Method and jig for tinning single QFN (Quad Flat No-lead) frame product

Abstract

The invention discloses a method and jig for tinning a single QFN (Quad Flat No-lead) frame product, and the method comprises the following steps: fixing the single QFN frame product on a clamp of the jig, and carrying out tinning operation; after tinning is completed, the jig is taken out for cleaning; and observing and the like. The single QFN frame type product is fixed on the clamp, each pin of the single QFN frame type product is conducted, then the whole set of installed jig is installed in a tinning groove, the state of the whole product in the tinning groove is simulated, and finally tinning operation of the single product is completed. The problem that tinning electroplating cannot be achieved due to the fact that pins are not conducted after a product is cut into single pieces is solved, the pin connection state before QFN frame products are cut into single pieces is perfectly simulated, normal tinning process operation is achieved, the tin layer effect after operation is consistent with the appearance / thickness of the whole tinned product, the tinning process requirement of the product is met, and the production efficiency is improved. And the yield of a production line and the reliability of products are effectively improved.

Description

Technical Field

[0001] The present invention relates to the technical field of packaging, and in particular to a method and a fixture for tinning a single QFN frame product. Background Art

[0002] At present, after some high-value QFN products are cut into single finished products, it is found that the tin layer of some finished products has abnormal appearance, resulting in a low yield rate of the finished products. At present, there is no effective way to solve the yield loss caused by abnormal appearance of finished products. Summary of the invention

[0003] The present invention provides a method and a fixture for tinning a single QFN frame product, aiming to solve the above-mentioned problems existing in the background technology.

[0004] The technical solution provided by the present invention is as follows:

[0005] A first aspect of the present invention provides a method for tinning a single QFN frame product, comprising the following steps:

[0006] Provide a jig, load the cut single target product into the jig, each set of the jig is loaded with 2n target products, and after loading, place the jig in the tinning tank of the tinning equipment for tinning operation;

[0007] After the tinning is completed, the jig is taken out and transferred to a cleaning tank of the tinning equipment to remove the residual solution;

[0008] After cleaning, the jig is taken out, and the target product that has been tinned is taken out from the jig, and the tinning condition of each pin of the target product is observed and confirmed. After confirmation, the tinning process of a single target product is completed;

[0009] Wherein, n is a positive integer ≥ 1, and the target product is a QFN frame product.

[0010] Furthermore, after the loading is completed, before the jig is placed in the tinning tank of the tinning equipment for tinning operation, it also includes:

[0011] The conducting pins of the fixture are energized so that each pin of all target products in the fixture is turned on.

[0012] Furthermore, each set of the fixture is loaded with 6 target products.

[0013] A second aspect of the present invention provides a jig, which is applied to the above-mentioned method of single-piece tinning of QFN frame products, comprising:

[0014] Fixture frame, fixture and conducting pins;

[0015] The clamps are symmetrically arranged on both sides of the fixture frame in the horizontal direction, and the conducting pins are connected to the fixture frame at intervals;

[0016] The fixture is a square structure, a mounting groove is provided on the surface of the fixture, screws penetrating the mounting groove are provided on adjacent two sides of the fixture, the target product is placed in the mounting groove, and the screws are used to fasten the target product;

[0017] The number of the clamps is 2n, where n is a positive integer ≥1.

[0018] Furthermore, conductive pads are provided between the target product and the side walls of the mounting slot and the screws.

[0019] Furthermore, the number of the clamps is 6, and the 6 clamps are arranged at equal intervals on both sides of the fixture frame.

[0020] Furthermore, the conducting pins are symmetrically arranged at two ends of the fixture frame.

[0021] Furthermore, before the tinning operation is performed, the conducting pin is connected to each pin of all target products.

[0022] Compared with the prior art, the present invention has the following beneficial effects:

[0023] The present invention provides a method and a jig for tinning a single QFN frame product. The jig is used to fix the single QFN frame product on the fixture through conductive pads and screws, so that each pin of the single QFN frame product is connected, and then the installed set of jigs is installed in the tinning tank to simulate the state of the entire product in the tinning tank, and finally the tinning operation of the single product is completed. The problem that the pins are not conductive after the product is cut into single pieces, resulting in the inability to tinn electroplating, is solved, and the pin connection state of the QFN frame product before being cut into single pieces is perfectly simulated, thereby realizing the normal tinning process operation. The tin layer effect after the operation is consistent with the appearance / thickness of the entire tinned product, meets the product tinning process requirements, and effectively improves the yield rate of the production line and the reliability of the product. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 A flow chart of the method for tinning a single QFN frame product provided by the present invention;

[0025] Figure 2 A schematic diagram of the structure of the fixture provided by the present invention;

[0026] Figure 3 This is the schematic diagram of the tinning electroplating principle mentioned in the present invention.

[0027] The reference numerals are as follows:

[0028] 1- fixture frame, 2- fixture, 3- mounting slot, 4- conducting pin, 5- screw, 6- conducting pad. DETAILED DESCRIPTION

[0029] In order to make the purpose, technical scheme and advantages of the embodiments of the present application clearer, the technical scheme in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the embodiments described below are part of the embodiments of the present application, rather than all of the embodiments. The components of the embodiments of the present application described and shown in the drawings here can be arranged and designed in various different configurations.

[0030] Therefore, the detailed description of the embodiments of the present application provided below in conjunction with the accompanying drawings is intended to represent only selected embodiments of the present application, and is not intended to limit the scope of protection claimed in the present application. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present application.

[0031] In the description of the embodiments of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "set", "install", "connect", and "connect" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection, an electrical connection, or can communicate with each other; it can be directly connected, or indirectly connected through an intermediate medium, and it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the embodiments of the present invention can be understood according to specific circumstances.

[0032] See also Figure 1 The present invention provides a method for tinning a single QFN frame product, comprising the following steps:

[0033] Step S1, providing a jig, loading the cut single target product into the jig, each set of the jig is loaded with 2n target products, and after loading is completed, placing the jig in a tinning tank of a tinning equipment for tinning operation.

[0034] Step S2: After the tinning is completed, the fixture is taken out and transferred to a cleaning tank of the tinning equipment to remove residual liquid medicine.

[0035] Step S3, after cleaning, take out the jig, take out the tinned target product from the jig, observe and confirm the tinning condition of each pin of the target product, and after confirmation, the tinning process of the single target product is completed.

[0036] Wherein, n is a positive integer ≥ 1, and the target product is a single QFN frame product.

[0037] Optionally, in step S1, after loading is completed, before placing the jig in a tinning tank of a tinning equipment for tinning operation, the method further includes:

[0038] The conducting pins of the fixture are energized so that each pin of all target products in the fixture is turned on.

[0039] Optionally, each set of the fixture is loaded with 6 target products.

[0040] Electroplating refers to the process of depositing a metal or alloy layer on the surface of a conductor, such as a metal, by electrolytic reaction in a solution with the help of external direct current.

[0041] Take copper sulfate plating bath as an example (such as Figure 3 as shown):

[0042] The copper sulfate plating solution mainly contains copper sulfate, sulfuric acid and water, and even other additives. Copper sulfate is the source of copper ions (Cu2+). When dissolved in water, copper ions will dissociate. Copper ions will be reduced (gain electrons) at the cathode (workpiece) and deposited into metallic copper. This deposition process will be affected by the conditions of the plating bath, such as copper ion concentration, pH, temperature, stirring, current, additives, etc.

[0043] The main cathode reaction: Cu 2+ (aq)+2e-→Cu(s)

[0044] During the electroplating process, the copper ion concentration in the bath decreases due to consumption, affecting the deposition process. There are two ways to solve this problem: 1. Add copper sulfate to the bath; 2. Use copper as the anode. Adding copper sulfate is more complicated, requiring analysis and calculation. Using copper as the anode is simpler. The main function of the anode is to be a conductor, connecting the circuit loop. But copper has another function as an anode, which is to oxidize (lose electrons) and dissolve into copper ions to replenish the consumption of copper ions.

[0045] Main reaction at anode: Cu(s)→Cu 2+ (aq)+2e-

[0046] Since the entire plating solution is mainly water, a side reaction of water electrolysis to produce hydrogen (at the cathode) and oxygen (at the anode) will also occur.

[0047] Cathode side reaction: 2H3O+(aq)+2e-→H2(g)+2H2O(l)

[0048] Anode side reaction: 6H2O(l)→O2(g)+4H3O+(aq)+4e-

[0049] As a result, the surface of the workpiece is covered with a layer of metallic copper. This is the mechanism of a typical plating bath, but the actual situation is very complicated. Autocatalytic plating and immersion plating.

[0050] Since each pin of a QFN frame product is not conductive after being cut into individual pieces, it is impossible to complete the tinning operation again. The present invention independently develops and designs a complete set of special jigs for tinning individual pieces of the product.

[0051] Fixtures such as Figure 2 As shown, the method for tinning the above-mentioned single QFN frame product includes a jig frame 1, a fixture 2 and a conducting pin 4, wherein the fixture 2 is symmetrically arranged on both sides of the jig frame 1 along the horizontal direction, and the conducting pin 4 is connected to the jig frame 1 at intervals.

[0052] The clamp 2 is a square structure, and a mounting groove 3 is provided on the surface of the clamp 2. Screws 5 penetrating the mounting groove are provided on adjacent sides of the clamp 2. A single QFN frame product is placed in the mounting groove 3, and the screws 5 are used to fasten the single QFN frame product.

[0053] The number of the clamps 2 is 2n, where n is a positive integer ≥1.

[0054] Optionally, conductive pads 6 are arranged between a single QFN frame product and the side walls of the mounting slot 3 and the screws 5, that is, conductive pads 6 are arranged around the single QFN frame product to prevent damage between the product and the side walls of the mounting slot 3 or the screws 5 due to friction.

[0055] In this embodiment, the conductive pad 6 can be a rubber strip wrapped in tin foil.

[0056] Optionally, the number of the clamps 2 is 6, and the 6 clamps 2 are arranged at equal intervals on both sides of the fixture frame 1.

[0057] Optionally, the conducting pins 4 are symmetrically arranged at two ends of the fixture frame 1 .

[0058] Optionally, before the tinning operation is performed, the conducting pin 4 is connected to each pin of all single QFN frame products.

[0059] The specific process of using this fixture is as follows:

[0060] 1. Manually load the cut single product (i.e. QFN frame product) into the installation slot 3 of the above-mentioned fixture, place rubber strips wrapped with tin foil around the product, and then fix the product with two screws 5. Each set of fixture can load 6 products at a time. After loading, it can be directly placed in the tinning tank of the tinning equipment and the tinning operation can be carried out using the process parameters of normal tinning operation.

[0061] 2. After the tinning is completed, take the fixture out of the tinning tank of the tinning equipment and transfer it to the cleaning tank of the tinning equipment to remove the residual medicine.

[0062] 3. After rinsing with clean water, take out the jig from the cleaning tank of the tinning equipment, take out the tinned product from the installation tank 3, and confirm the tinning condition of each pin of the product under a 45x microscope. After confirmation, the tinning process of a single product can be completed.

[0063] The jig provided by the present invention fixes a single QFN frame product on the fixture 2 through a conductive pad 6 and a screw 5, so that each pin of the single QFN frame product is connected, and then the installed set of jigs is installed in the tinning tank to simulate the state of the entire product in the tinning tank, and finally complete the tinning operation of the single product. The problem that the pins are not conductive after the product is cut into single pieces, resulting in the inability to tinn electroplating, is solved, and the pin connection state of the QFN frame product before being cut into single pieces is perfectly simulated, thereby realizing the normal tinning process operation. The tin layer effect after the operation is consistent with the appearance / thickness of the entire tinned product, which meets the product tinning process requirements, and effectively improves the yield rate of the production line and the reliability of the product.

[0064] The above is only the best specific implementation of the present application, but the protection scope of the present application is not limited thereto. Any changes or substitutions within the technical scope disclosed in the present application shall be included in the protection scope of the present application. Therefore, the protection scope of the present application shall be based on the protection scope of the claims.

Claims

1. A method for tinning a single QFN frame product, characterized in that: The following steps are involved: Provide a jig, load the cut single target product into the jig, each set of the jig is loaded with 2n target products, and after loading, place the jig in the tinning tank of the tinning equipment for tinning operation; After the tinning is completed, the jig is taken out and transferred to a cleaning tank of the tinning equipment to remove the residual solution; After cleaning, the jig is taken out, and the target product that has been tinned is taken out from the jig, and the tinning condition of each pin of the target product is observed and confirmed. After confirmation, the tinning process of a single target product is completed; Wherein, n is a positive integer ≥ 1, and the target product is a QFN frame product.

2. The method for tinning a single QFN frame product according to claim 1, characterized in that: After the loading is completed, before the jig is placed in the tinning tank of the tinning equipment for tinning operation, it also includes: The conducting pins of the fixture are energized so that each pin of all target products in the fixture is turned on.

3. The method for tinning a single QFN frame product according to claim 1 or 2, characterized in that: Each set of the fixture is loaded with 6 target products.

4. A jig, used in the method for tinning a single QFN frame product as described in any one of claims 1 to 3, characterized in that: include: Fixture frame, fixture and conducting pins; The clamps are symmetrically arranged on both sides of the fixture frame in the horizontal direction, and the conducting pins are connected to the fixture frame at intervals; The fixture is a square structure, a mounting groove is provided on the surface of the fixture, screws penetrating the mounting groove are provided on adjacent two sides of the fixture, the target product is placed in the mounting groove, and the screws are used to fasten the target product; The number of the clamps is 2n, where n is a positive integer ≥1.

5. The fixture according to claim 4, characterized in that: Conductive pads are arranged between the target product, the side wall of the mounting groove and the screw.

6. The fixture according to claim 5, characterized in that: The number of the clamps is 6, and the 6 clamps are arranged at equal intervals on both sides of the fixture frame.

7. The fixture according to claim 5 or 6, characterized in that: The conducting pins are symmetrically arranged at two ends of the fixture frame.

8. The fixture according to claim 7, characterized in that: Before the tinning operation is performed, the conducting pin is connected to each pin of all target products.

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