JPH10163240A - Method of forming ball grid array system contact - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for forming a solder contact in the contact region of a ball grid array system semiconductor device. SOLUTION: This method forms a solder contact 31 in the contact region 32 of a ball grid array system semiconductor device 30. The semiconductor 30 is preheated, and a plurality of solder forms are directly punched in the contact region 32 on a semiconductor substrate, from a solder material sheet. A solder preform is again fluidized by heating the substrate and the solder forms, and the solder contact 31 is formed on the semiconductor substrate.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor device, and more particularly, to a semiconductor device having a ball grid on a semiconductor device.
The present invention relates to a method of forming an array contact.

[0002]

BACKGROUND OF THE INVENTION Integrated circuit densities have increased over the past several years to meet the higher performance requirements of integrated circuits. Package sizes are becoming smaller and smaller to meet the same high performance requirements, and consequently the pin densities for packages are becoming higher.
The higher pin density means that the pitch of the I / O connection lead wires becomes finer. Ball grid array (BGA) style packages meet this high pin density requirement and are being used to replace current QFP packages due to the benefits of BGA over traditional quad flat packages (QFP) . BGA
Packages have fewer coplanar problems, have automatic alignment capabilities, and are more productive than QFP packages.

[0003] Although many types of ball mounting techniques are available, all require a complicated ball mounting process, and it is difficult to arrange the balls uniformly on the substrate. One example of a ball mounting method uses a feeder that feeds the solder paste directly onto the substrate. Since the volume of the applied solder paste can vary, the metal content of each solder ball can vary. It is difficult to control the height of the solder balls.
Although the productivity of this feeding method is low, the main advantage is that the ball height is low. Another method is to attach a preformed ball. There are two ways to do this, one for plastic packages and the other for ceramic packages. Eutectic solder balls are used for a plastic BGA package, and high-temperature solder balls are used for a ceramic BGA package.

[0004] In another method, solder wire bonds are used to form BGA balls. Wire bonder is
A solder wire is bonded onto a lead wire pad of a substrate. The solder wire is reflowed to melt the solder into the ball. The productivity of this method is low and has a problem with the height of the solder balls. In each of the above methods, a uniform height or size of the ball cannot be ensured, and the ball cannot be reliably installed at a desired position on the semiconductor package.

[0005]

SUMMARY OF THE INVENTION The present invention is a method for forming solder contacts in a contact area of a ball grid array semiconductor device. The semiconductor is preheated and a plurality of solder foams are punched directly from a sheet of solder material into contact areas on the semiconductor substrate. The semiconductor and solder preform are then heated to reflow the solder and form contacts on the semiconductor substrate. BRIEF DESCRIPTION OF THE DRAWINGS The technical advance and its objects according to the present invention will be discussed below with reference to the accompanying drawings and by understanding the novel features set forth in the appended claims, the following description of preferred embodiments of the present invention. Will be clear from the description.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENT FIG. 1 shows a semiconductor device 10 including a substrate 11 and a row of solder ball contacts 12. Each solder ball is attached to an underlying contact point (see FIG. 4). The contact points may be passages extending into the substrate 11 to contact elements of the semiconductor chip, or may be conductors on the substrate that interconnect with other circuits or contact pads on the semiconductor device. . FIG. 2 shows a semiconductor substrate 1 mounted on a carrier 15 and located below a punch 18 having a plurality of punch dies 19.
Figure 6 is a schematic diagram showing 6 and strips or rolls 17 of solder plates. After placing the semiconductor substrate 16 under the punch 18, the punch 18 is started and a plurality of solder forms 20 are punched by the die 19 (see FIG. 3). In FIG. 3, the solder form 20 is shown in a state of being aligned on the substrate 16.

FIG. 4 shows a semiconductor substrate 16 having a stamped solder form 20 positioned in a region 21. Each of contact areas 21 may be a passage extending into substrate 16 to contact an element on the semiconductor chip, or a conductor on the substrate interconnecting with another circuit or contact pad on the semiconductor device. You may. Solder sheet 1
Before punching 7, solder flux is applied to each contact area 21.
It may be applied on top. No flux is applied to the area 22 between the contact areas 21. Although the solder foam is shown as a cube or rectangular form, it may have any desired geometric shape. FIG. 5 shows the substrate 16 and the solder balls 20a after the substrate 16 and the solder form 20 are heated to melt the solder preform and reflow. Only the contact area 21 is wet by the solder, and the molten solder foam 20
Form spheres 20a, which form the contacts of a ball grid array semiconductor device.

The solder plate 17 is of a uniform thickness, for example, 90/10 Sn / Pb or 63
/ 37 Sn / Pb composition. Thickness is based on the height of the contact being used. The basic process will vary slightly depending on the solder composition. Depending on the solder, the solder foam may not completely melt during reflow. Eutectic solder or flux may be placed over the contact area on the substrate. If the solder plate is a eutectic solder, a flux layer is placed on each contact area to remove any oxide on the contact area. The viscosity of the flux is important. If the flux has a high viscosity, it will hold the solder foam on the contact area during reflow. A 325-500 mesh size solder flux can be used.

After punching the solder foam into the substrate contact area, the substrate and the foam are heated to reflow the solder. The substrate and solder foam are heated in a range from about 150 ° C to about 225 ° C. The reflow time is between about 3.5 minutes and 5.5 minutes. FIG. 6 is a side view of one solder ball mounted on a substrate, and FIG. 7 is a side view of a high-temperature solder foam. In FIG. 6, reflowed solder balls 31 are shown, which are made from low temperature solder. Solder ball 31 formed by reflow
Is attached to the substrate 30. There is a solder fillet 32 around the base of the solder ball. In FIG. 7, hot punched foam is used as a contact. During reflow, the low eutectic solder melts and solders the solder foam to the contact area. The heating / reflow process may be performed in an N2 environment. FIG. 7 shows a substrate 35 on which a high-temperature solder foam 36 is attached. Low temperature solder 37 attaches solder form 36 to substrate 35.

FIG. 8 shows a process when a solder ball is formed.
It is shown in The substrate may be prepared (45), for example, by cleaning, applying a solder flux to the contact basin, forming and mounting solder balls thereon. The substrate is heated (46) to melt the solder flux. The preform is soldered in an N2 environment, for example, 63/3
Punching directly from a sheet of 7SnPb solder to the contact area on the substrate. The solder reflows to form solder balls (48). A second embodiment of the method is shown in FIG. A substrate is prepared (50) and a solder flux or solder paste is applied to contact areas on the substrate (51). The preform is connected to a solder sheet, for example, 90/10 SnP
b or punch directly from a solder sheet of the 63 / 37Sn / Pb solder composition onto the substrate. The substrate and then heated to reflow the solder (53) to form the solder contacts. Next, the substrate is cleaned (54).

The following items are disclosed in connection with the above description. 1. A method of forming solder contacts in a contact area of a ball grid array type semiconductor device, comprising: preheating a semiconductor substrate; and punching a plurality of solder forms directly from a sheet of solder material into a contact area of the semiconductor substrate. And reflowing the solder foam by applying heat to form solder contacts on the semiconductor substrate. 2. Item 1. The method according to Item 1, wherein the reflow of the solder is H
2. A method characterized in that the method is performed in an atmosphere. 3. 2. The method according to claim 1, wherein a solder flux is applied to the contact area, and then the solder foam is punched on the substrate. 4. The method of claim 1 wherein the substrate is preheated to a temperature in the range of 150 ° C to 225 ° C. 5. Item 1. The method according to Item 1, wherein the solder sheet is 63
/ 37 Sn / Pb, 90/10 A method characterized by being a solder selected from a Sn / Pb solder composition. 6. Item 2. The method according to Item 1, wherein the substrate and the solder foam are reflowed for a period of 3.5 to 5.5 minutes. 7. A method of forming a solder contact on a contact area of a ball grid array type semiconductor device, comprising: applying a solder flux to a contact area of a semiconductor device substrate; A method comprising punching a plurality of solder forms; and reflowing the solder forms and solder flux by applying heat to form solder contacts on the semiconductor substrate. 8. Item 8. The method according to Item 7, wherein the substrate is preheated to a temperature in a range from 150 ° C to 225 ° C. 9. Item 7. The method according to Item 7, wherein the solder sheet is 63
/ 37 Sn / Pb, 90/10 A method characterized by being a solder selected from a Sn / Pb solder composition. 10. Item 8. The method according to Item 7, wherein the substrate and the solder foam are reflowed for a period of 3.5 to 5.5 minutes. 11. The method of the present invention provides a solder contact (3) at a contact area (32) of a ball grid array semiconductor device (30).
Form 1). The semiconductor (30) is preheated and a plurality of solder foams are punched directly from a sheet of solder material into contact areas (32) on the semiconductor substrate. Heat the board and solder foam to reflow the solder preform,
A solder contact (32) is formed on a semiconductor substrate.

[Brief description of the drawings]

FIG. 1 shows a semiconductor device having a ball grid array type contact.

FIG. 2 shows the semiconductor device under a punch for placing a solder preform on a substrate.

FIG. 3 shows a substrate with a solder preform.

FIG. 4 is a perspective view of a substrate provided with a solder foam.

FIG. 5 shows the substrate and solder balls after solder reflow.

FIG. 6 shows a solder ball attached to a substrate.

FIG. 7 shows a solder foam attached to a substrate.

FIG. 8 is a flow diagram of one embodiment of a process for forming and attaching solder contacts.

FIG. 9 is a flow chart of a second embodiment of a process for making and installing solder balls on a substrate.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Semiconductor device 11 Substrate 12 Solder ball contact 15 Carrier 16 Semiconductor substrate 17 Solder plate 18 Punch 19 Punch die 20 Solder foam 20a Spherical body 21 Contact area 22 Area between contact areas

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Joyce Sue Taiwan 234 Young Ho Lane 32 Ali 1-4F

Claims (1)

[Claims] 1. A method of forming solder contacts in a contact area of a ball grid array type semiconductor device, comprising: preheating a semiconductor substrate; and forming a plurality of solders directly from a sheet of solder material to the contact area of the semiconductor substrate. A method comprising punching a foam and reflowing the solder foam by applying heat to form solder contacts on a semiconductor substrate.