JP2986179B2 - Wafer edge coating method and apparatus - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to forming a connection portion (bump) for bonding to a printed circuit board on a wafer on which an integrated circuit (IC) is formed. The present invention relates to a method and an apparatus for coating an edge of a wafer for preventing plating from being attached to the edge.

[Prior art] In order to mount an IC on a printed circuit board, for example, a bump serving as an electrode connection portion is formed in advance on an IC chip on a wafer, and the wafer is cut into each IC chip. A method of bonding the upper lead by bonding is employed.

As a conventional bump formation method, there is a vapor deposition method, that is, a method in which a mask is formed in a portion other than an IC lead portion on a wafer, and a bump is formed by depositing a metal film.
However, in the case of the vapor deposition method, it is difficult to align a mask with a large-sized wafer, and there is a problem such as a warpage of the mask, which is not practical.

Therefore, in recent years, a plating method as shown in FIGS. 5 (a) to 5 (c) has been developed, and bumps can be formed even on a large-sized wafer without causing the above-described problems. According to this plating method, the wafer W is placed on a rotary support called a spinner, and a solder adhesion preventing film (resist) L is formed on the surface of the wafer W.
Then, the resist L is applied to the IC lead portion R by exposing it, and the resist L is removed by exposing the IC lead portion R (FIG. 9A). Next, a copper plating process is performed on the wafer W to form a copper plating layer P on the IC lead portion R, and further, a solder layer S is formed on the copper plating layer P by laminating (FIG. 2B). Thereafter, the bumps V were formed by removing the resist L on both surfaces and reflowing the solder layer S (FIG. 3C).

[Problems to be Solved by the Invention] In the conventional plating method described above, the resist is applied to both the front and back surfaces of the wafer W, but the end surface of the wafer W remains exposed. In other words, the resist cannot be applied to the end face of the wafer W when the wafer W is placed on the spinner.

However, the silicon and copper forming the wafer have a strong affinity, and if the end face of the wafer W is left bare, copper plating will adhere. In particular, when eutectic solder is used for the solder layer, the copper plating layer must be formed thick, so that the amount of copper plating adhered to the edge of the wafer increases. If such a large amount of copper plating adheres to the edge of the wafer, there is a disadvantage that when the wafer is cut in a later process, irregular cracks or chips are generated from the edge, and the yield of produced IC chips is reduced. Was.

The present invention has been made in view of such circumstances, and a method of coating an edge of a wafer that can prevent plating from adhering to the edge of the wafer and improve the yield of IC chips, and an implementation of the method. It is an object of the present invention to provide a suitable wafer edge coating apparatus.

[Means for Solving the Problems] In order to achieve the above object, the wafer edge coating method of the present invention arranges a plurality of wafers side by side at regular intervals and arranges the plurality of wafers substantially. Simultaneously rotating, while applying the photocurable resin to the end surface and the end surface side portion over the entire circumference of the plurality of wafers, as a method of irradiating the light-cured resin applied portion with a light beam, more preferably, After irradiating the light-cured resin with the light beam, the application of the photo-curable resin is stopped, and the irradiation of the light beam is repeated at least once.

In addition, the wafer edge coating apparatus of the present invention includes a storage unit configured to store a plurality of wafers arranged side by side at regular intervals, a rotation unit configured to rotate the plurality of wafers substantially simultaneously, and a rotation unit configured to rotate the plurality of wafers. Coating means for applying a photocurable resin to end faces and end face side portions of respective wafers, and irradiation means for irradiating light rays to the end faces and end face side portions of the plurality of rotating wafers coated with the photocurable resin. Preferably, the photocurable resin application means is configured to include a roller that applies the photocurable resin almost simultaneously to end surfaces and end surface side portions of the plurality of wafers, More preferably, the roller has a first roller to which a photocurable resin is adhered, and a concave portion into which an end surface and an end surface side portion of the plurality of wafers enter an outer peripheral surface, There a photocurable resin filled in the concave portion from over La as structure comprising a second roller for applying the end surface and the end surface sides of the plurality of wafers.

[Operation] Since the present invention has the above-described configuration, a photocurable resin layer can be formed on the edge of the wafer, and the bonding between the plating and the silicon is interrupted by this layer. It will not adhere.

The photo-curable resin to be used only needs to have a low affinity for plating and no dissolution in the plating solution. For example, an ultraviolet-curable resin (trade name: Hard Rock (Electrochemical Industries, Ltd.) Co., Ltd.) can be used.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

1 is a side sectional view showing an embodiment of a wafer edge coating apparatus according to the present invention, FIG. 2 is a partially cutaway front view of a wafer storage basket, and FIG. 3 is a perspective view showing a means for applying a photocurable resin. FIG. 4 is a front view showing a roller portion of the means.

First, an embodiment of the device of the present invention will be described with reference to these drawings.

In FIG. 1, reference numeral 10 denotes a box-shaped apparatus main body, and a lid 11 is detachably attached to an upper opening. Inside the apparatus main body 10, a mounting frame 12 of a wafer storage basket (wafer supporting means) 20, a feed roller (wafer rotating means) 30, a photocurable resin coating means 40, and a light source 50 are provided. Reference numerals 13 and 14 denote ventilation holes. In particular, a light blocking plate 15 is provided below the ventilation holes 13 to prevent external light from entering the wafer W.

Partitions 21 are arranged at regular intervals inside the wafer storage basket 20, and a large number of wafers W are vertically stored between the partitions 21 (see FIG. 2). An opening 22 having a length shorter than the diameter of the wafer W is provided at the bottom, and a lower portion of the wafer W is partially exposed from the opening 22. Further, a mounting flange 23 is provided on the outer peripheral edge of the upper end of the basket 20, and the flange 23 is placed on the mounting frame 11 and can be loaded into the apparatus main body 10.

The feed roller 30 is provided at a position where the wafer W exposed from the bottom opening 22 of the wafer storage basket 20 loaded in the apparatus main body 10 abuts and the wafer W is slightly lifted. The feed roller 30 is driven to rotate by a drive motor (not shown). Further, the outer peripheral surface of the feed roller 30 is coated with a slip preventing member 31 having a large coefficient of friction such as soft rubber to increase the frictional force between the wafer W and the wafer W to be brought into contact by gravity, thereby ensuring the wafer W. The device to rotate it is made.

As shown in FIG. 3, the coating means 40 of the photocurable resin is provided with first and second rollers 41 and 42, and the rotating shafts 43 and 44 of the rollers 41 and 42 mesh with each other. Gears 45, 46
Are attached to both ends. Furthermore, the rotation axis of the first roller 41
A pulley 47 is attached to 43, and is configured to receive a driving force from a driving motor (not shown) via a transmission belt 48. The first roller 41 is rotated by this driving force, and the second roller 42 is also rotationally driven via the gears 45 and 46.

Below the first roller 41, a container 49 filled with a photocurable resin is provided, and the lower portion of the first roller 41 is immersed in the photocurable resin in the container 49. Also, the second roller 42
Are formed with collars 42a, 42a at both ends, and the collars 42a, 42a are in contact with the first roller 41. Therefore, an intermediate portion between the collars 42a, 42a (hereinafter, referred to as
A gap having a constant depth d is formed between the first roller 41 and the concave portion 42b (referred to as a concave portion) as shown in FIG.

The photocurable resin is filled in the gap, adheres to the peripheral surface of the second roller 42 while rotating at a certain depth d, and rotates. The wafer W is in contact with the peripheral surface of the second roller 42 and is driven to rotate by the feed roller 30 as described above. Here, it is preferable that the rotation of the wafer W by the feed roller 30 and the rotation of the second roller 42 are synchronized.

The photo-curing resin application means 40 is provided on a moving table (not shown) and is movable in the direction of arrow a in FIG.

The light source 50 is composed of the feed roller 30 and the photo-curing resin coating means 40.
Between the end face of the wafer W and both side portions of the end face (hereinafter, referred to as “light-curable resin”).
Irradiation is performed on the edge formed simply by the side of the end face). In this embodiment, an ultraviolet lamp is used as the light source 50.
An openable shutter 51 is provided on the front surface of the light source 50, and irradiates the edge of the wafer with light only when the shutter 51 is open, and blocks the light when the shutter 51 is closed. I do. Further, a fixed shutter 52 is provided between the light-curing resin coating means 40 and the light source 50 to prevent light from leaking into the coating means 40.

Next, an embodiment of a wafer edge coating method according to the present invention, which is performed using the above-described apparatus, will be described.

First, the wafer W is vertically stored in the wafer storage basket 20, and the basket 20 is loaded into the apparatus main body 10. At this time, the feed roller 30 and the photocurable resin
Are stopped, and the shutter 51 is kept closed.

Next, the feed roller 30 is driven to rotate the wafer W in the counterclockwise direction in FIG. 1, and at the same time, the first and second rollers 41 and 42 in the photocurable resin coating means 40 are rotated. At the same time, the shutter 51 is opened to irradiate the edge of the wafer W with a light beam.

Since the feed roller 30 has the slip prevention member 31 on the peripheral surface, the feed roller 30 can surely come into contact with the end face of the wafer W, and can rotate stably even if the wafer W has a notch such as an orientation flat.

In the photo-curing resin application means 40, the photo-curing resin adhered to the first roller 41 is filled in the concave portion 42b of the second roller 42, and the edge of the wafer W entering the concave portion 42b is always in a uniform state. (See FIG. 4). Therefore, it is possible to accurately control the amount of application, and therefore, it is possible to apply the minimum amount. Therefore, the photocuring of the edge after that can be performed smoothly.

Subsequently, the photocurable resin applied to the edge of the wafer W is irradiated with a light beam from the light source 50 to cure the resin.

In this manner, the photocurable resin can be uniformly applied and cured, so that there is no adhesion of plating, and it is easy to remove the coating material at the edge after plating.

The application of the photocurable resin and the irradiation of the light beam are continued until the multilayer film of the photocurable resin is formed over the entire periphery of the edge of the wafer W. Then, the second roller 42 is moved away from the edge of the wafer W by moving the coating means 40 of the photocurable resin, and the wafer W is rotated twice while being irradiated with the light beam. That is, the pre-stage processing alone is not enough to cure the photocurable resin attached to the end face side of the wafer W. Therefore, the wafer W is further rotated twice while being irradiated with the light beam, so that the resin W is sufficiently cured.

The wafer W whose edge is coated with the photocurable resin in this manner has no risk of plating adhered to the edge in a subsequent plating process. Then, the photocurable resin at the edge is removed from the wafer W by lift-off.

Note that the present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the scope of the invention.

For example, the structures of the apparatus main body and each means are not limited to those in the above-described embodiment. In particular, the apparatus main body and the wafer storage basket have much room for design change as appropriate in consideration of the work space, the work scale, and the like.

Further, in the embodiment of the method described above, the application of the photocurable resin and the irradiation of the light beam are performed over the entire circumference of the wafer, and then the light beam is irradiated while the wafer is rotated twice. Depending on the curing characteristics, the operation may be terminated without performing the subsequent operation, or the operation may be replaced with the latter operation by separately providing a light irradiation box and irradiating light.

[Effects of the Invention] As described above, according to the wafer edge coating method of the present invention, plating is prevented from adhering to the wafer edge,
This has the effect of improving the yield of IC chips.

Further, according to the wafer edge coating apparatus of the present invention, the above method can be performed simply and quickly.

[Brief description of the drawings]

1 is a side sectional view showing an embodiment of a wafer edge coating apparatus according to the present invention, FIG. 2 is a partially cutaway front view of a wafer storage basket, and FIG. 3 is a perspective view showing a means for applying a photocurable resin. FIG. 4 is a front view showing a roller portion of the same means, and FIGS. 5 (a), (b) and (c) are cross-sectional views showing a bump forming step of a wafer. 10: Apparatus body, 11: Mounting frame 20: Wafer storage basket 22: Opening, 23: Flange 30: Feed roller 31: Slip prevention member 40: Light curable resin application means 41: First roller, 42: Second roller 42a: collar, 42b: recess 45, 46: gear, 49: container 50: light source, 51: shutter

Continuation of the front page (56) References JP-A-1-265523 (JP, A) JP-A-63-141370 (JP, A) JP-A-2-298036 (JP, A) JP-A 64-33742 (JP) , U) (58) Field surveyed (Int.Cl. ⁶ , DB name) H01L 21/60

Claims (5)

(57) [Claims] A plurality of wafers are arranged side by side at regular intervals, and the plurality of wafers are rotated substantially simultaneously to form photo-curing on end faces and end face side portions around the entire circumference of the plurality of wafers. A method for coating an edge of a wafer, comprising applying a resin and irradiating a light beam to a portion where the photocurable resin is applied. 2. A plurality of wafers are arranged side by side at a fixed interval in a lateral direction, and the plurality of wafers are rotated substantially simultaneously to form a photocurable resin on end faces and end face side portions around the entire circumference of the plurality of wafers. Along with applying the resin, after irradiating the light-cured resin with a light beam at the applied location, the application of the photo-curable resin is stopped, and the irradiation of the light beam is repeated at least once or more. Edge coating method for the wafer. 3. A storage section for storing a plurality of wafers side by side at a fixed interval in a horizontal direction; a rotating unit for rotating the plurality of wafers substantially simultaneously; an end face of each of the rotating plurality of wafers; Coating means for applying a photocurable resin to an end face side; and irradiation means for irradiating a light beam to the end face and the end face side of the plurality of rotating wafers to which the photocurable resin is applied. Characteristic edge coating equipment for wafers. 4. The apparatus according to claim 3, wherein said means for applying the photocurable resin comprises a roller for applying the photocurable resin almost simultaneously to the end faces and the end face side portions of said plurality of wafers. Wafer edge coating equipment. 5. The roller has a first roller for adhering a photocurable resin, and a concave portion on the outer peripheral surface into which the end surfaces and the end surface side portions of the plurality of wafers enter, and the first roller fills the concave portion. The wafer edge coating apparatus according to claim 4, comprising a second roller for applying the photocurable resin to the end surfaces and the end surface side portions of the plurality of wafers.