CN102403244A - Method for manufacturing semiconductor chip - Google Patents

Abstract

The invention provides a method for manufacturing a semiconductor chip, which includes: forming a lead frame of the semiconductor chip by stamping; welding a semiconductor wafer to one side of the lead frame; The lead frame is turned over, and the cylindrical crystal oscillator is welded to the other side of the lead frame; the wafer, the lead frame and the crystal oscillator are plastic-packed to form a chip. In the chip packaging method of the invention, the cylindrical crystal oscillator and the wafer are packaged together, which can ensure the stability of the chip and reduce the cost of the chip at the same time.

Description

Manufacturing method of semiconductor chip

【Technical field】

The invention relates to a method for manufacturing a semiconductor chip, in particular to a welding and packaging method for the semiconductor chip.

【Background technique】

A semiconductor chip is usually an integrated circuit composed of many transistors that can perform certain functions. Usually, a chip needs an external clock to provide an accurate clock frequency. In order to ensure the reliable function of the integrated circuit, the clock frequency provided to the circuit must be stable and reliable. Existing chips are generally installed on a circuit board, and the clock frequency is provided by an external crystal oscillator, but such a chip provided by an external crystal oscillator will occupy a certain amount of space, and the area occupied by the entire circuit is relatively large. , the integration level is not high, and secondly, because the crystal and the chip are separated, the working environment will always be different, so that there will be errors in the cooperation between the crystal and the chip, which will affect the stability of the chip. Moreover, the crystal oscillators used in existing chips are usually patch crystal oscillators, but since the cost of patch crystal oscillators is relatively high, it is not conducive to reducing the cost of the entire chip, so it is necessary to improve the existing chip structure and packaging methods.

【Content of invention】

The object of the present invention is to provide a method for manufacturing a semiconductor chip, which packages the cylindrical crystal oscillator together with the wafer, which can ensure the stability of the chip and reduce the cost of the chip.

In order to achieve the aforementioned object, the present invention provides a method for manufacturing a semiconductor chip, which includes: stamping and forming a lead frame of the semiconductor chip; welding a semiconductor wafer to one side of the lead frame; The lead frame is turned over, and the cylindrical crystal oscillator is welded to the other side of the lead frame; the wafer, the lead frame and the crystal oscillator are plastic-encapsulated to form a chip.

Further, the lead frame includes a rectangular wafer carrying portion in the middle, the wafer carrying portion includes a first side, a second side, a third side and a fourth side, from the outer frame of the lead frame Extending obliquely to the first side of the bearing part to form two first guide pins, and extending from the opposite side of the two first guide pins along a direction parallel to the first side of the bearing part to form a weld for welding the aforementioned crystal oscillator foot.

Further, before turning the lead frame over to weld the crystal oscillator, it also includes a step of setting a recessed tray on the side of the lead frame where the wafer is welded to prevent the wafer bonding wires from being touched by the outside.

Further, before welding the cylindrical crystal oscillator to the lead frame, it also includes the step of bending the pins of the cylindrical crystal oscillator, and weaving the bent crystal oscillator into a crystal oscillator braid.

Further, welding the crystal oscillator to the lead frame is to automatically weld the crystal oscillator to the lead frame by using the crystal oscillator tape.

Compared with the existing chip packaging method, the chip packaging method of the present invention packages the cylindrical crystal oscillator and the wafer together, which can ensure the stability of the chip and reduce the cost of the chip at the same time. In the packaging process, the cylindrical crystal oscillator is automatically welded on the lead frame by bending it first and then weaving it into a braid, which is convenient and quick to weld. After the wafer is soldered, the lead frame is turned over to solder the crystal oscillator. When soldering the crystal oscillator, a recessed tray is used to protect the bonding wire on the wafer and the lead frame side, which can ensure the safety of the bonding wire on the wafer side.

【Description of drawings】

FIG. 1 is a schematic side view of the structure of the chip of the present invention.

Fig. 2 is a plan view of a lead frame of the chip of the present invention.

FIG. 3 is a flow chart of the chip manufacturing method of the present invention.

FIG. 4 is a schematic diagram of a recessed tray used in the soldering process of the chip manufacturing method of the present invention.

【Detailed ways】

Reference herein to "one embodiment" or "an embodiment" refers to a particular feature, structure or characteristic that can be included in at least one implementation of the present invention. "In one embodiment" appearing in different places in this specification does not all refer to the same embodiment, nor is it a separate or selective embodiment that is mutually exclusive with other embodiments.

Please refer to shown in Fig. 1, it shows the structural representation of the chip of the present invention, as shown in the figure, the chip of the present invention comprises a lead frame 1, the wafer 2 that is installed on the lead frame, connects wafer and lead frame Wire bonding 3, a crystal oscillator 4 mounted on the lead frame, and a packaging shell 5 covering the wafer, crystal oscillator, and wire bonding.

Referring to FIG. 1 and shown in FIG. 2 , the lead frame 1 is formed by stamping flat metal, which includes a square wafer carrier 11 in the middle. As shown in FIG. 2 , the wafer carrier 11 is rectangular , which includes a first side 111 , a second side 112 , a third side 113 and a fourth side 114 . The connection pins 13 extending outward from the center of the first side 111 and the third side 113 can be connected with the outer frame 12 of the lead frame 11 for fixing the carrying portion 11 . The outer frame of the lead frame extends obliquely to the first side 111 of the carrying portion to form two first guide pins 14, and extends vertically from the outer frame of the lead frame to the second side 112 and the fourth side of the carrying portion to form a second The two guide pins 15 first extend obliquely from the outer frame of the lead frame to the third side 113 of the carrying portion and then extend vertically to form the third guide pin 16 . Two soldering legs 17 are relatively extended from opposite sides of the two first guiding legs along a direction parallel to the first side of the carrying portion.

The aforementioned crystal oscillator 4 is a cylindrical crystal oscillator in one embodiment of the present invention, which has two pins 41 .

Referring to FIG. 2 and shown in FIG. 1 , the aforesaid wafer is mounted on the carrying portion of the lead frame, wherein the circuit on the wafer is connected to the leads on the lead frame by wire bonding. The aforementioned crystal oscillator is installed on the other side of the lead frame opposite to the chip, wherein the two pins 41 of the crystal oscillator are respectively corresponding to the two welding pins 17 welded on the lead frame. The entire packaging shell packages the wafer, the crystal oscillator and the lead frame together to form a semiconductor chip.

Wherein the circuit contained in the wafer of the semiconductor chip of the present invention includes a crystal oscillation circuit matched with the crystal oscillator, and the combination of the crystal oscillator and the crystal oscillation circuit can generate a frequency signal of the intrinsic frequency of the crystal.

The crystal oscillator of the semiconductor chip of the present invention and the wafer are respectively installed on both sides of the lead frame and packaged together. On the one hand, the integration degree can be improved; The consistency of the environment improves the working stability of the whole chip. Moreover, the packaged crystal oscillator of the present invention adopts a cylindrical crystal oscillator, and the chip cost is relatively low.

Please refer to FIG. 3 , which shows a flowchart of the chip manufacturing method of the present invention. As shown in Figure 3, the chip manufacturing method of the present invention comprises the following steps:

Step S1: stamping to form the lead frame of the semiconductor chip, wherein the structure of the lead frame is as shown in Figure 2, which includes a square wafer carrier 11 in the middle, and the wafer carrier 11 is rectangular and includes a first side 111 , the second side 112 , the third side 113 and the fourth side 114 . The connection pins 13 extending outward from the center of the first side 111 and the third side 113 can be connected with the outer frame 12 of the lead frame 11 for fixing the carrying portion 11 . The outer frame of the lead frame extends obliquely to the first side 111 of the bearing part to form two first guide pins 14, and extends vertically from the outer frame of the lead frame to the second side 112 and the fourth side of the bearing part to form the second The two guide pins 15 first extend obliquely from the outer frame of the lead frame to the third side 113 of the carrying portion and then extend vertically to form the third guide pin 16 . Two soldering legs 17 are relatively extended from opposite sides of the two first guiding legs along a direction parallel to the first side of the carrying portion.

Step S2: welding the semiconductor wafer to one side of the lead frame; please refer to FIG. 1 , the semiconductor wafer is welded to one side of the lead frame.

Step S3: Connect the wafer to the leads of the lead frame by wire bonding; please refer to FIG. 1 to connect the semiconductor wafer to the leads of the lead frame by wire bonding.

Step S4: Turn the lead frame over, and solder the cylindrical crystal oscillator to the other side of the lead frame.

Step S41: before turning the lead frame over to solder the crystal oscillator, it also includes the step of setting a recessed tray 6 on the side of the lead frame where the wafer is soldered to prevent the wafer bonding wires from being touched by the outside. As shown in Figure 4, the tray 6 is in a concave shape, because it covers the bonding wires of the wafer inside, after turning over the lead frame, the bonding wires on one side of the wafer will not be touched by the outside, preventing the wafer from being touched. If the bonding wire is broken, the yield rate of the chip can be improved.

Step S42: Before soldering the cylindrical crystal oscillator to the lead frame, it also includes the step of bending the pins of the cylindrical crystal oscillator and weaving the bent crystal oscillator into a crystal oscillator braid. Because the cylindrical crystal oscillator usually includes a cylindrical crystal oscillator body and two pins extending from the crystal oscillator body, usually the two pins are all upright. For welding the cylindrical crystal oscillator on the lead frame, the present invention firstly connects each Bending the vertical pins of each crystal oscillator, and then weaving the bent crystal oscillators into crystal oscillator tapes, when soldering the crystal oscillators to the lead frame, use automatic equipment to solder the crystal oscillators in the tape to the corresponding ones one by one. on the lead frame. The pins of the crystal oscillator are correspondingly welded to the soldering pins 17 of the lead frame.

Step S5: Plastic-encapsulate the wafer, lead frame and crystal oscillator to form a chip. As shown in Figure 1, the wafer, lead frame, crystal oscillator, and bonding wires connecting the wafer and lead frame are plastic-encapsulated to form a chip.

In the chip packaging method of the invention, the cylindrical crystal oscillator and the wafer are packaged together, which can ensure the stability of the chip and reduce the cost of the chip at the same time. In the packaging process, the cylindrical crystal oscillator is automatically welded on the lead frame by bending and then weaving into a braid, which is convenient and quick to weld. After the wafer is soldered, the lead frame is turned over to solder the crystal oscillator. When soldering the crystal oscillator, a recessed tray is used to protect the bonding wire on the wafer and the lead frame side, which can ensure the safety of the bonding wire on the wafer side.

The above description has fully disclosed the specific implementation manners of the present invention. It should be pointed out that any changes made by those skilled in the art to the specific embodiments of the present invention will not depart from the scope of the claims of the present invention. Accordingly, the scope of the claims of the present invention is not limited only to the foregoing specific embodiments.

Claims (5)

1. the manufacturing approach of a semiconductor chip, it comprises: punching press forms the lead frame of semiconductor chip; Semiconductor crystal wafer is welded in the one side of said lead frame; Utilize routing that wafer is connected with the lead foot of lead frame; With the lead frame upset, be welded in cylindrical crystal oscillator the another side of said lead frame; Wafer, lead frame and crystal oscillator are carried out plastic packaging process chip.

2. the method for claim 1; It is characterized in that: said lead frame comprises the rectangle wafer carrying portion in the middle of being positioned at; Said wafer carrying portion comprises first side, second side, the 3rd side and four side; Housing from lead frame forms two first lead foots to the first side of supporting part diagonally extending, extends to form the welding foot of the aforementioned crystal oscillator of welding relatively along the direction that is parallel to the supporting part first side from a relative side of two first lead foots.

3. the method for claim 1 is characterized in that: before with lead frame upset welding crystal oscillator, the one side that also is included in lead frame welding wafer is provided with the step of a depression pallet to avoid the wafer routing to be touched by the external world.

4. the method for claim 1, it is characterized in that: before cylindrical crystal oscillator was welded in lead frame, it also comprised the bending pins with cylindrical crystal oscillator, and the crystal oscillator after will bending is compiled into the step of crystal oscillator braid.

5. method as claimed in claim 4 is characterized in that: it is to adopt said crystal oscillator braid automation that said crystal oscillator is welded in said lead frame that said crystal oscillator is welded in said lead frame.

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