JP3978118B2 - Grinding head structure with cup wheel type grindstone - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a grinding head structure including a cup wheel type grindstone used for surface grinding (including polishing) of semiconductor substrates such as silicon wafers, germanium wafers, aluminum wafers, and glass substrates, and metal plates.
[Prior art]
[0002]
As the cup wheel-type grindstone 5, an annular peripheral wall 5a shown in FIG. 5 and a fan-shaped grindstone piece 5d on the lower surface thereof are formed with a slit 5f through which a grinding fluid flows between the grindstone pieces adjacent to each other with an adhesive. A cup wheel type grindstone having a height of 3 to 5 mm fixed in this way (Japanese Utility Model Laid-Open Nos. 61-144959, 61-144961, 61-144962, and Japanese Patent Laid-Open No. 62-181875) is used. It had been.
In this cup wheel type grindstone, since the grinding liquid is supplied from the outside of the grindstone to the grinding surface, the use efficiency of the grinding liquid is poor.
[0003]
In order to increase the utilization efficiency of the grinding fluid, a center system in which the grinding fluid is supplied to the ground surface from the inside of the cup wheel type grindstone is preferable.
The following are known as center-type cup wheel type grindstones.
(1) A grinding fluid supply hollow shaft mounting hole is opened at the center of the base portion of the grindstone main body, and a fluid path extending radially outward from the center is provided. A cup wheel-type grindstone (Japanese Patent Laid-Open No. 60-232877) in which a diamond grindstone piece is fixed between the end portions of the liquid receiving passages of the peripheral wall of the contact surface with the work.
[0004]
(2) As shown in FIG. 4, a cup-type base metal 2 having an annular peripheral wall 18, a grindstone piece 6 provided on the lower end surface 4, and a liquid receiving recess formed on the upper end surface of the base metal 12. 14 and a liquid supply hole 16 having one end opened at the inner bottom surface of the liquid receiving recess and the other end opened at a position closer to the inner surface side than the peripheral wall portion 2b of the base metal lower surface, and an inner peripheral surface 8 of the peripheral wall portion. Is a wheel wheel type grindstone 1 for a surface grinding machine having an inclined surface that spreads outward from the top to the bottom (Japanese Patent Laid-Open Nos. 5-69339, 6-278036, 9-38866, and 2000). -94342, Japanese Patent No. 2503158, Japanese Patent No. 25000285). In the cup wheel type grindstones shown in these publication groups, the grinding liquid is supplied to the liquid receiving recess 14 on the upper surface of the base metal by using a supply nozzle, and the grindstone pieces 6 are passed through the inclined grinding liquid supply holes 16. The grinding fluid is guided to the workpiece contact surface.
[0005]
(3) As shown in FIG. 3, a ring-shaped peripheral wall 18 and a bottom wall 20 provided at one end thereof are provided to form a cup, and have a grinding fluid introduction hole 28 penetrating through the bottom wall, A work surface is obtained when the grinding stone piece 30 provided on the lower surface of the peripheral wall is slidably brought into sliding contact with the work plane 14 while being rotated around the axis while being supplied with the grinding fluid to the inside of the peripheral wall through the grinding liquid introduction hole. And a main body 34 that covers the inner surface opening of the bottom wall 20 of the grinding fluid introduction hole 28 at a predetermined distance from the inner surface of the bottom wall 20 and is fixed to the bottom wall. A cup-type grindstone provided with a rotary impeller 16 in which a plurality of blade portions 42 erected in a direction opposite to the rotation direction toward the outer peripheral side toward one outer surface on the bottom wall side of the main body portion are erected at a predetermined interval in the circumferential direction. (Japanese Patent Laid-Open No. 9-38666).
The rotary impeller 16 acts like a pump to pump the grinding liquid to the sliding contact surface between the grindstone piece and the workpiece.
[0006]
Since the cup-type grindstone of (1) has the liquid receiving channel opening end between the grindstone pieces, the amount of grinding liquid escapes to the outside of the grindstone by centrifugal force, and the utilization rate of the grinding liquid is low.
[0007]
The cup-type grindstone of (2) is limited in the mounting position of the nozzle for supplying the grinding liquid to the liquid receiving recess 14 and the diameter of the work substrate is increased to 200 mm, 300 mm, and 400 mm. As the thickness becomes as thin as 20 to 100 μm, the chance of grinding dust to enter between the printed circuit surface of the work and the adhesive film protecting it increases, which is not preferable.
[0008]
The cup-type grinding wheel provided with the rotary impeller of the above (3) has a large amount of grinding liquid supplied to the grinding wheel piece, and grinding scraps and abrasive grains enter between the printed circuit surface of the work and the adhesive film protecting it. Although there is an advantage that the opportunity is reduced, the mounting positions of the plurality of nozzles 46 for supplying the grinding liquid to the grinding liquid introduction hole 28 are limited, and the nozzle mounting structure is complicated.
[0009]
[Problems to be solved by the invention]
The present invention simplifies the supply of the grinding fluid to the grinding head structure by fixing the grindstone to the rotating shaft provided with the grinding fluid introducing section, and also provides a water supply guide below the rotating shaft to remove grinding waste and abrasive grains. The present invention provides a grinding head structure provided with a cup wheel-type grindstone that rarely has an opportunity to penetrate between the printed circuit surface and the adhesive film that protects the printed circuit surface.
[0010]
According to a first aspect of the present invention, a cup-shaped base metal is formed by an annular peripheral wall in which a grindstone piece is annularly planted at a predetermined interval and a bottom wall provided at one end thereof. A cup wheel type grindstone used for grinding a work surface is hollowed by a grindstone piece rotated around an axis while being supplied and being brought into sliding contact with the work surface. A grinding head structure supported on a shaft,
Having a central recess on the upper surface, the passage groove provided radially outwardly from the central recess, a water supply guide having an inclined portion of the two-stage inclined outwardly gradually becomes loose, the water supply guide The central inclined portion a has an inclination of 30 to 60 degrees with respect to the horizontal plane, and the outer inclined portion b has an inclination of 5 to 20 degrees with respect to the horizontal plane, and faces the outer inclined portion b. lower surface of the annular flange which is inclined outwardly such that a space portion in which the lower surface of the inclined portion b and the annular flange is formed is gradually narrowed, via an annular flange fixed to the lower periphery of the hollow shaft Fixed to the lower part of the hollow shaft, and the base of the cup wheel type grindstone is fixed to the annular flange via an annular protrusion, and a bowl-shaped lid is formed by the bottom wall, the annular protrusion and the annular flange. When the grinding fluid rotates on the hollow shaft More a structure to prevent the leaking out, grinding liquid supplied to the interior of the hollow shaft central recess of the water supply guide channel groove, is introduced by way of the inclined portion of the two-stage to the inside of the peripheral wall, Further, the present invention provides a grinding head structure characterized in that it is supplied to the work surface where the workpiece and the grindstone piece are in sliding contact with each other by the centrifugal force generated by the rotation of the water supply guide around the hollow axis.
[0011]
Since the grinding liquid is supplied to the hollow shaft, the structure of the grinding head portion is disclosed in FIG. 4 provided with the conventional nozzle , or is cleaner than the grinding head structure disclosed in FIG. 3, and the grinding operation is easy. . In addition, the grinding fluid supplied to the central recess of the water supply guide increases the momentum of the flow when entering the channel groove, and the centrifugal force is also applied to increase the pumping force. , The opportunity for these to enter between the printed circuit surface of the workpiece and the adhesive film protecting it is rare. Moreover, the supply of the grinding fluid to the sliding contact surface of the grindstone piece and the work surface was facilitated by providing the inclined portion of the outer peripheral portion of the water supply guide in multiple stages.
[0012]
In the grinding head structure of the present invention, the inclined portion of the water supply guide has two steps, the central inclined portion a has an inclination of 30 to 60 degrees with respect to the horizontal plane, and the outer inclined portion b has a horizontal plane. The lower surface of the annular flange having an inclination of 5 to 20 degrees with respect to the outer inclined portion b is arranged so that the space formed by the inclined portion b and the lower surface of the annular flange is gradually narrowed. It is inclined toward .
[0013]
Since the space formed by the two inclined surfaces of the water supply guide and the lower inclined surface of the annular flange gradually narrows, the pressure of the grinding fluid pumped increases, and the grinding debris and abrasive grains are quickly removed from the slits between the grindstone pieces. Missed out of the wheel.
[0014]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the present invention will be described in detail with reference to the drawings.
FIG. 1 is a cross-sectional view showing a grinding head structure according to the present invention, in which dimensions are shown in an example of surface grinding of a 300 mm diameter substrate. FIG. 2 is a plan view of a water supply guide used in the grinding head structure of the present invention. The cross section of the water supply guide 59 shown in FIG. 1 is the figure seen from the II cutting | disconnection line in FIG.
[0015]
As shown in FIGS. 1 and 2, the grinding head structure 50 of the present invention is cup-shaped with an annular peripheral wall 51 in which a grindstone piece 54 is annularly planted at a predetermined interval and a bottom wall 52 provided at one end thereof. A base metal 53 is formed to form a cup wheel type grindstone. The grinding liquid is guided to the hollow portion 58 of the hollow shaft 57 by using a pump and a water supply pipe (not shown), and passes through the flow path space 64 formed by the upper surface of the water supply guide 59 and the lower surface of the annular flange 56. Then, the grinding liquid is supplied to the surface of the grindstone piece 54 and the work surface in sliding contact with each other.
[0016]
The base metal 53 of the cup wheel type grindstone is fixed to an annular protrusion 55 with a bolt 67, and this annular protrusion 55 is fixed to an annular flange 56 with a bolt 68, and the annular flange 56 is fixed to the lower part of the hollow shaft 58. . Reference numeral 70 denotes an oil seal. A bowl-shaped lid is formed by the bottom wall, the annular protrusion, and the annular flange to prevent the grinding fluid from leaking from the upper side when the hollow shaft rotates.
[0017]
The water supply guide 59 is fixed to the lower surface of the annular flange 56 with bolts 69 so that the shaft center 59a thereof coincides with the shaft center 57a of the hollow shaft. This water supply guide has a central recess 60 on the upper surface, and is provided with channel grooves 61 radially outward from the central recess, and two-stage inclined portions 62 and 63 that gradually become inclined outward. Have. The grinding fluid supplied to the hollow shaft interior 58 is guided to the central recess 60 and introduced into the inner space 66 of the peripheral wall 51 via the flow channel groove 61 and the two inclined portions 62 and 63, and A structure is adopted in which the grinding fluid is supplied to the machining surface where the workpiece and the grindstone piece are in sliding contact with each other by the centrifugal force generated by the rotation of the water supply guide around the hollow shaft center 59a.
[0018]
The plurality of inclined portions of the water supply guide have two stages, the inclined portion a62 on the center side has an angle α of 30 to 60 degrees with respect to the horizontal plane, and the outer inclined portion b63 has an angle β of 5 to 20 with respect to the horizontal plane. The lower surface of the annular flange facing the outer inclined portion b is inclined outward so that the space formed by the inclined portion b and the lower surface of the annular flange becomes gradually narrower. Yes. The inclination angle of the lower surface of the annular flange is such that the inner angle γ is 35 to 60 degrees and the outer angle θ is 10 to 20 degrees. In the water supply guide 59 of the 300 mm base grinding head structure shown in FIG. 1, the angle α is 45 degrees, the angle β is 10 degrees, the angle γ is 45 degrees, and the angle θ is 15 degrees.
From the viewpoint of design, the length of the inclined surface of the inclined portion a on the center side is preferably shorter than the inclined surface of the inclined portion b on the outer side.
[0020]
Aluminum is used as the material of the base metal 53, and glass fiber reinforced resin is used as the material of the water supply guide 59. The grindstone piece 54 is formed by molding abrasive grains such as diamond abrasive grains and CBN abrasive grains with an adhesive such as phenol resin or epoxy resin, and is provided annularly at equal intervals on the lower surface of the peripheral wall. In the cup wheel type grindstone, the height of the slit between the grindstone pieces is preferably 3 to 10 mm, the lateral width of the grindstone piece is 2 to 7 mm, and the length of the grindstone piece divided by the slit is preferably 10 to 50 mm. The inner diameter of the grinding liquid introducing hollow portion 58 is preferably about 25 mm.
[0021]
【Example】
Example 1
As a grinding device, a precision surface grinding device SVG502MK-II (trade name) of Okamoto Machine Tool Co., Ltd. was used, and a grinding head structure equipped with a cup wheel type diamond grinding wheel shown in FIG. 1 was fixed to the hollow spindle of the device. .
On the substrate holder, the surface of the printed circuit board of the 200 mm diameter semiconductor substrate with the adhesive protective film attached is held so that the silicon substrate surface faces upward (the adhesive film faces downward), and the substrate holder is held at 100 min ⁻¹ . The hollow spindle was rotated at 300 min ⁻¹ , the grinding head structure was lowered while supplying the grinding liquid to the hollow part of the hollow spindle, and the grindstone piece was slidably contacted with the silicon substrate surface of the semiconductor substrate for 2 minutes of grinding.
After grinding the substrate, brush-scrubbing the ground surface of the substrate, spin-drying, and observing whether dust (abrasive grains and grinding debris) exists between the adhesive film and the printed wiring of the semiconductor substrate, There was no dust.
[0022]
【The invention's effect】
The grinding head structure of the present invention has a structure in which the grinding liquid is introduced from the hollow shaft and the grinding liquid is supplied to the grindstone piece of the cup-type grindstone and the sliding surface of the workpiece surface via the water supply guide. The structure around the cup-type grindstone is simple, and a large amount of grinding fluid is pumped between the grindstone piece of the cup-type grindstone and the sliding surface of the work surface, so there is dust between the adhesive film and the printed wiring on the semiconductor substrate. Will not accumulate.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view showing a grinding head structure of the present invention.
FIG. 2 is a plan view of a water supply guide used in the grinding head structure of the present invention.
FIG. 3 is a partial cross-sectional view of a grinding head provided with a cup wheel type grindstone. (Known)
FIG. 4 is a cross-sectional view of a cup wheel type grindstone. (Known)
FIG. 5 is a perspective view of a cup wheel type grindstone. (Known)
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 50 Grinding head structure 51 Perimeter wall 52 Bottom wall 53 Base metal 54 Grinding stone piece 55 Annular protrusion 56 Annular flange 57 Hollow shaft 59 Water supply guide 60 Central recessed part 61 Channel groove 62 Inclined part a
63 Inclined part b
64 Flow path 65 Outlet 66 Space

Claims (1)

A ring-shaped peripheral wall in which grindstone pieces are planted annularly at a predetermined interval and a bottom wall provided at one end form a cup-shaped base metal, and rotate around the axis while supplying grinding fluid to the inside of the peripheral wall. A grinding wheel structure in which a cup wheel type grindstone used for grinding a work surface is supported on a hollow shaft by a grindstone piece implanted in the lower part of the peripheral wall being brought into sliding contact with the work surface. There,
Having a central recess on the upper surface, the passage groove provided radially outwardly from the central recess, a water supply guide having an inclined portion of the two-stage inclined outwardly gradually becomes loose, the water supply guide The central inclined portion a has an inclination of 30 to 60 degrees with respect to the horizontal plane, and the outer inclined portion b has an inclination of 5 to 20 degrees with respect to the horizontal plane, and faces the outer inclined portion b. The lower surface of the annular flange is inclined outward so that the space formed by the inclined portion b and the lower surface of the annular flange is gradually narrowed , and the annular flange is fixed to the lower periphery of the hollow shaft. Fixed to the lower part of the hollow shaft, and the base of the cup wheel type grindstone is fixed to the annular flange via an annular protrusion, and a bowl-shaped lid is formed by the bottom wall, the annular protrusion and the annular flange. When the grinding fluid rotates on the hollow shaft More a structure to prevent the leaking out, grinding liquid supplied to the interior of the hollow shaft central recess of the water supply guide channel groove, is introduced by way of the inclined portion of the two-stage to the inside of the peripheral wall, Further, the grinding head structure is characterized in that the work is supplied to the work surface where the work piece and the grindstone piece are in sliding contact with each other by the centrifugal force generated by the rotation of the water supply guide around the hollow shaft.

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