TWI518809B - An assembly method of flip chip mounting - Google Patents

Description

Method of preparing a semiconductor device applied on a flip-chip mounting process

The present invention relates to a method of fabricating a semiconductor device, and more particularly to a method of fabricating a semiconductor device for use in a flip-chip mounting process on a wafer level.

Flip chip technology is widely used in semiconductor packaging technology, mainly to mount wafers with metal bumps on metal carrier or circuit board and other similar carrier substrates, to achieve some special use of flip chip The device is implemented in substantially two steps, such as picking up the bare wafer or completing the packaged device with the gripper and flipping it, then transferring the wafer or device to the load-bearing structure with another grip to achieve electrical connection between the two Mechanical combination. A very obvious problem is that the operation is complicated and the production efficiency and its lowness, which is commonly known as the so-called hourly production unit per Hour (UPH), are seriously affected.

At the same time, under the current wafer-level packaging process technology, it is considered that the front side of the wafer needs to be plasticized to improve the physical strength of the wafer, but the molding compound also covers the front cutting path. The cutting reference target cannot be obtained in the subsequent cutting process and the cutting step is unsustainable. In order to solve such a problem, U.S. Patent No. 6,107,164 discloses a method of cutting a sufficiently deep trench on the front side of a wafer, then covering the front side of the wafer with a plastic layer, and performing grinding from the back side of the wafer to thin the wafer to the trench. The grooves are exposed from the back, which requires the grooves to be deep enough or the wafer to be sufficiently thin. These harsh constraints are obviously not conducive to the actual application; on the other hand, we know that from wafer to sheet The power chip, the back side of the wafer is subjected to the steps of grinding and etching, ion implantation to metallization, and etching is an indispensable step to eliminate the lattice damage on the back side of the wafer caused by the grinding, which is followed by One problem is that once the molding compound filled in the trench is polished from the back side of the wafer to the exposed state, it is easily corroded in the etching step.

The packaging steps S1 to S12 shown in Fig. 1 are a general description of the prior art. In steps S1 to S2, after the wafer incoming inspection is passed, the wafer is pasted onto a bonding film with the side of the wafer facing up, and then the wafer cutting step is performed as shown in S3. The wafer is diced and separated from the wafer, and the bonding material is coated on the carrier substrate (such as lead-frame/substrate, etc.) as shown in S4, and then the wafer is flipped to the front by a specific flip device as shown in S5. The electrode/contact terminal is facing downward, and the wafer is flip-chip mounted on the carrier substrate by an adhesive material, and the front electrode/contact terminal and the receiving area on the carrier base (such as a designated metal region or pad) ) Electrical and mechanical combination. Then, as S6 performs the step of reflow soldering, step S7 is to mold the bare wafer with a plastic sealing layer formed by a molding compound, and S8 is to completely cure the plastic sealing layer under high temperature conditions, and print on the plastic sealing layer as shown in FIG. For example, the product batch, the specification, the manufacturer, and the like, and then the carrier substrate and the plastic sealing layer are cut to obtain a separate semiconductor device containing the wafer as shown in FIG. 10, and the steps S11 to S12 are performed after the product is inspected without defects. And shipping.

The present application is based on how to replace the existing flip-chip methods in wafer level packaging techniques. The following various preferred embodiments of the present application are presented.

In one embodiment, the present invention provides a method of fabricating a semiconductor device for use in a flip-chip mounting process, comprising the steps of: covering a front side of a wafer with a first molding layer, the first molding layer having a radius smaller than the wafer Radius to leave a first annular region not covered by the first plastic encapsulation layer at the edge of the front side of the wafer; a straight line pair extending along each of the dicing streets to the ends of the first annular region The first plastic sealing layer is cut to form a plurality of reference lines; the wafer is flipped to the back side thereof, and the back surface is polished to thin the wafer; a metal layer is deposited on the thinned back side of the wafer; and the wafer is flipped to the minus The metal layer on the back of the thin layer faces downward and adheres a layer of adhesive film on the metal layer; the first plastic sealing layer and the wafer and the metal layer are cut along the reference line to form a plurality of semiconductor devices, and the semiconductor device includes a front surface a wafer having a top molding layer formed by cutting the first plastic sealing layer and a bottom metal layer having a back surface formed by cutting the metal layer; simultaneously flipping the adhesive film adhered to each of the wafers and the respective bottom metal layers to the bottom metal Upward, and attaching another adhesive film on each top plastic sealing layer; peeling off the adhesive film adhered on the bottom metal layer, and picking up and mounting the semiconductor device onto the carrier substrate without flipping to realize Flip mount.

In the above method, a plurality of pads are disposed on the front surface of the wafer included in the wafer, and metal bumps are implanted on the pads before the first plastic layer is formed on the front surface of the wafer.

In the above method, in the step of forming the first plastic sealing layer, the first plastic sealing layer completely covers the metal bumps; and after forming the first plastic sealing layer, grinding and thinning the first plastic sealing layer to each metal The bumps are exposed from the first plastic seal layer.

In the above method, in the step of forming the first plastic sealing layer, the thickness of the first plastic sealing layer is smaller than the height of the metal bumps, so that each of the metal bumps is exposed from the first plastic sealing layer.

In the above method, before the first plastic sealing layer is formed on the front side of the wafer, cutting is performed along the cutting channel to increase the depth of the cutting channel, so that after forming the first plastic sealing layer, the molding compound filled along each cutting channel is located. A straight line formed by a portion of the cutting path exposed in the first annular region, and the first plastic sealing layer is cut to form a plurality of reference lines.

In the above method, in the step of back grinding of the wafer, only the central region of the back surface of the wafer is ground to form a circular groove while leaving the peripheral portion of the wafer having the original thickness to form a support at the edge of the wafer. a ring; and after the grinding of the wafer is completed, the peripheral portion of the wafer with the support ring is cut away.

In some embodiments, a method of fabricating a semiconductor device for use in a flip-chip mounting process includes the steps of: performing a dicing along a scribe line on the front side of the wafer to increase the depth of the scribe line; a plastic layer; flipping the wafer to the back side thereof, performing grinding on the back side to thin the wafer; depositing a metal layer on the thinned back side of the wafer; and thinning the back side of the wafer with a metal layer Side, grinding a peripheral portion of the metal layer around the edge of the wafer and a peripheral portion of a portion of the thickness of the wafer to form an annular groove around the edge of the wafer recessed on the thinned back surface thereof, to the scribe line A portion of the inner filling molding compound at both ends of the cutting path is exposed in the annular groove; an adhesive film is adhered to the first plastic sealing layer; and the molding compound filled along each cutting channel is exposed at both ends of the cutting channel A straight line formed by a portion in the annular groove cuts the first plastic seal layer, the wafer, the metal layer, and the molding compound filled in the scribe line to form a plurality of semiconductor devices; The pickup and the semiconductor device is mounted onto a carrier substrate to achieve a flip-chip mounting.

In the above method, in the step of back grinding of the wafer, only the central region of the back surface of the wafer is ground to form a circular groove while leaving the peripheral portion of the wafer having the original thickness to form a support ring at the edge of the wafer. And in the step of forming the annular groove, the support ring is also ground together while grinding the peripheral portion of the metal layer and a peripheral portion of a portion of the thickness of the wafer.

In the above method, in the step of cutting the first plastic sealing layer, the wafer, the metal layer and the molding compound filled in the cutting lane, the cutter width of the cutting blade is greater than or equal to the width of the deepened cutting channel, and the crystal After the circle is cut, a plurality of wafers are formed, and the molding compound filled in the dicing streets is completely cut after being cut, so that the sidewalls of the wafer are exposed.

In the above method, in the step of cutting the first plastic seal layer, the wafer, the metal layer and the molding compound filled in the scribe line, the cutter width of the cutter is smaller than the width of the etched rib having a deeper depth, and the wafer passes through After the dicing, a plurality of wafers are formed, and the molding compound filled in the dicing streets is cut to form a first side molding layer covering the side walls of a portion of the wafer near a portion of the front side.

In some embodiments, a method of fabricating a semiconductor device for use in a flip-chip mounting process includes the steps of: performing a dicing along a scribe line on the front side of the wafer to increase the depth of the scribe line; a plastic layer; flipping the wafer to the back side thereof, performing grinding on the back side to thin the wafer; depositing a metal layer on the thinned back side of the wafer; and thinning the back side of the wafer with a metal layer Side, grinding a peripheral portion of the metal layer around the edge of the wafer and a peripheral portion of a portion of the thickness of the wafer to form an annular groove around the edge of the wafer recessed on the thinned back surface thereof, to the scribe line a portion of the inner filling molding compound at both ends of the cutting path is exposed in the annular groove; an adhesive film is adhered to the first plastic sealing layer; and along each side of the thinned back side of the wafer The inner filling plastic molding material is located at a straight line formed by the portion exposed at the two ends of the cutting channel in the annular groove, and the metal layer and the wafer are cut to form a plurality of strips respectively corresponding to the vertical direction of the cutting track. And forming a second plastic sealing layer on each of the bottom metal layers formed by the cutting of the metal layer; the molding material filled in each of the cutting channels is located at the two ends of the cutting channel exposed in the annular groove Straightening, cutting the first and second plastic sealing layers and the molding compound filled in the cutting lane and the cutting groove, respectively, to form a plurality of semiconductor devices; picking up and mounting the semiconductor device to the carrier substrate without flipping Up to achieve flip-chip installation.

In the above method, in the step of back grinding of the wafer, only the central region of the back surface of the wafer is ground to form a circular groove while leaving the peripheral portion of the wafer having the original thickness to form a support at the edge of the wafer. In the step of forming the annular groove, while the peripheral portion of the metal layer and the peripheral portion of a portion of the thickness of the wafer are ground, the support ring is also ground together.

The above method is characterized in that the second plastic sealing layer is cut to form a bottom plastic sealing layer covering the bottom metal layer; and the molding compound filled in the cutting channel and the cutting groove is cut to form the first side adjacent to each other a plastic sealing layer, a second side plastic sealing layer, the first side plastic sealing layer is coated on a sidewall of a portion of the wafer near a front side thereof, and the second side plastic sealing layer is coated on the back of the wafer One side of a portion of the thickness of the side wall.

The above method is characterized in that: the second plastic sealing layer is cut to form a bottom plastic sealing layer covering the bottom metal layer; and the molding compound filled in the cutting channel and the cutting groove is cut and respectively formed to be spaced apart from each other a side plastic sealing layer, a second side plastic sealing layer, the first side plastic sealing layer is coated on a sidewall of a portion of the wafer near a front side thereof, and the second side plastic sealing layer is wrapped around the wafer On the side wall of a portion of the thickness portion of the back side, the side wall portion of the portion of the middle portion of the wafer is bare.

In some embodiments, a method of fabricating a semiconductor device for use in a flip-chip mounting process includes the steps of: covering a front side of a wafer with a first molding layer; flipping the wafer to a back side thereof, and implementing the back side thereof Grinding to thin the wafer; depositing a metal layer on the thinned back side of the wafer; grinding the peripheral portion of the metal layer around the edge of the wafer to form a thinned backside of the wafer at the edge of the wafer a second annular region covered by the metal layer; an adhesive film adhered to the first plastic sealing layer; and a second annular region is formed by detecting the second annular region through the wafer from the second annular region by means of infrared detection Overlapping both ends, and cutting the metal layer, the wafer, and the first plastic seal layer by using the straight line formed by the detected ends to form a plurality of semiconductor devices; picking up the semiconductor device without flipping Mounted to the carrier substrate for flip-chip mounting.

In the above method, in the step of back grinding of the wafer, only the central region of the back surface of the wafer is ground to form a circular groove while leaving the peripheral portion of the wafer having the original thickness to form a support ring at the edge of the wafer. And in the step of grinding the metal layer, the support ring is first ground.

These and other advantages of the present invention will no doubt become apparent to those skilled in the <RTIgt;

100. . . Wafer

100a. . . Support ring

101. . . Wafer

103. . . First annular zone

105, 105'. . . cutting line

106. . . Annular groove

107. . . Second annular zone

110. . . Metal pad

111. . . Metal bump

115. . . incision

120. . . First plastic seal

120'. . . Top plastic layer

120"...top molding

121. . . Baseline

130. . . Metal layer

130'. . . Bottom metal layer

140. . . Adhesive film

150. . . Circular groove

160. . . Adhesive film

170. . . Cutting slot

180. . . Second plastic seal

180'. . . Bottom plastic seal

200. . . First plastic seal

200A. . . Semiconductor device

200B. . . Semiconductor device

200C. . . Semiconductor device

200D. . . Semiconductor device

200E. . . Semiconductor device

200E'. . . Semiconductor device

240. . . Cutting knife

250. . . Grinding wheel

1200. . . Molding compound

1200'. . . First side plastic seal

1800. . . Molding compound

1800'. . . Second side plastic seal

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.

FIG. 1 is a schematic flow chart of flip-chip installation in the current technology.

2A-2L are one embodiment of the present invention for forming a support ring on the back side of the wafer to thin the wafer.

2M is a top plan view of a first annular region that is not covered by a first plastic encapsulation layer at the edge of the front side of the wafer.

3A-3C are embodiments in which it is not necessary to form a support ring on the back side of the wafer.

4A-4J are embodiments of forming an annular groove that is recessed at the edge of the wafer at its thinned back side.

5A-5D are embodiments in which cutting is performed along a scribe line to increase the depth of the scribe line.

6A to 6F are embodiments in which a peripheral portion of a metal layer is ground to form a second annular region.

7A-7E are embodiments in which the metal bumps are not completely encapsulated.

8A-8C are embodiments in which the steps of FIG. 7D are completed to further form another plastic seal layer on the back side of the wafer.

Figures 9A-9D are three embodiments in which the sidewalls around the wafer are completely uncovered, a portion of the sidewalls are covered, and all of the sidewalls are completely covered.

Referring to the vertical cross-sectional view of the wafer 100 shown in FIG. 2A, the wafer 100 generally includes a plurality of wafers cast together, and a plurality of longitudinal and lateral Scribe lines 105 are disposed on the front surface to define adjacent portions. The boundaries between the wafers can be used as a cutting reference target to separate the wafers from the wafer in subsequent dicing processes, which are well known to those skilled in the art and will not be described again. Moreover, a plurality of metal pads (Pad) 110 are prepared in advance on the front surface of any of the wafers as electrodes for connecting the power source to the GND, or for transmitting signals to the external circuit. Generally, each of the pads 110 is first plated with a sub-bump metal layer UBM (not shown), such as Ni/Au, and then the metal bumps 111 are soldered to the pads 110, typical metal bumps. 111 such as a solder ball, or a copper or other metal body of various shapes such as a spherical or columnar shape or a wedge shape, and then a first plastic sealing layer 120 is formed to cover the front surface of the wafer 100. The first plastic sealing layer 120 is usually a ring. An oxygen resin type molding compound is prepared as a raw material. In an alternative embodiment, the first molding layer 120 is only over the central area of the front side of the wafer 100, and does not completely cover all areas of the front side thereof, as shown in the vertical cross-section of FIG. 2C or the top view of FIG. 2M. The cross section of the first molding layer 120 is also substantially circular, and its radius is smaller than the radius of the wafer, so that a first ring not covered by the first molding layer 120 is left at the front side of the wafer 100 near its edge. Region 103, and both ends of each of the dicing streets 105 extend into the first annular region 103.

As shown in FIG. 2C to FIG. 2D, if the first plastic sealing layer 120 completely covers the metal bumps 111, it is necessary to polish and thin the first plastic sealing layer 120 until the metal bumps 111 are exposed from the first plastic sealing layer 120. . The first molding layer 120 may be cut along a straight line extending from each of the cutting passages 105 to the ends of the first annular region 103, and a plurality of strips are cut on the first molding layer 120 as shown in FIG. 2E. The groove structure is used as the reference line 121. It is obvious that any one of the reference lines 121 coincides with a corresponding one of the dicing streets 105 in the vertical direction. Due to the physical support of the first mold layer 120, the mechanical strength of the wafer 100 is increased, so the wafer 100 can be ground sufficiently thin. In FIG. 2F, the side of the wafer 100 is turned upside down, and the center of the back surface of the wafer 100 is ground by an unillustrated grinding wheel to form a circular groove 150. The thinned region, in this step, retains the original thickness of the peripheral portion of the wafer 100, so that on one side of the back side, a support ring 100a is formed near the edge thereof. Setting the radius of the circular groove 150 to be smaller than the radius of the first plastic seal layer 120, the support ring 100a has a portion overlapping the first plastic seal layer 120, which further improves the mechanical strength of the wafer.

Then, as shown in FIGS. 2G to 2H, a metal layer 130 is deposited on the thinned back surface, and the metal layer 130 is also circular in cross section, and then the peripheral portion of the wafer 100 with the support ring 100a is cut by laser cutting. . In some embodiments, after the wafer is thinned, steps including etching and dopant implantation on the thinned back surface are included, as this is not the focus of the present application and will not be described in detail. As shown in FIG. 2I, the wafer 100 is flipped to the side of the thinned back side of the metal layer 130 with the side facing down, and a layer of adhesive film 140 is adhered to the metal layer 130, and the first plastic package is adhered along the reference line 121. The layer 120 and the wafer 100 and the metal layer 130 are cut. As shown in FIG. 2J, the dicing blade 240 forms a slit 115 therein, and after the wafer 100 is diced, a plurality of independent wafers 101 are formed, and the first plastic sealing layer 120 is formed. After cutting, a top molding layer 120' covering the front surface of the wafer 101 is formed, and the metal layer 130 is cut to form a bottom metal layer 130' on the back surface of the wafer 101, thereby obtaining a plurality of individual semiconductor devices 200A. In the device 200A, a wafer 101, a top molding layer 120', a bottom metal layer 130', and a metal bump 111 soldered on the pad 110 of the wafer 101 are coated, and a top molding layer 120' is coated on each of the metal bumps. Around the side walls of the 111, the metal bumps 111 are all exposed from the top molding layer 120'. As shown in FIG. 2K, the adhesive film 140 and each wafer 101 are flipped together, and the adhesive film 140 adhered to each of the bottom metal layers 130' faces upward, and another adhesive film is adhered to each of the top plastic sealing layers 120'. 160, then the adhesive film 140 adhered to each of the bottom metal layers 130' is peeled off as shown in FIG. 2L, wherein the adhesive films 140, 160 may each be an ultraviolet (UV) film. At this point, the metal bumps 111 of the semiconductor device 200A that are in electrical contact with the external circuit are all facing downward, and the ordinary wafer bonding apparatus can pick up the semiconductor device 200A directly from the bonding film 160 to the carrier substrate (such as a metal base). On the socket or PCB), the same flip-chip effect can be obtained without the need for special wafer flip-chip equipment to take a separate flip action for each wafer.

In some embodiments, the wafer 101 is a vertical power chip, and the current flows from the front side thereof to the back side or the opposite direction. Typically, such as a MOSFET or the like, at least one of the plurality of pads 110 includes solder as a source and a gate. The pad, while the bottom metal layer 130' is the drain.

In some embodiments, the wafer 100 does not need to be ultra-thin, and the ordinary grinding level is sufficient for the purpose of reducing the substrate resistance, in which case the support ring 100a need not be formed. For example, after the steps of FIG. 2E are completed, the wafer 100 can be directly flipped to the back side thereof upward as shown in FIGS. 3A-3C, and the entire surface of the wafer is integrally polished and thinned to make the wafer 100. Uniform thinning, not just grinding at the center of the back side, then depositing the metal layer 130, then flipping the wafer 100 to the side of the thinned back metal layer 130 facing down, and on the metal layer 130 Adhesion of a layer of adhesive film 140, the subsequent steps are exactly the same as the methods of Figures 2J-2L.

In some embodiments, the first annular region 103 reserved on the front side of the wafer 100 is not indispensable. For example, as shown in FIGS. 4A-4B, after the metal bumps 111 are implanted on each of the pads 110, A cut is performed on the front side of the wafer 100 along the scribe line 105 to deepen the depth of the scribe line 105, after which the formed first mold layer 120 completely covers the entire front surface of the wafer 100. Assuming that the original depth of the scribe line 105 is the first depth, the deepened scribe line 105' of FIG. 4A has a second depth, the second depth is greater than the first depth, and the value of the second depth is approximately the wafer thinning After the final thickness is between one-half and two-thirds. Wherein, since the original depth of the scribe line 105 is very shallow relative to the second depth or the thickness of the wafer itself, it can be substantially ignored. As shown in FIG. 4B, after the first plastic sealing layer 120 is formed to cover the front surface of the wafer, the first plastic sealing layer 120 completely covers the metal bumps 111, and then the first plastic sealing layer 120 is ground and thinned, as shown in FIG. 4C. Until each of the metal bumps 111 is exposed from the first plastic seal layer 120. While the molding compound is used to form the first molding layer 120, a part of the molding compound is filled in the cutting lane 105', and the molding compound 1200 located in each cutting lane 105' and the first molding layer 120 form an integral structure. The wafer 100 is then flipped over to its back side up and polished on its back side to reduce its thickness, as shown in Figure 4D, in some alternative embodiments, the grinding method is the same as described above, on the back side On one side, a support ring 100a is formed near its edge, and a metal layer 130 is deposited on the thinned back side of the wafer 100.

Next, as shown in FIG. 4E, using the grinding wheel 250, on the side of the wafer 100 with the thinned back side of the metal layer 130, around the edge of the wafer 100, while the peripheral portion of the metal layer 130 and the wafer 100 are The peripheral portion of a portion of the thickness of the back side is subjected to grinding, and the support ring 100a is polished away in this step. The grinding wheel 250 can be considered to be circularly moved about the central axis of the wafer 100 to form an annular groove 106 that is recessed at the edge of the wafer 100 at its thinned back surface, as shown in FIG. 4F. The respective radii of the wafer 100 at a portion of the thickness of the metal layer 130 and the back side of the wafer 100 are simultaneously reduced. The depth of the grinding of the annular groove 106 can be adjusted until the portion of the molding compound 1200 filled in each of the cutting passes 105' at both ends of the cutting path 105' is exposed in the annular groove 106 (top view of Fig. 4G). 4H, an adhesive film 160 is adhered to the first plastic sealing layer 120, and the principle of a straight line can be determined according to two points. The molding compound 1200 filled in each cutting channel 105' is exposed at both ends of the cutting channel 105'. A straight line formed by a portion in the annular groove 106 simultaneously cuts the first plastic sealing layer 120, the wafer 100, the metal layer 130, and the molding compound 1200 filled in the cutting lane 105', and forms a slit 115 therein. Referring to the top view of FIG. 4I and the vertical cross-sectional view of FIG. 4J, a plurality of semiconductor devices 200B are formed. In some embodiments, the adhesive film 160 may be adhered to the first plastic sealing layer 120 to form the annular groove 106. That is, in FIG. 4E, the adhesive film 160 is adhered to the first plastic sealing layer 120. Perform the grinding step.

It should be noted that the semiconductor device 200B is not significantly different in structure from the semiconductor device 200A shown in FIG. 2L, except that if the blade width of the cutting blade 240 forming the slit 115 in the cutting step is larger than that of the cutting path The width of the 105' is narrow, and the molding compound 1200 in the cutting path 105' is inevitably not completely cut, but is formed on the side wall of the wafer 101 covered with a part of the thickness on the side close to the front side of each wafer 101. The first side plastic sealing layer 1200', the first side plastic sealing layer 1200' is substantially a square cylindrical outer casing, the cross section of which is a circular box with a rectangular opening, the first side plastic sealing layer 1200' and the top plastic sealing The layers 120' are joined in a unitary structure.

In the embodiment of FIGS. 5A-5D, the only difference from the steps of FIGS. 2A-2E is that after the metal bumps 111 are implanted on each of the pads 110, the front side of the wafer 100 is cut along the scribe lines 105. The depth of the dicing street 105 is deepened to form a dicing street 105' having a second depth, so that after the first plastic sealing layer 120 is formed and ground and thinned, the molding compound 1200 can be filled along each dicing street 105'. A straight line formed by a portion exposed at the both ends of the cutting path 105' exposed in the first annular region 103 cuts the first plastic sealing layer 120 to form a plurality of elongated reference lines 121 (ie, achieves the same shape as FIG. 2E). Effect), the subsequent steps are exactly the same as Figures 2F~2L.

In some embodiments, for example, as shown in FIGS. 6A-6C, after the metal bumps 111 are implanted on each of the pads 110, the formed first molding layer 120 completely covers the entire front surface of the wafer 100, and is first. After the plastic layer 120 is subjected to the polishing thinning, the wafer 100 is flipped to the back side thereof, and the center region of the back surface is polished to thin the wafer while leaving the peripheral portion of the wafer 100 having the original thickness to form the back side. A support ring 100a is disposed near the edge of the wafer, and then a metal layer 130 is deposited on the thinned back side of the wafer 100, and then a paste film 160 is pasted on the first mold layer 120. On the back side of the wafer, the peripheral portion of the metal layer 130 is polished around the edge of the wafer 100 by the grinding wheel 250, and the grinding wheel 250 is considered to be circularly moved around the central axis of the wafer 100. In the step of polishing the peripheral portion of the metal layer 130, the grinding wheel 250 also simultaneously polishes the support ring 100a (Figs. 6C to 6D), which corresponds to reducing the radius of the metal layer 130. In this embodiment, a second annular region 107 not covered by the metal layer 130 may be obtained on the thinned back surface of the wafer 100 near the edge of the wafer 100, and then detected by infrared rays. Transmitting the two ends of each of the dicing streets 105 from the second annular region 107 from the second annular region 107 through the wafer 100, and using the detected two ends to form a metal layer 130, the wafer 100 The cutting is performed with the first plastic sealing layer 120 to obtain a plurality of semiconductor devices 200C which are not different from the semiconductor device 200A of FIG. 2L. This embodiment solves the problem that the infrared rays cannot penetrate the metal layer having a certain thickness.

In some embodiments, as shown in FIGS. 7A-7B, after the depth of the dicing street 105 is deepened, the first molding layer 120 completely covering the entire front surface of the wafer 100 is formed. At this time, the thickness of the first molding layer 120 is insufficient. Each of the metal bumps 111 is completely covered, for example, the thickness thereof is smaller than the height of the metal bumps 111, so that the metal bumps 111 are all exposed from the first plastic seal layer 120. The wafer 100 is then flipped over to the back side thereof, as shown in FIG. 7C, and the back side is subjected to grinding to reduce its thickness, and then a metal layer 130 is deposited on the thinned back side of the wafer 100, followed by a thinned back surface thereof. On one side, the grinding wheel 250 is used around the edge of the wafer 100, while the peripheral portion of the metal layer 130 and the peripheral portion of the wafer having a portion of the thickness on the back side of the wafer 100 are ground to form a surrounding wafer 100. An annular groove 106 at the edge recessed on the back surface thereof, the annular groove 106 having a grinding depth until the portion of the molding compound 1200 filled in the cutting path 105' at both ends of the cutting path 105' is in the annular groove Exposed in 106 (Fig. 7D). Similarly, an adhesive film (not shown) is adhered to the first plastic seal layer 120, and then on the side of the thinned back surface of the wafer 100, the molding compound 1200 filled in each of the cutting passes 105' is located at the cutting pass 105. A straight line formed by a portion exposed at the both ends of the annular groove 106, and the metal layer 130, the wafer 100, the first plastic sealing layer 120, and the molding compound 1200 filled in the dicing street 105' are cut to form a plurality of semiconductors. The device 200D has no difference from the semiconductor device 200A shown in FIG. 2L except that the metal bumps 111 are exposed from the top molding body 120" formed by cutting the first plastic sealing layer 200. .

It is to be noted that in the illustrated semiconductor device 200D, the sidewall of the wafer having a portion of the thickness on the side close to the front side of the wafer 101 is not covered with any side molding layer, which is slightly different from the semiconductor device 200B of FIG. 4J. . Actually, if the blade width of the dicing blade 240 forming the slit 115 is adjusted, for example, the dicing blade 240 having a blade width equal to or larger than the width of the dicing street 105' is used, a structure similar to the semiconductor device 200D is formed, and conversely, the blade width is smaller than the dicing street. The cutter 240 of the width of 105' forms a structure similar to the semiconductor device 200B.

In some embodiments, such as after the completion of FIGS. 7A-7D, the cutting step of FIG. 7E is not performed, but the molding compound filled in each of the cutting lanes 105' is first on the side of the thinned back side of the wafer 100. a line 1200 is formed at a portion of the dicing street 105' exposed in the annular groove 106, and the metal layer 130 and a portion of the wafer 100 having a thickness on the back side of the wafer 100 are cut to form a plurality of cutting grooves 170. The plurality of cutting grooves 170 and the plurality of cutting channels 105' are respectively in one-to-one correspondence in the vertical direction (FIG. 8A), and the metal layer 130 is cut to form a plurality of bottom metal layers 130'. In some embodiments, the cutting slot 170 has a depth that extends into contact with the cutting track 105'. Then, a second molding layer 180 is covered on each of the bottom metal layers 130' as shown in FIG. 8B, and a second molding layer 180 is formed by using a molding compound, and a part of the molding compound is filled in the cutting groove 170, and is located in each cutting. The molding compound 1800 in the groove 170 is integrally formed with the second molding layer 180. Then, the molding compound 1200 filled in each of the cutting lanes 105' is located at a line formed by the portion of the cutting lane 105' exposed inside the annular groove 106, and the first molding layer 120, the second molding layer 180, and the filling layer are filled in The molding compound 1200 in the cutting lane 105' and the molding compound 1800 in the filling cutting groove 170 are cut to form a plurality of semiconductor devices 200E, and the second molding layer 180 is cut to form a bottom molding covering the bottom metal layers 130'. The layer 180' is formed, and the first molding layer 120 is cut to form a top molding layer 120" covering the front surface of each wafer 101, and each of the metal bumps 111 is exposed from the top molding layer 120".

Similarly, the width of the slit 115 varies with the knife width of the cutter 240, which also determines whether the side walls of the wafer 101 are covered with a side molding layer. For example, the sidewall of the wafer 101 in FIG. 7E is not covered by any of the side molding layers formed by the cutting of the molding compound 1200 filled in the cutting lane 105'. In contrast, in FIG. 8C, the cutting blade 240 is The width of the blade is smaller than the width of the cutting path 105' and the cutting groove 170. Then, the molding compound 1200 filled in the cutting path 105' is cut to form a first side molding layer 1200', and the molding compound 1800 filled in the cutting groove 107 is A second side molding layer 1800' is formed after cutting. The first side plastic sealing layer 1200' is coated on the sidewall of the wafer of a portion of the thickness of the wafer 101 near the front side thereof, while the second side plastic sealing layer 1800' is coated on the side of the wafer 101 near the back side thereof. A portion of the thickness of the wafer is on the sidewall. The first side plastic sealing layer 1200' and the second side plastic sealing layer 1800' are presented as a square cylindrical outer casing structure without a top cover and a bottom cover, each of which has a rectangular cavity with a rectangular cross section to accommodate the wafer, and the cross section thereof is An annular box with an internal rectangular opening. In this way, in the semiconductor device 200E, the first side plastic sealing layer 1200' and the top plastic sealing layer 120" are integrally connected, and the second side plastic sealing layer 1800' is connected with the bottom plastic sealing layer 180' to form a whole, and the wafer The side walls of 101 are completely sealed by the first side molding layer 1200' and the second side molding layer 1800' adjacent to each other, so that the wafer 101 at this time is completely sealed. Optional not shown in other figures In an embodiment, the cutting groove 170 does not reach the depth of contact with the cutting track 105', and there is a gap between the two, except that the first side plastic sealing layer 1200' covers a part of the thickness near the front side of the wafer. On the side wall of the wafer 101, and the second side plastic encapsulation layer 1800' is coated on the sidewall of a portion of the thickness of the wafer near the back side of the wafer, the sidewall of the portion 1010 of the intermediate portion of the wafer 101 is still The bare, as shown in FIG. 9D, semiconductor device 200E', in which case the first and second side plastic encapsulation layers are spaced apart from each other.

In order to understand the structure of the semiconductor devices 200A, 200B, 200E, and 200E' in more detail, FIGS. 9A to 9D are schematic views in which they are multiplied and compared, respectively, because the semiconductor devices 200C, 200D and the semiconductor device 200A are not structurally different. Not listed.

Referring to the flow chart shown in FIG. 1 in the background art, it is found that the final state of the semiconductor devices 200A to 200E obtained by all the methods of the present application are each having the metal bumps 111 facing downward, which means that the ordinary wafer bonding apparatus ( Non-dedicated wafer flip-chip devices can be picked up directly from the adhesive film 160 onto the carrier substrate for pasting without having to flip. If the metal bump 111 itself is a solder material, it can be directly soldered to a receiving area (such as a specified metal area or pad) on the carrier substrate, and if the metal bump 111 does not have a bonding function, it is also in the receiving area. Additional coating of the bonding material to achieve electrical and mechanical bonding of the two. In other words, any of the methods for obtaining a semiconductor device disclosed in the present application can replace the steps S2 to S3 of the dashed line in steps S1 to S12 of FIG. 1 , and the step of substituting the chip in the dotted line does not require the use of a wafer flip device. The wafer can be picked up onto the carrier substrate by conventional wafer bonding equipment to achieve flip-chip mounting, while the other steps S1, S4, S6~S12 can be completely identical.

The exemplary embodiments of the specific structures of the specific embodiments have been described above 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 Any and all equivalent ranges and contents within the scope of the claims are intended to be within the spirit and scope of the invention.

100a. . . Support ring

130. . . Metal layer

250. . . Grinding wheel

Claims (16)

A method of fabricating a semiconductor device for use in a flip-chip mounting process, comprising the steps of:
Covering a front surface of the wafer with a first plastic sealing layer, the first plastic sealing layer having a radius smaller than a radius of the wafer to leave a first ring not covered by the first plastic sealing layer at an edge of the front surface of the wafer Area;
Cutting a first plastic sealing layer to form a plurality of reference lines along a straight line formed by each of the cutting paths extending to both ends of the first annular region;
Flip the wafer to the back side up and perform grinding on the back side to thin the wafer;
Depositing a metal layer on the back side of the thinned wafer;
Flip the wafer to the thinned back side with the metal layer facing down and a layer of adhesive film adhered to the metal layer;
Cutting the first plastic encapsulation layer and the wafer and the metal layer along the reference line to form a plurality of semiconductor devices, the semiconductor device comprising a front surface with a top molding layer formed by cutting the first plastic sealing layer and a back surface with a metal layer Cutting the formed bottom metal layer of the wafer;
Simultaneously flipping the adhesive film adhered to each wafer and each of the bottom metal layers until the bottom metal layer faces upward, and another adhesive film is adhered to each of the top plastic sealing layers;
The adhesive film adhered to the bottom metal layer is peeled off, and the semiconductor device is picked up and mounted on the carrier substrate without flipping to achieve flip-chip mounting. The method of claim 1, wherein a plurality of pads are disposed on a front surface of the wafer included in the wafer, and are disposed on each of the pads before forming the first plastic layer on the front side of the wafer. Planted with metal bumps. The method of claim 2, wherein in the step of forming the first plastic seal layer, the first plastic seal layer completely covers the metal bumps; and after forming the first plastic seal layer, The first plastic seal layer is subjected to grinding and thinning until each of the metal bumps is exposed from the first plastic seal layer. The method of claim 2, wherein in the step of forming the first plastic seal layer, the thickness of the first plastic seal layer is smaller than the height of the metal bump, so that each metal bump is from the first plastic seal. Exposed in the layer. The method of claim 1, wherein before the first plastic layer is formed on the front side of the wafer, cutting is performed along the scribe line to increase the depth of the scribe line, thereby forming the first plastic layer. The first plastic sealing layer is cut to form a plurality of reference lines along a straight line formed by a portion of the cutting passage filled in each of the cutting passages exposed at the two ends of the cutting passage. The method of claim 1 or 5, wherein in the step of back grinding of the wafer, only the central region of the back surface of the wafer is ground to form a circular groove while the wafer remains intact. a peripheral portion of the thickness to form a support ring at the edge of the wafer; and after the polishing of the wafer is completed, the peripheral portion of the wafer with the support ring is cut away. A method of fabricating a semiconductor device for use in a flip-chip mounting process, comprising the steps of:
Cutting along the scribe line on the front side of the wafer to increase the depth of the scribe line;
Covering a front surface of the wafer with a first plastic seal layer;
Flip the wafer to the back side up, and perform grinding on the back side to thin the wafer;
Depositing a metal layer on the back side of the thinned wafer;
On the side of the wafer with the thinned back side of the metal layer, the peripheral portion of the metal layer and the peripheral portion of a portion of the thickness of the wafer are ground around the edge of the wafer to form a recess around the edge of the wafer. Thinning an annular groove on the back surface, and a portion of the molding compound filled in the cutting path at both ends of the cutting path is exposed in the annular groove;
Adhering a paste film on the first plastic seal layer;
Cutting a first plastic layer, a wafer, a metal layer and a molding compound filled in the cutting channel along a straight line formed by a portion of the molding material filled in each of the cutting channels exposed at the two ends of the cutting path, Forming a plurality of semiconductor devices;
The semiconductor device is picked up and mounted on a carrier substrate without flipping to achieve flip-chip mounting. The method of claim 7, characterized in that in the step of back grinding of the wafer, only the central region of the back surface of the wafer is ground to form a circular groove while retaining the original thickness of the wafer. a peripheral portion to form a support ring at the edge of the wafer; and in the step of forming the annular groove, the support is also performed while grinding a peripheral portion of the metal layer and a peripheral portion of a portion of the thickness of the wafer The rings are ground together. The method of claim 7, wherein the step of cutting the first plastic seal layer, the wafer, the metal layer, and the molding compound filled in the cutting lane, the cutter width of the cutter is larger than Or equal to the width of the deepened scribe line, the wafer is cut to form a plurality of wafers, and the molding compound filled in the scribe line is completely cut after being cut, so that the sidewall of the wafer is exposed. The method of claim 7, characterized in that in the step of cutting the first plastic seal layer, the wafer, the metal layer and the molding compound filled in the cutting lane, the cutter width of the cutter is smaller than The depth of the deepened scribe line is deepened, and the wafer is cut to form a plurality of wafers, and the molding compound filled in the scribe line is cut to form a sidewall covering a portion of the thickness of the wafer near the front side thereof. The first side of the plastic layer. A method of fabricating a semiconductor device for use in a flip-chip mounting process, comprising the steps of:
Cutting along the scribe line on the front side of the wafer to increase the depth of the scribe line;
Covering a front surface of the wafer with a first plastic seal layer;
Flip the wafer to the back side up, and perform grinding on the back side to thin the wafer;
Depositing a metal layer on the back side of the thinned wafer;
On the side of the wafer with the thinned back side of the metal layer, the peripheral portion of the metal layer and the peripheral portion of a portion of the thickness of the wafer are ground around the edge of the wafer to form a recess around the edge of the wafer. Thinning an annular groove on the back surface, and a portion of the molding compound filled in the cutting path at both ends of the cutting path is exposed in the annular groove;
Adhering a paste film on the first plastic seal layer;
On the side of the thinned back side of the wafer, the metal layer and the wafer are cut along the straight line formed by the portion of the dicing material filled in each of the dicing streets which are exposed in the annular groove at both ends of the dicing street, respectively forming a plurality of cutting grooves in which the cutting paths are overlapped in the vertical direction; and a second plastic sealing layer is covered on each of the bottom metal layers formed by cutting the metal layers;
A straight line formed by a portion of the cutting material filled in each of the cutting channels which is exposed in the annular groove at both ends of the cutting path, and the first and second plastic sealing layers and the molding compound filled in the cutting channel and the cutting groove respectively Cutting to form a plurality of semiconductor devices;
The semiconductor device is picked up and mounted on a carrier substrate without flipping to achieve flip-chip mounting. The method of claim 11, wherein in the step of back grinding of the wafer, only the central region of the back surface of the wafer is ground to form a circular groove while retaining the original thickness of the wafer. a peripheral portion to form a support ring at the edge of the wafer; and in the step of forming the annular groove, while grinding the peripheral portion of the metal layer and a peripheral portion of a portion of the thickness of the wafer, The support rings are ground together. The method of claim 11, wherein the second plastic sealing layer is cut to form a bottom plastic sealing layer covering the bottom metal layer; and the molding compound filled in the cutting channel and the cutting groove is cut. Forming a first side plastic sealing layer and a second side plastic sealing layer respectively adjacent to each other, the first side plastic sealing layer covering the sidewall of a portion of the thickness of the wafer near the front side thereof, and the second side plastic sealing layer Covered on the sidewall of a portion of the thickness of the portion of the wafer near the back side thereof. The method of claim 11, wherein the second plastic sealing layer is cut to form a bottom plastic sealing layer covering the bottom metal layer; and the molding compound filled in the cutting channel and the cutting groove is cut. Separatingly forming a first side plastic sealing layer and a second side plastic sealing layer, the first side plastic sealing layer is coated on a sidewall of a portion of the wafer near a front side thereof, and the second side is plastically sealed. The layer is coated on the sidewall of a portion of the thickness of the portion of the wafer near the back side thereof, and the sidewall of the portion of the intermediate portion of the thickness of the wafer is bare. A method of fabricating a semiconductor device for use in a flip-chip mounting process, comprising the steps of:
Covering a front surface of the wafer with a first plastic seal layer;
Flip the wafer to the back side up, and perform grinding on the back side to thin the wafer;
Depositing a metal layer on the back side of the thinned wafer;
Grinding a peripheral portion of the metal layer around the edge of the wafer to form a second annular region of the thinned back surface of the wafer that is not covered by the metal layer at the edge of the wafer;
Adhering a paste film on the first plastic seal layer;
Detecting, by infrared detection, the ends of each of the dicing streets that overlap the second annular region from the second annular region, and using the detected straight ends to form a metal layer, a wafer, and the first The molding layer performs cutting to form a plurality of semiconductor devices;
The semiconductor device is picked up and mounted on a carrier substrate without flipping to achieve flip-chip mounting. The method of claim 15, wherein in the step of back grinding of the wafer, only the central region of the back surface of the wafer is ground to form a circular groove while retaining the original thickness of the wafer. The peripheral portion is formed by forming a support ring at the edge of the wafer; and in the step of grinding the metal layer, the support ring is first ground.