and the surface polishing apparatus 10 according to the present invention can control the thickness of various coating surfaces formed on the surface of the lead frame, Can be made.

The surface grinding apparatus 10 according to the present invention may be disposed in the main frame F and may have various control units or display units for operation. The surface grinding apparatus 10 can be operated according to a predetermined condition, for example, by a program, and the operating state can be displayed on the display unit. Also, the operating conditions are input through the input unit, and thus the surface grinding apparatus 10 can be operated. Therefore, the surface grinding apparatus according to the present invention is not limited by the operation method or whether or not an additional apparatus for operation is installed.

The lead frame for the semiconductor package can be conveyed along the conveying line SL through a conveyor operated by the conveying unit 12 and the conveying unit 12 is rotated by the operation of the drive unit M, And a housing in which a plurality of roller units facing each other and a roller unit are accommodated. The transfer unit 12 is provided with a plurality of nip rollers or pinch rollers including a roller unit and a plurality of pins for movement of the lead frames introduced through the inlet unit 13 and the inlet unit 13, Roller unit. The roller units can be arranged to face each other, and the lead frame can be transported between the roller units. The interval and the pressure of the roller units facing each other can be adjusted, and the roller unit can be operated by a drive unit M such as a motor.

The balance spindle module 11 may have a rotary roller structure in which a rotary shaft is disposed along a longitudinal direction in a cylindrical shape, and a cylindrical peripheral surface may be coated with a material such as diamond like carbon (DLC). DLC coatings refer to amorphous carbon based materials and can have high hardness, high corrosion resistance and abrasion resistance. The balance spindle module 11 can be coated with a material having high surface hardness and low friction coefficient and chemical stability. In addition, the substrate may be coated with an amorphous material to have a surface roughness (Ra) of 0.8 nm or less, for example, a mirror coating. The coefficient of friction of the material coated on the surface of the balance spindle module 11 may have the same or higher coefficient of friction than that of the coating material for surface coating of the polishing belt (GV) with a low coefficient of friction. Thus, the coated surface of the lead frame can be stably ground by the abrasive belt. The surface of the balance spindle module 11 needs to be coated with a material that stably supports the lead frame while being deformed by the pressure applied to the lead frame at the same time. The DLC coating may be coated on the surface of the balance spindle module 11 by any material having similar physical properties and by way of example, and the present invention is not limited to the embodiments shown.

A polishing module for the operation of the polishing belt GV can be arranged above the balance spindle module 11 and the polishing module comprises a contact spindle unit 14 arranged to face the balance spindle module 11, And a driving roller unit 16 disposed above the tension unit 15 and disposed above the tension unit 15 to adjust the tension of the grinding belt GV. The abrasive belt GV can have a plate shape and can be rotated along the peripheral surface of the cylindrical contact spindle unit 14. [ The surface of the lead frame can be polished or ground by the grinding belt GV. The polishing module may be arranged to move up and down along a Z-axis module 17 operated by a drive unit M1 such as a servo motor. The grinding belt GV can be moved downward and brought into contact with the balance spindle module 11 as the polishing module moves up and down. Concretely, when the lead frame is moved along the conveying line SL by the conveying unit 12 and moved in the direction of the balance spindle module 11, at the same time, the grinding belt GV is moved downward, The surface of the lead frame can be brought into contact with the surface of the lead frame. Thereafter, the lead frame can be polished by the abrasive belt GV while being supported by the balance spindle module 11. [

The surface on which the abrasive belt GV is brought into contact with the coating surface of the lead frame can be coated with an abrasive material. The abrasive material may be, for example, diamond and the abrasive material may be coated on the surface of the abrasive belt (GV) in a uniform thickness. As described above, the coefficient of friction of the abrasive material may be smaller than the coefficient of friction of the material of the balance spindle module 11. Thus, the lead frame can be grinded by the grinding belt (GV) while being stably held on the peripheral surface of the balance spindle module (11). The rotational direction of the balance spindle module 11 and the rotational direction of the polishing belt GV may be opposite to each other. For example, the balance spindle module 11 is rotated counterclockwise corresponding to the discharge direction of the lead frame, and the polishing belt GV can be rotated clockwise. And the coated surface of the grinding belt GV can be polished with the EMC coated surface of the lead frame.

Frictional heat can be generated in the process of grinding the lead frame by the grinding belt GV and the cooling water supply units WS1 and WS2 can be disposed in front of and behind the transfer unit 12 for cooling the lead frame. The cooling water jetted from the cooling water supply units WS1 and WS2 into the lead frame can be discharged to the discharge unit WD along the transfer unit 12 below the balance spindle module 11 and the cooling water supply units WS1 and WS2 The cooler 18 may be disposed inside or outside the casing UP. Air may be injected together with the supply of cooling water, and the cooling water and air may have the function of discharging chips or sludge generated in the polishing process.

The polishing apparatus 10 according to the present invention may be composed of a main frame F and a casing UP arranged above the main frame F. [ Various input means, a monitor or an observation window for an operation instruction or an operation observation of the operator (WO) can be arranged in the casing UP. When the lead frames are inputted along the transfer unit 12 according to the input of the work start signal of the worker (WO), the polishing process can proceed.

Fig. 2 shows an embodiment of the structure of the transfer unit 12 applied to the surface grinding apparatus according to the present invention.

2, the transfer unit 12 includes one roller row R1 and two roller rows R2 arranged to face up and down, which are operated by a drive unit M, Can be transferred between the first roller R1 and the second roller row R2 and transferred to the balance spindle module 11. [ And the inflow unit for the inflow of the lead frame, such as a nip roller, is fixed by the roller bracket 211. And the nozzle units 212 forming the cooling water supply unit described above can be respectively disposed at the inlet and the outlet of the transfer unit 12 and the air nozzles for supplying air can be disposed together with the nozzle unit 212 or separately . For example, the nozzle unit 212 may consist of a pair of nozzles disposed above and below the lead frame, with cooling water being sprayed from one nozzle and air being sprayed from the other nozzle. The cooling water stored in the storage tank 22 may be supplied to the nozzle unit 212 by the supply fan 214. And the cooling water sprayed to the lead frame through the nozzle unit 212 can be collected together with the chip or sludge through the discharge tube 23 and discharged to the outside through the discharge unit described above.

The drive unit M such as a motor can be connected to one roller row R1 or two roller rows R2 via a power transmission means V such as a belt and can be connected to the drive unit M and the roller rows R1, ) Can be made in various ways. The balance spindle module 11 may be in the form of a drum or cylinder that is rotatable about a central axis and may be driven independently or rotated by rotation of the abrasive belt described above.

The nozzle unit 212 or the balance spindle module 11 may have a variety of configurations, and the present invention is not limited to the embodiments shown.

FIG. 3 shows an embodiment of a vertical module applied to a surface grinding apparatus according to the present invention.

As described above, the polishing module can be moved up and down by the operation of the Z-axis module, and the Z-axis module includes a ball screw 32 operated by a drive unit M1 such as a servo motor; A moving block 33 which is moved up and down in accordance with the rotation of the ball screw 32; Linear guides (331, 332) for guiding the moving block (33) up and down; And a detection unit 36 for detecting the operating state of the moving block 33. [

The driving unit M1 can be a servo motor which can easily adjust the rotation angle, and can control the rotation of the ball screw 32 extending in the vertical direction. The box-shaped moving block 33 can be precisely adjusted and moved up and down by the rotation of the ball screw 32. The movement of the moving block 33 is guided by the linear guides 331 and 332 and the moving position or the balanced state of the moving block 33 can be detected by the detecting unit 36. [ A cable chain 35 for supplying power necessary for operation of the apparatus can be disposed at an appropriate position and the Z axis module can be supported by a suitable fixed frame 31. [

The polishing module can be moved up and down by the vertical module or the Z axis module, and the polishing module can be coupled to the Z axis module by the engagement bracket CB.

4 shows an embodiment of a polishing module applied to a surface polishing apparatus according to the present invention.

4, the contact spindle unit 14, the tension unit 15 and the drive roller unit 16 can be arranged in a direction perpendicular to the triangular shape, and can be formed into a drum or a cylinder shape, respectively. The abrasive belt 41 can be made in a planar shape and can be rotated while contacting the circumferential surfaces of the drive roller unit 16, the tension unit 15 and the contact spindle unit 14. [

The contact spindle unit 14 can be brought into contact with the upper surface of the lead frame and the tension unit 15 can be arranged movably in the tension adjusting frame 43. [ Specifically, the tension unit 15 can be moved in a direction perpendicular to the moving direction of the polishing belt 41 along the moving groove 431 formed in the tension adjusting frame 43. The tension unit (15) can be moved by the operation of the tension adjustment drive unit (42). The driving roller unit 16 can be rotated by the driving actuator 45 and the rotational force of the driving actuator 45 can be transmitted to the axis of the driving roller 16 by the power transmitting means.

According to the present invention, a skew detection unit such as a laser unit is disposed for adjusting the skew of the abrasive belt 41, and a tension detection unit such as a load cell may be disposed for tension measurement of the abrasive belt 41. [

5A and 5B illustrate an example of a position adjustment process of the polishing module in the surface polishing apparatus according to the present invention.

5A and 5B, the lead frame CF can be conveyed by the conveying unit disposed above the main frame F, and the balance spindle module 11 is rotated . And a polishing module in which the contact spindle unit 14, the tension unit 15 and the driving roller unit 16 are arranged in order above the lead frame CF can be located. And the abrasive belt 41 can be rotated so as to be in contact with the lead frame CF by the drive roller unit 16. [

The polishing module can be fixed to the moving block 33 by the engaging bracket CB and moved up and down along the axis block VA. The axis block VA may be the Z axis module described above. The axial block VA can be in a rectangular parallelepiped shape and the moving block 33 can be in the shape of a hollow box surrounding the axial block VA. The moving block 33 can be moved up and down by the rotation of the ball screw rotated by the operation of the driving unit M1, as described above. And a detection unit 36 for measuring tension and skew of the abrasive belt 41 may be disposed at one end of the tension unit 15. [

Referring to FIG. 5B, the moving block 33 can be moved up and down by linear guides 331 and 332 disposed at four corners of a hexahedron shaped axial block VA. A laser sensor may be installed for meandering, the laser sensor may be set to have a beam width of 5 to 20 mm at the target point, and the predetermined edge of the abrasive belt 41 may be the target point. The meander of the abrasive belt can be measured by irradiating the laser beam having the beam width shown above to the target point and receiving the reflected wave. If meandering occurs in the abrasive belt 41, the meandering can be adjusted by adjusting the relative position of the moving block 33 with respect to the four linear guides 331, 332. A skew adjusting motor such as a servomotor for adjusting skew can be provided and the skew of the abrasive belt 41 can be adjusted by adjusting the relative position by the skew adjusting motor.

The tension of the abrasive belt 41 can be measured by the load cell and if the rotation axis of the tension unit 15 is moved in a direction perpendicular to the moving direction of the abrasive belt 41 . For example, the rotation axis of the tension unit 15 is movably coupled to the adjustment bracket 55, and the tension of the abrasive belt 41 can be adjusted by moving the rotation axis by the drive unit. The adjustment bracket 55 may function similar to the adjustment frame described above. A tension adjusting unit for adjusting the tension can be disposed, and the tension of the abrasive belt 41 can be adjusted by the movement of the rotating shaft by the tension adjusting unit.

The skew or tension of the abrasive belt 41 can be measured by various sensors, can be adjusted in various ways, and the present invention is not limited to the embodiments shown. Further, the detection information measured by the detection unit 36 may be periodically transmitted to the control unit, and the control unit may have an adjustment table associated with the operation on the abrasive belt 41. When the meandering or tensioning of the abrasive belt 41 is required, the adjustment driving unit may be operated to adjust the meandering or tension. As described above, the surface polishing apparatus according to the present invention makes it possible to automatically adjust the meandering or tension.

The lead frame surface grinding apparatus according to the present invention permits the overcoating of the coated surface of the lead frame to be eliminated while enhancing the reliability by mechanical polishing and machining. Further, the lead frame surface grinding apparatus according to the present invention has a built-in type spindle, which improves the operating precision. The lead frame surface grinding apparatus according to the present invention is capable of constant speed and variable speed while allowing tension or skew to be automatically adjusted. In addition, the leadframe surface device according to the present invention has the advantage of being able to apply one or more belts.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it will be understood by those of ordinary skill in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention . The invention is not limited by these variations and modifications, but is limited only by the claims appended hereto.

10: Surface grinding device 11: Balance spindle module
12: transfer unit 13: inflow unit
14: contact spindle unit 15: tension unit
16: driving roller unit 17: Z-axis module
18: cooler 22: storage tank
23: exhaust tube 31: fixed frame
32: ball screw 33: moving block
35: Cable chain 36: Detection unit
41: abrasive belt 42: tension adjusting drive unit
43: tension adjusting frame 45: driving actuator
55: Adjustment bracket 211: Roller bracket
212: nozzle unit 214: supply fan
331, 332: linear guide 431: moving groove
CB: Coupling bracket CF: Lead frame
F: main frame GV: abrasive belt
M: drive unit M1: drive unit
R1: 1 roller column R2: 2 roller column
SL: Transfer line UP: Casing
V: Power transmission means VA: Axial block
WD: Exhaust unit WO: Worker
WS1, WS2: Cooling water supply unit

Claims (2)

A transfer unit (12) for transferring a lead frame having a coated surface to be polished;
A balance spindle module (11) disposed under the transfer unit (12) and arranged so as to be able to contact the surface of the lead frame;
A cylindrical contact spindle unit 14 disposed above the transfer unit 12 and arranged to face the balance spindle module 11, a contact spindle unit 14 disposed above the contact spindle unit 14, A polishing unit comprising a tension unit 15 for adjusting the tension of the abrasive belt rotated by the tension unit 15 and a driving roller unit 16 disposed above the tension unit 15; And
And a Z axis module (17) for up and down movement of the polishing module,
The peripheral surface of the cylinder of the balance spindle module 11 is made of DLC coating and the coating material of the polishing belt GV has a coefficient of friction smaller than that of the coating material of the balance spindle module 11, The abrasive belt is moved downward in accordance with the upward and downward movement of the polishing module along the axis module 17 and is contacted with the balance spindle module 11,
The Z-axis module is composed of a rectangular parallelepiped shaped axial block (VA) and a hollow moving box block (33) surrounding the axial block (VA). The abrading module includes a movable bracket (CB) (33) and is moved up and down along the axis block (VA). The linear motion sensor according to claim 1, wherein the meandering of the abrasive belt is measured by a laser sensor, and a relative position of the moving block (33) to linear guides (331, 332) arranged at four corners of the axis block So that the meandering of the abrasive belt is controlled.

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