JP2014236039A - Semiconductor device manufacturing method - Google Patents

Abstract

An object of the present invention is to suppress the growth of a plated metal film in a portion other than the surface of a lead. A laser beam is irradiated to a resin portion in a dam formed between a plurality of leads exposed from a main body sealing portion formed in a lead frame, and a part of the resin portion in the dam is then radiated. Remove. Thereafter, after heating the lead frame LF, the lead frame LF is subjected to a cleaning process to remove the adhered metal Mvd attached to the resin portion 6dm in the dam. Thereafter, the lead frame LF is immersed in a plating solution to form a metal film on the surfaces of the plurality of leads. [Selection] Figure 18

Description

  The present invention relates to a semiconductor device manufacturing technique, for example, a technique effective when applied to a semiconductor device including a step of forming a plating film on the surface of a lead exposed from a sealing body.

  International Publication No. 2011/004746 (Patent Document 1) describes a method of manufacturing a semiconductor device in which a resin between leads exposed from a sealing body is removed by irradiating a laser.

International Publication No. 2011/004746

  There is a technique of exposing a side surface of a lead by irradiating a resin between a plurality of leads exposed from a sealing body with a laser. If the metal film is formed on the side surface of the lead by plating, the wettability of the solder used when mounting the semiconductor device to the lead is improved, so that the mounting strength of the semiconductor device can be improved.

  The inventor of the present application examined the above technique, and found that in the step of forming a metal film on the surface of the lead after the laser irradiation by plating, a hook-shaped metal easily grows in the vicinity of the surface of the lead.

  Other problems and novel features will become apparent from the description of the specification and the accompanying drawings.

  A method for manufacturing a semiconductor device according to an embodiment includes the following steps. That is, in the manufacturing method of the semiconductor device of one embodiment, the resin part in the dam is irradiated with laser light to the resin part in the dam formed between the plurality of leads exposed from the main body sealing part. A step of removing is included. The method for manufacturing a semiconductor device according to an embodiment includes a step of immersing a lead frame in a plating solution to form a metal film on the surfaces of the plurality of leads. The method for manufacturing a semiconductor device according to an embodiment includes a step of heating and cleaning the lead frame after removing the resin portion in the dam and before forming the metal film. It is.

  According to the above-described embodiment, the growth of the plated metal film can be suppressed at a portion other than the surface of the lead.

It is a top view of the semiconductor device which is one embodiment. It is a bottom view which shows the mounting surface side of the semiconductor device shown in FIG. It is sectional drawing along the AA line of FIG. FIG. 2 is a perspective plan view showing an internal structure of the semiconductor device in a state where the sealing body shown in FIG. 1 is seen through. FIG. 5 is an explanatory diagram showing an assembly flow of the semiconductor device shown in FIGS. It is a top view which shows the whole lead frame structure prepared at the base-material preparation process shown in FIG. FIG. 7 is an enlarged plan view of one of a plurality of device forming units shown in FIG. 6. FIG. 8 is an enlarged plan view showing a state in which a semiconductor chip is mounted on the die pad shown in FIG. 7 via a bonding material. It is an expanded sectional view along the AA line of FIG. FIG. 9 is an enlarged plan view showing a state in which the semiconductor chip shown in FIG. 8 and a plurality of leads are electrically connected via wires. It is an expanded sectional view along the AA line of FIG. FIG. 11 is a plan view showing a state in which a sealing body is formed in the device forming portion of the lead frame shown in FIG. 10. It is an expanded sectional view along the AA line of FIG. FIG. 6 is a cross-sectional view showing a state in which a lead frame is arranged in a molding die and resin is supplied into a cavity in the sealing step shown in FIG. 5. It is an enlarged plan view which shows the state which removed the resin part in a dam shown in FIG. 12, and the resin part in a gate. It is an enlarged plan view of the dam part periphery shown in FIG. FIG. 17 is an enlarged cross-sectional view schematically showing a state in which resin is being removed by laser irradiation in a cross section taken along line AA in FIG. 16. It is explanatory drawing which shows the detail of the adhesion metal removal process shown in FIG. FIG. 17 is an enlarged plan view showing a state in which a mark is formed on the upper surface of the main body sealing portion after the attached metal shown in FIG. 16 is removed. FIG. 20 is an enlarged plan view showing a state in which a metal film is formed on the exposed surface of the lead frame shown in FIG. 19 from the resin. It is explanatory drawing which shows the outline | summary of the plating process by the electroplating method. FIG. 6 is an enlarged plan view showing a state where each device forming unit is singulated in the singulation step shown in FIG. 5. It is an enlarged plan view which shows the state which irradiated the laser beam to the adhesion metal shown in FIG. 16, and removed a part of adhesion metal. It is an enlarged plan view which shows the modification with respect to FIG.

(Description format, basic terms, usage in this application)
In the present application, the description of the embodiment will be divided into a plurality of sections for convenience, if necessary, but these are not independent from each other unless otherwise specified. Regardless of the front and rear, each part of a single example, one is a part of the other, or a part or all of the modifications. In principle, repeated description of similar parts is omitted. In addition, each component in the embodiment is not indispensable unless specifically stated otherwise, unless it is theoretically limited to the number, and obviously not in context.

  Similarly, in the description of the embodiment, etc., regarding the material, composition, etc., “X consisting of A” etc. is an element other than A unless specifically stated otherwise and clearly not in context. It does not exclude things that contain. For example, as for the component, it means “X containing A as a main component”. For example, “silicon member” is not limited to pure silicon, but includes a SiGe (silicon-germanium) alloy, other multi-component alloys containing silicon as a main component, and other additives. Needless to say, it is also included. Moreover, even if it says gold plating, Cu layer, nickel / plating, etc., unless otherwise specified, not only pure materials but also members mainly composed of gold, Cu, nickel, etc. Shall be included.

  In addition, when a specific number or quantity is mentioned, a numerical value exceeding that specific number will be used unless specifically stated otherwise, unless theoretically limited to that number, or unless otherwise clearly indicated by the context. There may be a numerical value less than the specific numerical value.

  Moreover, in each figure of embodiment, the same or similar part is shown with the same or similar symbol or reference number, and description is not repeated in principle.

  In the accompanying drawings, hatching or the like may be omitted even in a cross section when it becomes complicated or when the distinction from the gap is clear. In relation to this, when it is clear from the description etc., the contour line of the background may be omitted even if the hole is planarly closed. Furthermore, even if it is not a cross section, hatching or a dot pattern may be added in order to clearly indicate that it is not a void or to clearly indicate the boundary of a region.

(Embodiment)
The technology described in the following embodiments can be applied to various package type semiconductor devices in which the leads are exposed on the lower surface side of the sealing body. In this embodiment, as an example, the present invention is applied to a QFN (Quad Flat Non-leaded package) type semiconductor device in which a plurality of leads which are external terminals are exposed from the sealing body on the lower surface (mounting surface) of the sealing body. The embodiment described above will be taken up and described. 1 is a top view of the semiconductor device of the present embodiment, FIG. 2 is a bottom view showing the mounting surface side of the semiconductor device shown in FIG. 1, and FIG. 3 is a cross-sectional view taken along line AA of FIG. . FIG. 4 is a perspective plan view showing the internal structure of the semiconductor device in a state where the sealing body shown in FIG. 1 is seen through.

<Semiconductor device>
First, the outline | summary of a structure of the semiconductor device 1 of this Embodiment is demonstrated using FIGS. The semiconductor device 1 according to the present embodiment is mounted on a die pad (chip mounting portion, tab) 2 (see FIGS. 2 to 4) and an adhesive 7 (see FIGS. 3 and 4) on the die pad 2. And a semiconductor chip 3 (see FIGS. 3 and 4). Further, the semiconductor device 1 includes a plurality of leads (terminals, external terminals) 4 arranged around the semiconductor chip 3 (die pad 2) and a plurality of pads (electrodes, bonding pads) PD of the semiconductor chip 3 (see FIG. 4). And a plurality of leads 4 are electrically connected to each other and a plurality of wires (conductive members) 5 (see FIG. 4). A plurality of suspension leads TL are connected to the die pad 2. The semiconductor device 1 also includes a semiconductor chip 3, a plurality of wires 5, and a sealing body (resin body) 6 that seals part of the plurality of leads 4.

<Appearance structure>
First, the external structure of the semiconductor device 1 will be described. The planar shape of the sealing body (resin body) 6 shown in FIG. The sealing body 6 has an upper surface 6a, a lower surface (back surface, mounting surface) 6b (see FIG. 2) opposite to the upper surface 6a, and a side surface 6c located between the upper surface 6a and the lower surface 6b. ing. As shown in FIG. 3, the side surface 6c is an inclined surface that is not orthogonal to the upper surface 6a and the lower surface 6b.

  Here, the corner portion 6p of the sealing body 6 refers to a peripheral area of a corner that is an intersection of any two sides (two main sides) intersecting among the four sides (four main sides) of the sealing body 6. Contains. Strictly speaking, as shown in FIGS. 1 and 2, the corner 6 p of the sealing body 6 is partially chamfered, so that the intersection of the main sides is more than the corner 6 p of the sealing body 6. Is also arranged outside. However, since the chamfered portion is sufficiently small compared to the length of the main side, in the present application, the center of the chamfered portion is regarded as the corner of the sealing body 6 for description. Specifically, the corner portion 6p is a region indicated by a dot pattern in FIGS. 1 and 2, and its boundary is defined as follows. That is, in the semiconductor device 1, a plurality of leads 4 are arranged along the four sides of the sealing body 6. Of the plurality of leads 4 arranged along each side, a region up to the lead 4 arranged next to the corner (center of the chamfered portion) of the sealing body 6 is defined as a corner portion. In this application, when it is described as the corner 6p of the sealing body 6 or the corner of the cavity, it is used as the same meaning and contents as described above, except where it is clearly stated that it is used with a different meaning and contents.

  As shown in FIGS. 1 and 2, in the semiconductor device 1, a plurality of leads 4 are arranged along each side (each main side) of the sealing body 6 having a square planar shape. The plurality of leads 4 are each made of a metal material, and in the present embodiment, for example, a metal film made of nickel (Ni) on the surface of a base material made of, for example, copper (Cu) or copper (Cu) (not shown). It consists of a laminated metal member formed. In the example shown in FIGS. 1 and 2, for example, a plurality of leads 4 having a width of 0.2 mm are arranged along each side at an arrangement pitch (inter-center line distance) of 0.5 mm. Further, the thickness of the lead 4 is, for example, 0.2 mm.

  The lower surfaces of the leads 4 (the lower surface of the inner portion 4 i and the lower surface of the outer portion 4 o shown in FIG. 3) are exposed from the sealing body 6 on the lower surface 6 b of the sealing body 6. Further, some of the leads 4 (outer portion 4 o) are also exposed from the side surface 6 c of the sealing body 6. Specifically, as shown in FIG. 3, a part (outer portion 4 o) of each of the plurality of leads 4 formed along each side of the sealing body 6 is a side surface 6 c (side) of the sealing body 6. Projecting outward from In the example shown in FIG. 3, it protrudes outward from the side surface 6c of the sealing body 6 by about 0.3 mm, for example.

  Although details will be described later, when the semiconductor device 1 is mounted on a mounting board (not shown), the leads 4 and terminals on the mounting board side are electrically connected via a connecting material such as solder. Therefore, by exposing the plurality of leads 4 from the side surface 6c in addition to the lower surface 6b of the sealing body 6, the bonding area between the connecting material and the lead 4 is increased, so that the bonding strength can be improved.

  In addition, as shown in FIGS. 1 to 3, the surface of the exposed portion of the plurality of leads 4 (and the lower surface, the upper surface, and the side surface of the outer portion 4o) is connected to the lead 4 and the solder material (joining material) during mounting. In order to improve the property (wetting property), for example, a metal film SD made of solder is formed. Thereby, when a solder material is used as a connecting material at the time of mounting, the wettability of the solder material can be further improved.

  The metal film SD (solder material) of the present embodiment is made of, for example, a so-called lead-free solder that does not substantially contain lead (Pb), for example, only tin (Sn), tin-bismuth (Sn-Bi). Or tin-copper-silver (Sn-Cu-Ag). Here, the lead-free solder means a lead (Pb) content of 0.1 wt% or less, and this content is defined as a standard of the RoHS (Restriction of Hazardous Substances) directive. Hereinafter, in the present embodiment, when a solder material or a solder component is described, it indicates lead-free solder unless otherwise specified.

  As shown in FIG. 2, the lower surface 2 b of the die pad 2 is exposed from the sealing body 6 on the lower surface 6 b of the sealing body 6. That is, the semiconductor device 1 is a die pad exposed type (tab exposed type) semiconductor device. The die pad 2 is made of a metal material having a higher thermal conductivity than the sealing body 6. In the example shown in FIG. 2, for example, nickel (Cu) is formed on the surface of a base material made of copper (Cu) or copper (Cu). It consists of a laminated metal member on which a metal film (not shown) made of Ni) is formed. As described above, the die pad exposed semiconductor device is a semiconductor in which the die pad 2 is not exposed by exposing a metal member (die pad 2) such as copper (Cu) having a higher thermal conductivity than that of the sealing body 6. Compared with the device, the heat dissipation of the package can be improved. 2 and 3, the lower surface 2b of the die pad 2 is formed with a metal film SD that functions as a bonding material at the time of mounting, and covers the lower surface of the substrate. The metal film SD is a plating film (solder film) formed by, for example, a plating method as described above.

  As shown in FIGS. 1 and 2, in the semiconductor device 1, a part of the suspension lead TL is exposed from the sealing body 6 outside the corner portion 6 p of the sealing body 6. Specifically, as shown in FIG. 4, one end portion of the suspension lead TL is connected to the die pad 2 (formed integrally), and the other end portion (exposed portion 11) is exposed from the sealing body 6. ing. Since the suspension leads TL are formed integrally with the die pad 2, the suspension leads TL are made of the same metal material as that of the die pad 2 including the exposed portions (fins and corner leads) 11. By exposing a part of the suspension lead TL from the sealing body 6 in this way, when the semiconductor device 1 is mounted on a mounting board (not shown), the exposed portion 11 can be joined to a terminal on the mounting board side. . Thereby, the mounting strength of the semiconductor device 1 can be improved. In the example shown in FIGS. 1 to 3, a metal film SD made of, for example, solder is formed on the exposed surface of the exposed portion 11. Thereby, the mounting strength of the semiconductor device 1 can be further improved. However, as a modification, a structure in which the exposed portion of the suspension lead TL as shown in FIG. 2 is not provided can be employed.

<Internal structure>
Next, the internal structure of the semiconductor device 1 will be described. As shown in FIG. 4, the upper surface (chip mounting surface) 2 a of the die pad 2 has a quadrangular shape in plan view. In the present embodiment, for example, it is a square. In the example shown in FIG. 4, the outer size (planar size) of the die pad 2 is larger than the outer size of the semiconductor chip 3 (planar size of the back surface 3b). As described above, the semiconductor chip 3 is mounted on the die pad 2 having an area larger than the outer size, and the lower surface 2b of the die pad 2 is exposed from the sealing body 6, thereby improving heat dissipation.

  Further, as shown in FIG. 4, the semiconductor chip 3 is mounted on the die pad 2. The semiconductor chip 3 is mounted at the center of the die pad 2. As shown in FIG. 3, the semiconductor chip 3 is mounted on the die pad 2 via the adhesive 7 with the back surface 3 b facing the top surface 2 a of the die pad 2. That is, it is mounted by a so-called face-up mounting method in which the surface (back surface 3b) opposite to the surface (main surface) 3a on which the plurality of pads PD are formed is opposed to the chip mounting surface (upper surface 2a). This adhesive material 7 is an adhesive material for die-bonding the semiconductor chip 3, and for example, an epoxy-based thermosetting resin can be used.

  As shown in FIG. 4, the planar shape of the semiconductor chip 3 mounted on the die pad 2 is a quadrangle. In the present embodiment, for example, it is a square. As shown in FIG. 3, the semiconductor chip 3 includes a front surface (main surface, upper surface) 3a, a back surface (main surface, lower surface) 3b opposite to the front surface 3a, and a space between the front surface 3a and the back surface 3b. And a side surface 3c. As shown in FIGS. 3 and 4, a plurality of pads (bonding pads) PD are formed on the surface 3a of the semiconductor chip 3, and in the present embodiment, the plurality of pads PD are provided on each surface 3a. It is formed along the side. Although not shown, the main surface of the semiconductor chip 3 (specifically, a semiconductor element formation region provided on the upper surface of the base material (semiconductor substrate) of the semiconductor chip 3) includes a plurality of semiconductor elements (circuit elements). Is formed. In addition, the plurality of pads PD are connected to each other via wiring (not shown) formed in a wiring layer disposed inside the semiconductor chip 3 (specifically, between the surface 3a and a semiconductor element formation region not shown). It is electrically connected to the semiconductor element.

  The semiconductor chip 3 (specifically, the base material of the semiconductor chip 3) is made of, for example, silicon (Si). In addition, an insulating film is formed on the surface 3a to cover the base material and wiring of the semiconductor chip 3, and each surface of the plurality of pads PD is exposed from the insulating film in the opening formed in the insulating film. doing. The pad PD is made of metal, and in the present embodiment, is made of, for example, aluminum (Al) or an alloy layer mainly composed of aluminum (Al).

  As shown in FIG. 4, for example, a plurality of leads 4 made of the same copper (Cu) as the die pad 2 are arranged around the semiconductor chip 3 (specifically, around the die pad 2). A plurality of electrode pads (bonding pads) PD formed on the surface 3a of the semiconductor chip 3 are composed of a plurality of leads 4 (inner portions 4i) positioned inside the sealing body 6 and a plurality of wires (conductive members). ) 5 are electrically connected to each other. The wire 5 is made of, for example, gold (Au), and a part (for example, one end) of the wire 5 is bonded to the pad PD, and the other part (for example, the other end) is bonded to the bonding region of the inner portion 4i. Has been. In addition, although illustration is abbreviate | omitted, the plating film is formed in the surface (specifically the surface of the plating film which consists of nickel (Ni)) of the bonding area | region of the inner part 4i. The plating film is made of, for example, silver (Ag) or gold (Au). By forming a plating film made of silver (Ag) or gold (Au) on the surface of the bonding region of the inner portion 4i, the bonding strength with the wire 5 made of gold (Au) can be improved.

  As shown in FIG. 4, a plurality of suspension leads TL are connected (linked) to the die pad 2. Each of the suspension leads TL has one end connected to a corner (corner) of the die pad 2. Each of the plurality of suspension leads TL has the other end extending toward the corner 6p (see FIG. 1) of the sealing body 6 and exposed from the sealing body 6 outside the corner 6p.

  By extending the suspension leads TL toward the corners 6p of the sealing body 6 (see FIG. 1), the arrangement of the leads 4 arranged along each side (each main side) of the sealing body 6 is changed. Since it can arrange | position without inhibiting, the number of the leads 4, ie, the number of terminals of the semiconductor device 1, can be increased.

  Although not shown, the portion (sealing portion) connecting the die pad 2 and the exposed portion 11 of the suspension lead TL is half-etched from the lower surface side, and the lower surface side is also sealed by the sealing body 6. It is sealed. Thereby, since the suspension lead TL can be fixed in the sealing body 6, it is possible to prevent the suspension lead TL from falling off the sealing body 6.

<Manufacturing process of semiconductor device>
Next, the manufacturing process of the semiconductor device 1 shown in FIGS. 1 to 4 will be described. The semiconductor device 1 in the present embodiment is manufactured along the assembly flow shown in FIG. FIG. 5 is an explanatory diagram showing an assembly flow of the semiconductor device shown in FIGS.

1. Substrate preparation step;
First, as a base material preparation step shown in FIG. 5, a lead frame (base material) LF as shown in FIG. 6 is prepared. 6 is a plan view showing the overall structure of the lead frame prepared in the base material preparation step shown in FIG. 5, and FIG. 7 is an enlarged plan view of one of the plurality of device forming portions shown in FIG.

  The lead frame LF prepared in this step includes a plurality of device forming portions (device region, product forming portion, product region) LFd inside the outer frame LFf. In the example shown in FIG. 6, the lead frame LF includes 14 device forming portions LFd in the row direction and 5 device forming portions LFd arranged in a matrix, and includes a total of 70 device forming portions LFd. The lead frame LF is made of metal, and in this embodiment, for example, a metal film (not shown) made of nickel (Ni) is formed on the surface of a base material made of copper (Cu) or copper (Cu), for example. A laminated metal film.

  In addition, frame portions LFs are arranged around each device forming portion LFd so as to surround each device forming portion LFd. Further, as shown in FIG. 7, the frame portion LFs is formed so as to surround the plurality of leads 4. In a sealing step (see FIG. 5) described later, a part of the frame portion LFs is supplied as a resin supply path. Further, the frame portion LFs is a region to be cut in an individualization step (see FIG. 5) described later.

  Further, as shown in FIG. 7, a die pad 2 having a quadrangular shape in plan view is formed at the center of each device forming portion LFd. One end of the suspension lead TL is connected to each of the four corners of the die pad 2 and is arranged so as to extend toward the corner of the device forming portion LFd. The other end of the suspension lead TL is connected to the frame portion LFs. The die pad 2 is connected to the frame portion LFs via the suspension lead TL, and is supported by the frame portion LFs.

  A plurality of leads 4 are formed around the die pad 2 between the plurality of suspension leads TL. Further, the plurality of leads 4 are respectively connected to the frame portion LFs arranged on the outer side of the plurality of leads 4 with respect to the die pad 2. The frame portion LFs is formed integrally with the plurality of leads 4, the suspension leads TL, and the die pad 2.

  Further, as shown in FIG. 7, a dam portion Ldm which is a gap portion surrounded by the side surface of one lead 4, the other lead 4, and the frame portion LFs is formed between adjacent leads 4. ing. The dam portion Ldm is formed between each of the plurality of leads 4.

2. Semiconductor chip mounting process;
Next, as a semiconductor chip mounting step shown in FIG. 5, the semiconductor chip 3 is mounted on the die pad 2 with an adhesive 7 as shown in FIGS. 8 is an enlarged plan view showing a state in which a semiconductor chip is mounted on the die pad shown in FIG. 7 via a bonding material, and FIG. 9 is an enlarged cross-sectional view taken along the line AA in FIG.

  In the example shown in FIG. 9, a so-called face-up mounting method in which the back surface 3 b (surface opposite to the front surface 3 a on which a plurality of pads PD are formed) of the semiconductor chip 3 is mounted facing the top surface 2 a of the die pad 2. Installed in. As shown in FIG. 8, the semiconductor chip 3 is mounted at the center of the die pad 2 so that each side of the surface 3 a is arranged along each side of the die pad 2.

  In this step, for example, the semiconductor chip 3 is mounted via an adhesive 7 that is an epoxy-based thermosetting resin. The adhesive 7 is a paste material that has fluidity before being cured (thermoset). is there. When the paste material is used as the adhesive material 7 in this way, first, the adhesive material 7 is applied onto the die pad 2, and then the back surface 3 b of the semiconductor chip 3 is adhered to the upper surface 2 a of the die pad 2. Then, after bonding, when the adhesive 7 is cured (for example, heat treatment is performed), the semiconductor chip 3 is bonded and fixed onto the die pad 2 via the adhesive 7 as shown in FIG.

  Further, in this step, the adhesive 7 and the semiconductor chip 3 are respectively disposed on the die pad 2 provided in each of the plurality of device forming portions LFd. Then, the semiconductor chip 3 is mounted on each device forming portion LFd.

  In the present embodiment, an embodiment in which a paste material made of a thermosetting resin is used for the adhesive material 7 has been described, but various modifications can be applied. For example, instead of a paste material, an adhesive material, which is a tape material (film material) having adhesive layers on both sides, is attached in advance to the back surface 3b of the semiconductor chip 3, and the semiconductor chip 3 is placed on the die pad 2 via the tape material. May be installed.

3. Wire bonding process;
Next, as a wire bonding step shown in FIG. 5, a plurality of pads PD and a plurality of leads 4 of the semiconductor chip 3 are connected via a plurality of wires (conductive members) 5 as shown in FIGS. 10 and 11. , Each electrically connected. 10 is an enlarged plan view showing a state where the semiconductor chip shown in FIG. 8 and a plurality of leads are electrically connected via wires, and FIG. 11 is an enlarged cross-sectional view taken along line AA in FIG. is there.

  In this step, for example, the lead frame LF in which the semiconductor chip 3 is mounted on the die pad 2 of each device forming unit LFd is disposed on the heat stage (lead frame heating table) HS. Then, the pad PD of the semiconductor chip 3 and the lead 4 are electrically connected via the wire 5. In the present embodiment, the wire 5 is connected by a so-called nail head bonding method in which, for example, the wire 5 is supplied via a capillary (not shown), and the wire 5 is bonded using ultrasonic waves and thermocompression bonding.

  A plating film made of, for example, silver (Ag) or gold (Au) is formed on a part of the lead 4 (bonding region disposed at the tip of the inner part 4i), and a part of the wire 5 is The lead 4 is electrically connected through this plating film. The wire 5 is made of metal, and in this embodiment, is made of, for example, gold (Au).

  In the example shown in FIG. 11, after connecting a part (end part) of the wire to the pad PD of the semiconductor chip 3, the other part of the wire 5 is bonded to the bonding region in the lead 4 (part of the upper surface 4 a of the lead 4). The wires are connected by a so-called positive bonding method. Further, the lower surface 4b located on the opposite side of the bonding region is in contact with the mounting surface HSa of the heat stage HS.

  In this step, the wires 5 are bonded to the plurality of leads 4 provided in the plurality of device forming portions LFd, respectively. Thereby, in each device formation part LFd, the semiconductor chip 3 and the plurality of leads 4 are electrically connected via the plurality of wires 5.

4). Sealing step;
Next, as a sealing step shown in FIG. 5, as shown in FIGS. 12 and 13, a sealing body 6 is formed, the semiconductor chip 3 (see FIG. 13), a plurality of wires 5 (see FIG. 13), and Each inner part of the plurality of leads 4 (see FIG. 13) is sealed with resin. 12 is a plan view showing a state where a sealing body is formed in the device forming portion of the lead frame shown in FIG. 10, and FIG. 13 is an enlarged cross-sectional view taken along line AA of FIG. FIG. 14 is a cross-sectional view showing a state where the lead frame is arranged in the molding die and the resin is supplied into the cavity in the sealing step shown in FIG.

  In this step, as shown in FIG. 13, the semiconductor chip 3 mounted in the device formation portion LFd, a part of the lead 4 provided in the device formation portion LFd, and the lead 4 and the semiconductor chip 3 are electrically connected. A sealing body 6 for sealing the wire 5 with resin is formed. In the example shown in FIG. 13, the sealing body 6 is formed so that the lower surfaces 4b of the plurality of leads 4 provided in the device forming portion LFd are exposed. In the example shown in FIG. 13, the sealing body 6 is formed so that the lower surface 2b of the die pad 2 provided in each device forming portion LFd is exposed.

  In this step, for example, after the lead frame LF is sandwiched between the molding dies 50 shown in FIG. 14, a softened resin is press-fitted into the molding dies 50 and then cured by applying heat to the resin. The sealing body 6 is formed by a so-called transfer mold method.

  As shown in FIG. 14, the molding die 50 includes an upper die (die) 51 disposed above the lead frame LF and a lower die (die) 52 disposed below the lead frame LF. The upper mold 51 includes a clamp surface (mold surface, pressing surface, surface) 51a for pressing the lead frame LF, and a cavity (recessed portion) 51b formed inside the clamp surface 51a. The lower mold 52 includes a clamp surface (mold surface, pressing surface, surface) 52a that is disposed so as to face the clamp surface 51a and presses the lead frame LF. In this embodiment, since a QFN type package is manufactured, a cavity is not formed inside the clamp surface 52a of the lower mold 52, but as a modification, a cavity is also formed in the lower mold 52. It can also be applied to the embodiment.

  In the sealing step, a sealing resin is press-fitted into the cavity 51b, and the inner portions of the semiconductor chip 3, the plurality of wires 5, and the plurality of leads 4 are sealed. And the main body sealing part (main body part) 6mb of the sealing body 6 shown in FIG. 12 is formed by thermosetting the resin supplied to the cavity 51b.

  In the example shown in FIGS. 14 and 15, a resin film (film material) 53 is disposed between the lead frame LF and the lower mold 52. A pressing force from the clamp surface 52 a of the lower mold 52 is applied to the lower surface side (back surface side, mounting surface side) of the lead frame LF via the resin film 53. For this reason, as shown in FIG. 14, the lower surface 4 b of the lead 4 and the lower surface 2 b of the die pad 2 are easily adhered to the resin film 53. By bringing the resin film 53 into close contact, it is possible to suppress the sealing resin from entering the lower surface 4b of the lead 4 and the lower surface 2b of the die pad 2. That is, the lower surface 4b of the lead 4 and the lower surface 2b of the die pad 2 can be exposed.

  Further, the molding die 50 of the present embodiment includes a plurality of cavities 51b, and the sealing body 6 is formed in a state in which each of the plurality of cavities 51b is disposed so as to correspond to the plurality of device forming portions LFd. The so-called individual sealing method is applied. In other words, in the sealing process of the present embodiment, the clamp surface 51a of the upper mold 51 of the molding die 50 shown in FIG. 14 is pressed around each of the plurality of device forming portions LFd.

  In this case, in addition to the main body sealing portion 6mb formed in the cavity 51b, as shown in FIG. 12, in the dam portion Ldm (see FIG. 7) which is a gap surrounded by the adjacent lead 4 and the frame portion LFs. The embedded resin part 6dm in the dam is formed. An in-gate resin portion 6g is formed in the gate portion Lg which is a resin supply port. Further, a vent-inside resin portion 6vt is formed in a vent portion that is disposed diagonally of the gate portion and discharges gas and excess resin in the cavity 51b (see FIG. 14) to the outside.

  Further, in the present embodiment, a gate portion Lg (see FIG. 12) is provided on the side of the cavity 51b shown in FIG. 14, and the resin is supplied by a so-called side gate method in which resin is supplied from the gate portion Lg into the cavity 51b. Supply. Also, as shown in FIG. 12, the frame portion LFs around the device forming portion LFd is a resin supply path to the gate portion Lg. Therefore, in this step, the runner sealing portion 6r is formed in the resin supply path provided in the frame portion LFs.

  In the example shown in FIG. 12, the spacer resin portion 6sp is connected to the vent internal resin portion 6vt. In the sealing process of the present embodiment, a flow cavity (not shown) is arranged between the adjacent device forming portions LFd separately from the cavity 51b shown in FIG. 14, and the cavity and the cavity 51b are connected to the vent portion. Connected through. As a result, the resin filled in the cavity 51b is further supplied into the flow cavity via the vent portion. Then, the spacer resin portion 6sp as shown in FIG. 12 can be formed by following the shape of the flow cavity.

  As shown in FIG. 5, after this step, a step of removing the runner sealing portion 6r shown in FIG. 12 (gate break step) is performed. In addition, after the gate breaking step, a heat treatment is performed on the plurality of lead frames LF on which the sealing body 6 is formed, and the resin constituting the sealing body 6 is fully cured (main body sealing portion baking step). I do. When performing the main body sealing portion baking process, the resin is temporarily cured by heating the resin through a molding die in the stage of the sealing process. As a modification, the resin can be fully cured with a molding die, but it takes time until the resin is fully cured. Therefore, it is preferable to house a plurality of lead frames LF in a heating furnace (not shown) and perform heat treatment in a batch from the viewpoint of improving manufacturing efficiency. Although details will be described later, the above-described main body sealing portion baking step is distinguished from the baking step described in the attached metal removing step shown in FIG.

5. Resin removal process (laser irradiation process);
Next, as a resin removal step shown in FIG. 5, the in-dam resin portion 6dm shown in FIG. 12 is removed. FIG. 15 is an enlarged plan view showing a state where the resin part in the dam and the resin part in the gate shown in FIG. 12 are removed. FIG. 16 is an enlarged plan view around the dam portion shown in FIG. FIG. 17 is an enlarged cross-sectional view schematically showing a state in which the resin is being removed by laser irradiation in the cross section taken along the line AA of FIG.

  In this step, as shown in FIG. 17, the resin portion 6 dm in the dam is removed by irradiating the laser beam Lz to a portion of the lead frame LF other than the main body sealing portion 6 mb (see FIG. 16). . Specifically, as shown in FIG. 17, a laser irradiation device LS, which is a light source of the laser beam Lz, is arranged on the upper surface LFa side of the lead frame LF, that is, on the chip mounting surface side opposite to the mounting surface, and the upper surface LFa. The laser beam Lz is irradiated from the side toward the dam portion Ldm.

  In the present embodiment, the irradiation position of the lead frame LF is scanned (sequentially changed) while irradiating the laser beam Lz. For example, in the present embodiment, the periphery of the main body sealing portion 6mb shown in FIG. 15 is circulated in a state where the laser light Lz (see FIG. 17) is output. The irradiation position scanning method can be performed by moving either one or both of the laser irradiation apparatus LS as the light source and the lead frame LF as the irradiation object.

  As described above, in the method of scanning the irradiation position in a state where the laser beam Lz is output, the laser beam Lz is irradiated so as to straddle the adhesion interface between the lead 4 and the resin portion 6 dm in the dam. Leakage can be suppressed and the removal performance of the resin part 6dm in the dam can be improved. Further, the irradiation operation can be performed more easily than when the laser beam Lz is selectively irradiated only on the resin portion 6dm in the dam.

  The laser light Lz is, for example, a YAG laser using yttrium, aluminum, and garnet crystals, and is a near infrared light having a fundamental wavelength of 1064 nm (nanometers). Further, the laser beam Lz has an output of about 40 W (watts), for example, and is output by a pulse operation of about 20 kHz (kilohertz). The focus of the laser beam Lz is adjusted to the surface of the resin part that is the removal target. Further, the line width and the laser interval of the laser beam Lz are, for example, about 40 μm (micrometers) and, for example, at a scanning speed of about 300 mm / second (300 millimeters per second), the main body sealing portion 6 mb shown in FIG. Scan the surroundings. The number of scans is, for example, about 3 times.

  Near-infrared light becomes a heat source for heating the irradiated object, and the resin that is the irradiated object can be removed thermally. The resin part 6dm in the dam, which is an object to be removed in this step, is an insulating resin body mainly composed of many filler particles such as a thermosetting resin such as an epoxy resin, a curing agent, and silica. In addition to the above, it contains many secondary raw materials. Therefore, by irradiating the laser beam Lz that is near infrared light, the object to be removed can be removed by a thermal action with little material selectivity.

  Each of the plurality of leads 4 has a cross section cut in a direction orthogonal to the extending direction, and the width of the upper surface 4a is smaller than the width of the lower surface 4b as shown in FIG. 17, and the side surface 4c1 and the side surface 4c2 Is a trapezoidal cross-sectional shape with an inclined surface. Thus, by making the side surfaces 4c1 and 4c2 of the lead 4 into inclined surfaces, in this step, even when the laser light Lz is irradiated from a direction perpendicular to the upper surface 4a, for example, the side surfaces 4c1 and 4c2 are irradiated. It becomes easy. As a result, the removal reliability of the resin part 6dm in the dam is improved. Further, in this step, if the in-dam resin portion 6dm can be surely removed and the side surfaces 4c1 and 4c2 can be exposed, a metal film can be formed so as to cover the side surfaces 4c1 and 4c2 in the plating step shown in FIG. Therefore, when the semiconductor device is mounted, the wettability between the lead 4 and the solder material can be improved.

  Although illustration is omitted, from the viewpoint of improving the ease of laser irradiation, as a modification to FIG. 17, the width of the upper surface 4a is larger than the width of the lower surface 4b, and the side surface 4c1 and the side surface 4c2 are inclined surfaces. An inverted trapezoidal cross-sectional shape is also conceivable. In this case, the laser irradiation device LS is disposed on the lower surface LFb side of the lead frame LF, that is, on the mounting surface side, and the laser beams Lz are irradiated from the lower surface LFb side toward the dam portion Ldm, thereby lasers the side surfaces 4c1 and 4c2. The light Lz is easily irradiated.

  Further, in this step, most of the resin portion 6dm in the dam is removed, but in order to prevent the main body sealing portion 6mb from being damaged due to erroneous irradiation of the laser light Lz or thermal influence, as shown in FIG. Laser irradiation is performed so as to leave a part of the main body sealing portion 6mb of the resin portion 6dm in the dam. Since the side surfaces 4c1 and 4c2 of the lead 4 are not exposed in the portion where the resin portion 6dm in the dam remains, a metal film cannot be formed in the plating step shown in FIG. However, if most of the in-dam resin portion 6dm is removed, there is no significant influence from the viewpoint of improving the mounting strength of the semiconductor device after completion.

  Here, as an embodiment different from the present embodiment, the metal described in FIG. 3 on the exposed surface of the outer portion 4o of the lead 4 after exposing the side surface of the outer portion 4o of the lead 4 in this step. An embodiment in which the plating step for forming the film is performed immediately is conceivable. However, according to the study by the present inventor, it was found that when the plating process is performed immediately after this process, a hook-shaped metal grows in the vicinity of the lead 4.

  When this saddle-shaped metal was examined in more detail, in many cases, the saddle-shaped metal was generated near the boundary between the lead 4 and the main body sealing portion 6mb shown in FIG. 16, and remained on the main body sealing portion 6mb side. It grows along the edge of the resin part 6dm in the dam. Therefore, depending on the degree of growth of the bowl-shaped metal, the adjacent leads 4 may be electrically connected to each other. Moreover, there is a concern that when the bowl-shaped metal falls, it becomes a conductive foreign matter.

  For this reason, when the cause of the occurrence of the saddle-like foreign matter was investigated, the saddle-like foreign matter is considered to be caused by the following causes. As described above, in the present embodiment, irradiation is performed in a state in which the laser beam Lz (see FIG. 17) is output from the viewpoint of improving the removal performance of the resin portion 6dm in the dam or performing the resin removal step efficiently. Scan position. For this reason, in this process, the laser beam Lz is irradiated to the lead 4 as well as the resin portion 6mb in the dam.

  However, when the lead 4 is irradiated with the laser light Lz, the metal material constituting the lead 4 shown in FIG. 16 scatters (vaporizes) around the lead 4 and adheres (deposits) on the resin portion 6dm in the dam. Hereinafter, in the description of the present embodiment, a metal material that adheres (deposits) to the in-dam resin portion 6dm due to laser irradiation is referred to as an attached metal Mvd. In the case where the lead 4 is made of a material mainly composed of copper (Cu), the adhesion metal Mvd has a composition substantially close to that of pure copper. FIG. 16 shows an example in which the attached metal Mvd is formed along the outer peripheral side of the in-dam resin portion 6dm. However, the attached metal Mvd may be formed in the main body sealing portion 6mb. However, as the distance from the lead 4 is shorter, more metal material is easily formed. Therefore, as shown in FIG. 16, the attached metal Mvd is formed in a band shape along the outer peripheral side of the in-dam resin portion 6dm. There are many cases.

  When the lead frame LF is immersed in a plating solution and the electroplating process is performed with the attached metal Mvd attached, a metal film is formed on the exposed surface of the lead 4 and metal is also formed on the exposed surface of the attached metal Mvd. Precipitate. It is considered that the plating metal deposited on the adhered metal Mvd is the above-described bowl-shaped metal. Further, as described above, the attached metal Mvd may adhere to the main body sealing portion 6mb. However, when the metal film is grown by the electrolytic plating method, the position closer to the lead 4 through which the current flows is larger in the plated metal. Easy to grow. Therefore, it is considered that the plating metal is more easily deposited on the adhesion metal Mvd attached to the in-dam resin portion 6dm than the adhesion metal Mvd attached to the main body sealing portion 6mb.

  As described above, it has been found that the bowl-shaped metal is generated when the lead 4 is irradiated with the laser in this step. However, from the viewpoint of improving the wettability of the lead 4 with respect to the solder, it is preferable to expose the surface of the lead 4 with certainty, so the laser beam Lz (see FIG. 17) is not irradiated on the lead 4 and It is difficult to selectively remove only the resin portion 6dm.

  Therefore, the inventor of the present application has studied a technique for removing the adhered metal Mvd causing caustic metal before the plating step shown in FIG. 5, and mechanically removing the adhered metal Mvd after oxidizing it. The present inventors have found that it is easy to remove the adhered metal Mvd. Details are described in the next section.

6). Adhered metal removal step;
Next, as the adhesion metal removal step shown in FIG. 5, the adhesion metal Mvd shown in FIG. 16 is removed. FIG. 18 is an explanatory diagram showing details of the attached metal removing step shown in FIG.

  As a method for removing the adhered metal Mvd shown in FIG. 16, the inventor of the present application first examined a method of removing the pressurized liquid (pressurized liquid) by spraying it toward the adhered metal Mvd. Specifically, for example, water pressurized to about 10 MPa (megapascal) is sprayed toward the resin portion 6 dm in the dam where the attached metal Mvd shown in FIG. 16 is formed, and then a metal film is formed on the surface of the lead 4. Then, the presence or absence and the formation state of the cage metal were evaluated. However, it has been found that the generation of wrinkle-like foreign matters cannot be reduced only by spraying the pressurized liquid after the resin removal step. As described above, the adhesion metal Mvd is deposited on the dam resin portion 6dm, and the adhesion strength between the dam resin portion 6dm and the adhesion metal Mvd is high. For this reason, it is considered that it is difficult to peel off the attached metal Mvd to the extent that the pressurized liquid is sprayed.

  Therefore, the inventor of the present application relates to a method of performing a process of reducing the adhesion strength between the adhered metal Mvd and the resin portion 6 dm in the dam as a pretreatment of the cleaning step (see FIG. 5) for spraying the pressurized liquid onto the adhered metal Mvd. investigated. Specifically, the adhesion to the in-dam resin portion 6dm is lowered by oxidizing the surface of the attached metal Mvd. As a method for oxidizing the attached metal Mvd, the lead frame LF on which the attached metal Mvd is formed is carried into a baking furnace (heating furnace) BK as schematically shown in FIG. 18, and heat treatment is performed in the baking furnace BK. A baking process is performed.

  The processing conditions in this baking process are, for example, setting the temperature in the baking furnace BK to 175 ° C. and heating for about 6 hours. Thereby, the surface of the adhesion metal Mvd is oxidized. For example, in the present embodiment, as described above, the adhesion metal Mvd is formed with a composition that is almost similar to pure copper, and thus is subjected to the baking process to become copper oxide (CuO). In the example shown in FIG. 18, a plurality of lead frames LF are stacked and arranged in the baking furnace BK, and the plurality of lead frames LF are collectively subjected to heat treatment. Therefore, even when the heat treatment time requires about 6 hours, a decrease in manufacturing efficiency can be suppressed.

  Next, in the present embodiment, a cleaning process is performed in which a pressurized liquid WJ that is a pressurized liquid (for example, water) is sprayed on the oxidized attached metal Mvd. In FIG. 18, as a pretreatment process that can be omitted, a chemical liquid immersion treatment process and an electrolytic processing process are shown, but an embodiment in which these processes are omitted and the cleaning process is performed will be described first.

  In the present embodiment, as described above, the adhesion strength between the adhered metal Mvd and the in-dam resin portion 6dm can be reduced by oxidizing the adhered metal Mvd in advance before the cleaning step. For this reason, in this step, for example, if the pressurized liquid WJ is sprayed toward the resin part 6dm in the dam at a pressure of about 10 MPa, the attached metal Mvd can be peeled off from the resin part 6dm in the dam and removed. it can.

  By the way, this inventor examined the modification which makes the main body sealing part baking process shown in FIG. 5 common with the baking process shown in FIG. That is, in order to remove the adhesion metal Mvd, it is necessary to perform a heat treatment after irradiating the laser beam. Therefore, the body sealing portion baking step shown in FIG. 5 is omitted, and the baking process for oxidizing the adhesion metal Mvd is performed. In the above, an embodiment in which the resin constituting the main body sealing portion 6mb is fully cured was studied. In this case, since the time required for the baking process can be shortened, the production efficiency can be improved. However, when the main body sealing portion baking step shown in FIG. 5 is omitted, the molded resin is cooled before it is completely cured. For this reason, even if the resin once cooled is baked again, it becomes difficult to ensure a desired resin strength. Therefore, it is preferable to perform the heat treatment for surely curing the resin constituting the main body sealing portion 6mb before the resin removal step, then perform the resin removal step, and then perform this step. That is, it is preferable to perform the baking process in this process and the main body sealing portion baking process shown in FIG. 5 separately.

  In addition, as described above, by performing the baking process for oxidizing the attached metal Mvd before the mechanical cleaning step, the attached metal Mvd can be easily separated from the resin portion 6dm in the dam, but the attached metal Mvd is more reliably attached. From the viewpoint of removing the above, the following modifications can be applied.

  First, as a first modification, as shown in FIG. 18, a chemical immersion process (also referred to as a chemical polishing process) can be added before the cleaning process. In this step, as schematically shown in FIG. 18, the surface of the attached metal Mvd is cleaned by immersing the lead frame LF in the chemical CCS. The chemical liquid CCS is a chemical cleaning liquid that cleans the surface of the attached metal Mvd using a chemical reaction, and is, for example, an acidic liquid. As described above, the chemical cleaning process is performed in advance before the mechanical cleaning step of spraying the pressurized liquid WJ onto the adhesion metal Mvd, so that the adhesion metal Mvd and the resin portion 6dm in the dam are more easily separated. In the present embodiment, the adhesion metal film Mvd is oxidized in advance, so that the reactivity with an acidic liquid can be improved as compared with pure copper.

  For this reason, in this modification, compared with the case where a chemical | medical solution immersion treatment process is not performed, it becomes easy to remove the adhesion metal Mvd in a mechanical washing | cleaning process. In other words, in the case of this modification, the cleaning time or the pressure of the liquid can be reduced in the mechanical cleaning step as compared with the case where the chemical solution immersion treatment is not performed. In this case, damage to the main body sealing portion can be reduced. As the chemical cleaning liquid, an alkaline liquid can be used in addition to the above acidic liquid. However, when the present inventor has evaluated the peelability of the adhered metal Mvd, it is more preferable to use an acidic chemical CCS.

  Furthermore, if the hydrogen ion exponent (ph) of the chemical solution CCS is reduced and the lead frame LF is immersed in a strong acid solution, the attached metal Mvd may be removed without performing a mechanical cleaning step. However, when the lead frame LF is immersed in a strong acid solution, the damage to the leads 4 is large. Therefore, even when performing the chemical solution immersion treatment step, it is preferable to apply in combination with a mechanical cleaning step of spraying the pressurized liquid WJ as shown in FIG.

  As a second modification, an electrolytic processing step can be added before the mechanical cleaning step as shown in FIG. In this step, as schematically shown in FIG. 18, the attached metal Mvd can be easily separated from the resin portion 6dm in the dam by passing a current through the lead frame LF while the lead frame LF is immersed in the electrolyte ELS. To be. In the example shown in FIG. 18, the lead frame LF is connected to the anode AP, and the cathode KP is inserted into the electrolyte ELS. When current is passed between the anode AP and the cathode KP in this state, a current flows through the electrolyte ELS, and the attached metal Mvd attached to the in-dam resin portion 6dm is easily peeled off. As a result, compared to the case where the electrolytic processing process is not performed, it becomes easier to remove the adhered metal Mvd in the mechanical cleaning process. In other words, in the case of the present modification, the cleaning time or the liquid pressure can be reduced in the mechanical cleaning step as compared with the case where the electrolytic processing is not performed. In this case, damage to the main body sealing portion can be reduced.

  As a third modification, a chemical solution immersion treatment step and an electrolytic processing treatment step can be performed before the mechanical cleaning step. In this case, since the number of pre-processing steps increases, the production efficiency decreases, but it becomes easier to remove the adhered metal Mvd in the mechanical cleaning step than in the first and second modified examples.

7). Mark formation process;
Next, as a mark forming step shown in FIG. 5, a mark Mk is formed on the upper surface 6a of the main body sealing portion 6mb as shown in FIG. FIG. 19 is an enlarged plan view showing a state in which a mark is formed on the upper surface of the main body sealing portion after the attached metal shown in FIG. 16 is removed. A mark Mk shown in FIG. 19 is a symbol (a symbol made up of numerals, characters, or figures) for identifying product information, and is formed by, for example, irradiating the main body sealing portion 6mb with a laser beam (not shown). The Since this step irradiates laser light, it can be performed together with the resin removing step described above. However, from the viewpoint of suppressing the mark Mk from being damaged by each process performed in the above-described adhered metal removing step, the mark forming step may be performed after the adhered metal removing step as shown in FIG. preferable.

8). Plating process;
Next, as a plating step shown in FIG. 5, as shown in FIG. 20, a metal film SD is formed on the exposed surfaces of the plurality of leads 4 from the main body resin portion 6mb. 20 is an enlarged plan view showing a state in which a metal film is formed on the exposed surface of the lead frame shown in FIG. 19 from the resin, and FIG. 21 is an explanatory view showing an outline of the plating process by the electrolytic plating method.

  In this step, a metal film SD (see FIG. 3) made of, for example, solder is formed on the surface of the metal member exposed from the resin by electrolytic plating. In the electroplating method, as shown in FIG. 21, a lead frame LF that is a workpiece to be plated is placed in a plating tank 60 containing a plating solution 61. At this time, the workpiece is connected to the cathode 62 in the plating tank 60. For example, in the example shown in FIG. 21, the outer frame LFf of the lead frame LF is electrically connected to the cathode 62. A metal film SD is formed on the exposed surface of the metal member connected to the outer frame LFf of the lead frame LF by applying a DC voltage, for example, between the cathode 62 and the anode 63 also disposed in the plating tank 60. (See FIG. 20). That is, in this embodiment, the metal film SD is formed by a so-called electrolytic plating method.

As described above, the metal film SD of the present embodiment is made of so-called lead-free solder that does not substantially contain lead (Pb). For example, only tin (Sn), tin-bismuth (Sn-Bi), Or it is tin-copper-silver (Sn-Cu-Ag). For this reason, the plating solution 61 used in this plating step is an electrolytic plating solution containing a metal salt such as Sn ²⁺ or Bi ³⁺ . In the following description, Sn-Bi alloyed metal plating will be described as an example of lead-free solder plating, but bismuth (Bi) is replaced with a metal such as copper (Cu) or silver (Ag), or bismuth. It can be replaced by an electrolytic plating solution containing not only (Bi) but also copper (Cu) or silver (Ag).

In the present embodiment, as described above, the plating process is performed in a state where the plurality of leads 4 are electrically connected to the outer frame LFf through the frame portion LFs. The die pad 2 is electrically connected to the outer frame LFf via the frame portion LFs and the suspension lead TL (see FIG. 15). Therefore, when a voltage is applied between the anode 63 and the cathode 62 shown in FIG. 21 in a state where the lead frame LF is immersed in the plating solution 61, current flows between both electrodes (between the anode 63 and the cathode 62). As described above, since the outer frame LFf of the lead frame LF is electrically connected to the cathode 62, Sn ²⁺ and Bi ³⁺ in the plating solution 61 are contained at a predetermined ratio in the lead 4 shown in FIG. Deposited on the exposed surface, a metal film SD is formed.

  As described above, according to the electrolytic plating method, the metal film SD is formed on the surface of the metal member exposed from the resin. Therefore, in the present embodiment, the upper surface 4a of the outer portion 4o of the lead 4 exposed outside the main body resin portion 6mb of the sealing body 6 shown in FIG. 16 and the lower surface 4b of the lead 4 (see FIG. 17) are covered. Then, the metal film SD is formed. Further, in the present embodiment, as shown in FIG. 17 in the resin removal step, the plating step is performed after exposing the side surfaces 4c1 and 4c2 of the lead 4, so that the side surfaces 4c1 and 4c2 of the lead 4 are covered. A metal film SD can be formed. As shown in FIG. 20, in this step, the metal film SD is also formed on the frame portion LFs of the lead frame LF. Although the film thickness of the metal film SD can be changed according to product specifications, for example, a film of about 10 μm to 20 μm is formed.

  Here, when the attached metal Mvd described with reference to FIG. 16 remains in the vicinity of the lead 4, the metal is also deposited on the attached metal Mvd when the metal film SD is deposited on the surface of the lead 4 in this step. As a result, a cage-like metal grows. However, according to the present embodiment, as described above, since the adhered metal removing step is performed before the plating step, the formation of a bowl-shaped metal in this step can be prevented or suppressed.

  By the way, in the baking process included in the above-described adhered metal removing process, the lead frame LF is heated in a baking furnace, so that an oxide film is formed on the surface of the lead 4 in addition to the adhered metal Mvd shown in FIG. Further, the surface of the lead 4 may become dirty or an oxide film may be formed on the surface of the lead 4 after the adhesion metal removing step is completed and before the plating step is started. In particular, when another process (for example, a mark forming process in the example shown in FIG. 5) is performed between the adhered metal removing process and the plating process, the probability that the surface of the lead 4 is contaminated is high. Therefore, in the plating step, it is preferable to clean the surface of the lead 4 and remove the oxide film or the like immediately before forming the metal film SD. The cleaning method for the lead 4 is applied by combining each pretreatment step (chemical solution immersion treatment step and electrolytic processing step) other than the baking step in the attached metal removal step and a mechanical washing step for spraying a pressurized liquid. Can do. In addition, when performing a chemical | medical solution immersion process at this process, the fats and oils component adhering to the lead | read | reed 4 can be effectively removed by using an alkaline washing | cleaning liquid as a chemical | medical solution.

  In addition, by performing cleaning immediately before the plating step, even if resin burrs remain in the vicinity of the exposed surfaces of the leads 4 and the die pad 2 (see FIG. 14), the resin burrs can be easily removed. Can do.

9. Individualization step;
Next, as shown in FIG. 22, as the individualization step shown in FIG. 5, the frame portion LFs to which the plurality of leads 4 and the suspension leads TL are connected is cut, and the plurality of device forming portions LFd are individually separated. Divide into pieces. FIG. 22 is an enlarged plan view showing a state in which each device forming unit is singulated in the singulation process shown in FIG.

  In this step, for example, a plurality of leads 4 are formed by press working using a punch (cut punch, cutting blade) and a die (pressing member, die) (not shown) which are press dies (die) for cutting. Each of the suspension leads TL is separated from the frame portion LFs.

  After this step, necessary inspections and tests such as an appearance inspection and an electrical test are performed, and what has passed is a completed semiconductor device 1 shown in FIG. Then, the semiconductor device 1 is shipped or mounted on a mounting board (not shown).

<Modification>
Although the invention made by the inventors of the present application has been specifically described above based on the embodiments, the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the scope of the invention. Needless to say.

(Modification 1)
For example, in the above-described embodiment, the QFN of the type in which a part of the plurality of leads 4 slightly protrudes (about 0.3 mm) on the four main sides of the quadrangular sealing body 6 in plan view. Explained. However, as a modification, the lead 4 protruding from the sealing body 6 is further lengthened and bent toward the mounting surface, so that it can be applied to a so-called QFP (Quad Flat Package) type semiconductor device. You can also That is, a resin part in the dam formed in a space (region) surrounded by two adjacent leads out of a plurality of leads (outer parts) protruding from the sealing body and a tie bar connecting the two leads. When the resin part in the dam is removed by irradiating with laser light, each step (after the attached metal removing step) described in the above embodiment can be applied.

(Modification 2)
Further, for example, in the above-described embodiment, the embodiment has been described in which the periphery of the main body sealing portion 6mb shown in FIG. 15 is circulated in the state where the laser light Lz (see FIG. 17) is output in the resin removal step. However, as a modification, the laser irradiation device LS (see FIG. 17) is scanned while linearly irradiating the laser beam Lz along each side constituting the peripheral portion of the main body sealing portion 6mb, and the laser irradiation device LS. Before changing the scanning direction, the irradiation of the laser beam Lz can be temporarily stopped.

(Modification 3)
Further, for example, in the above embodiment, the embodiment in which the attached metal Mvd formed in the resin removal step is oxidized and then removed by the mechanical cleaning step has been described. However, after the resin removal step shown in FIG. 5 and before the baking step, the amount of the adhesion metal Mvd is reduced by irradiating the adhesion metal Mvd formed on the resin portion 6dm in the dam with laser light. Variations are also conceivable. FIG. 23 is an enlarged plan view showing a state where a part of the attached metal is removed by irradiating the attached metal shown in FIG. 16 with a laser beam. FIG. 24 is an enlarged plan view showing a modification to FIG.

  In the modification shown in FIG. 23, laser light is irradiated to each of the remaining portions of the in-dam resin portion 6dm where the adhered metal Mvd is formed. As a result, part of the sealing metal Mvd is removed, so that the amount of the adhesion metal Mvd to be removed can be reduced in the above-described adhesion metal removal step.

  In the modification shown in FIG. 24, linear scanning is performed so as to trace the attached metal Mvd shown in FIG. 16 while irradiating the laser beam. At this time, since the laser light of this modification is irradiated on the lead 4 in addition to the attached metal Mvd, the output (energy amount per unit time) is higher than that of the laser light Lz described with reference to FIG. Irradiate in a small state. In this modification, since the area of the object to be removed by laser irradiation is small compared to the resin removal step described above, the output can be reduced. The modification shown in FIG. 24 is the same as the modification shown in FIG. 23 in that the part of the attached metal Mvd is removed to reduce the amount of the attached metal Mvd to be removed in the above-described attached metal removal step. It is. In the case of the modification shown in FIG. 24, the irradiation time of the laser beam can be shortened compared to the modification shown in FIG. 23, so that the manufacturing efficiency can be improved.

(Modification 4)
Further, for example, in the above-described embodiment, the embodiment in which the temperature in the baking furnace BK is set to 175 ° C. and heated for about 6 hours in the baking process of the adhered metal removing process has been described. However, various modifications can be applied to the heating temperature and the heating time. From the viewpoint of oxidizing the adhered metal Mvd, the heating time can be shortened by increasing the heating temperature. However, from the viewpoint of suppressing the deterioration of the main body sealing portion 6mb, the heating temperature is preferably set to be equal to or lower than the temperature of the main body sealing portion baking step shown in FIG.

(Modification 5)
Further, for example, in the above-described embodiment, as a modification of the adhered metal removing step, the embodiment in which the chemical liquid immersion treatment step and the electrolytic processing treatment step are performed before the mechanical cleaning step with the pressurized liquid has been described. However, as a further modification, a chemical solution immersion process or an electrolytic processing process can be added after the mechanical cleaning process.

(Modification 6)
Further, for example, in the above-described embodiment, the embodiment in which the laser beam is irradiated so that a part of the resin portion 6dm in the dam on the main body sealing portion 6mb side remains in the resin removing step has been described. However, as a modification, the entire dam resin portion 6dm may be removed. Even in this case, the attached metal Mvd is formed on the peripheral edge of the main body sealing portion 6mb. Therefore, if the attached metal Mvd is not removed, the adhering metal Mvd is not removed along the peripheral edge of the main body sealing portion 6mb. A shaped metal will be formed.

(Modification 7)
Furthermore, the modified examples can be applied in combination within a range not departing from the gist of the technical idea described in the above embodiment.

DESCRIPTION OF SYMBOLS 1 Semiconductor device 2 Die pad (chip mounting part, tab)
2a Top surface (chip mounting surface)
2b Lower surface 3 Semiconductor chip 3a Surface (main surface, upper surface)
3b Back surface (main surface, bottom surface)
3c Side 4 Lead (terminal, external terminal)
4a Upper surface 4b Lower surface 4c1, 4c2 Side surface 4i Inner portion 4o Outer portion 5 Wire (conductive member)
6 Sealing body (resin body)
6a Upper surface 6b Lower surface (back surface, mounting surface)
6c Side surface 6dm Resin part in dam 6g Resin part in gate 6mb Main body sealing part (main part)
6p Corner portion 6r Runner sealing portion 6sp Spacer resin portion 6vt Vent inside resin portion 7 Adhesive 11 Exposed portion (fin, corner lead)
50 Molding mold 51 Upper mold (mold)
51a Clamp surface (mold surface, pressing surface, surface)
51b Cavity (recessed part)
52 Lower mold (mold)
52a Clamp surface (mold surface, pressing surface, surface)
53 Resin film (film material)
60 Plating tank 61 Plating solution 62 Cathode 63 Anode AP Anode BK Bake furnace (heating furnace)
CCS Chemical liquid ELS Electrolyte HS Heat stage (Lead frame heating stand)
HSa mounting surface KP Cathode Ldm Dam part LF Lead frame (base material)
LFa Upper surface LFb Lower surface LFd Device formation part (device area, product formation area, product area)
LFf Outer frame LFs Frame portion Lg Gate portion LS Laser irradiation device Lz Laser light Mk Mark Mvd Adhered metal PD pad (electrode, bonding pad)
SD Metal film TL Suspended lead WJ Pressurized liquid

Claims (19)

A semiconductor device manufacturing method including the following steps:
(A) Body sealing for sealing the semiconductor chip by sealing the inner part of each of the semiconductor chip mounted on the lead frame and the plurality of leads electrically connected to the semiconductor chip with a resin Forming a resin portion within the dam formed between the outer portions adjacent to each other among the outer portions of the plurality of leads exposed from the main body sealing portion;
(B) After the step (a), the step of removing the resin part in the dam by irradiating the plurality of leads and the resin part in the dam with a first laser beam;
(C) After the step (b), a step of heat-treating the lead frame on which the main body sealing portion is formed;
(D) After the step (c), a step of performing a cleaning process on the lead frame on which the main body sealing portion is formed;
(E) After the step (d), a step of immersing the lead frame in which the main body sealing portion is formed in a plating solution to form a metal film on the surface of the outer portion. In claim 1,
In the step (b), the method of manufacturing a semiconductor device, wherein the first laser beam is irradiated so that a portion of the resin portion in the dam on the main body sealing portion side remains. In claim 2,
In the step (b), the first laser light is irradiated so as to straddle the boundary between the resin part in the dam and the outer part. In claim 3,
A method of manufacturing a semiconductor device, wherein after the step (c) and before the step (d), the lead frame on which the main body sealing portion is formed is immersed in an acidic chemical solution. In claim 3,
A method of manufacturing a semiconductor device, wherein after the step (c) and before the step (d), the lead frame on which the main body sealing portion is formed is immersed in an electrolytic solution and the lead frame is energized. . In claim 2,
A semiconductor device that irradiates the remaining portion of the resin portion in the dam formed by the step (b) with the second laser light after the step (b) and before the step (c). Production method. In claim 6,
The method of manufacturing a semiconductor device, wherein an output of the second laser light is smaller than an output of the first laser light. In claim 2,
In the step (d), a method of manufacturing a semiconductor device, in which a pressurized liquid is sprayed toward a remaining portion of the resin portion in the dam formed in the step (b). In claim 1,
A method of manufacturing a semiconductor device, wherein a mark is formed on the main body sealing portion after the step (d) and before the step (e). In claim 9,
A method for manufacturing a semiconductor device, wherein after the formation of the mark and before the step (e), a cleaning process is performed on the lead frame on which the main body sealing portion is formed. A semiconductor device manufacturing method including the following steps:
(A) Body sealing for sealing the semiconductor chip by sealing the inner part of each of the semiconductor chip mounted on the lead frame and the plurality of leads electrically connected to the semiconductor chip with a resin Forming a resin portion within the dam formed between the outer portions adjacent to each other among the outer portions of the plurality of leads exposed from the main body sealing portion;
(B) After the step (a), the step of removing the resin part in the dam by irradiating the plurality of leads and the resin part in the dam with a first laser beam;
Here, a metal adheres to the resin,
(C) a step of oxidizing the metal adhering to the resin after the step (b);
(D) After the step (c), a step of removing the metal adhered to the resin by performing a cleaning process on the lead frame on which the main body sealing portion is formed;
(E) After the step (d), a step of immersing the lead frame in which the main body sealing portion is formed in a plating solution to form a metal film on the surface of the outer portion. In claim 11,
In the step (b), the first laser beam is irradiated so that a portion of the resin part in the dam on the main body sealing part side remains,
In the step (c), the metal attached to the remaining portion of the resin portion in the dam formed in the step (b) is oxidized. In claim 11,
In the step (b), the first laser light is irradiated so as to straddle the boundary between the resin part in the dam and the outer part. In claim 13,
A method of manufacturing a semiconductor device, wherein after the step (c) and before the step (d), the lead frame on which the main body sealing portion is formed is immersed in an acidic chemical solution. In claim 13,
A method of manufacturing a semiconductor device, wherein after the step (c) and before the step (d), the lead frame on which the main body sealing portion is formed is immersed in an electrolytic solution and the lead frame is energized. . In claim 12,
A method of manufacturing a semiconductor device, comprising: irradiating a second laser beam toward the remaining portion of the resin portion in the dam after the step (b) and before the step (c). In claim 16,
The method of manufacturing a semiconductor device, wherein an output of the second laser light is smaller than an output of the first laser light. In claim 11,
A method of manufacturing a semiconductor device, wherein a mark is formed on the main body sealing portion after the step (d) and before the step (e). In claim 18,
A method for manufacturing a semiconductor device, wherein after the formation of the mark and before the step (e), a cleaning process is performed on the lead frame on which the main body sealing portion is formed.

Images