TW201547061A - Forming method of packaging substrate - Google Patents

Abstract

The purpose of the present invention is to provide a forming method of packaging substrate to prevent a grinding grindstone and the cutting blade of a cutting tool from being over-wearing. The solution is a forming method of packaging substrate to form a packaging substrate comprising a substrate, plural device chips carried on the substrate, and a sealing resin layer to seal the device chips. It is characterized by comprising: a forming step of sealing-resin-layer to form, on the substrate, a sealing resin layer sealing the plural device chips carried on the substrate; a semi-hardening step to half harden the sealing resin layer after implementing the forming step of sealing-resin-layer; a thinning step to thin the sealing resin layer to a predetermined thickness by a grinding means or a cutting means of a cutting tool after implementing the semi-hardening step; and a complete hardening step to completely harden the sealing resin layer after implementing the thinning step.

Description

Method for forming package substrate Field of invention

The present invention relates to a method of forming a package substrate in which a plurality of element wafers mounted on a substrate are covered with a sealing resin layer.

Background of the invention

In the manufacturing process of the component package, a plurality of component wafers obtained by dividing a semiconductor wafer are mounted on a substrate, and the component wafer mounted on the substrate is sealed with a sealing resin to form a package substrate.

In order to protect the element wafer from impact or moisture, it is important to seal the element wafer with a sealing resin. In general, as the sealing material, by using a sealing material in which a filler formed of cerium oxide is mixed in a resin, the thermal expansion coefficient of the sealing material can be made close to the thermal expansion coefficient of the substrate, and heating due to the difference in thermal expansion rate can be prevented. The package is broken at the time.

After resin sealing of a plurality of element wafers mounted on the substrate, the sealing resin can be heated to be cured. Thereafter, by dividing the substrate, it is possible to manufacture an individual component package in which the component wafers are buried.

In recent years, with the thinning of electronic devices, component packaging has also been It is expected to be thinned and an attempt is made to form a sealing resin layer of a package substrate to be thin. However, when a thin sealing resin layer is to be formed, there is a problem that voids are generated inside the sealing resin layer or warpage is formed in the sealed package substrate. Thus, it is considered that after the sealing resin layer having a thickness higher than the required thickness is formed, the sealing resin layer is thinned by using a grinding device or a tool cutting device.

Prior technical literature Patent literature

Patent Document 1: Japanese Patent Laid-Open Publication No. 2010-043663

Summary of invention

However, when the sealing resin layer is thinned, since the sealing resin layer which has been completely hardened is extremely hard and contains a filler such as ruthenium dioxide, there is a grinding stone and a tool cutting device which cause the grinding device. The problem of excessive wear of the cutting edge of the tool.

The present invention has been made in view of such problems, and an object thereof is to provide a method of forming a package substrate capable of preventing grinding grindstone and tool cutting edge from being excessively worn.

A method of forming a package substrate according to the present invention is a package for forming a package substrate including a substrate, a plurality of component wafers mounted on the substrate, and a sealing resin layer sealing the component wafer on the substrate A method of forming a substrate. It is characterized by its inclusion: a sealing resin layer forming step of forming a sealing resin layer for sealing a plurality of element wafers mounted on the substrate; and a semi-hardening step of performing the sealing resin layer forming step to semi-harden the sealing resin layer; a thinning step, after performing the semi-hardening step, thinning the sealing resin layer to a predetermined thickness by a grinding means or a cutter cutting means; and a complete hardening step of completely curing the sealing resin layer after performing the thinning step .

According to the present invention, since the sealing resin is thinned by the grinding means or the tool cutting means in a state where the sealing resin is semi-hardened, excessive wear of the grinding stone or the cutting edge of the tool can be prevented. Further, since the occurrence of warpage can be suppressed in the semi-hardened state, it is possible to prevent the occurrence of warpage on the package substrate and the inability to attract and hold by the holding means.

10‧‧‧Working table

11‧‧‧Package substrate

12‧‧‧ grinding unit (grinding means)

13‧‧‧Substrate

14‧‧‧ Spindle

15‧‧‧Component chip

16‧‧‧ grinding wheel seat

17‧‧‧ sealing resin layer

20‧‧‧ grinding wheel

22‧‧‧ grinding wheel abutment

24‧‧‧ grinding grinding stone

32‧‧‧Tool cutting device

34‧‧‧Base

36‧‧‧ pillar

38‧‧‧rails

40‧‧‧Tool cutting unit (tool processing method)

42‧‧‧Mobile abutments

44‧‧‧Ball screw

46‧‧‧pulse motor

48‧‧‧Tool cutting unit feed mechanism

50‧‧‧shell

52‧‧‧ Spindle

54‧‧‧ pedestal

56‧‧‧Motor

58‧‧‧Tool wheel

60‧‧‧Tool Tools

62‧‧‧blade (tool cutting edge)

64‧‧‧Working table mechanism

66‧‧‧Working table

67‧‧‧Flexible cover

68‧‧‧First Wafer匣

70‧‧‧2nd wafer crucible

72‧‧‧ wafer transfer robot

74‧‧‧ Positioning mechanism

76‧‧‧Locating pin

78‧‧‧ Wafer loading mechanism (loading arm)

80‧‧‧ Wafer removal mechanism (unloading arm)

82‧‧‧Rotary cleaning unit

84‧‧‧Washing water spray nozzle

X, Y, Z, Y1, a, b‧‧‧ directions

Fig. 1 is a longitudinal sectional view of a package substrate in a state in which a thick sealing resin layer has been sealed.

Fig. 2 is a partial cross-sectional side view showing a grinding step (thinning step).

3 is a perspective view of a tool cutting device.

Fig. 4 is a partial cross-sectional side view showing a thinning step by a cutter cutting device.

5(A) is a longitudinal cross-sectional view of the package substrate after the thinning step; and FIG. 5(B) is a thin view of the flip chip bonding of the element wafer. A longitudinal cross-sectional view of the package substrate after the step.

Figure 6 is a longitudinal cross-sectional view of the package substrate after the complete hardening step.

Form for implementing the invention

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. Referring to Fig. 1, there is shown a longitudinal sectional view of a package substrate on which a thick sealing resin layer has been formed. In the package substrate 11, a plurality of element wafers 15 are mounted on the substrate 13, and the element wafer 15 is sealed by the sealing resin layer 17 (sealing resin layer forming step).

As the sealing resin used in the sealing resin layer 17, in order to make the thermal expansion coefficient of the sealing resin layer 17 close to the thermal expansion coefficient of the substrate 13, it is preferable to use an epoxy resin or the like in which a filler formed of cerium oxide is mixed. .

In the method of forming a package substrate of the present invention, after the step of forming the sealing resin layer, a semi-hardening step of semi-curing the sealing resin layer is performed. In the semi-hardening step, for example, the sealing resin layer 17 is heated at about 100 ° C for a predetermined time to semi-harden the sealing resin layer 17.

After the semi-hardening step is performed, a thinning step of thinning the sealing resin layer 17 to a predetermined thickness may be performed. The thinning step using the grinding means (grinding unit) 12 will be described with reference to Fig. 2 . Figure 2 is a partial cross-sectional side view showing the thinning step by means of grinding.

In Fig. 2, a grinding wheel 20 attached to a tip end of a spindle 14 fixed to a grinding means (grinding unit) 12 is detachably mounted by a plurality of screws (not shown). The grinding wheel 20 is in the ring-shaped grinding wheel base The outer periphery of the lower end portion of the stage 22 is formed by fixing a plurality of grinding stones 24 in a ring shape.

The thinning step by the grinding means 12 is along the arrow a In the direction shown, the working chuck 10 is rotated at, for example, 300 rpm, and the grinding wheel 20 is rotated in the direction indicated by the arrow b at, for example, 6000 rpm while driving a grinding unit feed mechanism not shown, for grinding. The grinding stone 24 of the wheel 20 is in contact with the semi-hardened sealing resin layer 17.

Then, the grinding wheel 20 is turned downward at a predetermined grinding feed rate The grinding feed is advanced by a predetermined amount, and the semi-hardened sealing resin layer 17 is thinned to a predetermined thickness (preferably less than the thickness of the element wafer 15).

On the other hand, when the component wafer 15 is flip-chip bonded to the base In the case of the plate 13, the back surface of the element wafer 15 may be thinned together with the semi-cured sealing resin layer 17, and the back surface of the element wafer 15 may be exposed. In the thinning step of the present embodiment, since the sealing resin layer 17 is thinned by the grinding unit 12 in a semi-hardened state, excessive wear of the grinding stone 24 can be prevented.

The thinning step of thinning the semi-hardened sealing resin layer 17 is also It is implemented by a cutter cutting device. Referring to Figure 3, a perspective view of the tool cutting device 32 is shown. The cutter cutting device 32 has a base 34, and a support 36 is erected behind the base 34. A pair of guide rails (only one of which is shown) 38 extending in the up and down direction is fixed to the stay 36.

And along the pair of guide rails 38, the tool cutting unit (tool machining The means 40 is mounted to be movable in the up and down direction. The cutter cutting unit 40 is mounted to move the housing 50 in the up and down direction along the pair of guide rails 38. On the base 42.

The tool cutting unit 40 includes a housing 50 that is rotatably received A main shaft 52 (see FIG. 4) in the casing 50, a motor 56 for rotating the main shaft 52, a pedestal 54 fixed to the front end of the main shaft 52, and a cutter wheel 58 detachably mounted on the pedestal 54. The tool wheel 58 has a tool tool 60 that is detachably mounted, the tool tool 60 having a cutting edge (tool cutting edge) 62 at the front end. The blade 62 is composed of a diamond blade.

The tool cutting unit 40 includes a tool cutting unit feeding mechanism 48. The tool cutting unit feed mechanism 48 is constituted by a ball screw 44 and a pulse motor 46 that allow the tool cutting unit 40 to move in the vertical direction along the pair of guide rails 38. When the pulse motor 46 is driven, the ball screw 44 is rotated to move the moving base 42 in the up and down direction.

The middle portion of the base 34 is provided with a work including a work chuck 66 As the chuck mechanism 64, the work chuck mechanism 64 is movable in the Y-axis direction by a work chuck moving mechanism not shown. 67 is a telescopic cover for covering the work clamping mechanism 64.

The first wafer 匣 68 and the second wafer are disposed on the front side portion of the susceptor 34 The crucible 70, the wafer transfer robot 72, the positioning mechanism 74 having a plurality of positioning pins 76, the wafer loading mechanism (loading arm) 78, the wafer unloading mechanism (unloading arm) 80, and the spin cleaning unit 82.

Further, on the center portion of the susceptor 34, a cleaning device is provided. The washing water spray nozzle 84 of the chuck 66 is used. In the state in which the working chuck 66 is positioned close to the wafer loading/unloading area on the apparatus side, the washing water jet nozzle 84 sprays the washing water toward the operating chuck 66.

Hereinafter, for the thinning step by the cutter cutting device 32, Description will be made with reference to Fig. 4 . The package substrate 11 in which the sealing resin layer 17 has been semi-hardened is sucked and held by the work chuck 66 of the cutter cutting device 32.

Then, the main shaft 52 of the cutter cutting device 32 is made at about 2000 rpm. The rotation speed is rotated and the cutter wheel feed mechanism 48 is driven to cut the blade edge (tool cutting edge) 62 of the tool tool 60 toward the semi-hardened sealing resin layer 17 by a predetermined depth, and the working chuck 62 is made, for example, at 1 mm/s. The semi-cured sealing resin layer 17 is thinned and cut in a state where the feed speed is moved in the direction of the arrow Y1.

During this cutting process (thinning step), the working chuck 66 is allowed. The thinning step is performed by performing the processing feed in the direction of the arrow Y1 without rotating. In the present embodiment, the sealing resin layer 17 is thinned by the cutting unit 40 in a semi-cured state, so that excessive wear of the cutting edge (blade) 62 can be prevented.

Referring to FIG. 5(A), the package substrate after the thinning step is shown 11 longitudinal section view. As clearly shown in Fig. 5(A), the semi-hardened sealing resin layer 17 is thinned to less than the thickness of the element wafer 15.

Referring to FIG. 5(B), the component wafer 15 is flip-chip bonded. A longitudinal cross-sectional view of the package substrate 11 after the thinning step is applied to the substrate 13. At this time, the back surface of the element wafer 15 may be thinned together with the semi-cured sealing resin layer 17, and the back surface of the element wafer 15 may be exposed.

After the thinning step is performed, the sealing resin layer 17 can be completely implemented. Hardening complete hardening step. In the complete hardening step, the sealing resin layer 17 is subjected to a longer time than the semi-hardening step at, for example, a temperature of 200 ° C. Heating is performed to completely cure the sealing resin layer 17. A longitudinal sectional view of the package substrate after the complete hardening step is shown in FIG.

32‧‧‧Tool cutting device

34‧‧‧Base

36‧‧‧ pillar

38‧‧‧rails

40‧‧‧Tool cutting unit

42‧‧‧Mobile abutments

44‧‧‧Ball screw

46‧‧‧pulse motor

48‧‧‧Tool cutting unit feed mechanism

50‧‧‧shell

54‧‧‧ pedestal

56‧‧‧Motor

58‧‧‧Tool wheel

60‧‧‧Tool Tools

64‧‧‧Working table mechanism

66‧‧‧Working table

67‧‧‧Flexible cover

68‧‧‧First Wafer匣

70‧‧‧2nd wafer crucible

72‧‧‧ wafer transfer robot

74‧‧‧ Positioning mechanism

76‧‧‧Locating pin

78‧‧‧ Wafer loading mechanism (loading arm)

80‧‧‧ Wafer removal mechanism (unloading arm)

82‧‧‧Rotary cleaning unit

84‧‧‧Washing water spray nozzle

X, Y, Z‧‧ Direction

Claims (1)

Method for forming a package substrate, the method for forming a package substrate for forming a package substrate including a substrate, a plurality of device wafers mounted on the substrate, and a sealing resin layer sealing the device wafer on the substrate A sealing resin layer forming step of forming a sealing resin layer capable of sealing a plurality of element wafers mounted on a substrate, and a semi-hardening step of performing the sealing resin layer forming step a resin layer semi-hardening; a thinning step, after performing the semi-hardening step, thinning the sealing resin layer to a predetermined thickness by a grinding means or a cutter cutting means; and a complete hardening step, after performing the thinning step, The sealing resin layer is completely hardened.