CN100530555C

CN100530555C - Wafer thinning method

Info

Publication number: CN100530555C
Application number: CNB200710168077XA
Authority: CN
Inventors: 蔡裕斌; 黄正一
Original assignee: Advanced Semiconductor Engineering Inc
Current assignee: Advanced Semiconductor Engineering Inc
Priority date: 2007-10-31
Filing date: 2007-10-31
Publication date: 2009-08-19
Anticipated expiration: 2027-10-31
Also published as: CN101150059A

Abstract

This invention relates to a method for getting wafers thinner including: providing a wafer with an active side and a back, setting several hump elements on the active side and putting the wafer in a die and forming a macromolecular material in the die to cover the active side of the wafer at least, solidifying the macromolecular material and removing the die, grinding the back of the wafer to get the wafer thinner, finally, removing the material to expose the active side of the wafer and the hump elements on it, which utilizes the die to enable the macromolecular material to cover the active side of the wafer and wrap the hump elements, in this way, stress generated in grinding the wafer is distributed on the wafer uniformly so as to avoid warp, break, crack of the wafer or peel off of the hump elements.

Description

Wafer thinning method

[technical field]

The invention relates to a kind of wafer thinning method, particularly relevant for a kind of wafer thinning method that prevents that the projection on wafer or the wafer from damaging.

[background technology]

For the thinning semiconductor package part; usually can implement one at the back side of wafer and grind processing procedure; with the thinning wafer; but because the active face of wafer has line pattern or is provided with various protruding members; for example projection or passive component; when therefore grinding thinning at the back side of wafer; must protect active face and protruding member with an adhesive tape or glued membrane; as shown in Figures 1 and 2; an existing wafer 100 has an active face 110; the side 130 that one back side 120 and one is 120 at this active face 110 and this back side; several protruding members 140 are arranged on this active face 110; one glued membrane 10 is covered on the active face 110 of this wafer 100; when grinding the back side 120 of this wafer 100; in order to protect this active face 110 and these protruding members 140; yet existing glued membrane 10 is by basalis 11; ultra-soft layer 12 is formed with adhesion layer 13; its expensive price and when between 140 of these protruding members apart from too hour; this glued membrane 10 can't cover this active face 110 of this wafer 100 fully and coat these protruding members 140; therefore when grinding the back side 120 of this wafer 100, the stress that is produced causes the situation of fragmentation and warpage to take place easily.In addition, because this glued membrane 10 does not cover the side 130 of this wafer 100, therefore when grinding, can cause this wafer 100 to burst apart, perhaps, when tearing off this glued membrane 10, this glued membrane 10 can will be arranged on the protruding member 140 of this active face 110 and peel off, in addition, if this glued membrane 10 does not remove and totally has cull yet and remain in this active face 110 and pollute.

[summary of the invention]

Main purpose of the present invention is to provide a kind of wafer thinning method, and it prevents silicon wafer warpage, fragmentation or bursts apart and can avoid the peeling off of protruding member on the wafer.

Wafer thinning method of the present invention utilizes mould 20 to make macromolecular material 30 cover active face 210, the side 230 of wafer 200 in die casting mode (molding method) and coats protruding member 240, the stress that is produced when make grinding this wafer 200 can be evenly distributed in this wafer 200, prevents these wafer 200 warpages, fragmentation or bursts apart and can avoid these protruding members 240 to peel off removing this macromolecular material 30.

For reaching aforementioned purpose of the present invention, the invention provides a kind of wafer thinning method, at first, one wafer with an active face and a back side is provided, can be provided with several protruding members on this active face, then, be placed on this wafer in one mould and filling one macromolecular material in this mould, this macromolecular material covers the active face of this wafer at least, afterwards, solidifies this macromolecular material and removes mould, then, the back side of grinding this wafer is with the thinning wafer, and is last, removes active face and these protruding member of this macromolecular material to manifest this wafer.

The present invention also provides a kind of wafer thinning method, and this macromolecular material also covers a side of this wafer, and it can avoid causing this wafer to burst apart when grinding the back side of wafer.

It is wax that the present invention also provides a kind of this macromolecular material, is to clean this wafer with hot water in removing the step of this macromolecular material, to remove this wax layer.

The present invention also provides a kind of wafer thinning method, at first, provides a wafer, and this wafer has an active face and a back side; Then, this wafer is placed in the mould; Afterwards, form a macromolecular material in this mould, this macromolecular material covers the active face of this wafer at least; Then, solidify this macromolecular material and remove this mould; Afterwards, grind the back side of wafer, with this wafer of thinning; At last, remove this macromolecular material to manifest the active face of wafer.

Compared to prior art, the present invention utilizes this mould to make macromolecular material cover the active face of this wafer and coats these protruding members, makes the stress that is produced when grinding this wafer be evenly distributed in this wafer, to prevent this silicon wafer warpage, fragmentation.In addition, macromolecular material of the present invention also covers the side of wafer, thereby can avoid causing wafer to burst apart when grinding the back side of wafer.

For above and other objects of the present invention, feature and advantage can be become apparent, cooperate appended graphicly, be described in detail below:

[description of drawings]

Fig. 1 be an existing wafer schematic cross-section, its active face glued membrane that has been sticked.

Fig. 2 is that existing this wafer is removed the schematic cross-section that produces warpage behind this glued membrane.

Fig. 3 A to Fig. 3 E is the schematic cross-section according to a kind of wafer thinning method of one first specific embodiment of the present invention.

Fig. 4 is that another kind of wafer is coated with the schematic cross-section of macromolecular material according to one second specific embodiment of the present invention.

The 5th figure is that another kind of wafer is coated with the schematic cross-section of this macromolecular material according to one the 3rd specific embodiment of the present invention.

[embodiment]

See also Fig. 3 A to Fig. 3 E, disclose a kind of wafer thinning method according to one first specific embodiment of the present invention, at first, see also 3A figure, one wafer 200 is provided, this wafer 200 has an active face 210, a back side 220 and at least one side 230 between this active face 210 and this back side 220, in the present embodiment, this active face 210 of this wafer 200 is provided with several protruding members 240, these protruding members 240 are selected from projection, soldered ball or passive component, in the present embodiment, these protruding members 240 are projections.Then, see also Fig. 3 B this wafer 200 is positioned in the mould 20, this mould 20 includes a mold 21 and a bed die 22, and this mold 21 is formed with a die cavity 23 with bed die 22, this wafer 200 is positioned on this bed die 22, and the active face 210 of this wafer 200 is towards this mold 21.In the present embodiment, the width W 1 of this die cavity 23 is slightly larger than the diameter W2 of this wafer 200.This wafer 200 has first height H 1, and these protruding members 240 have one second height H 2.Preferably, the height H 3 of this die cavity 23 is greater than the sum total of this first height H 1 and second height H 2.Afterwards, see also Fig. 3 C, in this mould 20, form a macromolecular material 30, this macromolecular material 30 can be the hot melt material, wax for example, and this macromolecular material 30 can have water-insoluble or repellency, this macromolecular material 30 is filled in the die cavity 23, and this macromolecular material 30 covers the active face 210 of this wafer 200 at least, in the present embodiment, the side 230 that this macromolecular material 30 covers to this wafer 200, and these macromolecular material 30 these protruding members 240 of coating, this macromolecular material 30 is selected from wax or special glue.Then; see also Fig. 3 D; solidify this macromolecular material 30 and remove mould 20; in the present embodiment, this macromolecular material 30 is a wax, and it covers the active face 210 of this wafer 200; side 230 also coats these protruding members 240; to protect this wafer 200 and these protruding members 240; in addition, in another embodiment, this macromolecular material 30 also can coat the back side 220 of this wafer 200; perhaps; see also Fig. 4, in another embodiment, this macromolecular material 30 does not coat side 230 fully; perhaps; see also Fig. 5, this macromolecular material 30 only coats the active face 210 and these protruding members 240 of this wafer 200, to save time and the cost that grinds; in addition; in different embodiment, the active face 210 of this wafer 200 can be formed with several grooves (figure does not draw), and this macromolecular material 30 is filled in these grooves.Afterwards; see also Fig. 3 E; the wafer 200 that is coated with this macromolecular material 30 is placed on the microscope carrier 40; the active face 210 of this wafer 200 is towards microscope carrier 40; the back side 220 with a grinding wheel 50 these wafers 200 of grinding; with this wafer 200 of thinning; because this macromolecular material 30 covers the active face 210 of wafer 200; side 230 and coat these protruding members 240; therefore in grinding the back side 220 processes, can utilize the side 230 of these macromolecular material 30 these wafers 200 of protection; to avoid in process of lapping, causing wafer to burst apart; and utilize this macromolecular material 30 to absorb positive pressure and the side direction shear stress that puts on this wafer 200, the warpage that produces to prevent these wafer 200 stress skewness; the fragment or the phenomenon of bursting apart.At last, remove this macromolecular material 30, can water, solvent or its mixture cleaning wafer 200 to be to remove macromolecular material 30, with the active face 210 and these protruding members 240 that manifests this wafer 200, clean this wafer 200 with hot water in the present embodiment, because this macromolecular material 30 has low-melting wax or special glue for water-insoluble and material are selected from, therefore be easy to remove and can be not soluble in water and pollute this wafer 200.Wafer thinning method of the present invention utilizes this mould 20 to make this macromolecular material 30 cover active face 210, the side 230 of this wafer 200 and coat these protruding members 240 in die casting mode (molding method), the stress that is produced when make grinding this wafer 200 can be evenly distributed in this wafer 200, prevents these wafer 200 warpages, fragmentation or bursts apart and can avoid these protruding members 240 to peel off removing this macromolecular material 30.

Claims

1. wafer thinning method, comprise: a wafer is provided, and this wafer has an active face and a back side; Cover the active face of this wafer; And the back side of grinding this wafer; It is characterized in that: before the step of the active face that covers this wafer, also comprise: this wafer is placed in the die cavity of a mould; In this mould, form a macromolecular material, this macromolecular material covers the active face of this wafer at least, after the step of the active face that covers this wafer, also comprise: solidify this macromolecular material and remove this mould, after the step at the back side of grinding this wafer, also comprise: remove this macromolecular material.

2. wafer thinning method as claimed in claim 1 is characterized in that: this wafer also has a side between this active face and this back side, and this macromolecular material covers this side.

3. wafer thinning method as claimed in claim 1 is characterized in that: this macromolecular material is the hot melt material.

4. wafer thinning method as claimed in claim 1 is characterized in that: this macromolecular material is selected from wax.

5. wafer thinning method as claimed in claim 1 is characterized in that: the width of this die cavity is greater than the diameter of this wafer.

6. wafer thinning method as claimed in claim 1 is characterized in that: the active face of this wafer is provided with several protruding members, and these protruding members are selected from projection, soldered ball or passive component, and this macromolecular material coats these protruding members.

7. wafer thinning method as claimed in claim 6 is characterized in that: this wafer has one first height, and these protruding members have one second height, and the height of this die cavity is greater than the sum total of this first height with this second height.

8. wafer thinning method as claimed in claim 1 is characterized in that: this active face of this wafer is formed with several grooves, and this macromolecular material is filled in these grooves.

9. wafer thinning method as claimed in claim 1 is characterized in that: removing this macromolecular material, is to clean this wafer by water, solvent or its mixture, to remove macromolecular material.

10. wafer thinning method as claimed in claim 9 is characterized in that: clean this wafer with hot water in removing the step of this macromolecular material.

11. wafer thinning method as claimed in claim 1 is characterized in that: this macromolecular material has water-insoluble.