JPH02304941A - Manufacture of semiconductor device - Google Patents

Abstract

PURPOSE:To improve the yield of a device by completely removing a resin by passing the device through two processes of ultrasonic cleaning, in which a NaOH group bulging the resin is contained as a component, in a pre-stage process and a process, in which water pressure is applied, in a post-stage process. CONSTITUTION:In a pre stage process, a NaOH group chemical layer 10 is heated, vibrated by an ultrasonic generator, and passed through the pre-stage process. In a post-stage process, water pressure is applied by an upper hydraulic nozzle 11 and a lower hydraulic nozzle 12, and the chemical is injected onto the whole surfaces of the surface and rear of a semiconductor device. That is, a resin is bulged and liberated from a frame first by ultrasonic-cleaning the device as the pre-stage treatment process of honing, and the resin is removed completely by passing the device through a water pressure process. Accordingly, the resin is taken off perfectly, and the device can be fed stably.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a method for manufacturing a semiconductor device, and particularly to a resin removal step after transfer molding.

[Prior art] As is well known, semiconductor devices are manufactured by die-bonding a semiconductor chip on which an integrated circuit is formed to a lead frame, wiring the element and lead frame with gold wire, and sealing them with resin using an injection molding machine. Semiconductor devices are manufactured by cutting off leads (tie bars) and bending the leads as necessary.

In FIG. 2, reference numeral 5 denotes a semiconductor chip bonded to the center of the bonding bat 3, and the bonding bat and the corresponding leads 4 are connected by wires 6, respectively.

The semiconductor chip 5 to which the leads 4 are connected as described above is integrally sealed with epoxy plastic to form the semiconductor device 1.

Incidentally, as semiconductor devices such as those described above become highly integrated and highly functional, semiconductor chips tend to become larger, have a larger number of bins, and have a finer pitch. In the past, such fine pitch type semiconductor devices were generally packaged with ceramic, but recently, to reduce costs, the quality of the epoxy plastic package (hereinafter referred to as resin package) determines the performance and reliability of the product. It plays a big role in the process.

[Problem to be Solved by the Invention 1] In order to manufacture the above-mentioned semiconductor device, first, as shown in FIG. (At this time, the tie bar cutting process caused some resin to form on both sides of the lead frame.) This resin was removed by passing through a hydraulic honing process. After that, the leads were cut by a forming process and bent as necessary to form a single product into a single semiconductor device.

As a result, problems like the one described above occur.

(1) Since the resin was dropped by water pressure during honing, the lead was bent due to the water pressure, and the lead frame got caught during loading in the forming process, which is a subsequent process, resulting in frequent conveyance failures.

(2) Resin cannot be completely removed by hydraulic honing alone, and during forming, the resin falls onto the mold at the same time as the lead is bent, and the resin adheres to the lead part of the semiconductor device or becomes attached as a condenser. Soldering was a process during semiconductor packaging, and many soldering defects occurred.

(3) The resin remaining on the lead portion of the semiconductor device adhered to the socket used for testing in the final inspection step, resulting in frequent test failures (continuous failures).

The present invention was made to solve the above problems.
The purpose is to stably supply semiconductor devices.

[Means for solving the problem 1: Before honing, use a NaOH-based chemical solution,
A feature is that an ultrasonic cleaning step is provided to make it easier to remove the resin from the semiconductor device after the tie bar is cut.

[Function 1] As a pre-honing treatment step, an ultrasonic cleaning step in a NaOH-based solution is performed to first swell and release the resin from the frame, and then a hydraulic step is performed to completely remove the resin.

[Example 1] A resin package was formed by molding a lead frame on which a semiconductor element was mounted, as shown in FIG. 3. 7 is a resin package, 8 is a tie bar, and 9 is a resin. This resin package is cut with tie bars in the pressing process,
The resin 9 was flowed into the honing process with it still attached. In this honing step, fluidization is performed by a two-step process according to the present invention.

First is the honing device, as shown in Figure 1, the Na
We devised a two-stage conveyance device that has an ultrasonic cleaning process that uses an OH-based chemical as a component, and a second stage process that uses only water pressure to drop the swollen resin. To explain this device in detail, the loader 15 transported one semiconductor device every three seconds. First, in the former step, the NaOH-based chemical liquid layer 10 is heated to about 60° C., vibrated by an ultrasonic generator, and passed through the former step for about 1 minute.Next, in the latter step, the upper water pressure nozzle 11 is heated. Water pressure of 150 kg/cm" was applied from the lower water pressure nozzle I2 and sprayed evenly onto the front and back surfaces of the semiconductor device. At this stage, the resin was completely removed. After this, the drying chamber 14
After blowing air for about 10 minutes, the semiconductor device was placed in the 16 unloader, and the honing process was completed. Here, the semiconductor device fluidized in the honing process had a lead pitch of 0.5 mm and a bottle number of 208 pins, and the falling state of the resin was investigated. To judge the falling situation, if there is even a slight amount of resin attached to the lead,
．． Those that were removed were counted as O. As a result, when counting one semiconductor device out of a plurality of semiconductor devices formed on a conventional lead frame, 168 of the 416 measurement points were determined to be "l". However, this time, the number of locations was significantly reduced to 16. Furthermore, a pilot run before mass production was conducted and the flow rate was 1000 (F). At this time, a sampling inspection was carried out at a rate of 10 (F) out of 100 (F), but no resin residue was detected.

We also inspected the bending of the lead part during hydraulic honing. With the conventional product, complete honing was possible at a water pressure of 750 kg/cm'', but bending occurred, so we worked to find a correlation between water pressure and lead bending, but still, the average bend was around 8 mm. It was inevitable.

However, the results of this test using this method were approximately 1 mm on average.
It has become possible to make a significant improvement.

Furthermore, when this semiconductor device was put into the forming process, which is a post-process, the lead frame was almost no longer caught in the loading section, and problems such as the machine stopping due to poor transportation were eliminated.

In addition, in the present invention, the resin is first swollen using a NaOH-based chemical solution in the first stage, and then the entire surface of the semiconductor device is hit with ultrasonic waves to remove a certain amount of resin, and then the resin can be completely removed by water pressure in the latter stage. Ta.

[Effect of the invention 1 As mentioned above, the honing device has a two-stage structure, that is,
The first step involves ultrasonic cleaning using a NaOH-based component that swells the resin, and the second step involves applying water pressure.
The resin can be completely removed through this process. This has the effect of reducing equipment troubles in post-processes and further improving the yield of semiconductor devices.

[Brief explanation of drawings]

FIG. 1 is a main sectional view of the present invention. FIG. 2 is a diagram showing a conventional semiconductor device. FIG. 3 is a diagram showing an embodiment of the present invention. 1...Semiconductor device 2. Lead frame 3...Die pad 4.・・・Lead 5...Semiconductor chip 6...Wire 7...Resin package 8...Tie bar 9...Resin 10... Ultrasonic cleaning room 11... Upper water pressure nozzle 12...Lower water pressure nozzle 14...Drying room 15...Loader 16...Unloader that's all Applicant: Seiko Epson Corporation Agent: Patent attorney Kisanbe Suzuki (and 1 other person) Figure 1

Claims (2)

[Claims] (1) After die bonding the semiconductor element to the lead frame, wiring the element and lead frame with gold wire, and sealing with resin in the transfer molding process, the honing process removes residual dirt from the resin. A semiconductor device characterized in that when honing the semiconductor device, burrs on the resin are completely removed by flowing through two processes: a cleaning process in which ultrasonic cleaning is performed using NaOH-based or similar chemical solution, and a hydraulic honing process. manufacturing method. (2) The method of manufacturing a semiconductor device according to claim 1, wherein the chemical solution used in the ultrasonic cleaning for removing burrs on the semiconductor device is a chemical solution that causes the resin to swell and release.