TWI450325B - A method for encapsulating wafer which support wafer backside sawing - Google Patents

Description

Chip packaging method for supporting cutting from the back side of wafer

The present invention generally relates to a method of fabricating an ultra-thin wafer, and more particularly to provide a wafer packaging method that supports dicing from the back side of a wafer to effect fabrication of an ultra-thin wafer.

In the wafer packaging process, the wafer is generally diced along the dicing track on the front side of the wafer to separate the wafer from the wafer. However, in some special packaging processes, such as wafer level packaging (WLP), it is sometimes necessary to cut the wafer from the back side of the wafer, but if the back side of the wafer is encapsulated by a molding material or the back side of the wafer is covered with other In the case of opaque materials, it is a thorny problem to align the dicing blade on the back side of the wafer with the scribe line on the front side of the wafer because there is no scribe line on the back side of the wafer.
U.S. Patent No. 6,107,164 discloses a wafer-level packaged semiconductor device and a method of fabricating a semiconductor device. The fabrication process is described in the drawings 1A-1D of the present application. This method is a typical example of fabricating a wafer-level package. example. As shown in FIG. 1A, the wafer included in the wafer 10 is originally provided with a pad 2 in which the bump electrode 4 is connected to the pad 2 via the copper interconnector 3. In the method, the cutting groove 22 is first cut on the front surface of the wafer 10 by the dicing blade 21, and then the surface of the wafer 10 with the bump electrode 4 is covered with a layer of resin 23, as shown in FIG. 1B, at this time, cutting The groove 22 is filled with the resin 23. Then, as shown in Fig. 1C, the resin 23 is subjected to lapping and polishing until the bump electrode 4 is exposed from the resin 23. As shown in FIG. 1D, in this method, polishing is required on the back side of the wafer 10 until the wafer 10 is thinned to expose the cutting groove 22 outside the back surface of the wafer 10 and filled in the cutting groove 22. The molding compound is then aligned on the back side of the wafer 10 by a dicing blade 26 to align the cutting grooves 22 to cut the wafer 10 to separate the wafers. The drawback is that the cutting groove 22 must first be cut on the front side of the wafer 10, and the cutting groove 22 must be controlled to have a certain depth, and the wafer 10 must be controlled to be thinned to a certain thickness, otherwise it is difficult to be on the back side of the wafer 10. The cutting groove 22 is ground. On the other hand, if another material is formed on the back surface of the thinned wafer 10 shown in FIG. 1D, the cutting groove 22 is covered, and the cutting blade 26 is difficult to align with the cutting groove 22.

In view of the above problems, the present invention provides a wafer packaging method for supporting dicing from the back side of a wafer, wherein the wafer preparation area of the wafer includes a plurality of wafers and a plurality of vertical and horizontal intersecting cutting lines on the front side of the wafer Defining the boundaries of each wafer, the method mainly includes the following steps:
Covering a support structure on the front side of the wafer;
Grinding the wafer on the back side of the wafer, and depositing a metal layer having a radius smaller than a radius of the wafer preparation area in a central region of the back surface of the thinned wafer, wherein the back side of the thinned wafer is located The area between the edge of the metal layer and the edge of the wafer constitutes an annular band;
Detecting the cutting line in the area of the endless belt by means of a penetrating photographic apparatus for detecting an extension of the cutting line extending from below the metal layer to below the endless belt in the horizontal direction while using the first cutting blade along A straight line formed by the extended portions at both ends of any one of the cutting lines cuts the thinned wafer and the metal layer.
In the above method, the support structure may be a molding material, and during the cutting of the thinned wafer and the metal layer, the support structure is also cut together and formed on the top of the front surface of the wafer. Floor.
In the above method, the support structure may be an adhesive film.
In the above method, in the process of polishing the wafer on the back side of the wafer, all the areas on the back surface of the wafer are simultaneously polished to uniformly thin the wafer.
In the above method, in the process of forming the metal layer, the projection of the edge of the formed metal layer in the vertical direction falls on a plurality of incomplete wafers near the edge of the wafer preparation region.
In the above method, in the process of cutting the metal layer and the wafer, a plurality of first type of cutting grooves which are vertically and horizontally intersected in the thinned wafer and separate the plurality of wafers are formed, the first type An extended portion of the cutting groove is formed in a region of the thinned wafer under the endless belt, and the metal layer is cut into a bottom metal layer on the back surface of the wafer; and further a plastic sealing process is performed to cover the metal with the molding compound Forming a plastic sealing layer on the layer, and the molding compound is further filled in the first type of cutting groove in the molding process;
After the molding process is completed, the molding layer and the molding compound filled in the first type of cutting groove are formed by a straight line formed by the second cutting blade along the molding compound filled in the extending portion of both ends of any one of the first type of cutting grooves. Cutting to form a second type of cutting groove that coincides with the first type of cutting groove; and in performing the cutting with the second cutting blade, the plastic sealing layer is cut into a bottom plastic sealing layer covering the bottom metal layer .
In the above method, the support structure may be a molding material, and the second support blade is also used to simultaneously cut the support structure into a top molding layer on the front side of the wafer.
In the above method, the support structure may be an adhesive film.
In the above method, the blade width of the second cutting blade may be smaller than the blade width of the first cutting blade; and the width of the second type of cutting groove formed is smaller than the width of the first type of cutting groove, and the second cutting blade is used The molding compound in the first type of cutting groove is cut into a side wall molding layer that is coated on the side of the wafer.
In the above method, the blade width of the second cutter may be equal to the blade width of the first cutter.
In the above method, the extension of any one of the first type of cutting grooves has no boundary with the edge of the wafer.
The present invention also provides another wafer packaging method for supporting dicing from the back side of a wafer, wherein the wafer preparation area of the wafer comprises a plurality of wafers and the boundaries of the wafers are defined by a plurality of vertically and horizontally intersecting dicing lines on the front side of the wafer. , characterized in that it comprises the following steps:
Covering a support structure on the front side of the wafer;
Grinding the wafer on the back side of the wafer to grind a grinding groove having a radius smaller than a radius of the wafer preparation area in a central region of the back surface of the wafer, the back side of the wafer being located at the sidewall of the polishing groove and the edge of the wafer The area between the ends constitutes an endless belt;
Depositing a metal layer in the grinding tank;
Detecting the cutting line in the area of the endless belt by means of a penetrating photographic apparatus for detecting an extension of the cutting line extending from below the metal layer to below the endless belt in the horizontal direction while using the first cutting blade along A straight line formed by the extended portions at both ends of any one of the cutting lines cuts the wafer and the metal layer.
In the above method, the supporting structure may be a molding material, and during the cutting of the wafer and the metal layer, the supporting structure is also cut together, and a top plastic sealing layer on the front side of the wafer is formed.
In the above method, the support structure may be an adhesive film.
In the above method, the thickness of the metal layer deposited in the grinding tank is the same as the depth of the grinding tank.
In the above method, during the formation of the grinding groove, the projection of the sidewall of the formed grinding groove in the vertical direction falls on a plurality of incomplete wafers near the edge of the wafer preparation area.
In the above method, in the process of cutting the metal layer and the wafer, a plurality of first type of cutting grooves intersecting and separating the plurality of wafers are formed, and an extension portion of the first type of cutting grooves is formed in the crystal a circle is located in a region below the endless belt, and the metal layer is cut into a bottom metal layer on the back side of the wafer; and a plastic sealing process is further performed, a plastic sealing layer is formed on the metal layer to form a plastic sealing layer, and the plastic sealing layer is formed Filling in the first type of cutting groove in the molding process;
After the molding process is completed, the molding layer and the molding compound filled in the first type of cutting groove are formed by a straight line formed by the second cutting blade along the molding compound filled in the extending portion of both ends of any one of the first type of cutting grooves. Cutting to form a second type of cutting groove that coincides with the first type of cutting groove; and in performing the cutting with the second cutting blade, the plastic sealing layer is cut into a bottom plastic sealing layer covering the bottom metal layer .
In the above method, the support structure may be a molding material, and the second support blade is also used to simultaneously cut the support structure into a top molding layer on the front side of the wafer.
In the above method, the support structure may be an adhesive film.
In the above method, the blade width of the second cutting blade may be smaller than the blade width of the first cutting blade; and the width of the second type of cutting groove formed is smaller than the width of the first type of cutting groove, and the second cutting blade is used The molding compound in the first type of cutting groove is cut into a side wall molding layer that is coated on the side of the wafer.
In the above method, the blade width of the second cutter may be equal to the blade width of the first cutter.
In the above method, the extension of any one of the first type of cutting grooves has no boundary with the edge of the wafer.
These and other advantages of the present invention will no doubt become apparent to those skilled in the <RTIgt;

2A-1 is a plan view of the front surface 100X of the wafer 100, and FIG. 2A-2 is a vertical cross-sectional view of the wafer 100. The other side opposite to the front surface 100X of the wafer 100 shown in the drawing is the back surface 100Y. The wafer preparation area 101 of the wafer 100 typically includes a plurality of wafers 101' that are cast together and defines the boundaries of the wafers 101' with a plurality of cross-cutting Scribe lines 102 located on the front side 100X of the wafer 100. The effect is that the wafer 100 can be diced along the dicing line 102 to separate the wafer 101' from the wafer 100. Since these technical features are well known to those skilled in the art, the present invention is not specifically described in detail. In order to facilitate the description of the present invention, the wafer preparation area 101 is deliberately depicted in FIG. 2A-1, and the cross section of the wafer preparation area 101 in the horizontal direction is substantially circular, and the wafer preparation area 101 and the wafer 100 are The radius of the coaxial and wafer fabrication region 101 is clearly less than the radius of the wafer 100. It is known to those skilled in the art that a circuit is generally formed on the wafer 100 only in the range of the wafer preparation area 101, and the front surface 100X of the wafer 100 is disposed on the edge 101a of the wafer preparation area 101 and the wafer 100. The area between the edges 100a constitutes the reserved endless belt 103, and it is generally considered that the area of the wafer 100 below the reserved endless belt 103 is a circuit blank area, i.e., no wafer is formed. In addition, the dicing line 102 on the front side of the wafer 100 is formed exactly in the wafer preparation area 101, which often does not extend into the reserved endless belt 103. It is worth mentioning that the reserved endless belt 103 largely facilitates the transportation and movement of the wafer 100, and the grip of any handling tool or glove or other process equipment can reach the reserved endless belt 103. The area does not contact the wafer preparation area 101, which is not only to prevent physical damage to the wafer 101' but also to electrostatic considerations. It can be seen that the annular reserved annular band 103 extends from the edge 100a of the wafer 100 toward the center of the back surface 100Y of the wafer 100, and its width. Equal to the radius of the wafer 100 minus the radius of the wafer preparation area 101, usually It is roughly between 1.2mm and 1.5mm. It should be noted that although the majority of the wafers 101' are wafers having normal morphology, those skilled in the art will recognize that some of the wafers 101'a in the area of the wafer preparation area 101 that are adjacent to and in contact with the edge 101a are not complete ( 2A-1 is shown in hatching. After all of the wafers 101' are separated from the wafer 100, it can be considered that this portion of the wafer 101'a incomplete wafer 101'a will eventually be discarded. Nonetheless, these incomplete wafers 101'a near the edge 101a provide some convenience to the present invention.
As shown in FIG. 2B, a supporting structure 200 for physically supporting the substrate 100 is formed on the front surface 100X of the wafer 100. The supporting structure 200 may be an adhesive film or a plastic sealing material or other suitable supporting body, etc., and the supporting structure 200 is beneficial. The mechanical strength of the wafer 100 is increased, otherwise the individual wafer 100 is easily broken once it is thinned to a certain extent. Referring to FIG. 2C, after the wafer 100 is polished on the back surface 100Y to thin the thickness of the wafer 100, it is usually a chemical mechanical polishing CMP, which is in the entire area of the back surface 100Y of the wafer 100. The polishing is simultaneously performed to uniformly thin the wafer 100, that is, the thickness of all regions of the thinned wafer 100' is the same. Further, as shown in FIGS. 2D-1 and 2D-2, a metal layer 300 is deposited on the central portion of the back surface 100Z of the thinned wafer 100'. In the process of forming the metal layer 300, the metal layer 300 is required to have a substantially circular cross section in the horizontal direction and a radius smaller than the radius of the wafer preparation region 101, and the metal layer 300 is the same as the back surface 100Z of the thinned wafer 100'. Center of the circle. Generally, after the wafer 100 is thinned, the step of implanting heavily doped ions on the back surface 100Z of the thinned wafer 100' is further included, after which the metal layer 300 is deposited to ensure the metal layer 300 and the thinned crystal. The back 100Z of the circle 100' has good ohmic contact because the wafer 101' is often used as a vertical power MOSFET wafer. Thus, the back surface 100Z of the thinned wafer 100' is located between the edge 300a of the metal layer 300 and the edge 100a of the wafer 100 to form an endless belt 104 (Fig. 2D-1), an annular endless belt 104 width Equal to the radius of the wafer 100 minus the radius of the metal layer 300 (Fig. 2D-2), Generally greater than D ₁ and D ₂ is approximately about 3 mm. The problem at this time is that the front side 100X of the wafer 100' is covered by the support structure 200, that is, the cut line 102 is blocked by the support structure 200, and it is difficult to perform cutting directly on the front side of the wafer 100'. The present invention therefore proposes to perform dicing from the back side 100Z of the wafer 100' and to cut the metal layer 300 together to form a metal electrode on the back side of the wafer 101', but those skilled in the art will recognize that the wafer 100' The back side 100Z is that no cutting line is provided to align with the cutting blade, and the cutting blade cannot directly align directly from the back side 100Z of the wafer 100' with the cutting line 102 of the front side 100X of the wafer 100'.
In some known auxiliary transmission alignment techniques, the cutting line 102 of the front side 100X of the wafer 100' can be detected from the back surface 100Z of the wafer 100' using a through-photographic apparatus, such as an infrared source camera (IR camera). It is a typical penetration camera. As shown in FIGS. 2D-1 to 2D-2, the detecting means of the IR camera can penetrate the metal layer 300 but can penetrate the crucible below the endless belt 104. Referring to Fig. 2D-3, a schematic view of the cutting line 102 in the region of the endless belt 104 using a penetrating photographic apparatus (not shown), although the portion of the cutting line 102 directly below the metal layer 300 cannot be detected. However, just because the radius of the metal layer 300 is smaller than the radius of the wafer preparation area 101, the IR camera is enabled to detect and capture the extended portion 102' of the cutting line 102 extending from below the metal layer 300 to below the endless belt 104 in the horizontal direction, The extended portion 102' is located between the edge 101a of the wafer preparation area 101 and the projection of the edge 300a of the metal layer 300 on the front side 100X, and it is apparent that the extended portion 102' does not overlap the metal layer 300 in the vertical direction. As long as the extended portion 102' at either end of any one of the cutting lines 102 is detected and positioned, a straight line can be positioned on the back surface 100Z of the wafer 100' according to the extended portion 102' at both ends of the selected one of the cutting lines 102. The line being positioned is exactly coincident with the arbitrary one of the cutting lines 102 in the vertical direction, and the cutting blade can perform cutting along the straight line to be positioned. It must be emphasized that since the radius of the metal layer 300 must be less than the radius of the wafer preparation region 101, otherwise no extension portion 102' can be used for IR detection, which is why the area of the wafer preparation area 101 is It is larger than the area of the metal layer 300, so that the back surface of a part of the wafer included in the wafer preparation area 101 is apparently not completely covered by the metal layer 300. In other words, the portion of the wafer that is not covered by the metal layer 300 does not function properly as a complete integrated circuit, and if these wafers are discarded, the yield may be lowered. However, since adjacent wafers 101'a are connected to each other and each wafer 101'a is distributed around a circular edge 101a, all of the incomplete wafers 101'a located on the wafer 100 are also approximately It can be presented as a ring structure (although the ring structure is not very regular). Therefore, a solution proposed by the present invention is to adjust the radius of the metal layer 300 such that the projection of the edge 300a in the vertical direction falls just in the portion of the wafer preparation area 101 near the edge 101a of the incomplete wafer 101'a. The upper side, that is, the edge 300a, overlaps the annular structure formed by the incomplete wafer 101'a in the vertical direction. As a result, in the wafer preparation area 101, only a part of the back surface of the incomplete wafer 101'a is not covered by the metal layer 300, and the other wafers 101' away from the edge 101a are normal products, so It is precisely those wafers 101'a that were originally incomplete that were abandoned, so that the yield would not be reduced.
As shown in FIG. 2E, an IR camera can be used to form a wafer on the back side 100Z of the wafer 100' using a first dicing blade 401 along an extended portion 102' of either end of any one of the dicing lines 102. 100' and the metal layer 300 are cut, and the cutting groove 102a formed in the wafer 100' shown in the figure is the cutting mark left by the first cutting blade 401 cutting the wafer 100' and the metal layer 300. During the dicing process, a plurality of vertically intersecting dicing grooves 102a are formed in the wafer 100' and the metal layer 300 is divided, for separating the plurality of wafers 101' from the wafer 100', and It is also used to cut the metal layer 300 into a plurality of spaced apart bottom metal layers 300', and one bottom metal layer 300' corresponds to the back side of one wafer 101'. Any one of the plurality of slit grooves 102a intersecting with one of the cutting grooves 102a corresponds to one cutting line 102. In one embodiment, as shown in FIG. 2E, the support structure 200 is a molding material, and all the straight lines formed along the extended portions 102' at both ends of the cutting line 102 are cut during the process of cutting the wafer 100' and the metal layer 300. The support structure 200 is also cut and formed into a top molding layer 200' on the front side of the wafer 101'. In another embodiment (not illustrated), if the support structure 200 is an adhesive film, the thickness thereof is generally relatively thin, and the support structure 200 does not have to be cut during the cutting of the wafer 100' and the metal layer 300. This facilitates the final removal of the wafer 101' with the top plastic layer 200' and the bottom metal layer 300' from the support structure 200.
In an embodiment as shown in FIGS. 3A-1 to 3C, the wafer 100' and the metal layer 300 are first diced according to the method shown in FIGS. 2A-1 to 2E to form a wafer 100'. The plurality of vertically intersecting cutting grooves 102b are separated and the metal layer 300 is divided. At this time, the metal layer 300 is still cut into a plurality of separated bottom metal layers 300', and a bottom metal layer 300' is correspondingly located. The back side of a wafer 101', but in this arrangement the support structure 200 is not cut. If the support structure 200 is an adhesive film, the cutting process cannot damage the support structure 200, and the formed cutting groove 102b is preferably just touching the support structure 200. If the support structure 200 is a molding material, in one case, the formed cutting groove 102b can still be selected to just touch the supporting structure 200; in another case, the partial cutting support structure 200 can be selected but the supporting structure 200 is not completely cut, That is, the depth of the cutting groove 102b is increased, and at this time, the cutting groove 102b extends in the vertical direction into the support structure 200, mainly to ensure that the wafer 101' cannot be peeled off in advance. As shown in FIG. 3A-2, in addition to the first type of dicing grooves 102b formed in the wafer preparation area 101, any one of the first type of dicing grooves 102b is formed in the area of the wafer 100' below the endless belt 104. The first type of cutting groove extends portion 102b-1. Further, as shown in FIG. 3B-1, a plastic sealing process is performed to form a plastic sealing layer 500 on the metal layer 300 by injection molding, and it is noted that the molding compound cannot be covered on the endless belt 104, since the molding compound before curing is liquid. Therefore, the molding compound is also filled in the first type of cutting groove 102b. In one embodiment, just because the molding compound is also filled in the first type of cutting groove 102b, when the first type of cutting groove 102b is formed, it is required to control that both ends of the first type of cutting groove 102b cannot be extended to the wafer 100. At the edge 100a, that is, the first type of dicing groove extending portion 102b-1 cannot be in contact with and contact with the edge 100a of the wafer 100' (Fig. 3A-2), otherwise the molding compound is filled in the first type of cutting groove. In the case of 102b, it is easy to flow from both ends of the first type of cutting groove 102b to the outside of the wafer 100'. For example, the first type of cutting groove extending portion 102b-1' shown in Fig. 3A-3 has been extended to interface with the edge 100a, and the molding compound easily escapes from the extending portion 102b-1'. After the generated overflow gel is cured, it is easy to adhere the wafer 100' to the molding device. Any attempt to forcibly remove the wafer 100' will cause the wafer 100' to be broken, which is what we do not want to see. of.
As shown in FIGS. 3B-2 and 3C, for any one of the first type of cutting grooves 102b, a straight line which can be formed by the molding compound filled in the extending portion 102b-1 at both ends (No. 3B-2) Figure), and the line is completely coincident with the arbitrary first type of cutting groove 102b in the vertical direction. If the second cutting blade 402 is used along the line formed by the molding compound filled in the extending portion 102b-1 at both ends of any one of the first type cutting grooves 102b, the molding layer 500, the wafer 100', and the filling in the first type are cut. The molding material in the groove 102b is cut a second time to form a second type of cutting groove 105 which coincides with the first type of cutting groove 102b along the first type of cutting groove 102b; and during the cutting process, the plastic sealing layer 500 is cut. The bottom molding layer 500' overlies the bottom metal layer 300', and the support structure 200 as a molding material is cut into the top molding layer 200' on the front side of the wafer 101'. If the support structure 200 is an adhesive film, it is not necessary to perform cutting on the support structure 200. In one case, if the blade width of the second cutting blade 402 is smaller than the blade width of the first cutting blade 401, the width of the second type of cutting groove 105 formed should be smaller than the width of the first type of cutting groove 102b, then the second cutting The knife 402 cuts the molding compound filled in the first type of cutting groove 102b into the side wall molding layer 500" coated on the side of the wafer 101'. In another case, the blade width of the second cutting blade 402 is exactly equal to the first cutting blade. The width of the blade of 401, the second cutting blade 402 just cuts off the molding compound filled in the first type of cutting groove 102b, at which time the side of the wafer 101' is a bare coating without any plastic sealing layer.
Based on the above inventive concept, the preparation method of another embodiment is as shown in FIG. 4A, FIG. 4A-4C, except that the wafer 100 is not integral when the back surface 100Y of the wafer 100 is polished. To reduce the thickness, a grinding wheel (not shown) having a radius smaller than the radius of the wafer 100 is used to polish only the central portion of the back surface 100Y of the wafer 100 to grind a grinding groove in the central portion of the back surface 100Y of the wafer 100. 110. The grinding groove 110 has a circular cross section in the horizontal direction and the grinding groove 110 is coaxial with the wafer 100. The radius of the formed grinding groove 110 is smaller than the radius of the wafer preparation area 101, and the radius of the grinding groove 110 can be adjusted by adjusting the radius of the grinding wheel. In the present invention, by adjusting the radius of the grinding groove 110, the projection of the side wall 110a of the grinding groove 110 in the vertical direction just falls on the portion of the incomplete wafer 101'a near the edge 101a in the region of the wafer preparation region 101. That is, the sidewall 110a of the grinding bath 110 overlaps exactly in the vertical direction with the annular structure formed by the plurality of incomplete wafers 101'a. The back surface 100Y of the wafer 100 is located in a region between the sidewall 110a of the polishing bath 110 and the edge 100a of the wafer 100 to form another annular strip 114 (as shown in the top view of FIG. 4B-2), and the annular annular strip 114 is from the crystal. circle 100 at the edge 100a extending toward the center of the back surface of the wafer 100 100Y, D ₃ having a width equal to the radius of the wafer 100 minus the radius of the polishing tank 110, Generally greater than D ₁ and D ₃ is approximately about 3 mm.
It is known to those skilled in the art that the thinner the wafer is polished, the more likely it is to cause warpage and fragility. In this embodiment, an advantage over the method shown in FIG. 2C is that since the area of the wafer 100 under the endless belt 114 is retained during the grinding process, even if the central area of the back surface 100Y of the wafer 100 is ground Further, since the wafer 100 is supported and tensioned by the region located under the endless belt 114, the wafer 100 to be polished and thinned as shown in FIG. 4A does not become warped. Generally, after the central region of the back surface 100Y of the wafer 100 is thinned, the method further includes the step of implanting heavily doped ions into the wafer 100 at the bottom of the grinding bath 110, and then depositing the metal layer 600 in the grinding bath 110. The metal layer 600 is ensured to have good ohmic contact with the area of the wafer 100 below the grinding bath 110. The thickness of the deposited metal layer 600 is substantially the same as the depth of the grinding groove 110, that is, the top surface of the metal layer 600 is substantially in the same plane as the back surface 100Y of the wafer 100, wherein the radius of the metal layer 600 and the grinding groove 110 The radius is the same size. Similarly, the cutting line 102 of the front side 100X of the wafer 100 can be detected from the back surface 100Y of the wafer 100 by using a penetrating photographic apparatus such as an IR camera. As shown in FIG. 4B-3, although the infrared source cannot penetrate the metal layer 600, Penetrating the crucible below the endless belt 114. In FIG. 4B-3, an IR camera (not shown) detects the cutting line 102 in the region of the endless belt 114, although it is not possible to detect the portion of the cutting line 102 located directly below the metal layer 600, but due to the metal layer 600 The radius is less than the radius of the wafer preparation zone 101, and the IR camera is capable of detecting the extension 102" of the cutting line 102 extending from below the metal layer 600 below the annular band 114 in the horizontal direction. Again, as long as the extension 102 of either end of the cutting line 102 is present "Detected by the IR camera, a straight line can be positioned on the back side of the wafer 100 according to the extended portion 102" at either end of the cutting line 102, and the straight line positioned is just in the vertical direction and the arbitrary cutting line 102. Therefore, as shown in FIGS. 4B-3 to 4C, the wafer 100 and the metal layer 600 are cut by a straight line formed by the first cutting blade 401 along the extending portion 102" at either end of any one of the cutting lines 102. To separate the plurality of wafers 101' from the wafer 100. As in the foregoing technique, the plurality of types of cutting grooves 112a which are formed by aligning the plurality of cutting lines 102 to form a plurality of vertical and horizontal crossings in the wafer 100 separate the plurality of wafers 101' from each other, and the metal layer 600 is cut into many A bottom metal layer 600', a bottom metal layer 600' corresponding to the back of a wafer 101'. In one embodiment, as shown in FIG. 4C, the support structure 200 is a molding material, and the support structure 200 is cut together and forms a top molding layer 200' on the front side of the wafer 101', and the metal layer 600 is cut into the wafer. 101' bottom metal layer 300' on the back. In another embodiment (not illustrated), if the support structure 200 is a cling film, the support structure 200 need not be cut.
In one embodiment, as shown in FIGS. 5A-5C, the wafer 100 and the metal layer 600 are first cut according to the method shown in FIGS. 4A to 4B-3 to form a metal in the wafer 100 and formed. The plurality of vertically intersecting cutting grooves 112b are divided by the layer 600. The method employed in this embodiment is not significantly different from the method shown in Figs. 3A-1 to 3C. Also, the support structure 200 may be an adhesive film or a plastic sealing material. In this embodiment, the first type of cutting groove 112b is formed in the wafer preparation area 101, and the first type of cutting groove 112b further includes an extension portion of the first type of cutting groove formed in the region of the wafer 100 below the endless belt 114. 112b-1. Then, a plastic sealing process is performed to form a plastic sealing layer 700 on the metal layer 600 by injection molding. Note that the molding compound cannot be covered on the endless belt 114, and the molding compound is also filled in the first type of cutting groove 112b, as shown in FIG. 5B. Shown. Also, it is required to control that both ends of the first type of dicing grooves 112b cannot extend to the edge 100a of the wafer 100, that is, the first type of dicing groove extending portion 112b-1 cannot be in contact with and contact with the edge 100a of the wafer 100. The wafer 100 shown in FIG. 5B is compared with the wafer 100' shown in FIG. 3B-1, if the distance from the bottom of the former grinding groove 110 to the front surface 100X of the wafer 100 is equivalent to the back surface 100Z of the latter. The distance 100X of the front surface of the circle 100', that is, under the condition that the grinding thicknesses of the two are the same, the first type of cutting groove extending portion 112b-1 shown in Fig. 5B and the first type shown in Fig. 3B-1 The depth of the dicing groove extension portion 102b-1 is different because the area of the wafer 100 under the endless belt 114 is not ground. Similarly, a molding material filled in the extending portion 112b-1 at both ends of any one of the first type cutting grooves 112b can form a straight line, and the straight line is perpendicular to the arbitrary first type cutting groove 112b. . Using the second cutting blade 402 along the line of the molding compound filled in the extending portion 112b-1 at both ends of any one of the first type of cutting grooves 112b, the molding layer 700 and the molding compound filled in the first type of cutting groove 112b Cutting is performed to form a second type of cutting groove 115 that coincides with the first type of cutting groove 112b in the first type of cutting groove 112b; and during the cutting process, the plastic sealing layer 700 is cut to cover the bottom metal layer 600' The bottom molding layer 700', while the support structure 200 of the molding material is cut into the top molding layer 200' on the front side of the wafer 101'. If the support structure 200 is a cling film, the support structure 200 does not have to be cut. Similarly, if the blade width of the second cutting blade 402 is smaller than the blade width of the first cutting blade 401, the width of the second type of cutting groove 115 formed should be smaller than the width of the first type of cutting groove 102b, and the second cutting blade 402 will The molding compound in the first type of cutting groove 112b is cut into a side wall molding layer 700" covering the side of the wafer 101'. In another case, the blade width of the second cutting blade 402 is exactly equal to the blade width of the first cutting blade 401. At this time, the side of the wafer 101' is covered without any plastic sealing layer.
The exemplary embodiments of the specific structures of the specific embodiments have been described above, and the presently preferred embodiments are presented by way of illustration and the accompanying drawings. Various changes and modifications will no doubt become apparent to those skilled in the <RTIgt; Accordingly, the appended claims are intended to cover all such modifications and modifications Any and all equivalent ranges and contents within the scope of the claims are considered to be within the spirit and scope of the invention.

2. . . Solder pad

3. . . Copper interconnect

4. . . Bump electrode

10, 100, 100’. . . Wafer

21, 26, 401, 402. . . Cutting knife

22, 102a, 102b, 105, 112a, 112b, 115. . . Cutting slot

twenty three. . . Resin

100a, 101a, 300a. . . edge

100X. . . positive

100Y, 100Z. . . back

101. . . Wafer preparation area

101’, 101’a. . . Wafer

102. . . Cutting line

102b-1, 102b-1', 112b-1. . . Cutting groove extension

102', 102"... extension

103. . . Reserved ring belt

104, 114. . . Ring belt

200. . . supporting structure

200’. . . Top plastic layer

300, 600. . . Metal layer

300’, 600’. . . Bottom metal layer

500, 700. . . Plastic layer

500’, 700’. . . Bottom plastic seal

500", 700". . . Side wall plastic seal

D ₁ , D ₂ , D ₃ . . . width

Embodiments of the present invention are described more fully with reference to the accompanying drawings. However, the attached drawings are for illustration and illustration only and are not intended to limit the scope of the invention.
1A to 1D are schematic flow charts showing a method of manufacturing a wafer-level packaged semiconductor device in the background art.
2A-1 to 2E are schematic flow charts of a wafer packaging method for performing dicing from the back side of the wafer in the first embodiment.
3A-1 to 3C are schematic flow charts of a wafer packaging method for performing dicing from the back side of the wafer in the second embodiment.
4A to 4C are schematic flow charts showing a wafer encapsulation method for performing dicing from the back side of the wafer in the third embodiment.
5A to 5C are schematic flow charts showing a wafer encapsulation method for performing dicing from the back side of the wafer in the fourth embodiment.

101’. . . Wafer

102b, 105. . . Cutting slot

102b-1. . . Cutting groove extension

200. . . supporting structure

200’. . . Top plastic layer

300’. . . Bottom metal layer

402. . . Cutting knife

500. . . Plastic layer

500’. . . Bottom plastic seal

500"... sidewall molding

Claims (22)

A wafer packaging method for supporting dicing from the back side of a wafer, the wafer preparation area of the wafer comprising a plurality of wafers and defining a boundary of each wafer by a plurality of cross-cutting lines at the front side of the wafer, comprising the steps of:
Covering a support structure on the front side of the wafer;
Grinding the wafer on the back side of the wafer, and depositing a metal layer having a radius smaller than a radius of the wafer preparation area in a central region of the back surface of the thinned wafer, wherein the back side of the thinned wafer is located The area between the edge of the metal layer and the edge of the wafer constitutes an annular band;
Detecting the cutting line in the area of the endless belt by means of a penetrating photographic apparatus for detecting an extension of the cutting line extending from below the metal layer to below the endless belt in the horizontal direction while using the first cutting blade along A straight line formed by the extended portions at both ends of any one of the cutting lines cuts the thinned wafer and the metal layer. The method of claim 1, wherein the support structure is a molding material, and during the cutting of the thinned wafer and the metal layer, the support structure is also cut together. And forming a top molding layer on the front side of the wafer. The method of claim 1, wherein the support structure is an adhesive film. The method of claim 1, wherein the polishing of the wafer on the back side of the wafer is performed simultaneously on all areas of the back surface of the wafer to uniformly thin the wafer. The method of claim 1, wherein in the forming the metal layer, the projection of the edge of the formed metal layer in the vertical direction falls on a plurality of incomplete wafers near the edge of the wafer preparation area. . The method of claim 1, wherein in the process of cutting the wafer and the metal layer, a plurality of first-type cutting grooves intersecting and separating the plurality of wafers are formed, An extension of a type of cutting groove is formed in a region of the thinned wafer below the endless belt, and the metal layer is cut into a bottom metal layer on the back side of the wafer; and further a plastic sealing process is performed to cover the plastic compound Forming a plastic sealing layer on the metal layer, and the molding compound is further filled in the first type of cutting groove in the molding process;
After the molding process is completed, the molding layer and the molding compound filled in the first type of cutting groove are formed by a straight line formed by the second cutting blade along the molding compound filled in the extending portion of both ends of any one of the first type of cutting grooves. Cutting is performed to form a second type of cutting groove that coincides with the first type of cutting groove; and the plastic sealing layer is cut into a bottom molding layer overlying the bottom metal layer. The method of claim 6, wherein the support structure is a molding material, and the support structure is also simultaneously cut into a top molding layer on the front side of the wafer using a second cutting blade. The method of claim 6, wherein the support structure is an adhesive film. The method of claim 6, wherein the second cutting blade has a blade width smaller than a blade width of the first cutting blade; and the second type of cutting groove formed has a smaller width than the first type of cutting groove The width of the molding compound in the first type of cutting groove is cut by a second cutting blade into a side wall molding layer covering the side of the wafer. The method of claim 6, wherein the second cutter has a blade width equal to a blade width of the first cutter. The method of claim 6, wherein the extension of any one of the first type of cutting grooves has no interface with the edge of the wafer. A wafer packaging method for supporting dicing from the back side of a wafer, the wafer preparation area of the wafer comprising a plurality of wafers and defining a boundary of each wafer by a plurality of cross-cutting lines at the front side of the wafer, comprising the steps of:
Covering a support structure on the front side of the wafer;
Grinding the wafer on the back side of the wafer to grind a grinding groove having a radius smaller than a radius of the wafer preparation area in a central region of the back surface of the wafer, the back side of the wafer being located at the sidewall of the polishing groove and the edge of the wafer The area between the ends constitutes an endless belt;
Depositing a metal layer in the grinding tank;
Detecting the cutting line in the area of the endless belt by means of a penetrating photographic apparatus for detecting an extension of the cutting line extending from below the metal layer to below the endless belt in the horizontal direction while using the first cutting blade along A straight line formed by the extended portions at both ends of any one of the cutting lines cuts the wafer and the metal layer. The method of claim 12, wherein the support structure is a molding material, and during the cutting of the wafer and the metal layer, the support structure is also cut and formed at the same time. The top molding layer on the front side of the wafer. The method of claim 12, wherein the support structure is an adhesive film. The method of claim 12, wherein the thickness of the metal layer deposited in the grinding bath is the same as the depth of the grinding bath. The method of claim 12, wherein in the forming the grinding groove, the projection of the sidewall of the formed grinding groove in the vertical direction falls on a plurality of incomplete wafers near the edge of the wafer preparation area. . The method of claim 12, wherein, in the process of cutting the wafer and the metal layer, forming a plurality of first-type cutting grooves that intersect vertically and horizontally and separate the plurality of wafers, An extension of a type of dicing groove is formed in a region of the wafer below the endless belt, and the metal layer is cut into a bottom metal layer on the back side of the wafer; and a further molding process is performed to cover the metal layer with a molding compound Forming a plastic sealing layer thereon, and the molding compound is further filled in the first type of cutting groove in the molding process;
After the molding process is completed, the molding layer and the molding compound filled in the first type of cutting groove are formed by a straight line formed by the second cutting blade along the molding compound filled in the extending portion of both ends of any one of the first type of cutting grooves. Cutting is performed to form a second type of cutting groove that coincides with the first type of cutting groove; and the plastic sealing layer is cut into a bottom molding layer overlying the bottom metal layer. The method of claim 17, wherein the support structure is a molding material, and the support structure is also simultaneously cut into a top molding layer on the front side of the wafer by a second cutting blade. The method of claim 17, wherein the support structure is an adhesive film. The method of claim 17, wherein the second cutting blade has a blade width smaller than a blade width of the first cutting blade; and the second type of cutting groove formed has a smaller width than the first type of cutting groove The width of the molding compound in the first type of cutting groove is cut by a second cutting blade into a side wall molding layer covering the side of the wafer. The method of claim 17, wherein the second cutter has a blade width equal to a blade width of the first cutter. The method of claim 17, wherein the extension of any one of the first type of cutting grooves has no interface with the edge of the wafer.