阅读说明：本技术 一种倒装器件封装方法及结构 (Flip-chip device packaging method and structure ) 是由 关承浩 李华楠 陈亮 于 2018-06-29 设计创作，主要内容包括：本发明提供一种倒装器件封装方法,所述倒装器件封装方法至少包括：将基板放置于预设位置,其中,所述基板上开设有至少一个上下贯穿的孔洞；将所述倒装芯片置于所述基板之上,且所述倒装芯片上的焊球与所述基板上的焊盘对应相接；对所述基板上的焊盘和所述倒装芯片的焊球进行焊接,并进行冷却处理；从所述孔洞中注入填充材料。另外,本发明还提供了一种倒装器件封装结构,应用本发明实施例,解决了现有技术中芯片四周注入填充材料,受流动速度等影响,会产生不同程度的空洞的问题。(The invention provides a flip-chip device packaging method, which at least comprises the following steps: placing a substrate at a preset position, wherein at least one hole penetrating through the substrate up and down is formed in the substrate; placing the flip chip on the substrate, wherein the solder balls on the flip chip are correspondingly connected with the bonding pads on the substrate; welding a welding pad on the substrate and a welding ball of the flip chip, and cooling; and injecting a filling material from the hole. In addition, the invention also provides a flip-chip device packaging structure, and by applying the embodiment of the invention, the problem that cavities with different degrees are generated due to the influence of flow speed and the like when the filling material is injected around the chip in the prior art is solved.)

1. A flip-chip device packaging method, comprising at least:

placing a substrate at a preset position, wherein at least one hole penetrating through the substrate up and down is formed in the substrate;

placing the flip chip on the substrate, wherein the solder balls on the flip chip are correspondingly connected with the bonding pads on the substrate;

welding a welding pad on the substrate and a welding ball of the flip chip, and cooling;

and injecting a filling material from the hole.

2. The flip-chip device packaging method of claim 1, wherein the temperature range of the soldering is: 180-260 ℃.

3. The flip-chip device packaging method of claim 1 or 2, wherein the filler material is composed of a thermosetting polymer and a silica filler.

4. The flip-chip device packaging method of claim 3, wherein the solder balls are spherical and the pads are square, rectangular, or circular.

5. The packaging method of claim 1, wherein the substrate is selected from a BT substrate, an FR4 substrate, an aluminum substrate, a copper substrate or a ceramic substrate.

6. A flip-chip LED package structure, the structure comprising: the flip chip comprises a substrate, a flip chip fixed on the substrate, at least one hole and a filler, wherein the at least one hole is arranged on the substrate in a penetrating mode, and the filler is filled between the substrate and the flip chip.

7. The package structure of claim 6, wherein the substrate and the chip are fixed by baking silver paste or solder paste.

8. The LED package structure of claim 6 or 7, wherein the substrate has a length and/or width of 3mm to 5 mm.

Technical Field

The invention relates to the technical field of flip-chip packaging, in particular to a packaging method and a structure of a flip-chip device.

Background

The LED chip is the earliest chip structure, and is also a chip structure commonly used in low-power chips. In the structure, the electrode is arranged above and comprises the following materials from top to bottom: P-GaN, a light emitting layer, N-GaN and a substrate. Therefore, the flip chip has a structure just opposite to that of the normal mounting, and is called a flip chip. Flip-chip packaging also has a flip-chip IC, in which a tin lead ball is deposited on an I/O pad, and then a chip is turned over and heated, and the molten tin lead ball and a ceramic substrate are combined to replace conventional wire bonding, so that the flip-chip IC gradually becomes the mainstream of future packaging, and is mainly applied to products such as a high-clock CPU (central processing unit), a GPU (graphic processing unit), a Chipset and the like at present.

In the existing flip chip packaging technology, the filling method of the filling material mainly has three types: conventional filling methods, no-flow filling methods and pressure injection filling methods. The traditional filling method comprises the following steps: distributing the filling material with raised temperature on one side or two sides of the chip by an injector through a template system and a power system, and sucking the filling material into a tiny gap between the chip and the substrate through the action of surface tension; no-flow filling method: changing the flow of the traditional filling method, so that the filling material is solidified together with the salient points of the chip when the filling material is subjected to reflow soldering; the pressure injection filling method comprises the following steps: the flip chip is placed in a specially prepared mold and a fill fluid is injected into the mold under pressure.

In the filling methods, filling materials are injected around the chip, and voids of different degrees are generated under the influence of flow speed and the like.

Disclosure of Invention

In view of the above-mentioned drawbacks of the prior art, an object of the present invention is to provide a method and a structure for packaging a flip chip device, which are used to solve the problem that voids are generated at different levels due to the influence of flow speed and the like when a filling material is injected around a chip in the prior art.

To achieve the above and other related objects, the present invention provides a flip chip device packaging method, including at least:

placing a substrate at a preset position, wherein at least one hole penetrating through the substrate up and down is formed in the substrate;

placing the flip chip on the substrate, wherein the solder balls on the flip chip are correspondingly connected with the bonding pads on the substrate;

welding a welding pad on the substrate and a welding ball of the flip chip, and cooling;

and injecting a filling material from the hole.

In a preferred embodiment of the invention, the temperature range of the welding is: 180-260 ℃.

In a preferred embodiment of the invention, the filler material consists of a thermosetting polymer and a silica filler.

In a preferred embodiment of the present invention, the solder ball is spherical, and the pad is square, rectangular, or circular.

In a preferred embodiment of the present invention, the substrate is a BT substrate, an FR4 substrate, an aluminum substrate, a copper substrate, or a ceramic substrate.

In addition, the invention also provides a flip LED packaging structure, which comprises: the flip chip comprises a substrate, a flip chip fixed on the substrate, at least one hole and a filler, wherein the at least one hole is arranged on the substrate in a penetrating mode, and the filler is filled between the substrate and the flip chip.

In a preferred embodiment of the present invention, the substrate and the chip are fixed by baking silver paste or solder paste.

In a preferred embodiment of the present invention, the length and/or width of the substrate is 3mm to 5 mm.

As described above, the flip chip device packaging method and structure of the present invention have the following beneficial effects: the lower part of the chip is provided with a hole corresponding to the support, and the hole is filled with the filling material, so that the filling material is adsorbed and diffused from the middle to the periphery, the void ratio is reduced, and the operation efficiency is improved.

Drawings

Fig. 1 is a schematic structural diagram of a substrate in the flip-chip device packaging method of the present invention.

Fig. 2 is a schematic view showing a connection between a substrate and a flip chip in the flip device packaging method of the present invention.

Fig. 3 is a schematic view showing another connection between the substrate and the flip chip in the flip device packaging method of the present invention.

Fig. 4 is a schematic view showing the filling effect of the filler in the flip-chip device packaging method of the present invention.

Fig. 5 is a specific implementation of the flip-chip device package device of the present invention.

Fig. 6 is a top view of the flip-chip device package device of fig. 5 of the present invention.

Description of the element reference numerals

1 substrate

11 holes

12 bonding pad

21 solder ball

3 filling material

4 electrodes

S101 to S104

Detailed Description

The embodiments of the present invention are described below with reference to specific embodiments, and other advantages and effects of the present invention will be easily understood by those skilled in the art from the disclosure of the present specification. The invention is capable of other and different embodiments and of being practiced or of being carried out in various ways, and its several details are capable of modification in various respects, all without departing from the spirit and scope of the present invention.

Please refer to fig. 1 to 4. It should be noted that the drawings provided in the present embodiment are only schematic illustrations of the substrate idea of the present invention, and the drawings only show the components related to the present invention rather than the number, shape and size of the components in actual implementation, and the type, number and ratio of the components in actual implementation may be changed arbitrarily, and the layout of the components may be more complicated.

As shown in fig. 1, there is provided a flip-chip device packaging method, including at least:

s101, placing a substrate at a preset position, wherein at least one hole penetrating through the substrate up and down is formed in the substrate.

The substrate is a basic material for manufacturing a PCB, and generally, the substrate is a Copper clad laminate, and in manufacturing of the single-sided and double-sided printed boards, hole machining, chemical Copper plating, Copper electroplating, etching and other machining are selectively performed on a substrate material Copper clad laminate (Copper-2lad I, amides, CCI.) to obtain a required circuit pattern. Further, aluminum substrate, ceramic, or the like may be used.

In the embodiment of the present invention, the substrate is provided with through holes from top to bottom, and the number of the through holes may be one, two, or three, and may be set according to the basic size and the requirement of subsequent filling.

After the above requirements are basically met, the substrate 1 is placed at a designated position for further operation, and the hole 11 is formed in the middle of the substrate.

S102, the flip chip is placed on the substrate, and the solder balls on the flip chip are correspondingly connected with the bonding pads on the substrate.

As shown in fig. 2, the solder balls 21 on the flip chip 2 are aligned with the pads 12 on the substrate, and then the flip chip is mounted on the substrate, resulting in the structure shown in fig. 3. It can be understood that the flip chip needs to form a circuit connection structure with the substrate, and the connection is performed by using solder joints, so that the accuracy of the position and structure of the solder joints must be ensured. In the embodiment of the invention, when the welding points on the flip chip are combined with the welding pads on the substrate, the welding balls are melted and can be automatically aligned with the welding pads under the action of surface tension at a certain temperature.

S103, welding the welding pads on the substrate and the welding balls of the flip chip, and cooling.

The solder balls on the flip chip are correspondingly connected with the bonding pads on the substrate and then baked to realize the connection of the welding points, and specifically, the die bonding can use bump welding (alloy solder balls) or conductive adhesive/solder paste and other methods. After baking, cooling treatment is performed to return to a normal temperature state. Specifically, reflow soldering may be employed or soldering may be performed under the same temperature conditions.

And S104, injecting a filling material from the hole.

After baking, the chip is fixed on the substrate, at which time the filling material 3 is added. The filling material is filled into the small hole through the small hole, the filling material can be absorbed and diffused from the center of the hole to the periphery under the capillary action, as shown in fig. 4, because the filling is carried out from the center, the air in the hole can be smoothly squeezed out, and the absorption and diffusion time is shorter than the diffusion time from one side of the chip to the other side.

In a preferred embodiment of the invention, the temperature range of the welding is: 180-260 ℃. Reflow soldering generally has a mode of ten temperature zones, eight temperature zones and the like, the temperature of each temperature zone is different, the retention time of materials in the temperature zones is also different, and the temperature is 180-260 ℃.

In particular, the filler material consists of a thermosetting polymer and a silica filler.

In a preferred embodiment of the present invention, the solder ball is spherical, and the pad is square, rectangular, or circular. The appearance of the solder ball is generally approximately spherical; the solder balls are typically larger than the pads so that the substrate and chip attach is robust.

In a preferred embodiment of the present invention, the substrate is a BT substrate, an FR4 substrate, an aluminum substrate, a copper substrate, or a ceramic substrate.

In addition, the invention also provides a flip LED packaging structure, which comprises: the flip chip comprises a substrate, a flip chip fixed on the substrate and at least one hole, wherein the at least one hole is arranged on the substrate in a penetrating mode.

In a preferred embodiment of the present invention, the substrate and the chip are fixed by baking silver paste or solder paste.

Fig. 2 shows an embodiment of a solder paste bonded package device, fig. 5 and fig. 6 show an embodiment of connecting a substrate and a chip through an electrode 4, fig. 6 is a front cross-sectional view of a flip-chip led die-bonded device, the chip is bonded together through silver paste/solder paste after baking (the baking temperature of the silver paste is generally 150-.

In a preferred embodiment of the present invention, the length and/or width of the substrate is 3mm to 5 mm.

In summary, the flip chip packaging method provided by the invention, the flip chip packaging method and the structure thereof have the following beneficial effects: the lower part of the chip is provided with a hole corresponding to the support, and the hole is filled with the filling material, so that the filling material is adsorbed and diffused from the middle to the periphery, the void ratio is reduced, and the operation efficiency is improved. Therefore, the invention effectively overcomes various defects in the prior art and has high industrial utilization value.

The foregoing embodiments are merely illustrative of the principles and utilities of the present invention and are not intended to limit the invention. Any person skilled in the art can modify or change the above-mentioned embodiments without departing from the spirit and scope of the present invention. Accordingly, it is intended that all equivalent modifications or changes which can be made by those skilled in the art without departing from the spirit and technical spirit of the present invention be covered by the claims of the present invention.